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Outdoor Free Flight Forum => Free Flight Scale => Topic started by: Squirrelnet on September 15, 2018, 01:58:25 PM



Title: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 15, 2018, 01:58:25 PM
I've spent some time trying work out what to build as a windy weather competition model. I toyed with a KK Piper Super Cruiser and the Ron Moulton Auster AOP9, which I built in my youth but in the end I quite fancy having a go at one of these.

The aim is a flying only model which can be used in Aeromodeller design comps too

Its from the APS plan by P Hayward and at 36" span looks ideal for a Redfin 030 TBR I have needing a home. The bearer position needs some altering so I can fit an ali plate and the banded on tail is probably not necessary but my tactic is it's the most 'Tomboy' like scale design I can find and my Tomboy has flown in 30mph wind on Salisbury Plain... mostly downwind obviously

Anyone have any experience of the design ? or cautionary tales.


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on September 15, 2018, 03:30:44 PM
Chris,
         Ian Lever built one of these and won the British Nats one windy year. I am sure he would be able to give you some pointers on the build. I think it has a quirky charm.
Ricky 


Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on September 15, 2018, 03:32:47 PM
I began building one from this plan years ago but discovered that there were quite a few inaccuracies. Could have been they crept into the digital version I'd downloaded, so just make sure you check all dimensions before cutting. I ended up using a great three view I found instead. Mine was for 5 channel indoor electric RC. There's a build thread on here somewhere. I did use the Hayward plan's decalage, which I found to be excessive, so I'd suggest building in an adjustable stab.

PM me your email and I'll send the three view I have.

You could also modify it to the Draco, a Wilga with a PT6 on the front.... https://youtu.be/PqhI4MeCn1c?t=1m12s (https://youtu.be/PqhI4MeCn1c?t=1m12s) ;)


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 15, 2018, 03:53:01 PM
Thanks both.

I'll have a look for the thread. Draco Wilga looks amazing but the original version with radial engine allows the Redfin to hide in an upright position which makes life much easier.

Monz thanks PM sent


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 16, 2018, 01:26:13 PM
Looking back at the thread of Monique's example, it looks fantastic, mine will be very much a flying only example

It looks like a go-er though as a project. I now have a decent 3 view thanks to Monique and I have modified the plan to fit a Redfin TBR in the upright position. I dropped the engine bearers to allow for an ali plate to mount the engine and corrected the obvious errors in the cowling when compared to the 3 view.

I also found a few pics of a nice example from Romania in yellow and blue and registered YR-VIS so I'll do it as this one I think... I like yellow aeroplanes :-) and the scheme is fairly straight forward.


Title: Re: PZL Wilga for .5cc diesel
Post by: faif2d on September 16, 2018, 05:43:28 PM
I know one of the test pilots for the F-16.  Back when they were doing the first tests out at Edwards probably in the early 1970's? someone had a Wilga there.  He said everyone had to take it around the pattern just so they could add it to the log book. It was, and still is, quite an exotic looking plane.


Title: Re: PZL Wilga for .5cc diesel
Post by: PaulM on September 17, 2018, 11:52:50 AM
 I have one of those redfin .030 engines , they are really unfussy , but ive found that they like to have intake primes , and the Wilgas cowl looks like it hides the intake away ..still should be ok with a prime through the port :)


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 17, 2018, 03:24:59 PM
Thanks Paul, good point. The plan is to modify the cowl so the top part is removable so I can get access to the tank and intake. I have found them to excellent little engines too

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: ffkiwi on September 17, 2018, 04:48:41 PM
Thanks Paul, good point. The plan is to modify the cowl so the top part is removable so I can get access to the tank and intake. I have found them to excellent little engines too

Chris

Those high strength little magnets are your friend in this situation-and with the range available now in disc, cube, cylindrical  shapes you are spoiled for choice when it comes to things like strut, cowl, and flying surface discreet retention options. The more I use them the more uses I am finding for them-even to the point of using them in my model boxes-where a couple glued to the interior frame hold things like removable undercarriage legs or skids safely-a better option than having such items rattling around loose-where they can punch holes in tissue etc...

 ChrisM
 'ffkiwi'


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on September 17, 2018, 05:00:24 PM
Yes they are very useful - I remember the days of sewing press studs to plywood. However the first time I used them I accidentally glued the second pair the wrong way round and the cowling hovered 2" above the model.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 17, 2018, 05:13:17 PM
Thanks Chris. I'm a big fan of magnets too. The Tomtit I'm building in another thread has the top cowl held on with them, I was thinking of a similar arrangement with this one


Quote
I accidentally glued the second pair the wrong way round and the cowling hovered 2" above the model.

I'm guilty of that one too...digging them out once the epoxy had dried was not fun. I now put a black mark on the outer edge of each pair, just don't mix the pairs up  :-\



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on September 23, 2018, 01:03:08 PM
The weather has scuppered my plans to go to the Festival of Flight today at Old Warden with heavy rain and wind, though as I type this it's looking rather nice outside with clear skies and light winds  >:(

 Anyway I thought I would use the time in a constructive way so I have made a start on the Wilga. The basic frame is from laminated 3/32" balsa and 1mm ply and looks to be a sturdy structure. Wide spacing of the engine bearers will allow the Redfin engine to be mounted on an 1/8" aluminium plate so I can adjust the thrust line without resorting to drilling engine mounting holes bigger

One thing I will change is the lifting section tailplane on P Haywards plan.  This may explain Monz's comment about the plan having too much declage, more would be needed to counter the lifting effect of the tail if it is replaced with symmetrical section one. I notice from the photos of the original it has a symmetrical section tail.

I'll check the incidences on the plan but I'll aim for 3 deg on the wing with the tail at zero and go from there. I guess I should check the 3 view drawings I have too to see what the original was set at


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 06, 2018, 01:20:21 PM
Much of the time in the workshop this afternoon was spent repairing my DH60 Moth for next weeks Selby Trophy but I managed a bit more on the PZL as well, so I now have a rear to the fuselage.

Sheeting the fuselage in 1/16th balsa looks to be the main challenge of the project. I'm not a fan of ammonia so it will be out with the wallpaper stripper tomorrow to steam some sections into shape. I'm just wondering wether to add some 3mm x .5 mm carbon strip to the tail boom to give some added strength... Yep think I'll do that . The original plan has 3/16" dowel for the rear cockpit bracing but I'm going to use 1/8" carbon rod anyway so some carbon strip in the rear fuselage can be bonded to that too make it bit more bounceable. It is intended to be a rough weather model ;)

 



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 07, 2018, 02:57:22 PM
I've added some carbon strip and some 1/8" carbon rod for the rear cockpit struts. It feels a lot stronger as a super structure now



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 27, 2018, 01:03:27 PM
I've not managed much on this one recently but it does now have legs at least  ;)

The struts as indicated on the plan aren't completely accurate to the 3 view and photos but as this is a flying only model I went with the plan rather than having to rethink the layout. 

As the Selby Trophy was cancelled I spent most of the afternoon tidying the workshop and putting models away for the winter. It's nice to have some space again, though the models have to share with more oily inhabitants  :-\



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 28, 2018, 01:42:32 PM
I finished off the basic under carriage structure this afternoon. Making sure it was all square looked tricky until I hit on the idea of aligning the axles with a couple of steel rules before soldering. It seems to have worked as early taxi tests ( chucking it across the workshop floor ) reveal it goes in straight line at least.

The fuselage is sheeted in 1/16" balsa , I'm not a fan of ammonia so it was out with the wallpaper stripper to create a small steam box using the large wallpaper attachment against a flat surface. A couple of minutes  on both sides and the hot soggy balsa easily moulds to the shape needed. I clamped up one side and left it to dry. The second side was glued on as it was clamped to shape, avoiding glue around the joins top and bottom. When thats dry I'll trim it and then fit the other side.

 


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on October 28, 2018, 02:31:13 PM
I don't think ammonia works on balsa like it does on basswood. Beware soaked balsa - it can shrink when drying (how do I know?)
Are you going with scale dihedral or that on the plan?


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 28, 2018, 02:46:43 PM
Thanks Bill :-) both sides now drying before fitting

Non scale dihedral on this one, I'm after a reliable flyer so the more like a sport model I can make it the better.


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on October 28, 2018, 08:24:14 PM
That shot down your workshop in #14 looks appealing SN. Interesting subject.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 29, 2018, 03:07:05 PM
Quote
That shot down your workshop in #14 looks appealing SN

..Keeps me out of trouble  ;).... or should that read - it means I'm always in trouble  :-\




Title: Re: PZL Wilga for .5cc diesel
Post by: 3view on November 03, 2018, 01:46:41 PM
You could also modify it to the Draco, a Wilga with a PT6 on the front.... https://youtu.be/PqhI4MeCn1c?t=1m12s (https://youtu.be/PqhI4MeCn1c?t=1m12s) ;)

Clicked on the above link and then spent the rest of the evening watching all 20 videos of the Wilga to Draco saga. Mike Patey is has an infectious enthusiasm.  Also I was completely ignorant if the flying cowboys/bush pilot scene. Looks fun landing in impossible places!

Squirrelnet, keep up the good work on your Wilga.

Steve


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on November 03, 2018, 02:10:22 PM

Clicked on the above link and then spent the rest of the evening watching all 20 videos of the Wilga to Draco saga.
Me too. 'The Wilga has very little dihedral'!


Title: Re: PZL Wilga for .5cc diesel
Post by: Glenn (gravitywell) Reach on November 03, 2018, 04:04:42 PM
Hi there.  I have just watched some really cool video's on youtube about this aircraft.  Do a search for "wilga draco"  Turbo prop variant.  Longer nose is usually a good thing for us!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 04, 2018, 01:35:21 PM
Quote
'The Wilga has very little dihedral'!

 There seems to be quite a bit of variation in dihedral, the Drago has non but the earlier ones had some at least. The Romanian Aero Club seem to have 3 of them all with slightly different angles, mine will be the one with the most dihedral ... and some !

Drago version looks great but I'm after a model that I can use a Redfin 030 TBR I have in an upright position so despite the shorter nose the radial version fits the bill. The videos are mesmerising, aircraft can't take off and land like that can they ?  

Work is progressing, slowly. I have found as Monz did before me that the Hayward plan has a few inaccuracies to the 3 view and photos, and is distinctly vague in the area around the cowling to fuselage transition.

 One thing I will correct is the missing rear part of the canopy, there is a whole top section not on the model. So with that I mind I have removed the 1/2" x 1/8" balsa strip which joins the top of the cockpit and replaced it with 2 3mm sections of carbon rod so that part of the structure is not visible through the new top bit canopy.  (pic 1)

I also noticed what looks like a weakness in the design and its back to that fuselage to cowling transition. The gap between the two is bridged by the 3/32"/1mm ply crutch former, front cockpit bracing ( doweling on the plan ) and the 1/16" balsa  skin only. I have added some 1/8" balsa sheet infill to help spread any hard landing stresses from the engine bearers more evenly back into the frame rather than snapping the nose off !!! (pic 2)

The Engine bay has also been modified to fit the side port rear intake of the Redfin with a sealed box section created behind the original firewall to give room for the venturi.. and a pinky to prime the engine  ;)  Engine is the 030 (0.5cc) TBR. Alex Phinn supplied this one with a black head and spinner for me ( I had ideas of a WW1 Rumpler C1 or similar but that will have to wait for another year ). (pic 3)

Once the full sheeting is on the fuselage it'll be difficult to get to the inside to paint so I gave the the bottom half a coat of matt black . I won't add much interior detail , though it will need a pilot, doesn't any aircraft ? and it will probably get a printed dashboard ( pic 4)

The technique of steaming the balsa with a wall paper stripper ( couple of mins both sides ) seems to have worked ok on the rear and lower fuselage sections so the top was done the same way. Its bound in place with masking tape and clamped with a batten on the flat bits, rubber bands tend to leave a mark in the softened wood. Its not glued at the moment, ( Thanks Bill - banana avoided  ;D)  just using the fuselage as a mould to form the panels. Once its dry I'll trim it to shape and glue it on. ( Pic 5)


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on November 05, 2018, 07:41:11 PM
Looking very neat. It is a bit of a structural challenge! I like your solution of the carbon rods and the sheet infill behind the firewall SN.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 11, 2018, 12:37:18 PM
Made a start on the wings. The core wing section seems very small with a tiny chord but the wings are a curious affair with large separate flaps and ailerons with full width LE slats both of which bring the chord up to a more reasonable looking amount.

