Hip Pocket Builders' Forum

Outdoor Free Flight Forum => Power => Topic started by: glidermaster on November 12, 2009, 03:52:04 PM



Title: New Model - for OS15FP
Post by: glidermaster on November 12, 2009, 03:52:04 PM
I am about to get cracking on a new model - not that I need one, but.....................

Anyway, I was contemplating high thrust line (HTL) a while back - but I've abandoned that idea, and instead I will build a Mk.2 of my 'Semislo' design - you can check out Mk.1 on page 2 of the 'Power Models' thread. Mk.1 has proven quite a good model.

I have made a series of small tweaks to the design;
1) - I have pushed the span up a little.
2) - I have made the tail a little bit bigger (as a percentage of wing area).
3) - I am intrigued by Brian Eggleston's airfoil work on bunting F1A gliders, so I have tweaked the leading edge profile of the airfoil to make it slightly more symmetrical in character
4) - Something I've been thinking about for a while, I'm going to build the wing 'All Washed Out'.

On that last point, the right tip will have 2mm washout, the left 5mm. The right inner will have 1.5mm washout from root to tip break, and the left inner 4mm (I am reviewing these numbers still - before starting to stick stuff together).

A little look at the plan.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 12, 2009, 03:56:12 PM
Apologies for the ropey picture - I'll try a different file format.

The plan shows a hard tank, but I'm thinking seriously about a bladder tank for this one. It will have pressure, so I guess I won't be flying it in Slow Open if I make any trips to the UK in the future.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 12, 2009, 08:23:59 PM
Ok this is embarrassing, I've done this many times in the past - one more try for a decent picture.


Title: Re: New Model - for OS15FP
Post by: gossie on November 12, 2009, 08:41:43 PM
We get the idea. :)
Looking forward to seeing the build.


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 06, 2010, 01:54:37 AM
I've done very little building this year for various reasons, but I have made a bit of progress with this model - namely the wing and tail.

Both surfaces are 'D box' structures, that is to say they have sheet balsa from the leading edge back to the main spars, top and bottom, and the top and bottom flanges of the main spar are joined with vertical grain balsa webs forming a very stiff closed cell in the front of the wing.

I selected some nice 1/16" sheet for the D box, which is a little thick for a modest size model such as this, and I sanded it thinner it in a simple jig. This consists of a 4 ft. long off-cut of 1/2" ply sanded nice and smooth, to which were epoxied 2 long rails 5" apart of 0.045" aluminium sheet picked from the scrap bin at work. The sheet balsa is held between the rails and sanded with a long block flipping over from time to time, until contact is made with the aluminium. It is a simple process, but actually takes quite a long time, and produces much mess.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 06, 2010, 09:27:57 AM
I tried something new to me on this wing; I built it 'tip-to-tip' meaning I built one wing tip, then jigged it to the right dihedral angle, and built the inner panel right onto it, then the other inner panel, then the last tip. I usually build the whole thing flat, then put in the dihedral (polyhedral). The 'tip-to-tip' system works well, I like it!

I built onto the lower D box sheeting, with no warps built in, then added the webs into the spars. I set the required warps when I added the top sheeting, and formed the close cell at the front of the wing.

One more little detail - there are no spar flanges in the tips, other than little tapered stubs at the tip joint. In other words the tips are just the sheeting and the webs.


Title: Re: New Model - for OS15FP
Post by: RobinB on October 07, 2010, 08:18:49 AM
Very timely for me that you've put this up, John.

I'm about to start on a 430 sq.in. Semislo-inspired wing, so I'll be following this with interest.

First question (probably the first of many!): What weight / grain is your D box sheeting?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 07, 2010, 11:30:19 AM
I typically use A or B grain for sheet surfaces, and I think the wood I used on this model is about 5lb/cu.ft.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 11, 2010, 08:33:46 PM
The wing and tail are done ready to cover.

The tail is almost the same construction as the wing - 1/32" sheet for the D box.

A good meaty centre dihedral brace in the wing from hard balsa. Typical 'Buskell' construction!

John


Title: Re: New Model - for OS15FP
Post by: RobinB on October 12, 2010, 05:57:12 AM
Nice-looking wing, John.
Did you web between the sheeting on the tips?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 12, 2010, 11:26:12 AM
Yes, Robin.
The tips only have stub spars extending 2 ribs bays from the tip joint. The rest of the tip is just sheeting and webs, which maintains the closed (torsion) cell philosophy.

Started covering last night - heavyweight modelspan for the wings, lightweight for the tail. Similar to the Trad Lad Vintage FAI model, I 'doped' the wood frames with water based acrylic sanding sealer (2 coats - rubbed down) and put the tissue on dry with glue stick on the open structure areas, and will allow it to sit a least 24 hrs before water spraying. The tissue over the sheeting is 'doped' on with more sanding sealer.

I actually only use real dope to seal/shrink the tissue on the open structure areas.

Note that I think this method inferior to the 'all dope' method, but the exposure to dope fumes (which I really don't like) is very much reduced. The Trad Lad wing has much more undercamber than this model, and the glue stick attached tissue held fast on the undercambered surface when water shrunk and properly doped.
John


Title: Re: New Model - for OS15FP
Post by: Scottl0413 on November 04, 2010, 09:32:46 AM
John, how's the build coming along on your new plane? Inquiring minds want to know!!

Scott


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 04, 2010, 10:56:43 AM
Kind of slow, Scott (but thanks for asking!).

I have made some progress covering the wing and tail, but it's been very busy at work, so modelling time has been at something of a premium for the last few weeks.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 01, 2011, 05:32:44 PM
Not much modeling time for me this Winter, and not much going on in the Power Models section here, either.

However, I have done a little work on the fuselage and the necessary hardware for this model.

The fuselage is a simple box of 1/8" sides and 3/16" top and bottom with 1/8" triangular longerons. Plenty of section thickness to allow shaping to a pleasing final cross section.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 01, 2011, 05:33:57 PM
The tank is sheet brass. Crankcase pressure and flood off for this one.


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 01, 2011, 05:37:45 PM
I have had my first crack at making a scroll type timer.

The clockwork movement is an old Autoknips vane regulated type, and I made the scroll and disk on the lathe. Compared to Seeligs etc the scroll is a bit large and crude, but screw thread turning is a new experience for me, and my lathe is so old that changing the settings is a fairly major undertaking involving removing/replacing several gear wheels.


