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Indoor Free Flight Forum => CO2 Power, Indoor => Topic started by: danmellor on May 07, 2016, 02:24:41 PM



Title: 1/16th Bristol Bulldog
Post by: danmellor on May 07, 2016, 02:24:41 PM
OK, after years of indecision, I've finally decided to take the leap into the BMFA Open Classes for next year's Indoor Nats. I will say now that this will be a long drawn out build thread! At the moment, I'm still putting documentation together for this, but if I post it now, it stops me chickening out!

I will be using Dave Causer's plan as a basis, scaled up to 1/16th. This works out at 25 3/8" span, which gives me a fighting chance of a reasonable wing loading. The bulldog has a decent wing area, sensibly sized tail surfaces and plenty of dihedral. The only nasty bits are the bi-convex section and the fully exposed radial. I'm going to flatten the wing section out, as I'd rather have a slower flight speed than a few static marks, but there is no getting round that radial.

I've got to do a few other bits and pieces before starting this, but I'm committed now...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: daveh on May 07, 2016, 03:32:26 PM
The good thing about indecision is that it saves you from making decisions.......

However, well done Dan - a great choice of prototype. A build I shall watch with much interest.

Dave


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on May 07, 2016, 03:45:48 PM
Like I said; this will take a while! At the moment, I have the Causer plan, the '59 AM with article and 3 view, the Scale Models with same 3 view but a couple more pics and some more stuff on the way from eBay! This will be GM300 powered. I think CO2 is at a disadvantage compared to the electric stuff that can sit on the floor and start up by themselves, but this is something I WANT to build.

Thanks for the interest,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: FreeFlightModeller on May 07, 2016, 05:06:22 PM
Look forward to it Dan  :)

Started drawing one up myself at one point ... can imagine Dave Causer's plan is a good one tthough.
Must take a look.


Title: Re: 1/16th Bristol Bulldog
Post by: SP250 on May 08, 2016, 04:25:32 AM
Dan

Couple of things which might make it easier for you because you have picked a really complicated aircraft with all its external details.
There were a few aircraft which had full cowlings so the exposed engine then only needs the cylinders doing and not the heads, valvegear and fairings.
There was a high altitude version with an extended wingspan.
Alf Granger did a superb Data Plan dated 1973 with many drawings and B&W photographs ISBN 0 903456 02 X

John


Title: Re: 1/16th Bristol Bulldog
Post by: Bryanair on May 08, 2016, 05:14:32 AM
I have the Alf Granger Data Plan book if you want to make me an offer for it Dan.

Bryan


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on May 08, 2016, 06:27:26 AM
Currently watching on eBay!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on May 12, 2016, 05:49:32 PM
I think I now have most of the documentation required. Half of me thinks "Great!" The other half thinks "What am I doing??!!" I could happily build Kit Scale models forever and there is no shame in that, but I want to have a try at a "Serious" scale model; if a toy aeroplane can ever be classed as serious! Some of the builds on here, and Mike Stuart's excellent ffscale site, are just awe inspiring and I wish I could approach that kind of level. You don't know until you try, as the phrase has it!

The plan will be enlarged to my intended size this weekend, so I can at least start making laminated outlines etc. whilst I finish the stuff on the board at the moment. The original plan just has ribs sliced from sheet, but I think I'm going to crib the Czech method and make a mould to the shape of the section then laminate two pieces of sheet before slicing the ribs off. That gives a much better grain direction in the finished rib.