The fuselage to cowling transition is a bit vague on the plan but I have done something that looks like the pics of the full size I have. I have added a fair bit if 1/2" balsa stiffening behind the rather vulnerable looking front former. The cowling I will make in balsa and permanently fix it to the fuselage. The engine access for fuelling , fitting and removal will be from above via a cut out in the cowling. I'll have to make a top cowling , probably out of epoxy glass. I was hoping I could do it all quickly using balsa but I think the moulded top cowl is the best answer



Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on November 13, 2018, 03:11:42 AM
The moulded sheets of balsa look neat SN. It will have loads of character.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on November 13, 2018, 03:15:18 AM
I think the plan blurb said it would be 'an ideal first scale model'!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 13, 2018, 03:03:11 PM
Quote
I think the plan blurb said it would be 'an ideal first scale model'!

Hopefully there weren't too many hopes and dreams that ended in a pile of warped balsa and riblets  :-\

I fancied building one after perusing the APS plans book as a lad ...glad I didn't now, I went for Ron Moulton's Auster AOP 9 instead


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 17, 2018, 01:35:46 PM
Pic 1 - Another model another Redfin, this one has black fins but it's the larger 030TBR, another special order from Alex Phinn. The cowling I'll do in balsa I think so I don't have to resort to plugs and moulds - I want this to be a quick build.  I'm thinking the top removable section could be steamed 1/32" balsa with a layer of carbon tissue underneath to give it some strength.

 I've not used carbon tissue before but I remember an article in AM from a while back, I'll dig that out, anyone here used it and have any pointers

I'm keen to push on with the other project I have running, the Hawker Tomtit but one of the things I need to do is spray the wings silver. I'm hoping I can finish this one and spray it, to use it as a bit of a learning curve before tackling the Tomtit. I did spray the fuselage but there's way too much paint on it for my liking and I'd like to work on my 'technique', particularly after reading Richard's articles in AM (and well get to a stage where there's more on the model than me !!!)..  and I've bought another airbrush since as well


Pic 2 -  Work continues on the 'simple' wing construction. Flaps/ailerons are one piece with a 1/32" sheet base, then glued to the end ribs which are full width to give the shape. I'll add some joining ribs in too where the original hinges are located.

 The LE slats are 3/32" sheet which, according to the original article, is steamed round a broom handle with a doweling LE added then sanded to an airfoil.... I'll tackle that tomorrow.



Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on November 17, 2018, 05:46:52 PM
Re the carbon tissue on balsa. Although I haven't used carbon tissue I imagine it would be very similar to light 3/4 oz glass cloth but more fragile.

I would consider giving the carbon tissue a light spray of hair spray to help support the fibres before cutting it out. Wetting  out on a slightly oversize piece on thin plastic(Freezer bag or similar). with another piece on top of the wet cloth.Then transferring it to the inside of your premoulded  balsa shell with the outside layer of plastic still attached, followed by placing back onto the mould/fuselage until it hardens. The outside layer of plastic can then be peeled off and the shell glued to the fuse structure.

I think this approach would work and the plastic layer on the outside would make it easier to handle without damage.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 18, 2018, 02:54:46 PM
Good thoughts John thanks for that

I sorted the centre section today , the ali tube is to take an internal rubber band for wing retention. The plan doesn't appear to show it but I will sheet the top of the centre section. I spent a while making sure all is straight with incidences etc, hopefully the workshop gremlins will leave it in place while the glue dries

My brooms have been given a new masking tape and steamed balsa handle too



Title: Re: PZL Wilga for .5cc diesel
Post by: USch on November 18, 2018, 03:33:39 PM
...steamed 1/32" balsa with a layer of carbon tissue underneath to give it some strength.


If you want "strength", not rigidity, use a light glass-cloth (around 25g/m2) and not carbon fibre. Much easier to apply, less costly and lighter than any carbon cloth you can find on the market. As weight concerns the most important thing is to use a very fluid resina (like the MGS 285 typ), maybe even diluite it with a bit of thinner. At the end glass fibre, being less rigid than carbon, is better suited to balsa.

Carbon tissue or carbon weave is not able to follow spherical body's and if not used with a lot of care tend to absorb a lot of resin.

Just my 2 pence worth...

Urs


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on November 18, 2018, 06:28:56 PM
I think you're correct Urs. Controlling the resin content in any tissue(it's very fragile and would pull apart)
would be difficult - I would rather use glass cloth.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Jez Wilkins on November 19, 2018, 07:56:59 AM
USch said
Quote
If you want "strength", not rigidity, use a light glass-cloth (around 25g/m2) and not carbon fibre. Much easier to apply, less costly and lighter than any carbon cloth you can find on the market. As weight concerns the most important thing is to use a very fluid resina (like the MGS 285 typ), maybe even dilute it with a bit of thinner.

Glass cloth can also be applied very successfully by using either 'Aerokote' (Deluxe Materials) or Nitrate Cellulose dope (both of which I have used myself).  I have also read of people using cyanoacrylate for this purpose, but have never tried this myself.

Cheers,

Jez Wilkins     


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 24, 2018, 01:17:05 PM
Thanks guys for your thoughts. I had actually pulled the trigger so to speak, on buying some carbon tissue before your replies came in so I will give it a go and report back.

It is quite robust to handle, more so than the light glass cloth I have and has a weight of just 10g/m2 . I bought some water based resin to try as well called Ezy-Kote ..hmmm two new variables.. maybe should kept that to one new thing ...  :-\

I rigged the dihedral into the model today and although more than the scale amount it looks fairly modest to me, helped by the fact that I picked a full size example with some dihedral rigged into as well. Some I notice are rigged at zero

Wing fixing is wire dowels with an internal rubber bands holding the wings together.


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on November 24, 2018, 02:00:35 PM
It's looking very nice. Will it be yellow over the black?!?
Please don't anyone else buy any carbon tissue - I've got some I'll never use


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 24, 2018, 02:21:48 PM
Yellow indeed .. as the pic in the background.  Interior of cockpit will be black though, if that's what you meant ?

I was interested to try Carbon Tissue, have you found it to be not very good?


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on November 24, 2018, 03:23:45 PM
No Chris; I was given it but haven't tried it and doubt I will


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on November 24, 2018, 06:46:54 PM
I like the way it captures the delicate structure and all those curves SN. Nicely done. Only the cowling to go. Good luck.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 25, 2018, 01:43:30 PM
Thanks John.  Bill... I'll give it a go and post the results..maybe its the new wonder material ?... ???

 I finished off the centre section today. A bit more deviation from the plan so it looks more like the photo with the small upper window and fuselage lines continued with the 1/2" balsa top for the cabin roof. I've added a triangular fairing in front of the upper window too, as per the photo

The LE Slats have been cut from the broom handle where they were drying, cut to the right size and razor planed into an aerofoil section. Everything is just taped together at the moment on the wings as I'll cover and paint the the various bits before finally gluing it all together.







Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on November 25, 2018, 02:13:02 PM
Lovely work, Chris; I do like Wilgas. (If it wasn't such a *****y awkward shape I might even be inclined to attempt one!)


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on November 25, 2018, 02:34:30 PM
This is just the sort of model we envisaged for the AM/MA event; something quirky and flyable. It looks so much better than the original with the reduced dihedral


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on November 25, 2018, 02:52:24 PM
Quote
reduced dihedral

Funnily enough this is what is shown on D Hayward's plan - 1" at the tip . But the model in photos from the 1970's looks more like my Tomboy, that looks more like 2" to 3" at the tip to me. I'll stick with my scale-ish setting, looks enough to me



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 01, 2018, 01:21:09 PM
Made a start on the cowling. I found a old tape roll is a useful former for forming the planking for the outer ring, when that was dry I added an inner ring which has suitably sized bottle stuffed in it to keep it round while it dries.

 I made a tailplane too. Unlike the plan, which has a lifting section tail this one is a symmetrical section. That may need a change in declage from the original D Hayward design so the plan is to rubber band it on to start with and then glue it down once the model is trimmed. I'm adding the elevator lines into the construction so it will look split but I may add a trim tab too which hopefully wouldn't loose too many marks  :-\ I was thinking of adding one to the fin too rather than hinging the entire rudder to make it a bit more reliable and easy to alter the trim for the conditions. I'm assuming that this kind of change is within the spirit of the AM/MA , the rest of the model is pretty much as per the plan



Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on December 01, 2018, 02:14:00 PM
I may add a trim tab too which hopefully wouldn't loose too many marks  :-\ I was thinking of adding one to the fin too rather than hinging the entire rudder to make it a bit more reliable and easy to alter the trim for the conditions. I'm assuming that this kind of change is within the spirit of the AM/MA , the rest of the model is pretty much as per the plan
Good ideas. For the AM/MA event it would take major and widespread changes to elicit raised eyebrows. There are no static marks. It's all about getting models in the air


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 01, 2018, 03:05:55 PM
Quote
For the AM/MA event it would take major and widespread changes to elicit raised eyebrows

Good to know - thanks Bill


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 02, 2018, 01:09:46 PM
I have added a fin to the Wilga, there's some flat 3mm carbon running up the central spar and across the top edge ( its on the other side) to add some rigidity . I've also added some panels lines so I can cover up to them and give the impression of separate elevators and rudder. Covering will be Esaki tissue over Mylar. I'll cut a trim tab into both the tail and rudder once it's all sanded to shape

Ive added a front face to the cowling but it now gives me flashbacks to a school woodwork project, hopefully this one won't end in the same way!

It's starting to look like a proper aeroplane now  8)



Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on December 02, 2018, 06:19:32 PM
Nice work SN.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: 3view on December 03, 2018, 05:18:54 PM
Nice subject and great modelling squirrelnet.

Just wondering if or how slats work at these scale sizes?

Steve


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 03, 2018, 05:38:40 PM
Just wondering if or how slats work at these scale sizes?

I’m not sure how effective they will be as slats for delaying the stall but in a model I think the key thing will be to keep both sides the same. I built a Bowden Meteorite which has similar slats but in the tips only . Its a good stable flyer even in a breeze but trimming it made me realise how critical the slot gap is. Any small difference resulted in an unwanted turn , I’m expecting the same from this one.

The experience of trimming the Meteorite lead me to think that if the gap is too small the slats merely add extra drag as air slows trying to get through the gap ,the turn was always towards the side with the narrower gap. It could well be that on a model all they do is add extra drag ? .... The Bowden Meteorite is rock steady though


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 08, 2018, 01:27:05 PM
Time to tackle the cowling   ;D.

I spent most of the day at work  :-\ so workshop time was a bit limited today but some progress was made

For those that are interested I stuck a long 6mm coach bolt through the centre line of the planked balsa cowling/pen holder and bolted it up tight with some large 2" washers so I could put the whole thing in a drill.

Some coarse 80 grit oxide paper was taped to the bench and the outside edge gently sanded down to the rear edge dimensions, I wore a dust mask for this.

With the rear edge at the right size I then used some good old 'boy scout' whittling with a snap knife to get the rough shape and then more sanding with the drill.

The result needs a bit more fine sanding work but looking the right shape at least


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 09, 2018, 01:12:33 PM
Some more work on the cowling today.

First thing, I made a dummy grill for the cowl from 1mm ply. I will cut this up later into inner and outer rings and add the grill slats from 1/64 ply but for now it finds the centre for where the engine needs to poke out. First problem was that the original AP plan has the thrust line slightly too high !!!  :-\ Hmmm.. great time to find out.

My original plan was to fit 1/8" Ali plates to mount the engine so I lowered the engine bearers to fit to the thrust line on the plan. OK you're probably ahead of me now, anyway the solution was to use 18swg Mild Steel for the engine plates instead, which with the rough guess of 3 deg downthrust and 3 degs right thrust I was able to make up some plates so the prop driver pokes out in the right place.

I'll sort some suitable length bolts for the engine, I'm not cutting those down as long 10BA bolts seem to be hard to find. The engine plates nuts are epoxied to the engine bearers to make them captive so I can permanently fix the cowling on and still have access to remove the engine...and possibly make up different engine plates with different thrust angles if needed.