Title: Re: New Model - for OS15FP
Post by: sgblake on March 04, 2011, 06:04:18 PM
Those OS FP motors make excellent freeflight engines! They are lightweight, cheap and powerful. I have been flying an OS FP .25 on the front of a Star Seeker from Flying Models for several years and have done very well with it -- I won AB Classic over some really good fliers and really hot airplanes at the Empire State Champs in 2009; I placed second this year. I have an OS FP .40 in my Class C classic model, which is a modified version of Bob Stalick's Hot Lumber design. However, it's too much power for the 600 sq. inch model, so I am downgrading to an FP .35 which bolts right in. The FP .40 is going to go into either a Pilfered Pearl 710 or a Satellite 780.

Nice design John!

Thermals, Simon


Title: Re: New Model - for OS15FP
Post by: I hate trees on March 15, 2011, 12:44:16 PM
Hi John,
I'm thinking of building a SLOP model with an OS15 fp, your model is most interesting. The aspect ratio looks very high for a lock down power model (approx 8.75 just from measuring my computer screen). Presumably the model will still transition ok etc?  What actual wing area is the model? I can't see too many obvious dims on the plan. Presumably the weight will come out around 15 oz? maybe a bit lighter? The stab looks a bit smaller than some models as well. Looks nice though, certainly prettier than, say, Dave Clarkson's layout ;)


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 15, 2011, 03:34:16 PM
Hi Adam,
There's always an element of doubt in a new design, I guess.............. but I just love designing models.

This model is a little bigger than a Mk.1 version I built in '02 and which is pictured on pg.2 of the 'Power Models' thread. Mk.1 flies well, and transition is usually good. I guess we'll see if it can handle a bit more aspect ratio.

This one (mk.2) is only 15 sq.ins bigger in the wing (375) and another 8 or so in the tail (now 100 sq ins). I will be a bit disappointed if the weight comes out over 14 oz. - i.e. I think it will be a little lighter than the mk.1.

I think the OS15FP is a great engine - perfect for SLOP.

John


Title: Re: New Model - for OS15FP
Post by: RobinB on March 16, 2011, 07:12:38 AM
John, I'm impressed that you're aiming for 14 oz. - that metal motor mount must be lighter than it looks!

I'm guessing you have to fit the tank in before you fit that mount to the fus? Neat looking setup, though.

I'm looking forward to the rest of the timer work, as I have some Monks timers that I've yet to make up the arm assemblies for
and I'd like to see how you do yours.

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 25, 2011, 01:51:28 PM
Timer Arms
10 thou brass sheet
39 thou music wire and brass tube to fit.

The pics pretty much show the rest - the hinge flap and brass tube are soldered together. The timer face plate is 25 thou 7075-T6 alu. As you can see, I screw the hinges to the faceplate with 10BA screws. When it's all fitted I scuff up the face plate surface, clean it and glue the hinges on with epoxy, just cinching down with the screws. When it's dry, dress off the screws flush with the underneath of the faceplate, then centre punch the screw end for a little 'rivet' effect. I haven't had one come off yet, but they can be 'recycled' if need be, without too much bother.

John


Title: Re: New Model - for OS15FP
Post by: RobinB on March 26, 2011, 04:31:30 AM
Aaaaaahhh..... bend the wires to line up with the disc AFTERWARDS!

I've done it the other way around before, and it got really tricky trying to fix the arm to the faceplate in absolutely exactly the right position.

(It usually resulted in some slight re-bending / adjustment, so I might as well have left the bending until afterwards anyway!)

Thanks, John

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 26, 2011, 01:10:35 PM
Finished timer pic attached.

When I eventually get this model into the air I'll be using instant DT, so both arms will be coming out of the disc window. Later a little bending of the DT arm will allow it to engage the scroll.

You've got it Robin, leave the arm overlength until later. Actually I need to replace the DT arm, it's not quite long enough!

On/Off is internal - and not made yet.

John


Title: Re: New Model - for OS15FP
Post by: gossie on March 26, 2011, 06:22:14 PM
Good stuff JB. :)


Title: Re: New Model - for OS15FP
Post by: applehoney on March 27, 2011, 12:24:45 AM
Quote
I'll be using instant DT,

Hopefully a couple of seconds delay? I just hate to see wings break off as the engine quits ..... :'(


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 27, 2011, 12:36:15 AM
Jim is correct, of course. :-\


Title: Re: New Model - for OS15FP
Post by: gossie on March 27, 2011, 05:05:06 AM
Jim is correct, of course. :-\

Is he ever wrong? And I mean that in the nicest way. :)


Title: Re: New Model - for OS15FP
Post by: Sandgroper on November 24, 2011, 07:46:39 AM
Has anyone tried attaching a pacifier/bladder to a hard tank to give it pressure?,it could be an easy way to make the SLOP model a better dual purpose model for open power etc.The 15LA is also a very good SLOP engine,it is lighter than the 15FP and performance is similar.Mine pulls 19,000+ on a 7x4 APC with 5% nitro fuel fitted with a homemade turbo plug head and pulls the Dixielander up very nicely.Fitting a OS LC3 long reach plug instead of the A3 gained about 1000rpm on the STD 15LA.Replacing the std 0.2mm head shim with a 0.1mm shim will give a little more rpm if like me you like low nitro fuel.


Title: Re: New Model - for OS15FP
Post by: RobinB on August 25, 2012, 04:19:55 AM
John,
As a follow-on from the dialogue about timers:- I was making an extra arm for an existing timer recently,
and found that to get the same stiffness as the existing arms I needed rather thicker wire.
(I have shop-bought piano wire).
Do you (or anyone) know what wire is used in Texas and similar timers?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on August 26, 2012, 11:41:08 AM
It's a good point Robin, 'Real' piano wire is the answer, I think, though bumping the wire up a gauge is OK most of the time.
I replaced the arms on my Seeligs for F1C (as I used permanently attached lines) and found the same thing.

McMaster-Carr is a useful source this side of the pond, at least, for many things that come under the heading of Hardware.
John


Title: Re: New Model - for OS15FP
Post by: Sandgroper on August 27, 2012, 09:58:29 AM
Hi Robin,
would that be the Texas 3F you are modifying/fixing,I have a 3F 111 in the T34,their site says the DT wire has already been beefed up from earlier models,mine are 48 thou.I have found the set of the tip in the scroll can be quite critical.If the arm is too long it tends to grab and stop the timer in the lower grooves,I opened and closed bends gently with two pairs of pliers until the tip of the wire was 1/32 closer to the pivot and this improved things,also the tip should sit inline with the scrolls inner bore when resting on top or it may jump out-any more inward may slow down the timer.The mainshaft in mine has a lot of clearance in the top bush and the rock has to be taken into account when setting the arm.
The 3F 111 is a fast running version and the tip has to cover a large contact point change in 3 mins so I feel the 3F 1 is a better choice as it will use less turns for three minutes.I find long scrolls a pain so I machined mine down to 8.2mm which gives me just over 3 mins with the arm in the bottom groove and use the second function for early DT.