Jumping the gun a bit, I would have liked to have done black anti-glare panels, as per the Profile drawings, but every other source says they are green... Damn!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: DHnut on May 12, 2016, 06:41:29 PM
Dan,
       This sounds a great if complicated build. I have a copy of the Granger monograph as well. I will follow with interest. I use the laminated rib method for the same reasons on hangar rat an peanut models. My experience with sliced ribs was one of frustration as they were somewhat fragile. I think you will find the anti glare panels were a very dark green almost black! Like the German black green of WW2.
Ricky


Title: Re: 1/16th Bristol Bulldog
Post by: FreeFlightModeller on May 12, 2016, 06:53:17 PM
Dan, did you see Robert Pajas' Bulldog at the 2010 Nats? ... it's on Mike's site if you didn't.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on May 13, 2016, 04:22:15 AM
I remember it, Russ! 9 cylinder Gasparin!!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on May 19, 2016, 07:47:24 PM
Some more bits of documentation turned up in the post this week. Sadly, none of them seem to agree with each other! Mostly just minor stuff, like colour, but one has a wingspan difference of 2 inches. Ah well, I will build to the consensus and tactfully not include the other stuff! I may be completely out of my depth, but I'm really looking forward to doing this...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 16, 2016, 07:50:27 PM
I've made a start! I've only got as far as laminating the tail surface outlines, but every little helps... Dave Causer's original plan has the forward fuselage covered with aluminium foil. I assume this is kitchen type stuff. Anyone done this? I would imagine a LOT of grain filling would need to be done before application. Maybe Humbrol MetalKote would be a better option. It's a while before I get to that point, but I'm trying to think ahead...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: ZK-AUD on June 16, 2016, 08:10:17 PM
Dan, for a man of your parts and capabilities the way to go could be to vac form those sections in either 10 thou styrene or even better in the thin plastic you can buy for presentation covers, which renders really thin lightweight high definition parts.  You could glue these panels over the built up structure with RC56 or have no structure underneath as the vac forms are self supporting.  Spray with Alclad in the metal of your choice.  That's how I'd do it.  Ditto the engine cowling parts.  I tried using aly foil once - not great.  doesn't like compound curves, wrinkles, rips, generally wrecks your life.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 16, 2016, 08:35:33 PM
Thanks for that! It will be a long time before I get to that point, but nice to know I have options. Thank you for the interest and back when there is some progress to report. Don't hold yer breath!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 21, 2016, 04:04:43 PM
I think my approach to this will be build one part at a time and finish it completely before starting another bit. Hopefully, this will SEEM a lot less work than building it all, covering it all etc. I've made a start at last and the fin/rudder are mostly built. Scale thickness is around 1/8th, so I built the outline and basic frame 1/16th thick, which then had 1/32" cap strips added on each side. These were then blended into the outline, which will hopefully give a much more "scale" effect than a 1/8th thick frame. It does mean nearly 70 separate parts in the fin/rudder alone, though! All good fun...

Cheers,

Dan.
 


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 23, 2016, 04:37:56 PM
Completed fin/rudder. Still needs a final sanding, but I'm quite pleased with it so far. I'm sure this will never be competitive against the big boys, but that's not the point. I'm already enjoying this!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: ZK-AUD on June 23, 2016, 04:49:28 PM
Why won't that be competitive?!


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 23, 2016, 05:14:42 PM
Because I think I lack the attention span to make it so! I will do it to the best of my abilities, but I have a lot to learn...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: Graham Banham on June 25, 2016, 01:02:37 PM
Superb and challenging choice Dan, and you certainly have the skills to pull it off.

Dave's plan is a great very accurate starting point. I have his Hawker Woodcock plan: not easy builds, but the results are well worth it.

Based on the wing area ( i make it 1113cm2) you could go to an all up weight approaching Mike Stuarts Fox Moth (around 90 something grams i believe), and the loading would stiil be very good for indoor.

Just don't do a More/Bader manoevre!
ATB
Graham


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 25, 2016, 02:55:48 PM
Cheers Graham!

I've also got the Woodcock plan, but the Bulldog just pipped it. I suspect it may take me a while, though...

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 26, 2016, 09:48:41 AM
All tailplane outlines now laminated. Hopefully, I can get the basic structure done before going back to work tomorrow night. As for the rudder; this will be a 1/16th thick basic structure with 1/32 capping added either side. I'm very impressed with how torsionally stiff this type of structure turns out. No doubt I can still induce massive warps, though...!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: DaddyO on June 27, 2016, 03:44:59 AM
Morning Dan

Not sure if you managed to get hold of the Granger plan book?  I've got a copy you can have if you pm me your address.