I couldn't resist another tape together assembly of the bits, this kind of thing keeps the momentum in the build for me.  Interestingly it balances on the main spar as is, I just need to make the covering and paint weigh the same as putting a prop on the engine... does anyone make lead propellers ?  8)

The cowling has been given a coat of resin and I have added a strip of carbon tissue to the inside to help give it some strength. I did a small test piece on some scrap 1/16" balsa so it'll be interesting to see how much stronger this makes it. I used Ezy-Kote which I have not used before and I have to say is funny stuff. It has no tack what so ever, unlike all the other resins I have used it makes it quite tricky to use. The tissue has to fit well as the resin is not going to stick it down as would be the case with epoxy finishing resin. Water clean up though is a huge bonus






Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 16, 2018, 12:13:31 PM
Last week I did a small test piece with carbon tissue and Ezy-Kote resin and the first thing that's apparent now it's dried is I should have stuck to the instructions.

They said to coat the piece with Ezy-Kote first and let it dry, I didn't and I can see why now. The resin is water based so as it dries on the balsa the balsa shrinks, the carbon tissue doesn't so you are left with wrinkles in the covering. I did two layers of tissue on the 1/32 sheet and a non scientific break test seemed to show little increase in strength over the untreated side. Bit surprised by that I expected a bit more from it.

Anyway didn't stop me putting another layer on the inside of the cowling and another coat of resin.

I've added a front to the cowling from 1/64 ply, I think the original had opening slats to control the engine temp so hopefully this looks a bit like having them half open.

Some carbon rod has been added around the front of the cockpit which will hopefully some strength to what still looks like a weak spot to me.

OK stupid question time....

I'm planning to spray the model with enamel paint thinned with cellulose thinners.

Is enamel paint diesel fuel proof ?

I'll give the engine bay a coat of Aero-Kote anyway but it would be good not to have to do the whole aircraft.



Title: Re: PZL Wilga for .5cc diesel
Post by: vtdiy on December 16, 2018, 12:48:25 PM
Amazing model!

Don't know about enamel mixed with cellulose thinners per se, but my one lung Lister type diesel engine generator is definitely painted with enamel and in service for 5 years. Rustoleum was the enamel. Not saying all brands and types of enamel would work, though -- just my experience with that one type and application.


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on December 16, 2018, 01:17:11 PM

Is enamel paint diesel fuel proof ?
I assume it's gloss, so yes.
My view on 'new' paints and glues is that if it doesn't smell dangerous or harmful, it's no good!
PS I'm sure you'll know this Chris - a white base coat under the yellow. I once did a yellow Jungmann without and even after 13 coats it wasn't right.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 16, 2018, 01:38:48 PM
Thanks Vitdiy. Good point I guess a lot of pre war machinery was painted in enamel and has survived the ravages of time very well

Quote
I assume it's gloss, so yes

So Matt enamel isn't fuelproof ?

Quote
if it doesn't smell dangerous or harmful, it's no good!

Not impressed with Eze-Kote at all, the lack of tack in a finishing resin where you're trying to produce an even finish and attach the FG matt/tissue is a real problem. Their water based sanding sealer 'SandnSeal'  works very well though - as a sanding sealer ... and looks very similar to Eze-Kote. I wonder if Eze-Kote is the same stuff but more concentrated ???


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on December 16, 2018, 01:55:05 PM

So Matt enamel isn't fuelproof ?
I think you would end up with grease spots, rather than the finish itself falling off, as it does with glow fuel. I have finished many models with matt enamel but always with Tufkote/Aerokote over it.
As Eric Coates described, you can get away with it on a colour dope finish if you mix your fuel with mineral oil (OK for a run-in Mills!) and clean down with ether, but why bother. I think he was concerned about cellulose repairs over a fuel proofer finish but I've never found a problem if careful.


Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on December 16, 2018, 02:03:55 PM
Loving the Wilga so far Chris.

Re 'eze kote'... If you go into B&Q and buy the Ronseal Diamond Hard water based floor sealer - same thing... but half the price. Same with Poly-C. Most of these 'modelling products' are re-bottled and re-branded from things you can buy elsewhere at half the price. I'll bet their sanding sealer, epoxy, cyano etc are the same.

I've limited experience with composites, but I'd only use the carbon tish with a laminating resin. With the left over 'water based floor sealer' you have, 25g/m² glass cloth works well it, but I'd seal the balsa first with a coat or three of proper sanding sealer. The glass cloth and WBPU give a flexible but firmish finish. much less firm than if using epoxy.

The added bonus with the Ronseal is that it comes in matt, gloss and semi gloss/matt, I use it on the large depron models.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 24, 2018, 12:31:01 PM
Ok so I think I now have a complete airframe  ;D

I've added a non scale trim tab to the rudder and elevator to make trimming easier. The elevator is banded on for trimming, once I've found a good setting I'll glue it down and use the trim tab for fine adjustment.

I toyed with the idea of adding the landing light to the LH wing tip but as the AM plan is not that faithful to the original it would be tricky to do so it looks right, so I think I'll leave it off... actually I think, looking at the pics it might be easier than I initially thought.. I have a plan

Just noticed I've still got the undercarriage fairing to do as well... I can start covering the rest though...apart from the left wing :-\

..so almost a complete airframe  ;)

Happy Christmas







Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on December 24, 2018, 02:59:16 PM

I toyed with the idea of adding the landing light to the LH wing tip but as the AM plan is not that faithful to the original it would be tricky to do so it looks right, so I think I'll leave it off... actually I think, looking at the pics it might be easier than I initially thought.. I have a plan
Do you mean a real LED landing light? That would be dead good/cool


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 24, 2018, 03:36:47 PM
..sadly not maybe I should have said Faux landing light... actually if I could work where to hide the battery so I can get to it....


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 26, 2018, 12:46:24 PM
Today we went for nice Boxing Day walk to a hill in the fog ;D from the top you could see for yards !!! It's my usual slope site as well strangely no one was flying.

I did manage a bit in the workshop though when no one was looking and made a faux landing light hole in the wing and gave the fuselage a nice christmasy pair of flared trousers.

Landing light is not wonderfully accurate but looks better than not having one I think. A bit litho plate and an acetate cover and it should look vaguely right from a distance.



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 27, 2018, 12:42:14 PM
I managed to find a bit of workshop time today, which I wasn't expecting so I set about making a quick dash for the Wilga.... in both senses

Some suitable sized holes where punched into some thin black plasticard and the instruments which by chance happen the about the right size in a pic downloaded from search where cut from a print out and stuck behind the holes. The fairing between dash and the bulkhead is white foam, from my airbrush compressor packaging, as are the other relief bits on the dash.  Hopefully it makes for a good passing resemblance through the large canopy as it whizzes past the judges head  ;).

The undercarriage fairing has been carved to shape . The top part of the fairing I think I'll do in paper so any undercarriage bending arrival results in crumpled paper rather than crumpled fuselage sides.

I even made a start on the covering  ;D


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 28, 2018, 03:39:01 PM
I got some covering done this morning. I love Mylar its so easy to use most other coverings see me struggling to get a decent wrinkle free finish

Inside the cockpit the dash gives hint of something the right shape without huge amounts of detail. I hope to try a similar trick with the pilot....


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on December 31, 2018, 01:53:18 PM
Yellow Esaki tissue over silvered mylar... I have a gold aeroplane  ;D

I added a 1mm carbon rod to the Aileron flap to add some stiffness as it looked a bit liable to warping , so just those and a the LE slats left to cover.

The fuselage will be painted . I was thinking of tissue covering it first but as its a complex shape it's probably easier to directly paint the balsa. It's had a couple of coats of sanding sealer already.





Title: Re: PZL Wilga for .5cc diesel
Post by: mick66 on January 01, 2019, 02:00:49 AM
Not wanting to teach granny but personally I would want to cover the fuselage.  Is there no way you can do it in sections, taking advantage of the panels lines etc?

Looking good though.  I covered my mini vintage Dinamite wing in silver Mylar and yellow jap and it looks quite eye catching.

Mike



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 01, 2019, 12:39:56 PM
Thanks Mike.

I had thought of covering with tissue following the panels lines but it would be fiddly job. For ease and speed I'm thinking some rattle can white primer and some 1200 wet and dry will give decent surface for the final paint. There are reinforcing mouldings on the original to add too making covering even trickier. The DH60 I built a few years ago uses the same method of painted balsa sheet and has proved fairly resilient and also it's fairly easy to repair - a very useful feature with FF :-)

I covered the flaps/ailerons today. The plan has them attached just at the end ribs but that looks like it could give variable gaps and maybe even allow flutter so I'll add some attachments along the TE in scale positions. Its similar with the LE Slats without the flutter issue so I'll add some spacers there too



Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on January 01, 2019, 07:05:06 PM
That is a wild gold finish on the wings and tail. You won't lose sight of that too quickly :)

Happy New Year

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 03, 2019, 03:05:25 PM
Thanks John Happy New Year to you too

I've added some reinforcing to the exterior of the fuselage before it gets primed so its looking quite Wilga like now.

Engine bay is painted and fuel proofed so the cowling has been permanently glued on.. and yes I can still get the engine in and out ;-)

The fin has been glued on too. Approaching the point where I'll have use my new Airbrush in anger  :-\


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on January 03, 2019, 03:10:33 PM
I knew something was missing! Those strips transform it


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 04, 2019, 01:19:17 PM
Thanks Bill

 I've added more reinforcing and given a final coat of sanding sealer so next stage is paint !

I made a first attempt at the front cowling which hopefully with be a piece of 1/32" moulded balsa strengthened with epoxy and carbon tissue. First stage is some balsa steamed and taped over the nose and left to dry to get the shape. My hope is I can make whole top section, which is painted matt black on the original, removable and held on with some neodymium magnets





Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on January 05, 2019, 06:00:42 AM
The fuselage certainly looks stronger now SN. :)

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 05, 2019, 01:10:02 PM
The fuselage certainly looks stronger now SN. :)

John

Thanks John. Hopefully not too much heavier as its already getting a bit porky  :-\.... I have a Mills .75 on standby


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 13, 2019, 01:12:39 PM
Well, the moulded 1/32" balsa cowling seems to have worked OK .

I gave the top side a coat of laminating epoxy and reattached it to the nose to dry in the right shape and then added a couple of layers of carbon tissue and laminating epoxy to the inside. Carbon tissue works much better with laminating epoxy than my earlier attempts with floor varnish/ Ezykote. I think that stuff is best left for floors or as a heavy duty sealer for engine bays, I can't say I'm that impressed with it.

The resulting 1/32' balsa carbon epoxy moulding seemed to have a useful amount of strength for a top hatch and after adding some structure to the inside so its sits right and locates in the engine bay it's looking like it will do the job. It fits very well using friction to hold it in but I'll probably add a couple of magnets for safety. The front of the cowling has a small opening so the engine has some cooling for those calm, hot summer days we will be flying in next year  8)

Right I have no excuses left I'm going to have to paint it next ..... :o


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on January 13, 2019, 02:00:27 PM
Looks great, Chris. Every inch a Wilga!


Title: Re: PZL Wilga for .5cc diesel
Post by: vtdiy on January 13, 2019, 03:28:48 PM
It's really an amzing looking plane!


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on January 13, 2019, 04:14:55 PM
Chris,
       The model is looking really nice. It is good that you are paying attention to engine cooling and ensuring the engine compartment does not fill with exhaust fumes. How large is your cooling air exit?
 Reingestion of exhaust gas really kills performance. It may be worth looking at an intake pipe into the engine to ensure clean air. Stan had this issue with a Mills 1.3 in a larger Auster that was cured this way.
Ricky


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 13, 2019, 04:30:04 PM
Thanks Pete and Vtdiy.

Ricky the outlet is slightly larger than the intake so hopefully it will work. Thanks for the heads up about excess exhaust gasses worth thinking about. The engine is a side port too with a rear venturi which could make matters worse


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 20, 2019, 01:04:04 PM
I didn't manage a huge amount on the Wilga this weekend but it is atleast now in primer and sanded , it still needs a few bits filling with light weight filler to fill the grain but not far off getting the airbrush out.

 The undercoat was from white enamel primer from Halfords in a rattle can which seems to work well as a base coat. I'll probably add some paper undercarriage fairings between the fuselage and the undercarriage legs before applying the top coat.

 I kept the fuselage sheet sections I cut out for the side windows so they can serve as easily installed masking for spraying, I just stuck some masking tape to the inside to hold them in place



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 26, 2019, 12:51:32 PM
I was hoping to spray some top coat on the fuselage today but, as ever, there's things I've forgotten to do  :(

First job was to make up the paper fairing for the top of the undercarriage. I stiffened it with some thin Cyno once it was stuck on. It's only glued to the undercarriage leg so should allow some movement on a hard arrival.

