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Cartoon Cutlass Wings Warping when glueing & covering.

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Mannyroad15/05/2016 16:19:21
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185 forum posts
81 photos

Hi,

I've decided to return to modelling after a 7 year break and have chosen to build the Cartoon Cutlass, featured a good few months ago in RCME.

I wanted a quick to build, small electric model that I could chuck in the car and go and fly whilst I sorted the engines and batteries etc out on my other planes (sadly, despite engine after run oil birng used, several engine bearing problems came to light, having been stored in garage for so many years).

Anyhow, all was going well, until I came across a problem I've encountered several times in the pat when building delta type wings from sheet balsa, namely the warping of the sheet balsa. It began as soon after gluing the top sheets in place for the K2 section wings. I'm not sure how Nigel Hawes glued the top sheets in place, i.e. what glue he used and how much, to prevent the wings warping when the glue dried.

The next problem I've found with these type thin balsa wings is that the shrink covering deforms the wings when being shrunk, and I even used an old power panel gel cell battery as dead weight to try to prevent it happening.

So, what is the best way to glue up and cover these type of wings to prevent them warping. Same goes for the thin balsa fins too; mine have developed a slight curve to them. Its annoying having spent time and materials, to see it all goe to waste.

Any thoughts would be greatly appreciated. And any tips for easing out the warping too (prefer not to waste all the work todate).

onetenor15/05/2016 16:43:16
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1900 forum posts

Heat is the answer to warp removing but can increase covering shrinkage Strip film and paint I think is the answer. St eam is the best heat to use

Keith Evans 315/05/2016 19:08:06
371 forum posts
81 photos

For the thin fin , insert a half inch by one inch strip of balsa ,say , of the same thickness across the grain direction of the fin itself , before covering .

Mannyroad15/05/2016 22:18:17
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185 forum posts
81 photos

Thanks guys for your comments. The cross-grain strips are indeed great for keeping sheet surfaces straight and they \re soething I've used numerous times in the past. As they weren't on the plan I presumed that warping wasn't going to be an issue with this build so decided to leave out; a mistake perhaps.

I'm not sure how the top sheet for the K2 section was glued on others models but I used PVA glue for this job. maybe in hindsight I should've just used thin epoxy strips along sheet edges and a few dabs in the mid-section to reduce wetting out the balsa too much; again, a mistake perhaps. i'd be interested to know how others approach the issue of preventing warping of wide sheet wings when glueing or, perhaps more importantly, when using shrink coverings.

Andy G.15/05/2016 22:28:02
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413 forum posts
215 photos

Just finished building mine and had no problems with anything warping, and I used thinner wood for the wings. I used PVA to join them, pinned down and weighed down overnight. Then covered using heavyweight tissue and Poly C. Same for the fins, the grain direction is important here of course. The model was then painted with Rattle cans. Pictures in my albums or in the cartoon Cutlass build thread on here.

Edited By Andy G. on 15/05/2016 22:29:03

Edited By Andy G. on 15/05/2016 22:34:30

Mannyroad15/05/2016 22:47:58
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185 forum posts
81 photos

Hi Andy,

Funny, I'd just finished reading your comments to the DOH thread when your message came in, so I recognised your avatar straight away.

Your Cutlass looks excellent, hope mine turns out as well. I used 6mm sheet for wings, as plan, and similar for the K2 front section. Wish I'd spot glued that sheeting rather than wetting out the whole surface; I'm reckoning that was my mistake. The warp isn't excessive, just noticeable and now I've glued it to the fus I'm waiting to see if that will pull most of it out.

Always had issues with large sheet wings, especially when heat shrinking. Will consider tissue and poly C in future, or glasscloth and the acrylic stuff by Falcon Models, which i've had good results with.

What motor/prop setup did you find worked well? Been reading about hand launch issues and that smaller 5x5 props can help reduce torque roll during launch. Did you have any issues hand launching?

Andy G.16/05/2016 09:25:43
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413 forum posts
215 photos

Hi Manny..

My local supplier didn't have sufficient 6mm sheet in stock so when I built mine I used the next size down. Saved a little weight as well as cash.. I was quite liberal with the pva when i built the wing, applied lots, then spread it out with a piece of scrap balsa to form a film right across the entire area... My airframe weight, with motor and servos fitted, but no radio, esc or battery fitted comes out at 624 gms or 1lb 6.5 ozs in old money. I've used a Turnigy D2830/11 1000kv motor, and anticipate using a 6x4 3 blade prop on a 3S lipo. Haven't maidened it yet, I have a bit of a shortage of rx's, so having to make a hard choice about which of my other planes to 'steal' one out of! Hopefully by this coming weekend I'll have it sorted. Mine's turned out fairly light, so I'm hoping that I can get away from the launch at lower power thus avoiding any torque issues.. Time will tell, I may just maiden it up on our local slope site, that way I can hurl it power off then apply throttle as it goes away from me, Fingers crossed!..