Cheers Phil


Title: Re: New Model - for OS15FP
Post by: glidermaster on December 28, 2012, 07:46:19 PM
November '09 I started this thread - good grief, still no 'new' model. :-[

I have to admit to being stuck at the front of the fuselage, and every time I got the thing out on the bench to work on it, the engine mount nagged at me as being all wrong.
Finally I bought an OS metal 'T' mount, and what a nice product.
So, out with the razor saw, some balsa, ply and epoxy, and this project is back on the right track, even if the schedule has gone out of the window.

Some other slight revisions are being contemplated, but I should be able to get this one done at long last!

John


Title: Re: New Model - for OS15FP
Post by: RobinB on December 29, 2012, 02:57:51 PM
You mean like this?
I have to join you in the confessional, John, as this pic is from a year ago.
The wing and stab are done, and the front end has been glassed since then but I'm stuck
(as usual) at the timer mounting stage.

Solzhenitzyn said "Two things rob people of their peace of mind: work unfinished
and work not yet begun".

He got that right  :-\

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on December 31, 2012, 03:27:30 PM
That's about it, Robin.
Here's my current status; tank in, pylon advancing, timer area almost ready for timer.
Quite a bit of progress.

Wearing my Dixielander T shirt today, in memory of old George.
John


Title: Re: New Model - for OS15FP
Post by: glidermaster on January 15, 2013, 10:59:46 AM
Some changes to the initial plan, and some progress.
I have been flying a number of all-locked-down models for several years, and on our small field there are some problems; in particular, glide circle.
My models at least, can wander a bit on glide, and as soon as they do, they're off the field, so I'm changing this model to have auto rudder and VIT.

I have built an internally sprung fin/rudder - weighs about 8gms as shown, which is a bit on the high side.
Anyway, that's a first for me, all my other models have external springs to the rudders - aka elastic bands!



Title: Re: New Model - for OS15FP
Post by: John on January 17, 2013, 10:18:32 AM
Hi John,

Where did you get your OS metal mount from as I was thinking this would be good for the two Cresendos that I still have yet to finish but other things got in the way.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on January 17, 2013, 11:21:17 AM
John,
Check out eBay - item no. 290490942679
That is what I bought, and where I bought it.

John


Title: Re: New Model - for OS15FP
Post by: FF Bruce on January 17, 2013, 09:20:14 PM
John,
   That does seem a little heavy for an auto rudder,8 gr. way back there.I don't think the ones I use weigh more than 2gr. if that.What do you think is making it weigh that much?Is that a brass hinge? 


Title: Re: New Model - for OS15FP
Post by: glidermaster on January 18, 2013, 12:54:39 AM
It's a brass tube hinge, Bruce.
The 8 grams is the whole fin, of course - and it's solid sheet - which might need to be revisited.........


Title: Re: New Model - for OS15FP
Post by: FF Bruce on January 18, 2013, 11:35:49 PM
So sorry John,I must read things more carefully.I thought you talking about just your auto rudder.My bad :-\


Title: Re: New Model - for OS15FP
Post by: glidermaster on February 01, 2013, 12:19:09 AM
No problem Bruce, I kind of guessed!

More progress - the fuselage is all closed up, and I'll be putting finish on it next.
The pics were taken on an antique tip-top table I've been restoring, and with which I am quite pleased. I just need to turn up 2 brass hinge pins, and it's done - the table that is.

John


Title: Re: New Model - for OS15FP
Post by: RobinB on February 01, 2013, 01:12:29 PM
Is the hole nearest the front for a bladder, John?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on February 01, 2013, 01:46:52 PM
No, it has a hard tank/crankcase pressure Robin.
The hole is the exit point for both feed and pressure. The tank can be removed fairly quickly by cutting the bottom of the fuselage.

It sort of indicates I don't have much faith in my soldering, perhaps!

I am liking the look of this model again, and I am contemplating scaling it up for an old OS25 FSR of my Dads, but maybe I should fly this one first.


Title: Re: New Model - for OS15FP
Post by: gossie on February 01, 2013, 03:37:02 PM
I like the  fuselage shape JB, and also of course hard tank on crankcase pressure..........in fact I'm only a few weeks behind you on a 40 ship.........wings first, and a pic next week.


Title: Re: New Model - for OS15FP
Post by: glidermaster on February 07, 2013, 11:01:58 AM
We achieved a bit of a landmark last night - the first time the model has been together.

255 grams as shown (no engine, no timer).
John


Title: Re: New Model - for OS15FP
Post by: Scottl0413 on February 07, 2013, 11:10:30 AM
John, love the lines of your plane. Can't wait to hear from you on your flying sessions. On another note I built a 585 Galaxie with an OS 25 FSR with a 9 x 3 APC prop and it was pretty darn fast! I ran it without a venturi, on bladder pressure, and 35% nitro!!!

Scott


Title: Re: New Model - for OS15FP
Post by: gossie on February 07, 2013, 03:50:54 PM
Niceeeeeee JB. :)


Title: Re: New Model - for OS15FP
Post by: RobinB on February 07, 2013, 04:58:28 PM
Looking good, John.

That's a good weight bearing in mind that motor mount must have added some.

Will you have the CG further forward now that you've fitted V.I.T?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on February 19, 2013, 12:18:53 AM
The original model has quite a chunk of lead under the tail (see pic.) to get the CG back to about the front of the trailing edge, and it still needs to go further. Simple answer is yes, I'll be looking to get it forward to about 70 to 75% back from the leading edge.

First coat of paint just went on the fuselage - not much point taking a picture of that, though!
John


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 20, 2013, 02:29:01 PM
I think I'm going to call this one a done deal now. The next reports will be from the crash-site - er - I mean flying field. :D
Just an address label, some fuel proofer, and some lines to the timer to go.

Weight has crept up to 15.75 oz. (450 grams) which is more than I wanted, and CG is a concern at 78% back (root chord). Depending on flight tests, I might size it up for one of my G.15s - that should make it a bit more exciting!