Cheers
Paul


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on June 29, 2016, 11:37:05 AM
Basic "core" of the tailplane together. This will be sanded to a uniform thickness before adding the 1/32" capping.

Cheers,

Dan


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 02, 2016, 10:25:31 AM
After going mad and blind looking at Bulldog pics, it appears that the elevators fit into partial shrouding of the leading edge where they are hinged to the tailplane. The aerodynamic balances appear to be more or less flat, whilst the tailplane tapers down to the tips. Good photos will prove this for the documentation. The publishers of Aeromodeller do a CD of the Hendon Bulldog; I think it may be worth a purchase...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: Prosper on July 02, 2016, 11:50:46 AM
Hi Dan, don't know if this pitcher helps or hinders. . .if the elevator noses are shrouded it looks like not by much. I've got a description which reads ". . .the balanced portions of the elevators are shielded. . ." (my italics) - I take that to mean that they've got fixed tailplane area ahead of them rather than dangling in the wind, as with a Fokker DVII's aileron balances for example. Could be wrong though. Very ambitious build - I looked at the Bulldog and chickened out. . .good luck!

Stephen.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 02, 2016, 12:08:19 PM
Ta for that, Stephen! Ive made the 1/32 capping on the spar extend back by 1/32" so a radius can be sanded in to take the elevator LE. So far, it looks pretty good, compared to pics. Obviously the LE on the forward projecting aerodynamic balances can't be shrouded, as then they would be fixed at neutral! As a first "serious" scale build, I could probably have chosen better, but you only live once!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 03, 2016, 05:22:57 PM
I've got the Causer/Aerographics Camel kit, and the instruction leaflet is a masterclass in detailing. I'll definitely be pinching a few of the techniques for the Bulldog. It'll at least get rib tapes, as such a huge expanse of wing needs something to bring it to life.

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: billdennis747 on July 04, 2016, 03:00:59 AM
I'll definitely be pinching a few of the techniques for the Bulldog. It'll at least get rib tapes, as such a huge expanse of wing needs something to bring it to life.
I would test that idea off the model first, Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 04, 2016, 08:40:06 AM
Probably wise, Bill! It will be a while before I get to that stage anyway. I'll have probably given up and taken up alligator wrestling or Russian Roulette using six shells long before then...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 04, 2016, 06:52:51 PM
Most of the tailplane and elevators are now sanded to shape. Just a few finishing touches needed. Luckily, the Bulldog had internal linkages for the elevators, so no horns and cables involved! I'm hoping the photo CD has a good few engine shots. I find it hard to visualise details like cylinders/exhausts etc. from drawings.

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 05, 2016, 07:24:15 PM
Progress so far. I've tried ordering some white Esaki from Flitehook three times, but have had no response. Anyone know anything?

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: ZK-AUD on July 05, 2016, 07:36:49 PM
Nice piece of work Dan.  I recently covered my Bristol Scout with the Dilley tissue rather than Esaki. It's good stuff.  Very nice to work with. 


Title: Re: 1/16th Bristol Bulldog
Post by: DavidJP on July 06, 2016, 05:57:52 AM
I know Pauline has been unwell Dan, so maybe John is a bit preoccupied at the moment - how much do you need - I have some Dilly tissue to spare and it seems as good as Esaki - may well be of course?  Otherwise try the Woodhouse emporium.  FF supplies.


Title: Re: 1/16th Bristol Bulldog
Post by: billdennis747 on July 06, 2016, 06:09:41 AM
Esaki has wet strength and can be pulled around a bit, if you like that sort of thing. Dilly hasn't.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 06, 2016, 07:05:56 AM
Thanks Bill and David. I'm not in a mad rush, so I'll wait for now...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 09, 2016, 04:33:19 PM
I've just realised that I have quite a few sheets of black Esaki, so I'm going to press on with that! The tail surfaces may end up being remade if I'm not happy with how they look anyway, so black is no big deal.

