Has anyone built this, or purchased plans?

Any comment on the 1" shorter outboard wing? Seems like for a 1/2A it would be less, since they don't even use that much sometimes for bigger ones now.
I was thinking that just offsetting the fuse outboard a 1/2" would be reasonable. Thoughts?
I'd do the wing in blue foam and Carboline though, maybe with molded wing tips. To keep the tips identical, and only one mold needed, I'd make the tip chord the same I think, as opposed to what the plans show. Thoughts?

Looks bitchin', in my opinion.

R,
Target

I'm pretty up on foam densities.
While a white foam wing with 1/32" balsa is pretty light, it still isn't finished.
Modern vacuum bagging of Carboline (it's like .006" thick, and NOT woven, unidirectional in 2 directions) with epoxy over foam that won't compress, the coring it out very thin should leave a finished product that I (hope) will be light enough, strong enough, and already fuel-proof.

http://carboline.info/

I haven't done it yet though, so just a theory at this point. One I hope to get time to prove, right or wrong.

Thanks for the reply on the tips, but for me, if I'm hot wiring foam, it's just as easy to use the same templates on two different length panels as it is to cut two identical wings then cut one shorter. Actually, maybe easier.

But double thanks on the shorter lines thing; I am kinda bummed I missed that. The smaller the radius, the greater the speed differential, now that you mention it!

Good food for thought!

Any leads on where these plans (printed) can be had?

R,
Target

I'm wondering if 100% will give me an accurate 1" = 1" scale though?
If it is off a bit it will be worthless. On my computer screen 97% is 1", 100% is over 1". Maybe this is of no relevance.
Has your experience been that there is no concern for this?

Also, what about copyright? I have had questions at some print places, not at others.

Thanks for the help, John.

R,
Target

By the way the original Cobra was in the defunct AAM in 1971, so I doubt anyone would care.

There's no guarantee that anyone's copier or copying service will give you a correct (near perfect) print anyway. I discovered that they are usually off enough for me to care.

When I went out for a copy for friends, my copier agreed that if the first copy was not right (in BOTH directions) I could give him a magnification factor to punch in, and he would run me an accurate copy. On a full sized ( say 50'-span) stunter, that was a 1/2" error for each 1% off. I just divided a key dimension by the length on the copy and got a number for them to use for correction. For instance, if a 50" wing came out at 49.5" on the first copy, 50/49.5 = 1.01. So I told them to run it off at 101%. It depends a lot on their equipment quality, and the length and width are not always off by the same amount. You just do your best, and if the equipment is sophisticated, you can go to the tenth of a percent. Building your 1/2-A should not require plans though to just adjust parts to the right size, if you know the intended span or any key part's dimension. Those copies can be expensive.

SK

Also, just a FWIW: moving the fuselage 1/2" is making one wing an inch longer than the other.

This page has the post by the guy who drew the plan  https://www.rcgroups.com/forums/showthread.php?1265873-Vintage-Old-Timer-Plans-PRE-1960-PLANS-ONLY/page31#post16055014
You probably could get a CAD version from him
John

Hey Target!
I've had this idea for a while but my health is slowing me down to try it myself .
It's simply this make the core a couple of inches longer. But you have to make the root a little longer and the tip a little shorter. Then cut the cores out, being careful to keep them smooth as possible. Now if you stick those cores back in, they will extend past the tip and be inside the root. Put everything back in their beds and cut the wing panel to the correct size. Then pull the lighting cores out and cover them with clear packing tape and wax them real good and PVA them.  Next put them back in the wing cores and vacuum bag as normal. After curing, pull the lighting cores out and you have an extruded wing that should be light and strong.

Tim Thompson. aka RWCLOUD.

Hi,
Yes, that is about what I have been thinking, but I don't see a reason to "core the cores" before I vacuum bag the skins on.... Am I missing something?
I would V-bag the panels first, separately, then core them, do the tip box, adjustable leadouts, bellcrank, then do the center joining and tips/flaps, etc....

I might evolve the plan as I go, but that is what I am thinking initially, anyway.
Should save a bunch of time finishing, and maybe some weight also.

A vacuum bagged carbon over balsa/foam profile fuse should be stiff and light too, I would think. And fuel-proof.

Thanks for your input. Please chime in if I am totally missing something, but I don't think I need to have the inner cores cut before vacuum bagging.

Vr,
target

Well, twice I've "missed " while cutting the inner cores out.  This is despite having everything lined up or so I thought. Running a rod a couple of feet through foam is tricky, at least it is for me. I'd hate to vacuum bagged a wing, then poke an 1/8 inch stainless steel rod through the skin . If I miss before it's bagged then all I've lost is some foam.  But then again Phil Barns I ain't.

Yeah, I  guess 8 1/2 inches would be no problem. Wow, didn't know you sold that many wings!

Best of luck with your project!
Blue Skies. .....Tim

Gravity, while often our enemy, can be our friend, huh, Doc?!
Well done.
I use a plumb bob on setting verticals when I know the stab is level....

Chris,
Jim Howell here.  I am the club member friend that got the plans for the 1/2A Cobra from the Chief, Ty Marcucci.  I don't know if you are still looking for info, but here's bit more.  The signature block, such as it is, says:

Cobra
Designed by Steve Wooley
Adapted to 1/2A by Howard Sullivan
Cad by Gene Rock 2004

Jim Howell