John


Title: Re: New Model - for OS15FP
Post by: PeeTee on March 20, 2013, 02:47:52 PM
Nice looking model John! How soon will you be able to get out and fly it? The weather here is still awful and I have models queueing up for trimming :(

Peter


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 20, 2013, 05:47:15 PM
Ditto Peter, I never thought I'd live anywhere where it rained more than Bristol (UK), but lo and behold I do.
Absolutely thrashing down, it is................... :(

I have a few models ready or near ready, and a couple of long term repairs that are coming up to being flyable.

I just finished a 20gram open rubber model that I'm fairly pleased with, I should post a picture of that, too.


Title: Re: New Model - for OS15FP
Post by: gossie on March 20, 2013, 07:09:54 PM
Agree, looks great John.
   We have had lots of rain here also.    It rained EVERYDAY from the 15th February until last weekend when we had a sunny one for a change, whilst we were away for a short break south of here.
  Rained again yesterday though, and it's a dark looking morning here.

I took a couple of pics of my beast underway........still a lot to go though.



Title: Re: New Model - for OS15FP
Post by: gossie on March 23, 2013, 12:24:49 AM
"glidermaster", where would you like the CG to end up on your power model?

Mines tail heavy at the moment before covering the stab etc. up the back.
  About 75% at the moment with that lump of a 40 rubber banded to the bearers.........I think I might need to re-hash the pylon to get the wing back a bit......I'd like my CG to be 50 to 60% as the other things I have with a 25 to 30% tail and VIT.
If I had had the brain power to have the wooden bearers longer things might have been okay, but I thought that motor was just sooooooo heavy it should balance about right.    Boo hiss.


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 23, 2013, 01:22:08 AM
Hi Howard,
My model has a 25% tail area, and I would have liked the CG to be ahead of 70% - I guess I got a bit carried away with the paint brush!
I guess I'll be making up a spacer or something to put between the mount and the front bulkhead.

Or, as I speculated, bolt another 20% of engine weight (and power) on the front.


Title: Re: New Model - for OS15FP
Post by: gossie on March 23, 2013, 07:09:23 AM
At 70% your better than me.    I could add weight on the nose, but don't want to do that.

I'm going to re-hash the pylon.   I did some navel gazing this afternoon and will add about 3 or 4 cm to the rear then extend the wing mount back......not hard to do......will then cut the front of the pylon at where the front of the wing is on more of an angle to the bottom front of the pylon.  It should look very streamlined and fast.

Will also set the stab. back as far it will go close to the VIT/DT arm.


Title: Re: New Model - for OS15FP
Post by: glidermaster on April 17, 2013, 12:07:42 AM
Sister ships, waiting for a spell of good weather.
Good enough today to get the lawn cut, but not good enough for flying.


Title: Re: New Model - for OS15FP
Post by: gossie on April 17, 2013, 01:31:42 AM
Pretty, and pretty. :)


Title: Re: New Model - for OS15FP
Post by: Scottl0413 on April 17, 2013, 08:47:49 AM
They are beautiful! Can't wait to hear about there flying!

Scott


Title: Re: New Model - for OS15FP
Post by: glidermaster on April 24, 2013, 01:24:38 PM
One stray detail on this build is the subject of fuel proofer.
I have, for a long time, used Ripmax Tuf-Kote, but used the last of my stock on an F1C wing recently.
During the search for an alternate I came across a water based paint WR-LPU - also available in clear and in small quantities, so I bought some.

I mixed a small sample of the clear and put it on a repaired wing tip of a 1/2A - 24hrs later I put some neat 25% nitro on the patch. It performed extremely poorly.

I had previously put some red WR-LPU on something else (not a model), and out of curiosity I put a pool of 25% nitro on that, too. The fuel didn't mark the finish at all - i.e. it performed extremely well, so the front of the new model is WR-LPU red - but I still need something for the doped wing and tail. MECOA sells some (apparently) crystal clear epoxy, so I guess I'll be getting some of that.

John


Title: Re: New Model - for OS15FP
Post by: FF Bruce on April 24, 2013, 09:31:15 PM
John,
   I'm on the same page as you.I'm not happy at all with clear Klass coat but the paint works fine.I'm going to try Fuller Plast.Used it in the 70's with good results only stopped using it because K&B super poxy came out and it worked so great.Friends love the way plast works ,I'll let you know how well it holds up to nitro.   Bruce   


Title: Re: New Model - for OS15FP
Post by: flydean1 on April 24, 2013, 09:52:41 PM
Where does one get Fuller Plast??


Title: Re: New Model - for OS15FP
Post by: FF Bruce on April 25, 2013, 11:33:30 PM
Dean had to make the old brain work but I did find a place I think it's in Florida, van-dee com/clear.htm   is there site.It's not cheep but if you can get a few guy's together and spilt it up it's not so bad.The smallest amount is a Gal. and that is $57 then there is the catalyst mixed at 16 to 1 a pint should do at $13 and if you need to spray it there's the thinner at $29 (some have used acetone).You might also try Aero Dyne they might sell it in smaller amounts. It was designed for guitars and they liked how easy it sanded and then polished out.        Bruce


Title: Re: New Model - for OS15FP
Post by: glidermaster on April 26, 2013, 11:17:57 AM
Does Fuller-Plast stink pretty badly, Bruce?

Ripmax Tuf-Kote does, but it's good fuel proofer, and I am thinking of trying to get my sister to send some over. Package quantities - about 1/2 pint costs $20 or so including catalyst.

Anyway, Tuf-Kote is really (I think) Rustin's Plastic Coating - which is available through Amazon in bigger quantities (I haven't checked shipping yet). It struck me that there were some similarities in the description of Fuller Plast - the smell would give it away, if it's the same stuff!

Another product we used in England was Interlux 2 Part boat paint, and it is very fuel proof - but expensive, and the catalyst didn't keep very well (we stored it in the fridge!) - I just spotted that they do a 2-part clear, available on Amazon for about $65 for a quart. If I hadn't just ordered a finishing epoxy from SystemThree I would probably get that.

Sorry for rambling.................

John

p.s. the VanDee place Bruce found was the only place I found that sells Fuller-Plast.


Title: Re: New Model - for OS15FP
Post by: glidermaster on July 19, 2013, 01:26:29 AM
First flight.


Shucks!