I'd even missed a bit of sheeting underneath the centre section  :-[ so all the masking had to come off so I could get to it. It did give a chance to put all together again which makes me more determined to get some yellow paint on it tomorrow.

Looking at the rear shot the Aileron/flap section will need multiple extra mounting points to keep the aileron gap even, the 'smile' its showing at the moment will have to be avoided  8)

I've added more filler to fill the grain and a final caot of undercoat where needed so it's out with airbrush tomorrow  :)


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on January 27, 2019, 12:49:12 PM
The Wilga made it into my cardboard spray booth today and got its first coat of yellow top coat.

Its Humbrol Gloss Yellow thinned 50/50 with cellulose thinners and sprayed with my new cheap Chinese airbrush, which I have to say I'm quite impressed with. The spray pattern even with the larger .5mm needle and nozzle is still quite small but then my experience is more rattle can and car spraying guns so it seemed to take an age to spray the whole airframe.

The finish is even with the airbrush but it will need further coats to get a good flat colour, its still a bit patchy. I doesn't look it in the pics but it's not right at the moment.

The cowling still needs more work so I'll give it another coat of white primer before applying more yellow top coat






Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 02, 2019, 01:20:10 PM
With a bit of rubbing down with wet 1200 paper and the nose re undercoated, after a lot more rubbing down,  hopefully it's out with airbrush again tomorrow. Just noticed the fin strake (?) doesn't match the photo  :-\.... still so long as I change it before the blue goes on.

As it's nearing completion I thought I'd better check the engine out. It's a Redfin 030 TBR MkII the same type I've used in a DH60 Moth. I bought it at the last Mayfly new from Alex at Redfin and he supplied it with a black head and spinner from the 020. It fired up very easily and settled into a nice burble to run in. There's a video here. I bought a rev counter which I'm hoping will give some consistency to scale comp flights.... well the engine speed at least !!

https://youtu.be/R53bEqjhhh8 (https://youtu.be/R53bEqjhhh8)




Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 03, 2019, 12:15:54 PM
Well it's looking a bit more yellow. The fuselage and nose will need another coat as I had a slight reaction in the paint on a small section, which is odd. I'll let it dry and rub that bit back with 1200 wet and dry and paint again.

Not sure why it reacted its the same surface prep as the rest of the airframe...I'm wondering if it was due to not mixing the paint enough as its from another batch of 50/50 enamel paint and cellulose thinner that I mixed up. Any thoughts out there ? see pic two

Edit - As it drying the effect is reducing. I'll still rub back and respray. Is it just too much paint and extreme orange peel ?


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on February 03, 2019, 12:34:01 PM
Well it's looking a bit more yellow. The fuselage and nose will need another coat as I had a slight reaction in the paint on a small section, which is odd. I'll let it dry and rub that bit back with 1200 wet and dry and paint again.

Not sure why it reacted its the same surface prep as the rest of the airframe...I'm wondering if it was due to not mixing the paint enough as its from another batch of 50/50 enamel paint and cellulose thinner that I mixed up. Any thoughts out there ? see pic two

Edit - As it drying the effect is reducing. I'll still rub back and respray. Is it just too much paint and extreme orange peel ?
I've had this occasionally when thinning with cellulose. When you think about it, a second coat of cellulose on enamel is asking for trouble. Yes, usually too much paint in slow-drying conditions. Less time between coats seems to help


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 03, 2019, 01:08:40 PM
Thanks for the info Bill. The lighter coats elsewhere didn't react so once its dry and rubbed down I'll try again with multiple light coats


Title: Re: PZL Wilga for .5cc diesel
Post by: vintagemike on February 04, 2019, 05:23:16 AM
Possibly the reaction is due to the first coat not properly dry before putting the second coat on top. reduced drying (evaporation of solvents) in cold (damp) conditions. this will happen even with similar materials, not just a mix of enamel and cellulose. The reason is that air drying solvents dry from the outside (top) of the layer of paint. This inhibits the drying/curing of whats underneath. Sorry if I,m trying to teach Granny to suck eggs but it can be overlooked 


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 04, 2019, 04:15:44 PM
Thanks Mike. I think trying to put too much on in damp conditions was most likely the cause...but I will mix the paint more throughly next time just in case


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 09, 2019, 01:26:19 PM
A rub down with a bit of wet 1200 wet and dry paper and a bit of a respray and the reacted part of the paint is sorted. It didn't happen at all this time but then it was warmer, drier and I applied multiple thin coats.... and mixed the paint for longer

 So thats enough yellow...  finally... this finishing business takes forever... blue next

I notice in the 2nd pic the fuselage strengthening strakes/mouldings don't look as straight as I thought they were... hmmm must be lens distortion ;-)


Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on February 09, 2019, 02:22:21 PM


... this finishing business takes forever...





Doesn't it just?

That is looking every bit a Wilga now. Lovely stuff!

How are you finding the spray box's effectiveness?


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 09, 2019, 02:32:03 PM
Thanks Monz

The spray box is a godsend. Previous spraying of models has involved masking off the entire workshop and still ending up with more on me than the model !

I have sprayed, both with the new airbrush I bought and aerosol cans ( for the primer) and it has made spraying much less of a coloured fog type of ordeal. I still spray enamel thinned with cellulose with a face mask with organic vapour filter but it has become a much more pleasant affair and I no longer need to mask off everything else in the workshop with dust sheets. So all in all a tenner well spent.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 10, 2019, 11:53:42 AM
Managed to get some blue paint on it today. There's still the stripe to do down the side of the fuselage but having only put a final coat on it yesterday I thought I'd leave that for next weekend



Title: Re: PZL Wilga for .5cc diesel
Post by: skycafe on February 10, 2019, 12:54:34 PM
Stunning, great job!


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on February 11, 2019, 07:39:56 AM
Very neat and realistic. Nice effort SN.
It'll be interesting to see how it flies with slats and flaps.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 12, 2019, 02:48:31 AM
Thanks John and Skycafe

Quote
It'll be interesting to see how it flies with slats and flaps

Indeed. I think gaps the gaps all equal will be key

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on February 12, 2019, 04:47:23 AM
Chris,
         If it flies anything like the Zaunkoneig it will be a hoot, with the stall turning into nose over and picking up speed again. The trick is definitely maintaining equal gaps. Your will definitely be more visible and have lots of presence. I have just started repainting the trim on the Comper wing that has been recovered and have decided the pin stripe is too small to replicate well at about .020 wide.
Ricky   


Title: Re: PZL Wilga for .5cc diesel
Post by: yagua on February 12, 2019, 09:41:50 AM
 :o :o :o :o


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 16, 2019, 12:33:43 PM
Quote
If it flies anything like the Zaunkoneig it will be a hoot

 Hoping for a stable flyer Ricky !!!! . The wing section on the Zaunkönig looks very similar in section so maybe not  :o. I have a Bowden Meteorite which has tip slats that is very stable but perhaps my optimism is miss placed. Still the grass is starting to grow so I'll find out soon ;-).

Hope the Comper is going well, .020" sounds too fine to me too.

Added the side stripe today after much masking with frog tape.

For the reg markings I plan to use painted water slide decal paper cut out into letters.

 I was thinking of using clear paper or would the solid backing of white decal paper be better ? any thoughts out there ???

I'm planning to spray the decal paper with enamel thinned with Cellulose thinner as I have some matt black paint and lots of thinners...actually I wonder if the cellulose will react with the decal paper... better check that out first... Hope  I can as I want to the use the same technique on my Hawker Tomtit which is the next victim in my cardboard spray booth

Chris



Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on February 16, 2019, 03:20:58 PM
If you're going to spray the decal paper, either will be fine. I do find the clear to be a bit stiffer and less prone to folding under itself when applying. If you're going to print, then the white.

I dissolved the decals on the Fokker with cellulose thinners, it ate it like it was nothing, so I'd spray a test piece first. It might not eat it if diluted with paint and has time to flash off, unlike the puddles of it that I was using.

PS with all those 'stringers' on the fus, the decal will narrow as it goes over them, so allow some extra in the height of the letters when doing them.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 16, 2019, 04:24:32 PM
Thanks Monz

I'll try a test piece. I hadn't thought of the stringers squashing the letters  :-\.  I'll adjust accordingly

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: Graham Banham on February 17, 2019, 09:38:05 AM
Either that or apply the parts of the lettering that fit between the stringers using decal (you could identify the precise shape of these with a paper template first) then touch in the stringer area with a brush? Will avoid guesswork with the vertical stretching of the letters, and trying to get decal  to conform around three sides of the stringer, regardless of setting solutions, etc.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 17, 2019, 12:43:54 PM
Either that or apply the parts of the lettering that fit between the stringers using decal (you could identify the precise shape of these with a paper template first) then touch in the stringer area with a brush? Will avoid guesswork with the vertical stretching of the letters, and trying to get decal  to conform around three sides of the stringer, regardless of setting solutions, etc.

Thanks Graham good idea, that's exactly what I have decided to do.

I've made up and printed out a decal sheet, I'll cut a stinger sized gap in each letter as Graham describes

I tried spraying some decal paper with enamel thinned with cellulose thinners and there was no obvious reaction. I'll see if it still works as a transfer once the paint has properly dried. I keep getting lots of popping ( small pin holes ) appearing - is this too thick a coat ? I do get impatient and want to get a nice solid coat on  :-\

I did the Romanian flag on the tail too. This one is modelled on one of a fleet of PZL Wilga's used as glider tugs by the Romanian Aero Club who fly out of Bucharest. I've opted for YA-VLC as its rigged with a bit of dihedral and the lettering on the blue fuselage stripe is in yellow rather than the harder to produce white used on some of the other aircraft





Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on February 17, 2019, 01:48:10 PM
I've sprayed decal with enamel/cellulose many times without problems.
What a fabulous model this has turned out to be. It never appealed to me before but this looks great.


Title: Re: PZL Wilga for .5cc diesel
Post by: 3view on February 18, 2019, 12:37:15 PM
Still the grass is starting to grow so I'll find out soon ;-).


Tell me about it.  Before global warming you used to put the lawn mower away in October and not get it out again till next April :)

Nice Wilga BTW

Steve 


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 19, 2019, 03:16:05 PM
Thanks both

The grass can't grow quickly enough for me... ;-)

 Hope you get some decent weather soon for the Chipmunk too

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on February 19, 2019, 03:58:48 PM
That Wilga's looking fabulous, Chris (and it'll be another for my YHWM gallery! http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=13128.0)
What an eye-catching model it will be.

Incidentally, browsing through a Polish book I've got, I realised I've got a really nice 3-view drawing of the lone Wilga prototype, SP-PAZ. It's a much simpler boxy shape than a proper Wilga like yours, but I'm thinking it would make a nice rubber model. I found these pics on the 'net, but I suspect there are not enough photos out there for proper documentation unfortunately.
(Sorry- don't mean to sidetrack your build thread.)


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on February 19, 2019, 04:15:50 PM
Lovely job, Chris :)


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 19, 2019, 04:27:55 PM
Thanks Pete. Nice YHWM thread

The prototype looks great and possibly a good deal lighter to build there's lots of wood in the AM version... My Wilga is a victim of Christmas excess and has put on some unwanted weight . I might need your source of solid helium you have clearly used in your PT3 to lighten the rear end.

The prototype has a Dornier DO27 look about it to me, I wonder if that was their inspiration or maybe they got there first ? It looks a bit ungainly on its long UC legs but I kind of like it



Title: Re: PZL Wilga for .5cc diesel
Post by: Graham Banham on February 19, 2019, 07:11:25 PM
Looking great Chris!

I too fancied the Wilga 1 as a subject but hit a brick wall with docs: photos are a problem, although the indications are it was red and white, and i couldn’t find a three view at all.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 20, 2019, 02:10:37 AM
I've found a few... and Monz kindly sent me some ( Thanks again Monz)



Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on February 20, 2019, 02:56:49 AM
That Wilga's looking fabulous, Chris (and it'll be another for my YHWM gallery! http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=13128.0)

I just went through the YHWM gallery and I do think there needs to be some sort of rule as regards the amount of non-yellow permitted for a model to qualify. For example there is a rather dodgy blue and yellow Storch on skis.


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on February 20, 2019, 05:00:35 AM
I just went through the YHWM gallery...  there is a rather dodgy blue and yellow Storch on skis.
I don’t quite see the problem; are you suggesting the Storch is somehow not a monoplane with a yellow high wing?