Back soon,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 16, 2016, 01:47:10 PM
I just bought a kit from eBay and it contains some white Esaki! I'm still waiting on my supplies arriving, but in the meantime, this will do nicely. Started covering the tail surfaces this afternoon, so I'll know if it looks any good soon...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: PeeTee on July 16, 2016, 05:09:02 PM
Quote
I've tried ordering some white Esaki from Flitehook three times, but have had no response. Anyone know anything?

Dan, have you had a reply yet? I saw John a couple of weeks ago and recall him mentioning that he was having computer problems  - it was away being fixed. Give him a call on the usual number and I'm sure he'll get it off to you pdq.

Peter


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 17, 2016, 09:08:13 AM
There are two schools of thought for adhering tissue. Tissue paste, or thinned PVA and dope/thinners. I never got on with the dope/thinners method, so this is a compromise. The structure was given a coat of full strength sanding sealer, which was then sanded back and the tissue applied with the new version of Deluxe Material's Tissue paste. This is great stuff! The main snag I found with the dope method was the overlaps. They just never wanted to stick down around the edges.

Back soon,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 17, 2016, 02:31:08 PM
Steam shrunk and first coat of dope on. They are looking good so far, but time will tell!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 17, 2016, 04:14:11 PM
I've ended up with a couple of small wrinkles. They may go with another coat of dope, but I doubt it. Esaki loses most of it's shrink with the water/steam shrink. Not the end of the world. I'll use these as practice for the rib tapes if the worst comes to the worst!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: billdennis747 on July 17, 2016, 04:53:20 PM
Dan I just cut them out (after one coat of dope) and patch. Then more dope and it's not noticeable. You're right, dope won't get rid of the wrinkles


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 17, 2016, 05:20:20 PM
Ta Bill. I'll see what it looks like tomorrow...

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: FreeFlightModeller on July 17, 2016, 06:40:23 PM
I like a radiused fillet to get rid of such wrinkles, but in this case it would probably spoil the scale look.

I sometimes wonder if we worry too much about wrinkles (myself included) ... I remember the Old Warden SE5a having wrinkles in just the same places as we get them.


Title: Re: 1/16th Bristol Bulldog
Post by: ZK-AUD on July 17, 2016, 07:25:53 PM
Nice job Dan - agree with Bill - just cut that bit out - you'll never know - you can feather the edges of such patches with 1500 grit wet and dry (used dry) followed by another light coat of dope around the edges.  On the subject of your edges being difficult to stick down, just run a wetted finger around first and then dope through - your recalcitrant Esaki won't stand a chance!


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 18, 2016, 02:13:23 PM
It's annoying when, as a modeller, you spend ages trying to get everything smooth, tight and wrinkle free etc., then you stand next to a real aeroplane that is a mass of lumps, bumps, raised seams and everything you try to avoid on a model!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on July 20, 2016, 02:12:34 PM
Most of the wrinkle has gone after another day or two shrinking. What remains will be under the proposed rib tape, so I may yet get away with it!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: Pit on July 21, 2016, 06:29:41 AM
It's annoying when, as a modeller, you spend ages trying to get everything smooth, tight and wrinkle free etc., then you stand next to a real aeroplane that is a mass of lumps, bumps, raised seams and everything you try to avoid on a model!

Cheers,

Dan.
That's why I've ceased worrying about it, unless the wrinkle/lump/bump is REALLY gross.  I guess you'd have to have a photo to prove that the real thing was so "poorly" done...


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on August 15, 2016, 09:29:45 AM
Not much progress for a while. I was busy getting stuff ready for the NCMAC Fun Fly at the weekend. I am, however, just about to steam the covered tailplane/elevators, so I'm still plodding on...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: Ex Member on August 16, 2016, 02:28:48 AM
Good news Dan.  ;D

Any pictures?