Title: Re: New Model - for OS15FP
Post by: PeeTee on July 19, 2013, 02:30:45 AM
John

Shame about that :( .....................although  Monty Python would say "'tis but a scratch"  ::)

I hope it goes back together easily and you can get it airborne before the summer's out.

Peter


Title: Re: New Model - for OS15FP
Post by: gossie on July 19, 2013, 06:16:40 AM
Nasty, but fixable.    Guess it went hard right after launch????    How long was the motor run???


Title: Re: New Model - for OS15FP
Post by: RobinB on July 23, 2013, 04:29:43 AM
Too much tail incidence on the power setting, John?


Title: Re: New Model - for OS15FP
Post by: glidermaster on July 23, 2013, 10:38:55 AM
Yes Robin, there's an explanation in the 'Went Flyin' thread.

I've replayed the grizzly few seconds in my head, and I can't work out how the right tip got damaged. It went basically straight, and rolled the left wing down.


Title: Re: New Model - for OS15FP
Post by: RobinB on July 24, 2013, 05:01:42 AM
Could be the shockwave - any discontinuity or weak(er) point in its path will give.

Our old clubmate Derek Wain once towed an A/2 in at some speed - it stuck in the ground vertically.
Fus, root and inner panels took the stress but the tips both broke off at their joints.

Robin



Title: Re: New Model - for OS15FP
Post by: glidermaster on September 22, 2013, 10:45:37 PM
The repair shop has made some progress.
Damage was not great - structurally, at least, but the covering suffered pretty badly.
Anyway, nearly there!


Title: Re: New Model - for OS15FP
Post by: martynk on September 24, 2013, 11:17:35 AM
A nice clean structural repair.

It will soon be airborne again, with just a hint of battle scarring.

Nice one

Martyn


Title: Re: New Model - for OS15FP
Post by: gossie on September 24, 2013, 05:52:12 PM
They always fly better after a couple of repairs.


Title: Re: New Model - for OS15FP
Post by: glidermaster on September 24, 2013, 07:48:46 PM
I hope so, Howard, it couldn't have flown much worse than that first flight!


Title: Re: New Model - for OS15FP
Post by: gossie on September 25, 2013, 12:07:58 AM
I hope so, Howard, it couldn't have flown much worse than that first flight!

Yeah I know, it's all a bit scary that first flight as one is never 100% sure just where they will head for.

A few weeks ago now I did get that 40 ship of mine gliding perfectly, nice and flat and floaty going to the right.  I have a good spot not far from here with a slope on it, and when the breeze is running up the slope gently it's ideal to get things gliding.
I had it set up where I thought it would be about correct, but when I pushed it away it went nose down so I kept screwing up the stab. until it looked good on the glide setting.  It has stab. tilt on it plus some right AR, so I felt quite comfortable with it.  No way could I fire any engine up there let alone a 40 with no muffler........I'd be arrested for sure.

I've just been up to a fairly small trimming field not too far away, got the 40 fired up with ear muffs on of course, ran the motor a couple of times and checked it did shut off at about three seconds then DT another couple of seconds later.
Tail was down about 3mm over glide setting with AR neutral.  It all takes to long and ya don't wanna bend it.
  Set it all up, fired it up and pushed it straight up hard, and at least it looked safe.  I made a couple of minor tweaks, did it again and can tell it's going right but I feel the nose is coming down at height, so that's where I'm at.
  Have screwed up the stab. with about 2mm difference between power and glide.  Maybe I'll do it again soon?????  But I think I'll now just take it to our Nats. starting in December to hopefully get it going really properly on a fairly big field.



Title: Re: New Model - for OS15FP
Post by: applehoney on September 25, 2013, 01:05:34 AM
 with ear muffs on of course

Huh, I never used ear muffs with my .40's in the past.....

What's that you say ?

Actually, I did sometimes wear ear prortectors; not so much for the noise but to pretend I could not hear those idiots who asked questions while I was preparing to launch


Title: Re: New Model - for OS15FP
Post by: glidermaster on September 25, 2013, 10:20:04 AM
I started to experience a definite hearing loss about half a dozen years ago, ironically after about 10 years without meaningful power flying.
Prior to that I used a heavy set of ear defenders for several years.

Now I have the set in the picture which work well, and can stay comfortably around my neck after the model has gone on its way. I think they were $10 or so.


Title: Re: New Model - for OS15FP
Post by: Hepcat on September 25, 2013, 10:58:58 AM
Glidermaster, John, I am sorry to see your beautiful aeroplane requiring repairs so early in life.  You mentioned in reply #68 that there was an explanation of what happened in the ‘Let’s go Flying’ thread but for some reason such an explanation never arrived at my computer.  I am interested because your opening post on this thread mentioned that you were trying a new washout arrangement.  Did that have anything to do with the dropping of the left wing that you said occurred before the model ‘stacked’?
Hepcat, John.


Title: Re: New Model - for OS15FP
Post by: glidermaster on September 25, 2013, 01:47:09 PM
Hi John,
This wing has washout on every panel - more on the left than the right.
I compensated for this in set-up, but fat fingered a button on the calculator, because I ended up wwwaaaayyy under elevated.
I also ended up switching tails with the Mk.1 version (this being Mk.2) - but I had already rigged the wing and tail mount, and failed to notice that the ply pads under the leading and trailing edges of the tail were different - the difference was less than I first thought, but still accounted for about 1/32" more positive on the tail.

Test glides looked OK, and I had about 3mm movement in the VIT (at the tail trailing edge), so I thought it would at least be safe.

Mk.1 has a standard washin/washout set up - washed out tips, washed in RH inner panel, flat LH inner.

John


Title: Re: New Model - for OS15FP
Post by: gossie on September 25, 2013, 06:15:09 PM
[quote author=applehoney

Actually, I did sometimes wear ear prortectors; not so much for the noise but to pretend I could not hear those idiots who asked questions while I was preparing to launch


Yep, agree with that one. It's awful.
   Couple of years ago running up a Rossi in a new model getting things right,had this fellow just kept talking regardless of my ear plugs in or not.  Not muffs or defenders that day.
When I'm fueling up these Rossi things of mine I can tell when the tank is full when I can hear the fuel start to come out of the very top vent on the tank that goes into the pressure nipple on the rear of the crankcase......can't see it as it's all hidden away.
He is a nice guy, really, but just kept talking about I have no idea what.   In the end I told him I was now totally deaf and could not hear a thing he was saying as I had the plugs in the ears.......not sure if he stopped or not, but I can vaguely remember him standing there with his hands over his ears when the good old Rossi was turning about 28.