Graham, this is the book with the Wilga 1 three-view. Let me know if want a scan of it. It’s got a LOT of gliders in too, but also a fine selection of obscure (to me anyway) but tempting Polish light aeroplanes. Lots of PZLs and LWDs among others.


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on February 20, 2019, 05:02:11 AM
YLWM would be deadest winners then :D :D

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Yak 52 on February 20, 2019, 05:46:13 AM
Looking great Chris!

I too fancied the Wilga 1 as a subject but hit a brick wall with docs: photos are a problem, although the indications are it was red and white, and i couldn’t find a three view at all.

Graham, there's a Wilga 1 side view here: https://www.rcgroups.com/forums/showthread.php?2732029-Wilga-32-35

Jon


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on February 20, 2019, 07:37:47 AM
I just went through the YHWM gallery...  there is a rather dodgy blue and yellow Storch on skis.
I don’t quite see the problem; are you suggesting the Storch is somehow not a monoplane with a yellow high wing?

Yes-that would be a MWAYHW. Who started this nonsense?!


Title: Re: PZL Wilga for .5cc diesel
Post by: Graham Banham on February 20, 2019, 01:59:16 PM
Thanks Jon,

Between us Pete and i have managed to locate two good three views, a colour profile, three complete photos (one colour) and a few part shots of the sole Wilga 1. A nice subject, but only enough docs really for a peanut, which is tempting!

Sorry Chris: thread hijack ends ;)


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 23, 2019, 01:47:39 PM
All hijacks welcome ;-)

Spent a nice relaxing afternoon putting the transfers on.

The side ones worked well using Graham's idea of chopping a stringer sized bit out of the relevant letters. I used Decal Fix to stick them too so they conform into the corners.

Slight disappointment with my yellow transfers on the blue stripe. Of course in retrospect transparent yellow over blue makes... yep dark greeny black.

I had the great idea over applying another yellow decal over the top but of course transparent yellow over greeny black ... yep darker greeny black !!!!



I think I might have to leave it , I can't think of a way of doing it without spending out on pro printed expensive dry transfer prints and for this model it's not really worth it... sorry PZL Wilga








Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on February 23, 2019, 02:22:57 PM
Chris, could you not print yellow onto white decal and cut out? I had a similar but easier problem on this Caproni. I don't know what made me think I could put a yellow and pale blue transfer over black, but putting a white decal disc on first sorted it.
Yes, it's dust


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on February 23, 2019, 02:23:40 PM
Looking great, Chris.
Cut vinyl would perhaps cover it ok?
Would gladly cut it for you if I can get the right yellow


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on February 23, 2019, 02:25:49 PM
... actually might have some yellow solartrim.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 23, 2019, 03:37:48 PM
Quote
Chris, could you not print yellow onto white decal and cut out?

Good thought Bill but the lettering is only 5mm tall and they would have to be cut as individual letters  :(

Russ that's a kind offer, yes a vinyl (solartrim ) would do it if you can cut that small. I can pm you a jpeg/pdf of the lettering if you are able to to do it

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: Graham Banham on February 23, 2019, 03:50:33 PM
Match the colours as close as you can and try printing the yellow lettering and blue background on thin (50gsm) white paper. This is very smooth and sold as layout pads for artists/architects as it can lay over an existing drawing and still allow it to be visible for corrections. Cut the logos out in word sized rectangles and glue to model with aliphatic. Touch in the white edges of the paper as necessary: the paper is so thin it will conform to the model and the edges will be practically invisible.


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on February 23, 2019, 04:15:16 PM
A PDF with 'proper' text would be preferable to a jpg ... so I don't have to trace anything,  though I will if necessary.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 24, 2019, 12:48:39 PM
Thanks for the help Graham and Russ

Fitted the aileron/flaps and leading slats today. I've used an extra spacer to help maintain an even gap

I've added a landing light into the tip too with a bit of litho plate. Just the glazing and pilot to go :-)


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on February 24, 2019, 07:53:47 PM
The registration looks neat SN. It's certainly a charming aircraft.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: ZK-AUD on February 24, 2019, 10:16:38 PM
It certainly is, and a very convincing model too.  Have you considered the glazing yet?   Looks like an ideal candidate for flanged vac-formed windows that plug in from the inside but are flush with the exterior skin


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 25, 2019, 01:44:58 PM
Thanks John

Mike - Great idea for the glazing but I don't have access to a vac machine unfortunately. I have had to use a low tech approach

For the screen I made a Balsa former and pulled some heated 10 thou acetate sheet over it. It gives the right sort of curve to profile of the screen, there's a small ripple in it which I didn't notice until I started cutting it out but I'm not going to worry about that.

The rear window was pulled over a suitably sized paint can and the one side window I have done was from an off cut of that . I kept the balsa I cut from the fuselage for the window aperture when skinning it, which proved a useful template for the glazing.

My method which I've used on other models is to butt join the window with the sheeting and align it with masking tape then apply some canopy glue with a brush so it runs into the joint. I apply between the tape holding it in place and when its dry apply the glue where the tape obscured it. This requires accurate cutting of the windows and careful sanding but hopefully better than just sticking it to the inside of the fuselage skin

The last photo shows the RH side window just propped in as I ran out of time but you get the idea.

For the window vents I applied a small circle of masking tape for the inner clear bit on to a scrap of acetate, then sanded the piece to get a matt finish. removing the tape reveals a clear inner circle. I then trimmed this with scissors and a sanding block to get an outer circle and stuck it onto the window with a tiny amount of canopy glue


Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on February 25, 2019, 02:29:29 PM
Looking the business now Chris.

You don't need a vac former to do the bulged windows. I did mine by plunge forming. Kept the window cutouts, added some thicker balsa to the form for depth and then plunged as normal. All my clear parts on models are plunge formed, but I need to build a vac former for a 3' canopy I need to do...


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 25, 2019, 02:35:59 PM
Thanks Monz

Quote
I need to build a vac former for a 3' canopy I need to do...

Blimey, are you building full size aircraft now ??


Title: Re: PZL Wilga for .5cc diesel
Post by: Monz on February 25, 2019, 02:38:11 PM
Thanks Monz

Quote
I need to build a vac former for a 3' canopy I need to do...

Blimey, are you building full size aircraft now ??

hahhaha, no, a quarter scale slope jet. Started it years ago and must get it finished.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 26, 2019, 02:33:55 PM
Well thats most of the glazing stuck down. 

 I just need to add a pilot before he gets sealed in when I add the left side window.  Whats the betting he breaks free on the first test glide  :D.

There's some edging for screen to add too but nearly there


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on February 26, 2019, 05:38:15 PM
Nice one Chris. My pilots also suffer the same reluctance to stay put. I use the seat belts as a restraint and it works for all but the most extreme arrivals. I think this will be a very competitive model and it can be trimmed for a short take off with a STOL like climb and not be peanalised. Not sure if it would be a bonus if you towed a glider if it could be trimmed to follow but sure would challenge the judges.
Ricky


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on February 26, 2019, 06:30:08 PM
I've made a start on the lettering, Chris ...  the Arial part works well, but some of the stencil parts are very fine with my version of the font. I think I will beef it up a little.
I found the solartrim, but it doesn't cut as well as the vinyl.
I'll report back as I progress further!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 27, 2019, 03:21:02 AM
Thanks Russ. It hadn't occurred to me that some parts would be so fine, beefing it up sounds good


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on February 28, 2019, 12:35:27 PM
I had a go at a pilot today.. Ok so I cheated and bought a 3d printed head from Tony Bennet's Finishing Touches site

 https://finishingtouches974021655.wordpress.com/?fbclid=IwAR15JKXfEgyGtn9I6EmTRoiJKkUwfIAv9DvVKV3N9-Cq-ghukct8vVY7Rfs (https://finishingtouches974021655.wordpress.com/?fbclid=IwAR15JKXfEgyGtn9I6EmTRoiJKkUwfIAv9DvVKV3N9-Cq-ghukct8vVY7Rfs)

The rest is carved from blue foam using Richard Crossley's technique to a lesser effect. I'll have another go at him later once his arms have stuck.

Looks like he'll do the job though. What do you stick a pilot foam in with to lessen the chance of him breaking free ?  - Copydex or some sort of rubbery glue ?




Title: Re: PZL Wilga for .5cc diesel
Post by: ZK-AUD on February 28, 2019, 12:41:14 PM
A dowel in his posterior and a drop of epoxy should do it


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on March 01, 2019, 12:55:10 AM
Hmm! painful.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: kkphantom on March 01, 2019, 04:47:07 AM
Nahh, it's only a small dowel....


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 01, 2019, 01:23:32 PM
I spent the day admiring and enthusing at the aircraft of the RAF Museum in Hendon. On the subject of pilots I like the way they have done their dummy pilots in the WW1 aircraft. They have added dummies to some of their aircraft but they have painted them all a flat grey colour, which works well for me. It's sort of saying were are not trying to convince you this is a 'real' pilot but it helps you gauge the scale  and how it may have been for the pilots that did fly them, which is similar to their use in FF Scale models?

Maybe I should do that with the Wilga Pilot. The inside of the cockpit is black anyway and I'm not sure painting the pilot black too would work either - it would look like its be flown by some supernatural shadow !!!. Maybe grey would work or maybe just very muted colours not sure  ?

I wonder if these larger pilots have a large broom handle in posterior and drop of epoxy to hold them in ?


I popped next door to Hannants on the way out and bought the basis for a possible future FF Scale project  ;)



Title: Re: PZL Wilga for .5cc diesel
Post by: ZK-AUD on March 01, 2019, 02:33:11 PM
Hmm! painful.

John

Well I suppose he's a Pole


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on March 02, 2019, 12:21:46 AM
Oh good grief Charlie Brown :D :D

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Jack Plane on March 02, 2019, 02:29:15 AM
I'm so late to this thread, I seem to have arrived at the 'posterior' end...  :o


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 02, 2019, 01:24:37 PM
The Wilga pilot has grown some legs and I've added a seat back as this can be seen when viewed from the side. Buying the 3d printed head has made life a lot easier and helped disguise my dodgy carving skills. He'll be seated on blue foam block with the inevitable dowel up the posterior to help locate him.

The rear view at the moment looks a bit like he's seated on the loo... actually as he has my trimming to endure thats probably fortunate. I'll paint that bit black so hopefully know one will notice


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 03, 2019, 01:23:42 PM
Ok so I decided to go for a more realistically painted pilot rather than the flat grey as used by the RAF Museum partly after re starting work on the Hawker Tomtit and looking at the Dave Banks pilot I'm fitting to that model and how well it sets the model off when its painted in a natural manner

I gave the blue foam a coat of Ezy-Kote and then painted him with Acrylic paints.I just went for muted colours to keep him low key. 

He's epoxied in with the inevitable posterior shaft type assistance which will hopefully keep him seated despite my attempts to trim the model so I will now seal him in by adding the left hand window.

The result is the sort of thing I was after...there's a pilot there but he doesn't draw the eye, he just blends in


Title: Re: PZL Wilga for .5cc diesel
Post by: Jack Plane on March 03, 2019, 01:29:04 PM
E's a skinhead!  :o

 ;D


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 03, 2019, 01:47:36 PM
Rude ...!  ;D


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on March 03, 2019, 06:08:30 PM
Not bad - The Wilga does look better with Mr Skinhead in the pilot's seat. :)

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on March 04, 2019, 02:24:50 AM
Very nice pilot, and I’m not going to be rude about him.

(I know better than to needlessly insult Lord Voldemort!  :o)


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on March 04, 2019, 03:14:36 AM
I admire anyone who makes their own pilot - I haven't a clue and my few feeble attempts were laughable. I think Kryten looks great and fits the model perfectly.


Title: Re: PZL Wilga for .5cc diesel
Post by: THB on March 04, 2019, 04:01:19 AM
Fly Hard


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on March 04, 2019, 04:22:14 AM
I think Kryten looks great and fits the model perfectly.
Kryten! Of course. Thank you. You can initiate smug mode: https://www.youtube.com/watch?v=JD9d0ZrBnLE


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 04, 2019, 04:31:45 AM
I'm sure the trimming will wipe the smug grin of his face ;-)





Title: Re: PZL Wilga for .5cc diesel
Post by: LASTWOODSMAN on March 04, 2019, 07:19:26 AM
Now that is a great looking realistic "sober" pilot (who knows what 'bottle the throttle' means LOL ), to go with your great looking realistic PZL Wilga.   :)

LASTWOODSMAN
Richard


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on March 04, 2019, 08:46:07 AM
The pilot looks great, Chris ..... the layer lines do remind me of a pinless Pinhead, from the film of the same name!

