Well it WAS going well...

MakMov · Post by **MakMov** » Fri Sep 30, 2011 9:43 pm

Not sure what the failure was though.

Covering the bottom of the main wing tonight with my new found way of spaying the tissue wet applying it to the frame and gluing it down with 50/50 white glue. So that is what I did and then clamped it to my magnetic bench so it wouldn't warp. Everything look fine until it dried.

When I pull it off the bench; however, on one side the tissue was split along the TE from the wing tip to the dehidral and then from the the TE to the LE at the dehidral rib.

Maybe stretched too far? 16 inch wing span too much to do in one piece of tissue? Sould have pre shrunk? Different tissue than the kit junk? Different method of applying the tissue? Donno.

I am just about all out of the kit tissue so I didn't have enought to redo so I just patched it, but I wonder what would have caused that to happen?

Still don't have the art quite figured out yet, I guess.

MakMov · Post by **MakMov** » Sat Oct 01, 2011 12:46 am

still just plugging along

MakMov · Post by **MakMov** » Sat Oct 01, 2011 12:55 am

everything was fine at this point.

it was after it dried the problem appeared.

MakMov · Post by **MakMov** » Sat Oct 01, 2011 2:18 am

Home stretch?

Phugoid · Post by **Phugoid** » Sat Oct 01, 2011 2:52 am

Hi,

Can I suggest that on your next build you support each wing half and the centre section seperately?

This will prevent each from warping, as I think you have it now the wing has nothing to keep if flat whilst the tissue dries.

I use some srtips of aluminium to keep the wing off the board and some metal blocks for weights. Although the picture shows just one wing (just the way this model builds), it works for those builds where the wings are joined early, you just stick the other bit out, do one side, then the other, then the centre section.

Also it is wise to cover and shrink the top and bottom of the wing at the same time, it has more of an equall pull then.

ADW 123 · Post by **ADW 123** » Sat Oct 01, 2011 7:38 am

You might want to cover the entire wing dry, and then shrink it panel by panel. on a 500 series, the wing can be done in two panesl. the center panel is so small on most of them, it they dont matter enough to worry about pinning them down directly to the mat. i just do half of the center panel on the left side when the left side is pinned, and the reverse to the other side. a light mist will due to shrink the tissue, otherwise you might definatly develop wrinkles. i think this is clearly illistrated here.

on your hellcat, since the center panel of the wing is so big, you will want to shrink panel by panel for three panels. hope this makes since on top of what phugoid said.

MakMov · Post by **MakMov** » Sat Oct 01, 2011 12:53 pm

Okay, back to the drawing board. I thought I had a good way of doing it simple and easy that would come out okay. Guess not. Oh well.

I alway just done one side at time the few times I have done it. Never really had any trouble with warpage.

How in the world would you cover the entire wing of a like a Spitfire with an eliptical wing.

I will try something different on the next one.

flash52 · Post by **flash52** » Sat Oct 01, 2011 1:29 pm

The leading and trailing edge of the Hellcat wing are pretty beefy so you can probably get away with doing the shrinking your way. The previous advice is excellent and I would only ad one thing. When you are shrinking the pinned down wing raise the rear tip of the wing 1/16 to 1/8 of an inch. This is called wash out. It helps prevent tip stall and makes a better flyer.

Phugoid · Post by **Phugoid** » Sat Oct 01, 2011 2:59 pm

The shape of the wing doesn't really make any odds. Cover the bottom of the wing first then the top. Flash is right, the wing on these models is pretty robust, but keeping it flat won't harm, as is the advice to ad some washout 1/16" would do ok I'd guess.

Andrew

MakMov · Post by **MakMov** » Sat Oct 01, 2011 3:31 pm

like I said I will try something new next time.

I was rummaging around my shop and found a whole box of domestic white Peck Polymer tissue ... like a life time supply 50pc, a box of of 5 peices of Japanese and I just picked up several sheets of 000 silkspan.

MakMov · Post by **MakMov** » Sat Oct 01, 2011 3:38 pm

Washout, huh, I know about it from my RC planes but never heard or read about using washout on a stick and tissue.

ADW 123 · Post by **ADW 123** » Sat Oct 01, 2011 4:58 pm

close eyes will notice that my wing has 3/32" sq. washout shim on the very back of the very last wing rib. You can think of washout like ailerons. the more washout, the less lift the wing produces (I think I got that right)

ADW 123 · Post by **ADW 123** » Sat Oct 01, 2011 10:43 pm

I also noticed how you wrap the tissue around the edge. In David's post about the spitfire wing, you will notice that the tissue wraps is cut with a very sharp razor blade. this ensures a neat finish, although your way works just fine.

check out this link- it illistrates some great work on covering, and some building. Even I improved dramatically after following every piece of advice in this thread. Hope it helps. you are taking the right road on your build. keep it up, but dont give up if there are some bumps! Happens all the time for me at least... If you need, take a break of a couple of days (or "sleep on it", and get back to it the next day with a refreshed mind). Ive taken weeks off of building at a time because I have gotten so frustrated running into bumps.

http://balsamodels.com/phpBB/viewtopic. ... +piper+cub

also this one- alot of good info

http://balsamodels.com/phpBB/viewtopic. ... highlight=

I would recomend reading through both of those, and ask questions if any. they help greatly!

good luck!

MakMov · Post by **MakMov** » Sun Oct 02, 2011 10:48 am

Thanks, very interesting in insightful.