I must admit I rather like talking and bulling on.......Remember our session JB?   But when your right in the middle of it..........GO AWAY PLEASE.
  Winding a rubber model with 100 grams X 16 strands always seems a good time to get talked to as well, particularly when getting close to 1000 turns.  I did have a guy kept counting odd numbers and saying other stupid things a few years ago whilst I was winding for a flyoff flight with about 40 or 50 people around both male and female, I shouted "SHUT THE F--- UP and his name......There was total silence and I went on to win that flyoff.


Title: Re: New Model - for OS15FP
Post by: martynk on September 27, 2013, 04:55:06 AM
Getting a bit off topic now, but I am now VERY deaf. I can hear perfectly upto 500Hz but almost totally deaf beyond that (at 2000Hz, my hearing capability is 1/100000th of what it should be).

I cant blame model aircraft engines, my cause was probably too many rock concerts and too much motorcycling (no earplugs). I still ride bikes (now with plugs) but the damage is done and is irreversible. Consequently, I wear very sophisticated and expensive (approx 6000USD) hearing aids. At the best they have restored some of my hearing but in testing I can only hear about 80% of what people say - far worse in a group environment. They are only AIDS not FIXES

Trust me, if you have any doubt - protect your ears

Martyn


Title: Re: New Model - for OS15FP
Post by: glidermaster on September 27, 2013, 05:03:08 PM
Wise words Martyn - my hearing loss is all high freq. too, but nowhere near as bad as yours - no rock concerts or motorbikes for me, though, it's all model engine related, I'm certain. One of my earliest memories as a child was being at Chobham with a bunch of people test running engines nailed to trees. I seem to remember crying, too!

Back in the UK many years ago a kid, standing about 5 metres away, shouted "Is that going to be noisy, mate?" just as the front of the F1C was heading for the starter. A split second later he got his answer.......
I don't like the noise of F1C - it's gone too far, I think, and we should have done something about it 20 years ago. One can't un-ring a bell though, can one.

OS15FP models are fine, though - to sort of head back to topic!

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 17, 2013, 10:20:05 AM
I got out for some more flying, and flew the repaired OS15FP model yesterday.
I put a 1/16" shim under the leading edge of the wing - and this time it survived!

This is now an easy model to fly.
I think this thread is probably complete!


Title: Re: New Model - for OS15FP
Post by: Badgerbill on October 19, 2013, 04:59:48 PM
I can't resist adding a postscript to this string, involving, as it does, Glidermaser and his use of ear defenders.

It would have been 1980 - maybe 1981 - when I accompanied John and his father to the Poitou contest in France. The Buskell family had booked a gite as a nice change from staying under canvas, and John and I shared a room. Separate beds I hasten to add.

I was more or less unaware at that stage of life that I was prone from time-to-time to snoring, but the extent of the problem became apparent when the alarm went off in the early hours so we could get to the flying field in good time, and I shot out of bed, expecting Glidermaster to have been similarly shocked awake, only to see him blissfully asleep with his ear defenders on...


Title: Re: New Model - for OS15FP
Post by: glidermaster on October 21, 2013, 11:29:30 AM
I had forgotten that, Bill!

I think it was 1987, though - just after the first Poitou World Champs.
Ah yes, those were the days................


Title: Re: New Model - for OS15FP
Post by: RobinB on November 07, 2013, 02:16:20 AM
John, what prop are using with the 15FP?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 07, 2013, 11:46:53 AM
Robin,
I am using a Master 8x4 cut down to 7.5" diameter. It seems to suit the OS15P well - Dave Clarkson recommended them.
To be honest, I haven't experimented much, but the prototype was flown on a APC 8x4 for a while. It seemed a bit too big, though.

I like the props Bruce Hannah and others are using on their OS III 15 models - a Norm Poti 8x3.5 glass prop (I think).

John


Title: Re: New Model - for OS15FP
Post by: adamescu on November 08, 2013, 09:33:55 AM
Robin,
I am using a APC 8x4 in my Lucky Lindy - Os Max 15 FP powered and its works very well /15200 rpm/

https://vimeo.com/63476176

Adam


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 08, 2013, 02:09:55 PM
Thanks Adam, that's a good video.

Watching it a couple of times, I have some observations (this is just opinion, not criticism);

In my opinion, 15200 RPM is a little on the slow side for this engine, and is well below peak power.
After launch the engine slows down, indicating that the propellor is loading up, not unloading. I prefer to select a prop that does the opposite - i.e. there is an increase in engine revs at launch, so that more power is being delivered by the engine to the propellor, not less.

Lucky Lindy is an FAI model from 1960, and most of my flying the last couple of years has been with vintage FAI models from the late 60's. I am flying 2 with Super Tigre G15s, both with the same propellor (self made). On Night Train it is almost an ideal prop, and you can hear it 'bite' on launch, the engine speeds up, and the model accelerates pretty well. I think it could possibly take just a little more pitch.
On Trad Lad, there is no audible pick up, so I think I'm at the limit of what the engine can deliver, and I need to explore my box of propellors a little more, and find one better matched to the airframe/engine combo.

John


Title: Re: New Model - for OS15FP
Post by: adamescu on November 09, 2013, 03:20:27 AM
John, thanks a lot for your opinion-advice.
When I saw your previous reply in this thread about props, I decided to put this video here with all informations, because my LuckyLindy /650Gram/ is a little bit lazy but stable.
Tomorrow I can try Master 8x4 cut down to 7.5" diameter to reach a peak. I have a question regarding the  fuel /the proportion of the consisttence /  what is best for OS15FP and about peak RMP ?
Best regards
Adam



Title: Re: New Model - for OS15FP
Post by: RobinB on November 09, 2013, 06:49:44 AM
I have a couple of good standard FP15s and another with a Nelson plug conversion.
On 25% nitro, the standards give 14,400 on APC 8x4 (0.33) and 17,500 (0.35) on APC 7x4.
The 'Nelsonised' one gives 15,500 (0.38) and 18,000 (0.38) on same props.
The figures in brackets are bhp values from a chart produced by Gordon Cornell some years ago.

OS quote a max. power of .41 bhp @ 17,000 for the 15FP and LA.
I just have the $20 optical cheapo tach that's sold under different brand names - I think OS have better equipment!
Also, their test engine probably wasn't just picked off the production line.