Progress with your lettering ... I got some yellow vinyl today. Hopefully a close enough shade.
'Weeding' has to be done carefully, but it gives you a spray mask too if you decide to take that direction (the tiny letter centres can just be seen)
Don't worry .... I will run a good few sets in case you need a practice run!
I'll try the Stencil font stuff next ... I have beefed it up by 0.1mm all round!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 04, 2019, 02:01:58 PM
That's looking really good Russ.

In retrospect, it would have been better to have used the vinyl letters as a mask on the yellow BEFORE I added the blue stripe. Removing the vinyl letters mask would have produced the easiest method.... I'm still learning how to finish

As it is vinyl letters over the Blue stripe should produce the result I'm after. Very appreciative of more than one go at it

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on March 04, 2019, 03:04:43 PM
I hope that you don't mind me posting progress here, Chris? .... I thought it might give others that are not familiar with vinyl lettering a bit of an insight.

I think I have cracked the other lettering too, though it required a very delicate weeding (removing the unwanted vinyl) process!
Normally I weed before I apply the transfer paper (in this case just masking tape). The required graphic is left on the backing paper.
In this case it was still too delicate, so I applied the masking tape transfer paper first. I then pulled all the vinyl from the backing and weeded with the masking tape holding the required parts better than the backing paper.
Still a bit of a delicate operation, but once done I pressed the vinyl back onto the backing paper so the the adhesive does not go off.
It's best to do this just before application for 'best sticking' .... so you will probably have to go through this yourself. A sharp scalpel blade and my recently rediscovered weeding tweezers helped!



Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 04, 2019, 04:03:55 PM
As someone 'not familiar with vinyl lettering' I'm very grateful for the extra insight too

I didn't realise masking tape would work as a transfer medium , I was imagining some specially low tack film - good to know



Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on March 04, 2019, 04:15:27 PM
Yes Chris, that's right ... usually it is a lower tack.
With such small parts the extra tack helps ... as long as the adhesive beats the masking tape with the final application!
It does have to be removed carefully, pulling the masking tape back in the same plane as the application surface, if you can follow my dodgy explanation?!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 05, 2019, 01:30:40 PM
Makes sense to me Russ.

Spent most of the day putting up a fence ! but I did manage to add some glazing strips to the canopy.  Apart from fitting the engine and finally balancing it (its not far off) I'm about ready to throw it at the scenery...I might wait for the scenery to grow a bit taller first :-)

Nearly there...


Title: Re: PZL Wilga for .5cc diesel
Post by: Jack Plane on March 05, 2019, 01:41:45 PM
Looking well excellent Chris!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 09, 2019, 12:21:12 PM
I had a go this afternoon with the vinyl lettering that Russ (FreeFlightModeller) has very kindly cut for me.

I used Microset decal softener to remove the first attempt at waterslide decals that turned dark green this softens them enough so can just peal them off. Russ had already kindly weeded a set from the backing sheet so it was too tempting not to try to fit them.  Looks excellent Russ thanks again.

Not sure they are quite straight looking at the photos but I have a few extra sets so I'll try again later. I didn't appreciate that there is no repositioning once the lettering held on the carrier masking tape actually sticks to the fuselage. The PZL 104 bit looks great and is in the right place.



Title: Re: PZL Wilga for .5cc diesel
Post by: Jack Plane on March 09, 2019, 04:14:30 PM
That's out-of-sight excellent.  Well done to both of you!


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on March 09, 2019, 04:40:52 PM
Wow ... that was quick! I'm glad it has worked for you.


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on March 09, 2019, 07:02:41 PM
Nifty results Chris and Russ.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 10, 2019, 02:24:42 PM
Thanks Jon and John

 I had another go applying Russ's excellent graphics and positioned these much better. It's a bit of a learning curve weeding the tiny letters away from the rest of the vinyl but I'm very happy with the result the lettering gives once it's lined it up correctly, it sets the model off nicely . Thanks again Russ

So that's just about done, bar the bit it was actually built for ... flying ...but that will have to wait for the weather. As I write this, gales whistle round the house and rain lashes on the roof.. I was going to take some pics outside ..perhaps not

Anyway here's some sort of finished shots in the calm and dry of the workshop


Title: Re: PZL Wilga for .5cc diesel
Post by: Pete Fardell on March 10, 2019, 02:57:35 PM
What a lovely job you’ve made of that, Chris and the markings look great. It’s a gleaming yellow gem of a model, which will light up the outdoor season. Looking forward to seeing it in action!


Title: Re: PZL Wilga for .5cc diesel
Post by: FreeFlightModeller on March 10, 2019, 03:45:49 PM
That looks fantastic, Chris.

Provided the cutter can cut the parts, then that is the easy part of the job ... the work is all in the weeding and application... you've certainly cracked it!


Title: Re: PZL Wilga for .5cc diesel
Post by: ironmike on March 12, 2019, 03:13:20 PM
What a great looking model squirrel


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on March 30, 2019, 03:19:03 PM
Thanks Mike

Well the weather was perfect today so the temptation to try it was too great and I headed to my local field for some intial test glides

Unfortunately the lack of grass cutting on the common has resulted in the growth of Hawthorn amongst the grass. I had encountered it on my last test glides with the Tomtit but with shorter grass its much more noticeable.. and it's everywhere

Very happy with the few glides I did do in a small clear bit, but reluctant to do more for risk of damage. I'll wait for the grass to grow a bit more and head to Port Meadow.

Very encouragingly it looks like its going straight, despite all the the flap and slat gaps that could easily upset the equilibrium.

There's a short video here https://youtu.be/KcOFtQi6uLE (https://youtu.be/KcOFtQi6uLE)of a couple of chucks, from the nose up stance it maybe over elevated but without further tests it's hard to tell ..it's not stalling but looks a bit nose up.... only more thorough testing will reveal what's going on....roll on spring !!!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 15, 2019, 04:28:45 PM
I'm very happy to report the PZL Wilga has successfully flown, having completed a number of flights at the Mayfly last weekend.

The Redfin needs almost full power to pull the model round but it looks very nice in the air under power and the slats and flaps seem to work well at stabilising the model and it even seems to self correct from any gusts trying alter the circuit. So I was very pleased with the model.... until the engine stopped  :-[

The glide is paving slab-esque to say the least. I did try gliding it first, honest and had something slightly less steep than in the video. I think that trying to achieve a decent glide with what are basically double full width air brakes on each wing is not really going to happen. After some helpful advice, thanks Gareth, I tried taping up the slot gaps  but a short power run revealed a vicious tip stall so I called it day. Without the slats the stabilising effects are completely lost which seems to indicate the slot and flaps are doing something

To get it glide I have a plan which involves building a couple of new wings of more conventional nature minus the slats, if I have the time, or failing that flying as is at the Nats next weekend and taking a hit.  I'll try for the new wings- I think I have a plan hope I have the time

https://youtu.be/G4dYjSN_-9g (https://youtu.be/G4dYjSN_-9g)


Title: Re: PZL Wilga for .5cc diesel
Post by: 3view on May 16, 2019, 12:50:47 PM
I think I have a plan hope I have the time.

Convert to electric and come down with some power on? ;D

Congratulations on your progress so far. You must be able to dial in a more positive glide, more noseweight? I'm sure the wilga can't be more draggy than a WW1 biplane?

Steve


Title: Re: PZL Wilga for .5cc diesel
Post by: RalphS on May 16, 2019, 01:32:56 PM
Lovely looking model.  Shame about the glide.  I built my Storch some time ago and early glide tests were disappointing.  I put that down to drag caused by the slots but as the model was needed to get free entry into the old Woodvale meet I persevered.  I found a nice little grassy slope and trimmed the model by moving the CG until the glide slope from a hand launch pretty well followed the actual slope.  Once this was okay I trimmed for power and the model flew well.  I find that the Storch needs to be launched slightly nose up, even on low power. This indicates to me that the slots do work.  Find a grassy slope before making new wings. Hand glides of draggy models from a height of 5' over flat ground don't give time to properly assess the glide.  Poor glides from powered heights can be final.  If moving the CG back does help the glide you may have to re-adjust thrust lines.  Best of luck.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 16, 2019, 03:31:53 PM
Thanks both - good thoughts.
 
Steve - I was thinking on the ride home of maybe fitting a timer to induce half throttle so I get a powered glide but that's not a quick solution as it would need a few mods and sourcing a suitable throttle and timer unit

Ralph - Thanks I will explore the glide a bit more...I know of just such a slope and maybe the best way out with only a week until the Nats

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: strat-o on May 16, 2019, 06:55:05 PM
Does the full-scale aircraft feature retractable slots?  I would guess not as I've seen a full-scale one tied down and it's slots were open.  But if it did, you could have the slots retracted which might solve most of your flight problems but then for static display, have them deployed.

Marlin


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on May 17, 2019, 03:48:05 AM
Chris
It could just be the combination of 12oz/sq ft (double the ideal) and high drag.
If you build new wings without slots, I've seen experts like Richard Crossley do work with the airbrush that would convince us the slots were there.


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on May 17, 2019, 05:02:28 AM
Chris,
        I think Ralph has put his finger on the problem. One of our members built the Zaunkonieg powerd with an AMCO .87 and it needed full power and climbed in a stable manner and if it slowed for any reason it nosed up slowed and the nose dropped and it picked up flying speed and resumed the climb. When the engine cut the glide was steep but stable and quite slow. Also Brian Conroy had a Storch theat behaved in a similar manner. I am sure someone can elaborate on that model as it flew at the UK Nats some while ago. Your 12 oz/ sq ft wing loading does not seem unreasonable for a monoplane.
Ricky 


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on May 17, 2019, 05:29:49 AM
The original blurb with the plan refers to a 'gentle glide'. Looking at the video again, it is a dive, not a high sinking rate. The blurb also mentions more packing needed under the tail so I would agree with Ralph - find a slope and keep packing till you get a stall and then start power trimming again.
Not sure why it would tip stall with the slots taped up - there aren't any warps are there?


Title: Re: PZL Wilga for .5cc diesel
Post by: Yak 52 on May 17, 2019, 06:23:27 AM
Looking at the video again, it is a dive, not a high sinking rate...

I must admit I thought this too Chris, although it's very hard to tell from a few seconds of video of course. I got the impression the model was slightly under elevated, even in the power phase. Giving it a bit more decalage and a smidge of downthrust might translate the power to more of a climb too.

Re taping up the slots - you might try taping the inner 2/3rds of the wing. This might still save some drag but control the tip stall?

It does look great in the air mate!

Jon


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 17, 2019, 04:40:56 PM
Thanks all for the thoughts

Strat-o  The slats and flaps are fixed on the Wilga I think

Ricky - The slats and flaps are certainly adding stability, with them taped up it felt like a faster brick in the glide rather than a better one. I think I will pursue the glide trimming first as its clearly not not right .. I wonder if the steep dive is result of not enough downthrust so during the power the phase the model is being held up by the motor at below its gliding speed so when the engine cuts it has to accelerate into its steep glide ?

Bill - I had 3/16 packing under tail to get that 'glide' , I joked the declage was 45 Deg but actually it wasn't far off !!! I think I will try a slope and retrim the glide. I'll try moving the cg back a bit too, its currently about 33% of chord so I can't go too far

Yak 52 - I'll try  a re trim first but that may work



Title: Re: PZL Wilga for .5cc diesel
Post by: TimWescott on May 17, 2019, 08:06:35 PM
I'll try moving the cg back a bit too, its currently about 33% of chord so I can't go too far

I wouldn't be too sure about that.  It's got a pretty long fuselage, big tail, and a skinny wing.  If you go by this page (http://www.zenithair.net/horizontal-tail-pitch-stability-and-control/) then you should be able to put it back behind 50% safely (note that I raised my eyebrows at this -- I may have flubbed the math, or mis-measured the Wilga 3-view on Wikipedia (https://en.wikipedia.org/wiki/PZL-104_Wilga#/media/File:%D0%9F%D0%97%D0%9B_%D0%9F-104_%D0%92%D0%B8%D0%BB%D1%8C%D0%B3%D0%B0_%D1%81%D1%85%D0%B5%D0%BC%D0%B0.jpg)).