Andrew


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on August 25, 2016, 08:15:13 PM
Back to the drawing board! My scale type structure distorted horribly when subjected to the terrifying shrinkage of Esaki... Version no.2 coming up...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on August 28, 2016, 02:24:19 PM
Slightly revised the structure to try and prevent the distortion that occurred. I'd forgotten just how much Esaki shrinks! At this rate, I may well be dead before this gets built.. Oh well!!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: billdennis747 on August 28, 2016, 02:38:51 PM
Dan
Very surprised to hear the structure has warped. It looked the business and the covering went well. Can you give us pictures?
In my experience, most shrinkage occurs at the water/steam stage, and non shrinking dope has little effect. Has it twisted, or pulled in?


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on August 28, 2016, 03:39:43 PM
It all shrunk up nicely, but distorted where the tailplane/elevators fit together. I can either build the same and pre-shrink everything or redo the structure to cope with the shrinkage. I did say this would be a long drawn out one...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: DHnut on August 28, 2016, 05:33:25 PM
Dan,
        I know I am being wise after the event, but I do not seperate the elevators from the stabiliser until after the doping stage when the structure has stabilsed about a week after the final doping. That has worked for me especially for peanut models. I flew the Comper 2 weekends ago with a new GM120 and it performed well. The old motor had a very slack little end fit on the piston. Is there a means of refitting or closing the ball up as you do on a Cox engine? Also is there a source of spares?
Ricky


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on August 28, 2016, 05:42:49 PM
I don't know Ricky. The Gasparin Website is still up and running, so that may be your best bet for spares. The trouble I had is all my own fault. I should have remembered that Esaki shrinks like a very shrinky thing if left to it's own devices. I said this would be a long running build!

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on October 02, 2016, 05:08:54 PM
I have been seduced by a couple of RC builds. Still stick and tissue and none of the foam/glass/ARTF stuff. This is, therefore, on hold for a bit. I WILL get back to it once I have psyched myself up to it again...

Cheers,

Dan.


Title: Re: 1/16th Bristol Bulldog
Post by: DHnut on October 02, 2016, 08:50:12 PM
Hi Dan,
           I have managed to order parts from a chap called Jiri who has a website and appears to deal in Gasparin spares. I am waiting for the parcel to arrive and will confirm my experience. I have put a new GM120 motor in the Comper and had good results. The improved dummy Pobjoy engines have resulted in having to apply some tail weight in one case. I also flew a small WACO ARE two weeks ago that is now starting to fly well on a GM63. One flight was timed at 35 seconds and more to come. I may try it at an upcoming indoor meeting. The modelis based on a Micro X kit.
  Ricky   


Title: Re: 1/16th Bristol Bulldog
Post by: Pit on October 03, 2016, 09:31:36 AM
Ricky,
what is the AUW of your Comper with the GM120?  That's the motor I put in my Citabria that I hope to finish in time for the IIFI in the Netherlands (detail in the outdoor scale Forum).

Pete


Title: Re: 1/16th Bristol Bulldog
Post by: DHnut on October 03, 2016, 06:04:30 PM
Pete,
         The Compers ( I have two )  weigh 100 and 105 gms respectively using a GM120 and GM160 respectively and are build from the Aerographics kit but with corrected tail outlines. They both fly flat and quite fast and safe but realistic for a racing aircraft, and will ROG with ease. With the dummy Pobjoy radial tail weight is needed. Is the Citabria a Hacker kit? I have a Piper Cub from the Hacker kit powered by a GM120 that is a suberb flier. Good luck with the build for the IIFI event.
Ricky     


Title: Re: 1/16th Bristol Bulldog
Post by: Pit on October 04, 2016, 09:01:11 AM
Thanks, Ricky!
I'm in the ballpark weight-wise.  The kit is from Turbinia (predecessor to Hacker).  Hacker took over the models, changing the Citabria designation to the Decathalon.  I haven't seen the Hacker version yet (I wonder if they changed the airfoil to the semi-symmetrical one?).

This Bristol build has gotten me a bit sidetracked as to what I will be building next... ::)


Title: Re: 1/16th Bristol Bulldog
Post by: danmellor on October 04, 2016, 11:29:55 AM
Nice to hear that others are getting on with stuff! I will be back to this when I've got some electric R/C out of my system...

Dan.