Incidentally, my Max III 15s also pull 18,000 on APC 7x4, albeit with 40% nitro.

So, Adam, your 15,200 sounds quite good, but our tachometers may not agree.

I think John is right, and a 7.5x4 could be worth a try.
However, as your hauling up a 650 gm Lindy perhaps a pitch reduction is the answer.
The problem I've found, though, is that 8x3 props are hard to find.

It's a guess as to how much your engine can pick up after launch - 500? 1000?

I use APC props as a common 'yardstick' for comparing different engines, and I've noticed
that the 8x4 loads the engines more that other makes. I've just started trimming an FP15 aeroplane
using an S-2 Series Master 8x4, and it definitely picks up after I launch.
Next time out, I'll try and remember to tach it.

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 09, 2013, 11:08:49 AM
That's all very good data, Robin.
I can't recall rpm for my OS15FP engines, but they are both standard engines. I use a fuel with approximately 15% Nitro (20% oil) - I say approximately, as I watered down some 25% nitro with straight, and wasn't very careful doing it - I run this in an OS20FP as well.

I have found that they run OK on 5% nitro, but are not happy on straight. Nitromethane is expensive in most areas of the world, and OS being a world brand, I suspect they are optimized for low nitro - say 5-15%.

What weight is your Lucky Lindy, Adam?


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 09, 2013, 11:28:26 AM
A thought occurs, matching props to planes - actually memories.
I produced a 5.5x3 1/2A prop many years ago, in carbon and glass. On my models which at the time were 275 sq ins, 7.5 oz models (Cox TD 051 - UK 1/2A) they were OK, but nothing spectacular. For whatever reason, I gave one to Alan Parker who was flying a 240 sq in 5.5 oz model, and he had spectacular results. Revs were very similar to my engine (21k ish), but he got a pronounced audible acceleration on launch - maybe over a thousand RPM (I'm guessing).
My Dad tried one on his 280 sq in model - weight 8.5 oz - his engines were Kustom Kraft, and turned 22k, but it sagged on launch by 1000 rpm.
My Dad's prop is 5 1/2 x 3 1/8, turning pretty similar rpm to my prop, and he got an engine acceleration on launching his model. That prop was very good on my models, but not very good at all on Alan's lightweight.
I still use this prop.

I don't understand what's happening, though.


Title: Re: New Model - for OS15FP
Post by: RobinB on November 09, 2013, 03:43:38 PM
Something to do with the mass of the prop?
The greater the rotating mass, the more energy is needed to accelerate it.

I'm right on the edge of the area where I know what I'm talking about,
so I'll venture no further  :)

A missing piece of the puzzle: have you any idea what prop Alan used originally?

Robin


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 09, 2013, 05:23:19 PM
No Robin, and it was a while back, of course.
It would have been one of the standard offerings - circa 1990 - possibly APC.

Russel Peers also had some of my props - and didn't like them...........


Title: Re: New Model - for OS15FP
Post by: Gnu on November 09, 2013, 05:25:11 PM
My guess is that any engine that slows after launch is fuel starved. Not a prop issue.


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 09, 2013, 05:51:04 PM
No, sorry Gnu.
We did enough flying with these various props to eliminate that possibility.

John


Title: Re: New Model - for OS15FP
Post by: FF Bruce on November 09, 2013, 06:09:27 PM
John I don't think APC props came out untill 1993 or 94 most used Cox props or a glass verison of it.In FAI,Bartills 7X3.5 prop untill 78 or so then we
made glass Cox copies.


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 09, 2013, 11:02:43 PM
You're probably right Bruce. Maybe Alan was using the black Tornado with white stripes on the blade tip.
It getting to be quite a long time ago now!
I still have some of the props I designed, but recently I made some more of my Dad's prop for one of my old Cox 1/2A models. Dad's prop is quite superior on that model.


Title: Re: New Model - for OS15FP
Post by: adamescu on November 10, 2013, 03:17:44 PM
Ahoj,

I had a flight today with my Lucky Lindy (650 Gram weight - OS15FP)  with APC 8x4 cut down to 7.5" diameter which made power 15350 RPM, but  after the launch the engine still slows down.  I use a fuel with approximately 10% Nitro (20% Castor) - it watered down Cox 25% nitro  with straight 85/15, and I wasn't very careful doing it, just a mix of left overs Cox and FAI fuel.

https://vimeo.com/79035927

Thanks for advice

Adam


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 10, 2013, 07:23:31 PM
Hi Adam, another good video!

In my opinon, on the most recent video, the engine slows down less after launch than previously, and then accelerates back to pre-launch rpm quicker than previously.

On the new video one cannot tell if climb pattern is the same, better or worse, and the engine run is shorter in the 2nd video than the first. It is impossible to judge climb height, of course.

Did you make incidence or rudder adjustments when using the 7.5 inch diameter propellor, Adam?

True comparisons are difficult here. Adam's Lucky Lindy is approx. 200 grams heavier than my first OS15P model, and it's bigger, too. I think Robin is correct, for the larger Lucky Lindy a reduction in pitch might be better than a reduction in diameter and a Master 8x3 prop is available.

If they are hard to get where you are, Adam, maybe I could find some and send them over.

John


Title: Re: New Model - for OS15FP
Post by: Gnu on November 11, 2013, 12:51:16 PM
Why would you think that the propeller is the cause of launch induced engine lag? Are you running a suction fuel system? Try pressure if the rules allow. If not, use a smaller venturi and keep the system compact (all tanks and lines near the engine). Use a remote pinch-off rather than looping a fuel line back to the timer. Fuel has mass and when the model accelerates the mixture will go lean.


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 11, 2013, 11:12:12 PM
Because (in the past) we've used the same aeroplane with different props, and done enough flying to eliminate non-prop factors. Most of these observations were from models with crankcase pressure fuel feed.

That's not to say all the things you've suggested don't have an effect though, Gnu, especially fuel system. For instance, I was flying my vintage FAI Night Train earlier in the year, and had the compression set a little bit low. It ran OK and held a peak setting OK, but when I launched the model, the revs sagged slightly. I changed the shims under the head because the engine was a bit touchy, and required that I hold the glow leads on for several seconds to get it to 'come in'. Getting the compression right liberated a little more RPM, and the engine now picks up a little on launch. This particular engine (G15) is the fastest example of the type that I have ever come across, and it`s running (static - before launch) very close to peak power. I think that I might be able to get a better result with a little bit more prop load (i.e. a slight drop in static rpm). We shall see. I am currently using a 7.25 x 3.125. I have another prop of 7.25 x 3.25, and one of 7.375 x 3.125 to try (these are all Buskell original props).