Given just how far back that thing says you can put the CG, I think I'd make a little balsa chuck glider to experiment with before I trusted my nice scale plane with the results.


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on May 17, 2019, 09:01:02 PM
I was not able to view your video - no doubt a problem at my end, however reading the comments leads me to the following conclusions.

The slats and flaps do appear to work on what is a fairly heavily loaded model but it is behaving as though it is under elevated on glide and power(needs full power to climb). I suspect that the slats and flaps are producing a heavy nose down pitching moment and as has been mentioned the CG will need to go back to enable the glide to flatten with a reasonable decalage, and also produce a better climb.

Tim's link is handy but I would think that 50% is too much and would think that Ralph's suggestion of using the slope is the best way to check at this point, as the effect of the slat/flaps will be too hard to incorporate and most likely be inaccurate on a small glider unfortunately.

Jon's(Yak52) idea of partial taping the slot is a good idea and could help (will also reduce the pitching moment) but it appears that the model needs the extra lift of the flaps/slots, as was shown by the increase in speed when they were fully taped up.

I wouldn't be surprised if the full size Wilga has large trim changes when using the flaps/slots.

Good luck with this Chris - it's a nice model.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: TimWescott on May 18, 2019, 08:24:46 PM
Tim's link is handy but I would think that 50% is too much and would think that Ralph's suggestion of using the slope is the best way to check at this point, as the effect of the slat/flaps will be too hard to incorporate and most likely be inaccurate on a small glider unfortunately.

I don't think the slats & flaps are going to make that much difference to stability.  Trim, yes -- stability, no.  Stability is a function of balance, where the surfaces are, and how much the coefficient of lift changes with angle of attack -- and as long as the airfoil isn't stalling, the change in coefficient of lift with angle of attack is pretty constant.  If taping over the slats is changing things, it's because you're changing the trim, not the stability.

I built a chuck glider.  It glided nicely on the first try with the CG well behind the 50% that I was calling out.  The tail moment arm is deceptively long, which, I think, plays with brains that are used to Piper Cubs.

Note that I used the 3-views from Wikipedia, which show a wildly inaccurate wing mounting, so the stab on my chuck glider is also wrong to match.


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on May 18, 2019, 09:59:53 PM
Quote
I don't think the slats & flaps are going to make that much difference to stability.  Trim, yes -- stability, no.
. Agree - but it is actually trim that was the reason for my suggestion of moving the CG back. I feel that there is a strong possibility that the slats/flaps are causing the airfoil to have a strong nose down pitching moment which the tail is struggling to handle(as per the comments of the large tail packing by Chris) at the current CG position. Thus moving the CG back should help to achieve trim balance, unloading the tail, - subject to retaining sufficient pitch stability.
The behaviour of slats/flaps at model Re's are fairly unpredictable and that's why I thought that Chris was basically stuck with some careful glides on his slope.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Indoorflyer on May 19, 2019, 10:41:11 AM
I used a Wilga drawing in the gallery, just for a quick BOTE calculation.  The ratio of stab area to wing area is .21 on this particular drawing.   I calculated a tail volume coefficient of .80.  CG position suggested by these calcs is 44%   


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 19, 2019, 01:31:51 PM
Thanks for all the help guys  ;D

I had resigned myself to building new wings but after hearing the discussion here I think it's worth pursuing the slatted and flapped version . It certainly looks good on power

Thanks Tim, I think you are onto something with the CG position as backed up by the others

Moving the CG back is the first thing I will try, it seems the best way forward. Now it's pointed out it behaves like a very nose heavy model as Jon said - it looks under elevated -  but my previous experience has been trimming with a cg much further forward which has thrown me a bit, this model is obviously very different.

 I think the nose down pitching increase from the slats and flaps sounds like the culprit too John. I like Jon's idea of partial covering of the slats. I built a Bowden Meteorite, a post war sports model designed by Col C E Bowden which has tip slats. It has a lovely glide and is remarkably stable it may be worth checking where the CG is on that now I think about it. I will try again with full slats and flaps first though

Before embarking on more glides I thought I better repair the damage to the undercarriage following it's 'nice gentle glide'. The undercarriage design isn't the best I've seen and isn't even that scale with forward wire braces. Anyway all strengthened now and new fairings for the legs, this time with some movement possible in the lower part to absorb some of the 'landing' loads

During trimming last weekend the model did turn right at one point, the rudder is very sensitive and it flew straight into a tree under power!  A combination of tissue over Mylar covering and good old luck meant there was no damage and after a bit branch bending we were able to get it out, I was very surprised it came out unscathed.

Here's some pics of the undercarriage damage - its actualy torn the thread and epoxy binding from the ply former. I would advise a different UC design if anyone does build one, maybe a torsion bar on the main legs ?

And a couple of pics of my old Bowden Meteorite.. with tip slats.. lovely glide and still going strong 7 years later though looking a bit tatty now  :-\ ... and yes the engine really is held on by rubber bands, it works very well




Title: Re: PZL Wilga for .5cc diesel
Post by: TimWescott on May 19, 2019, 05:25:00 PM
Moving the CG back is the first thing I will try, it seems the best way forward.

Just had to shout this one out because of the (perhaps unintentional) play on words.

Before embarking on more glides I thought I better repair the damage to the undercarriage following it's 'nice gentle glide'. The undercarriage design isn't the best I've seen and isn't even that scale with forward wire braces. Anyway all strengthened now and new fairings for the legs, this time with some movement possible in the lower part to absorb some of the 'landing' loads.

I was going to suggest leaving the undercarriage off for the rough part of test flying, at least if you have grass to fly on -- but, it's too late, and I can understand someone not wanting to go there.


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on May 19, 2019, 05:44:32 PM
It is really interesting how we all get fixated on a particular line of thought and ignore the obvious. We almost have too much information available sometimes. Chris, Ian Lever had a Wilga that did one year at the Nationals and he might be able to give you an indication of his trim settings.
It seems the one area of weakness in design is often the undercarriage, especially when the model gets larger when a little bit of give is often preferable to trying to absorb the energy in the air frame. Even on smaller models I try and work in a torsion bar of some sort. It has reduced damage.
Ricky
 


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on May 19, 2019, 07:45:41 PM
Fair bit of damage there Chris - what a pain! Very nice Bowden model and I noticed that the Colonel was keen on using lots of shock absorption on his UC's.

The highly cambered  airfoil on the Metorite would have had a large nose down pitching moment and I feel would have required a fairly aft CG for trim so agree it's worth looking at.

Good luck with the repairs and further testing.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 20, 2019, 02:53:04 AM
Quote
Ian Lever had a Wilga that did one year at the Nationals and he might be able to give you an indication of his trim settings.

I haven't spoken to Ian directly but quote I have from him is 'It flew like a brick until I tissued over the slats'. This was my plan too or rather build another pair of wings with a cheeky bit of extra chord and span to help the wing loading... if that's allowed for AM designs ?

However as the AM comp is Saturday and there are some idea on here about getting a better glide I thought I'd try that first.

John I will check the Meteorite


Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: Yak 52 on May 20, 2019, 05:08:50 AM
Hi Chris,

I had a closer look at the plan and ran some numbers through Hepcat's calculator. Tail Volume is 0.87 - in other words massive! This is a classic case of a high aspect wing tricking the eye. While the geometry of the aircraft looks fairly normal what matters for pitch stability is the tail moment arm measured in relation to the wing chord. In this case the tail moment arm is 3.5 times the chord. Most scale models are 2-3 times (ish.)

This is great for stability but it does mean that the CG can go back further than you would think. The calcs gave me 51% with a stable static margin of 10%.

The other thing I spotted on the plan is that the wing section is pretty thick at 15%. This will be responsible for quite a lot of the drag issues even without the slats and flaps!

So I think it's worth persevering with the trimming. You seem to have the right amount of power if you can get it a little floatier :)


Jon


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 20, 2019, 08:59:10 AM
Thanks Jon.

That's very interesting, yes pursuing with slats and flaps at the moment. After reading your post I think I'll reset the CG at 45% and try that with a bag a of plastercene on hand if needed.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 20, 2019, 01:00:12 PM
Interestingly the CG on the Bowden Meteorite is at 38% so about normal for a sport model. The tip slats are small though, just  6" per side on a 48" wing

Finished the Undercarriage repairs, paint is still drying. I just need to add the paper fairing between the leg and the fuselage skin.


Title: Re: PZL Wilga for .5cc diesel
Post by: Pit on May 21, 2019, 06:09:03 AM
Hey Chris,
if you're looking to throttle that Redfin, Martin Lambert (the same Lambert from IIFI), in Germany, makes carbs for it and other deezils, along with some nice turbines.  I've seen the jewels, and, tho a bit pricey are works of art.  I've got his contact info someplace but a search for "Lambert turbines" might turn up the data.

Pete


Title: Re: PZL Wilga for .5cc diesel
Post by: Jack Plane on May 21, 2019, 09:44:03 AM
Chris, I've got Martin's email address - will PM you.

Jon


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 21, 2019, 09:58:18 AM
Thanks both. I think I saw one at Old Warden on an engine, they are certainly beautiful bits of kit.


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on May 23, 2019, 06:55:50 AM
Just leafing through the Plans Handbook. The Wilga is recommended as 'an ideal first scale subject', so what's all the fuss about?!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 23, 2019, 04:47:07 PM
Quote
The Wilga is recommended as 'an ideal first scale subject'

I hope we haven't lost too many future free flight scale flyers with such careless talk


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on May 23, 2019, 04:57:26 PM
There are a few plans that come into that catagory that I would question their suitability for a beginner. I think you would have to look at some of the newer designs to find appropriate models as some of the older designs have structural flaws. Also the trimming notes are sparce to say the least and in some cases somewhat misleading. Your experience with the Wilga will be very useful and could be the subject of a piece in Aeromodeller together with any mods made to the model. The ebenezer plan was great.
Ricky


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 24, 2019, 02:01:33 PM
Thanks Ricky, interesting idea

I certainly wonder how many of the old 1950's FF Scale designs were actually built and flew and how many were designers fantasy.

Right thanks to a gentle slope, some long grass and the excellent advice on here by various people all pointing in the same direction (Huge thanks to all  ;D)  I have reset the the CG to 45% and a 'not bad' glide has resulted.  I tried a few angled launches too and it seems to self correct so looking like there is still a margin for stability as you guys predict.

The undercarriage legs split again, even with just test glides so they now have been wrapped in a layer on LW glasscloth and epoxy resin so hopefully that means they will survive a bit better.

Off to the FF Nationals tomorrow so looking forward to trying again, I've added a gnat's more downthrust too in anticipation of an increased  angle of climb under power ....hopefully my guesses prove right  :-\



Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on May 24, 2019, 02:36:01 PM
I certainly wonder how many of the old 1950's FF Scale designs were actually built and flew and how many were designers fantasy.
I suspect quite a few fell into that category. Many are the stories of models being hung from strings for photos. I built the Stan Perry Flycatcher - an absolute plumber's toolbag. I met a bloke from Stan's club who had built one - also untrimmable - and he said even Stan's never flew.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 24, 2019, 02:51:18 PM
Quote
an absolute plumber's toolbag

  :D That phrase is going stay with me for sometime !!!  :D



Title: Re: PZL Wilga for .5cc diesel
Post by: TimWescott on May 24, 2019, 03:41:13 PM
...I've added a gnat's more downthrust too in anticipation of an increased  angle of climb under power...

I would expect that after trimming for the further-back CG the thing will have less of a tendency  to go pitch-up under power -- here's my wish that if you're surprised, it's not a BAD surprise!


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 24, 2019, 05:00:50 PM
Thanks Tim, I'll keep you posted


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on May 24, 2019, 07:38:14 PM
Good luck with it Chris. Here's to good weather, sunshine and little to no wind! Asking a bit I imagine :) Good luck to all you fellows flying in the Nats.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on May 26, 2019, 12:35:34 AM
 Chris,
        Well done the Wilga looks very realistic with a good sit in the air. Just a thought, but the real aircraft will usually have a steep approach as all the slots and flaps are deployed with a lot of power on so you are not out of scale in flight terms. Even when clean I doubt if the real one has any sort of glide, probably like the average WW1 aircraft of about 1 in 3. 
Ricky


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 26, 2019, 12:59:35 PM
Thanks Ricky.