Andy.

Edited By Andy G. on 16/05/2016 09:28:13

Jim Carss17/05/2016 10:23:26
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2064 forum posts
80 photos

Nice to have you back after 7 yrs Mr Manny.

wink 2

ps I have a nice aluminium spinner that would fit the Cutlass.

smile p

Mannyroad17/05/2016 17:55:04
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185 forum posts
81 photos

Hahaha! You still got that spinner of MINE eh? Haha!

By the way, how did you figure it was me?

Jim Carss19/05/2016 13:22:47
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2064 forum posts
80 photos

Dear Mr Manny,

How could I ever forget 178 mannyroad,would probably make a good email address.

Sorry for the delay in responding,just returned from a couple of days in the north Yorkshire moors.

I'll send email ASAP,

Jimbo smile p

Mannyroad31/05/2016 00:14:23
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185 forum posts
81 photos

Andy,

have you maidened the Cutlass yet? If so how did it go?

Andy G.31/05/2016 08:33:57
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413 forum posts
215 photos

Manny.

No, not yet. I have had a bit of a building spree lately which has resulted in more models than I have receivers for! I decided the only spare rx would firstly go into an electrified Westwings Orion, that's now had it's maiden, but needs a couple more trimming flights and then the rx can be swapped over to the Cutlass. I'll post the outcome ASAP.

Jim Carss31/05/2016 15:31:54
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2064 forum posts
80 photos

**LINK**

Just posted this link for foam wings and the last two posts,one from Pat and the other from Manny have disappeared

??

 

Edited By Jim Carss on 31/05/2016 15:36:08

Mannyroad01/06/2016 00:12:53
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185 forum posts
81 photos

Jim, those posts are on my Purple Haze thread. Just checked out the foam wing link to BillKits. interesting that he does a built up wing Fun Fly 15 that isn't too dissimilar to the Purple Haze. I bet it flies every bit as good too. And the kit is likely to be as cheap as ordering foam wings alone. Hmmmm...something to consider.

By the way, Andy, thanks for the update. Looking forward to hearing about its maiden. My Cutlass will be powered by a Turnigy 2826-10 1400kv motor, providing 205w max. Should be just right. Only hiccup I hit fitting the motor is that I should've started the hatch cover closer to the back of the fus, because its nigh on impossible to get the motor mount nuts onto the screws. Might have to epoxy a second ply plate on and simply woodscrew the motor mount on.

Jim Carss01/06/2016 09:35:16
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2064 forum posts
80 photos

Stupid boy crook must be the old timers syndrome.

The Purple Haze wing should be easy to build for a manny of your talent,if you get stuck,send it to NE1.smile

JImbo

Mannyroad01/06/2016 12:58:38
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185 forum posts
81 photos

Jim, if it were a built up wing that would be easy. I was hoping to have foam wings, I'm lazy, but I don't have the means or the experience to be confident of cutting my own. I reckon I'd ruin the first copule of attempts, at least!!

Jim Carss01/06/2016 13:12:45
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2064 forum posts
80 photos

Looks like you will have to spend some cash my man.

I built a Spinks Acromaster from the Pilot kit plan and got a pair of foam wing from Billkits, £45 not exactly cheap.

Keep at it

wink 2

Mannyroad18/06/2016 22:03:31
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185 forum posts
81 photos

Andy,

Did you use blue foam for the canopy? I've never used it before and am having a lot of difficulty trying to cover it with solarfilm. The film just seems to stick to the foam immediately when heat is applied and so it's not going round the double curvature without wrinkling. I could glass mat it but I really wanted the aluminium finish like in the RCME one.

Any helpful suggestions? Anyone?

Mannyroad18/06/2016 22:04:49
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185 forum posts
81 photos

Jim,

I think I should've done it in balsa, like you would. I think it's better than blue foam as it's easier to cover.

Andy G.19/06/2016 08:18:50
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413 forum posts
215 photos

Manny

I used pink foam for my canopy and as the rest of the build I covered it with heavyweight tissue using Poly-C. The rear half was then painted to match the fuselage, whilst the front part was covered with pieces of aluminium foil adhesive tape that's used for securing pipe lagging on industrial heating installations. It can be tricky and a little fiddly to get it crease free but once it's on looks good and sticks like you know what to a blanket! A couple of bits of vinyl trim strip to simulate framing and cover the edge between tape and paint finishes the job neatly. I believe a roll of this is quite expensive ( let's just say mine was gifted to me!) but if you like to try some I'll gladly post you enough to cover yours and to practice with first.

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