John



Title: Re: New Model - for OS15FP
Post by: Gnu on November 12, 2013, 07:13:07 PM
Sounds like it might be a cooling issue, ie. excessive cooling. Fully loaded at static and at running temperature, it may be cooling beyond optimum as the load is removed after launch. ?? More compression and or nitro? Hotter plug?


Title: Re: New Model - for OS15FP
Post by: FF Bruce on November 12, 2013, 08:48:18 PM
Gnu,
  I've heared the RPM loss that John is talking about.And for the most part it's the prop and the way the motor is set up.Not that your idea's aren't valid they are but I think we are talking about a dia. pitch thing here.On the motors that I remember were timed to turn fast but the prop had a little to much pitch or dia. so untill the motor could get to the desired RPM's there was a lag untill the air speed could let the prop unload and then let the motor run as set up.That's my guess anyway.


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 13, 2013, 12:18:27 AM
Is what I've described contrary to your experience, Gnu?

I'm quite prepared to accept that there may be shortcomings in my engine set up, but some of my related experiences where with my Dad, and he knew all there is to know about getting the best from engines.

He knew a bit about props, too.


Title: Re: New Model - for OS15FP
Post by: Gnu on November 13, 2013, 12:57:37 AM
I dunno. A lag I could understand, but a sag? Maybe just lag and doppler make it sound like the engine is sagging. I'm out of ideas. I used to de-pitch the tips of my props and the engine would wind up all the way up.


Title: Re: New Model - for OS15FP
Post by: adamescu on November 13, 2013, 04:53:11 AM
Thanks a lot Gent's

Jonh, I didn't do any rudder adjustment, not yet, but I will put a little bit left trim on rudder and maybe more wash in ?
Gnu, I am using a suction fuel system with remote pinch-off so I put a "pipe knee" on tank to get more pressure inside.
Well, finally, I´ve found and bought two props Master 8x3, and 10% more Nitro into the fuel, so will see this Saturday on the last event of this year.

Best regards

Adam


Title: Re: New Model - for OS15FP
Post by: Gnu on November 13, 2013, 03:22:31 PM
Let us know the result of the changes.


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 13, 2013, 04:08:58 PM
Yes, Adam, let us know how it goes.
Just be aware that, depending on the temperature at your event, higher nitro can make starting difficult.

However, that advice applies more if hand starting!

John


Title: Re: New Model - for OS15FP
Post by: adamescu on November 17, 2013, 06:24:12 AM
Ahoj,
thanks to all, I can say that Master 8x3 is the best choice that I can get, with 17500 RPM Lucky Lindy accelerate much better much than with APC 8x4
https://vimeo.com/79565663
and some more video from our event shoot by my junior
https://vimeo.com/79565868 - The Lucky Lindy powered by OS 15 LA - by J.Jirasky - also tried Master 8x3 and climb was much better ...
https://vimeo.com/79565869 - The Top Banana by C.Patek - MP JET .061 Diesel
and one powered by Rapier
https://vimeo.com/79566332

;)

Adam


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 17, 2013, 10:55:06 AM
That is great adam, junior is pretty good with that camera!


Title: Re: New Model - for OS15FP
Post by: martynk on November 18, 2013, 05:28:19 AM
That Lucky Lindy is very nice. What period model is it?

Martyn


Title: Re: New Model - for OS15FP
Post by: adamescu on November 18, 2013, 06:42:48 AM
Thanks Martyn,

The Lucky Lindy - Larry Conover was a winner of F.A.I. Power Championships in 1960 - after 12th Flyoffs

http://aeromodelismovolarlibremente.blogspot.co.uk/2009/06/lucky-lindy-de-larry-conover-usa-1957.html

Here are some more pictures of my ship

https://picasaweb.google.com/adam.jenik/GEODIZZY#

Ahoj

Adam


Title: Re: New Model - for OS15FP
Post by: martynk on November 18, 2013, 08:47:15 AM
Thanks Adam

That means that it would qualify for classic power in the UK. Interesting design with those triple fins as well.

Martyn


Title: Re: New Model - for OS15FP
Post by: adamescu on November 23, 2013, 08:07:41 AM
Hello all,
Ive just found a very interesting prop on the APC web for free flight, for example 7.625x3.25 // 7.8x4
//  8x3.75W and etc., maybe good one for OS 15FP ?
Do you have any experiences with this prop ? material ?  it is twice as expansive in this special category as a standard prop for example 8x4 .
Thanks a lot
Best regards
Adam


Title: Re: New Model - for OS15FP
Post by: Scottl0413 on November 24, 2013, 07:24:14 AM
Adam, the 7.8 x 4 apc is the prop of choice hear in the states for high performance .21 engines, i.e. Rossi's, K&B 3.25's and 3.5's, super tigre Series X .21's etc. APC's 8x4 tends to come apart on rpm's over 20K!!

Scott


Title: Re: New Model - for OS15FP
Post by: glidermaster on November 24, 2013, 11:33:47 PM
I've never seen them, but I think 7.625 x 3.25 sounds about right for an OS15FP.
Of course, the airframe makes a difference too, but it would be worth trying, I think.

John


Title: Re: New Model - for OS15FP
Post by: glidermaster on August 02, 2016, 01:42:22 PM
This thread has been silent for a while now, but when I moved house last year the wing of the OS 15 model got damaged when I dropped another box of models on it.
Anyway, I recently turned this little pile of balsa and spruce into a new wing. A bit of tissue, and I'll be ready to go again.

JB


Title: Re: New Model - for OS15FP
Post by: gossie on August 02, 2016, 05:51:14 PM
Sweet JB.   And no black balsa in the mix.   How unusual, but oh how nice.


Title: Re: New Model - for OS15FP
Post by: glidermaster on March 02, 2017, 11:10:39 PM
Back from my first trip to Fab. Feb. at Lost Hills.
I picked up a 2nd in Vintage FAI, but it didn't go so well with this model.

Still in the trimming stages, this is what happens when the timer doesn't work...........
........ inevitable really, when you don't start it.
Luckily the ground was soft, or it could have been badly damaged.......


Title: Re: New Model - for OS15FP
Post by: gossie on March 03, 2017, 03:03:04 AM
Oh dear me, but man made, man can fix it.

You have answered my question elsewhere....."How did Night Train go?"  Well done.