Despite its rather too STOL final approach I'm very happy with the Wilga, it looks great under power and well worth continuing with the slats and flaps. In the Flying Only Comp at the Nats I came a very happy 4th, which considering its death wish glide at Old Warden, I can only thanks you guys for the help particularly with the CG position.

It's currently 45% and think I will try a tad further back still, stability was very positive under power in the blustery conditions and I'm also thinking of more downthrust as my power speed my still be less than the gliding speed, which will always end in a bad transition.

My epoxy glassed undercarriage fairing failed again so before I attempt something more radical I'll try the same design with a 1/32" ply reinforcer and layer of epoxy glass over the top


Title: Re: PZL Wilga for .5cc diesel
Post by: ZK-AUD on May 26, 2019, 04:05:49 PM
Chris I've been lurking and quietly liking this build as it has progressed.    Those steep arrivals are a challenge but I was looking at this problem and wondered whether you could try going the other way and make the leg extremely rigid.  (liteply leg covers epoxied on and silk bound with a piece of carbon rod running through the middle parallel to the existing wire) Then articulate and spring / damp the trailing arm section as per the real one  - a clothespeg style spring would do it.

Here's a rough-as-guts sketch of how I would approach it.  Ideally the articulated section would be silver soldered to the brass tube but you'd get away with soft solder with a good fillet.  The step in the brass tube is your forward stop against the spring tension


Title: Re: PZL Wilga for .5cc diesel
Post by: Yak 52 on May 26, 2019, 04:54:04 PM
Very glad to hear it flew well Chris!  :)

At 45% you have a static margin of 16%, still fairly forwards in general terms. 5-15% is normal, depending on the model, with FF scale models tending towards the high side. Considering the generous tail volume (what you have is more like a duration model) you could afford to go a bit further back still.

Jon


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on May 26, 2019, 06:55:48 PM
That's good news. I'm glad it performed well and as Jon mentions you still should be able to come back a little further. Mike's suggestion of an articulated, sprung trailing section to the UC leg is possibly a solution to your UC problems.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on May 26, 2019, 07:35:00 PM
Chris,
        Your use of the 1/32" ply reinforcement should work. I am building (slowly) a Broussard and have used a similar approach with two facing pieces of 1/32" ply and a core of 1/8" epoxied around the leg and a torsion bar in the fuselage. The reinforcement should allow the trailing section to give a bit as the leg will be significently stiffened. The video was great and the glide reminded me of watching an RAAF Caribou on approach at Amberly where the nose seemed to point at the ground. Great spectacle. The way it coped with what appeared to increasing wind was impressive, clearly the slats were working.
Ricky     


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on May 28, 2019, 04:03:50 PM
Nice design Mike thanks.

My first step is a 1/32" ply reinforcer in addition to the balsa fairing wrapped in epoxy glass from last time. Its very similar to Ricky's thoughts.  There is a little movement allowed in the wheel and axle thanks to the triangular section cutout in the centre of the fairing.( see pic in post 205) . The right hand leg has survived fine but in inside leg with a left hand 'glide' did not.

 If this one fails I'll try your idea Mike, as I'd already repaired it   ;)

Jon - That's good to know next step is a bit more tailweight


Title: Re: PZL Wilga for .5cc diesel
Post by: TimWescott on May 28, 2019, 04:18:33 PM
I think you may find that more spring is required than the original had.  If I could figure it out, I'd recommend something that lets the LG collapse completely, then spring back.

But then, I fly control line because I'm not smart enough for free flight, so...


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on July 21, 2019, 12:59:50 PM
I think you're right Tim it needs more springing. If I was going to build another...I'm not.. I would use a torsion bar on the main former which I would beef up to 1/8' liteply to cope. I would forget the thinner gauge front supports on the plan, they are not even scale anyway.

I have had to make some changes to the Wilga though.

I tried some more trimming at the Eddie Riding event a few weeks back but I couldn't get enough power out of the .5cc Redfin to haul the model into a decent climb. I tried again at Old Warden last weekend but despite fresh fuel there's not enough power to produce a decent climb out.

I think after the initial burst of power from the freshly run in 030 Redfin, the edge has just gone off the engine and I can't quite squeeze enough out it. The cure is hopefully an easy one - I bought the 049 version from Alex Phin at Old Warden. This really is a big brother to the 030 and the hope is, it will be able to warble away quite nicely to carry the Wilga aloft.

The downside is it's a bit heavier ! what was the wing loading again... oh well let's not worry about that  :-\

I fitted the original engine using metal plates attached to much wider spaced bearers than would be usual. This means a couple of hours work making new plates for the new engine and the 049 is installed.

The engine is a tighter fit in the engine bay but no major surgery was required and even the cowling still fits, though it will need hole in it now to clear the compression screw. I have substituted a hardened steel allen bolt as it gives a cleaner more scale like look than the supplied comp screw.

Pic 1 The Redfin TBR 049 compared to the Redfin TBR MK II 030

pic 2  Engine fitted with 3mm Aluminium plates

Pic 3 and Pic ... it fits !!!

The only 'downside' so far is now have a spare Redfin 030 TBR... Hmmm a reduced size John Watters Albatros CIII perhaps ??....


Title: Re: PZL Wilga for .5cc diesel
Post by: DHnut on July 21, 2019, 04:05:19 PM
The joy of using engine mounting plates. I am sure the extra power will be sufficient and a steeper climb will not be out of place as it is a STOL aeroplane. How much is the weight gain? Surely not too much. Lok forward to seeing it in August.
Ricky 


Title: Re: PZL Wilga for .5cc diesel
Post by: OZPAF on July 21, 2019, 06:37:30 PM
Good luck with the trimming Chris. Hopefully that should do the job.

John


Title: Re: PZL Wilga for .5cc diesel
Post by: 3view on July 22, 2019, 07:07:07 AM
There's no replacement for displacement :)


Title: Re: PZL Wilga for .5cc diesel
Post by: griffin10010 on October 03, 2019, 02:08:19 PM
Chris,
        Well done the Wilga looks very realistic with a good sit in the air. Just a thought, but the real aircraft will usually have a steep approach as all the slots and flaps are deployed with a lot of power on so you are not out of scale in flight terms. Even when clean I doubt if the real one has any sort of glide, probably like the average WW1 aircraft of about 1 in 3. 
Ricky


Title: Re: PZL Wilga for .5cc diesel
Post by: griffin10010 on October 03, 2019, 02:47:53 PM
Hello. Been reading the comments for the Wilga. The plan is mine, P Hayward. Nice to see it is still being made. This was probably my most successful model ever. I had no issues with the slats, trimming or flying. Indeed on one enthusiastic hand launch the port wing swivelled on its mounting wires resulting in anhedral on the port wing, I thought that would be the end but all the Wilga did was fly in right hand circles.no heavy landing at all. I never did any repairs to this model, it never crashed. I flew it do death. On the comment it Flew Like a Brick until the slats were covered
would suggest the flying problem lies elsewhere. I always thought Aeromodellers description, Ideal first scale model a bit ambitious considering
the fuselage construction. I built a free flight Dornier 28, twin Mills .75. if anyone is interested I could dig out some photos and do a write up on it, it only flew once though.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 03, 2019, 03:16:09 PM
Thanks for posting P Hayward, very pleased to hear from the designer of the model

It's a lovely design and a great little model. I really enjoyed building it, though as you say the fuselage construction is not really suitable as a first model. It does fly very well under power but I'm struggling to get any sort of glide out of it as you have read.  Mine is a bit on the portly side though which is not helping - its around 14ozs from memory with not a lot of wing area to hold it up.. I would be very interested if you can remember the weight of your model...a lot less I'm guessing.

Did I read in the AM article that your first one run was over by a van at the Nats !!!

 I would be very interested to learn more about your twin Mills .75 engined Dornier as I'm sure would many members on here, photos would be great.

Chris


Title: Re: PZL Wilga for .5cc diesel
Post by: billdennis747 on October 03, 2019, 03:58:19 PM
I built a free flight Dornier 28, twin Mills .75. if anyone is interested I could dig out some photos and do a write up on it, it only flew once though.

Yes please!


Title: Re: PZL Wilga for .5cc diesel
Post by: griffin10010 on October 04, 2019, 05:45:20 AM
Yes. The first Wilga met its demise being run over by a van at the Nats, attempting its first flight, a R.O.G. smashed to pieces, salvaged the engine though.
The second I built in time for Old Warden. 6 weeks? Aeromodeller were originally to include it as a free plan then decided to do it as an article. I never weighed my planes, didn't have any scales. A guy came round from AM, draughtsman, and took my original plans, drawn on lining paper and these were reproduced for AM. When I did the model I never gave a thought to the slats or lifting tail plane, I just scaled up from the AM article. I can't understand the poor glide mentioned, I don't ever remember repairing the Wilga, I used to tend to throw the models away if they got damaged and the glide was fine. I can't understand the comment, flew like a brick till the slats were covered over. Very unusual looking plane though, very pretty I always thought, I had never seen one made before. Peter.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 04, 2019, 03:56:09 PM
I admired the design in my youth but never got any further than looking at picture in the Aeromodeller Plans Handbook, it's only after returning to the hobby that I decided to actually build one. I was hoping to try it out again at the Selby Trophy this weekend but sadly the weather has put paid to that one.

 There must something I'm doing wrong, I did notice looking back at the original article that the slot gaps on your model look quite tight. Mine however look somewhat larger. Maybe that is having an effect ( see pics )

Are you still active in the hobby Peter ?


Title: Re: PZL Wilga for .5cc diesel
Post by: griffin10010 on October 05, 2019, 09:04:24 AM
Hello. I see what you mean regarding the flap gaps, you might only be getting lift from the main wing, considerable difference in wing area, plus the gap may be interfering with the airflow and producing drag. Might be worth closing the gap and trying. It might also explain the apparent lack of engine power as well. Not sure if you are aware, there is a photo of me on the net holding the plane in plan view and there is definately no gap
along with a more comprehensive write up on trimming along with the comment that some models, scale and otherwise simply refused to fly!
I think the photo would have been Old Warden 1970.
The sink rate of your very pretty Wilga on the glide is alarming, there is very little suggestion of a glide at all, this was not my experience
so something is amiss. I am 75 now and no longer building models, we came to Spain 12 years ago, bought about a dozen R.C. models and gear with me thinking I would fly regularly, great weather, only to find the local flying sites had been lost, not that much difference to the U.K. f you haven't seen the photo let me know and I will tell you how to find it. Peter.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 05, 2019, 12:52:49 PM
Quote
Not sure if you are aware, there is a photo of me on the net holding the plane in plan view and there is definately no gap
along with a more comprehensive write up on trimming along with the comment that some models, scale and otherwise simply refused to fly!
I think the photo would have been Old Warden 1970.

 Thanks for that Peter. I did google search with various permutations but I can't find the picture. I think you may be onto something with the slot gaps though,I will have a look at that.

I look forward to hearing about your Dornier 28 if you get a chance

Chris



Title: Re: PZL Wilga for .5cc diesel
Post by: marcin_pl on October 05, 2019, 01:08:43 PM
Check if an exit slot of the slots is smaller (thinner) than the entrance one. If it's opposite slots will produce a lot of turbulence and drag.
Living in Poland I'm quite familiar with Wilgas (I flew her mamy times). In real it is not a glider at all. The sink rate of any Wilga is high because she was designed for a tow plane, so fast descent enables quick return to the airfield for another glider.


Title: Re: PZL Wilga for .5cc diesel
Post by: griffin10010 on October 06, 2019, 07:46:14 AM
Hello Chris. After reading the Wilga pilots notes it would appear the problem does indeed  lie with the flaps. Ref the photo I mentioned. Google, scroll down to
OZ: PZL wilga 35 plan-free download-outerzone that should bring you to the page with the photo, there are a couple of downloads which will show the full write up.
Any problem come back to me. Ref the Dornier, not sure if I have any photo's left, my wife goes to the UK Wednesday, I will look and see if I have any. What was
interesting with the Dornier was we actually got to fly in the full size! Peter.


Title: Re: PZL Wilga for .5cc diesel
Post by: Squirrelnet on October 07, 2019, 04:31:35 PM
Thanks Peter I have that now.

 I Hope you have some luck with Dornier pics. Was flying in the fullsize related to building the model or did the ride inspire the build ?

Quote
Check if an exit slot of the slots is smaller (thinner) than the entrance one.

Marcin that is the opposite to what I would have expected I will check that out too

Chris