Mystery foam wings

[Roger_Pion]

Fellows, I have a couple mystery foam wings here and a small dilemma.  I think the wings are Buccaneer 46 and Gypsy 35 so they ought to make good flyers.  I want to build them sooner or later.

My dilemma is that I don't know the first thing about sheeting foam wings and I don't want to ruin them by accident.  Does anyone know of a professional wing sheeting service I might send them to and get them done right?

[Crist Rigotti]

Those wings look like the ones I used to cut.  Where did you get them from?

[Dennis Leonhardi]

Bob Hunt - Robin's View Productions in the Vendors Corner -

   https://stunthanger.com/smf/robin's-view-productions/

You'll get professional service and be very satisfied!


Dennis

[Roger_Pion]

Thanks guys, I'll get in touch with Bob.  I don't know why, but I thought he only does his own cores.

Crist, I got one set, the smaller one I think, about 10 years ago from Jim Silhavy.  That's why I think it's the Gypsy 35, pretty sure he told me that.  And I got the larger set on-line but I can't remember from who.  I found it in my attic in a box labeled Buccaneer 46 wing.

[Howard Rush]

I lost a set of Bob Hunt Impact foam wings. They are somewhere in my shop. If anybody finds them, please let me know.

[Jim Svitko]

I have to agree with Motorman.  Get some already sheeted foam wings from a supplier to get you in the air faster.  Keep your foam wings and seek out some help on how to do the sheeting and other steps yourself.

It may look intimidating at first but with a little help you can do it.

[BYU]

I lost a set of Bob Hunt Impact foam wings. They are somewhere in my shop. If anybody finds them, please let me know.

Can I keep them if I find them ? 


Wait   .    . What’s this?

[Alan Resinger]

Howard, loom in the cabinet marked props.😁😁😁😁

[Air Ministry .]

I lost a set of Bob Hunt Impact foam wings. They are somewhere in my shop. If anybody finds them, please let me know.

They must be with my Merco 61 Wrist pin .

[Steve Helmick]

I watched a Windy video on sheeting foam wings once. When I woke up from my nap, it was repeating the same stuff over again. Confused the heck out of me, and I've yet to attempt to sheet a foam wing.

There are a couple of things about it that bother me.

1) Is knowing that the place I'm going to put the stack of bucks/cores/skins and heavy weights is really...really...flat. I asked Howard, and he said he used the shop floor. I know enough about the way concrete is poured, worked and levelled that I would not be comfortable with doing that. A certified granite inspection table would be swell, or a calibrated CMM table, or even the table of a milling machine that wasn't 50 years past its prime. Table saw, maybe, if it's big enough.
2) I have some balsa that would work, and I think I could glue them together into skins ok. I would NOT ever use contact cement to apply the skins to the cores, would consider Gorilla Glue (but would make a few test panels before doing wing cores), but would likely get some good slow hardening epoxy from System 3 or similar...2 hour or so. I doubt that I'd attempt to stack both cores, 4 skins and bucks in one go, and most likely would apply 1 skin at a time for the first attempt or two.
3) After the wing halves are joined (would foam cores work for a 2 piece wing?), I'd put some fiberglass over the seam, with epoxy. I see conflicting opinions on how much fiberglass/epoxy to put on the seam, but I also read stories about wings failing in flight, and that frankly has me spooked.
4) Look in the cabinet marked "Props".       Steve

[Jim Svitko]

At first, I also had reservations about foam wings, but after using foam for many years now, I doubt if I would go back to all-wood wings.  Foam is faster, I can built it straighter, and the weight penalty, if there really is one versus all-wood construction, is not enough to worry about.

For foam wing construction, my flat surface is the "table" that Tom Morris supplied some time ago as part of his wing building system.  He might still have this item available.  I do not know what the material is.  It reminds me of phenolic.  It is 3/4 inch thick and as flat and straight as you can make a surface.  There are two long pieces of angle iron attached to one side.  It works well for the foam wing sheeting process.

I do only one side of one wing panel at a time.  I use slow cure epoxy to attach skins to the foam.   I have used nothing else because the epoxy works well enough so why change?  A coat or two of clear dope on the adhesive side of the sheeting will prevent excessive epoxy soaking into the sheeting.  When I heard of this trick, I tried it and I was amazed at how little epoxy I used since I could spread it in such a thin layer.  You might not think this would be enough adhesive but it is.  And, much less weight.

I put the wing back into the cradle, using masking tape to hold everything in place, to keep the core from shifting in the cradle. At a local metal supply warehouse, I got a sheet of 1/4 inch thick 6061 aluminum plate, 16 inches X 32 inches.  I put this plate on the assembly and then weigh it down with barbell plates.  I leave it overnight. 

I make skins from butt joining separate sheets.  I use Sigment for this.  It is necessary to get a good, straight edge on both pieces to minimize gaps.  It takes a bit of time to sand them and get them straight but worth the effort.

Joining the two wing panels can be tricky because alignment is so critical.  You have to take your time, making sure everything is straight.  Glass cloth and epoxy go over that center joint.

I have seen foam wings fold up in flight.  If that happens, it is usually due to some error in the building process or due to damage from a hard landing with wing mounted landing gear.  I have yet to see a fully sheeted foam wing fail in flight.  As far as that stub spar goes, there are varying opinions.  I do not think the spar reinforcement is needed in a smaller plane.  For something 600 squares or larger, it might be a good idea to put it in.  I have done it with and without the spar without issues.

The wing that Tom Dixon said folded on Bob Baron was due to Bob's insistence of keeping weight down.  There was no wood stub spar and I think Bob might have only partially sheeted this wing (leading edge, trailing edge, and center sheeting) and then finished it with cap strips and film covering.  I met Bob Baron shortly before his death and he was a stickler for weight control.

I have built smaller planes (Gieseke Nobler size) partially sheeted with capstrips and covered with poly span or thermal span and they have held up.  Now, unless I want to get that period look for a Classic plane, every foam wing I build now is fully sheeted.  It is much faster than messing with some type of covering and sanding open bays.  And, after doing foam wings both ways, I see no difference in weight so I will take the easy way.

[Steve Helmick]

When you build a partially sheeted foam wing (sheeted LE, TE, cap strips at rib locations, etc.), do you sheet the center section after joining the two halves? I would think that would solve most of the folding wing problem, with just a wee bit of FG & epoxy on the LE and TE sheet joints.    Steve

[Jim Svitko]

When I did partially sheeted foam wings, I did the center sheeting on each panel before joining the two panels.  The center sheeting was cut at an angle (wider at the leading edge than trailing edge) or there was a large radius  where the center sheeting joined the leading edge and trailing edge sheets.

I never tried it the way you mentioned (sheet the center after joining the panels).  Even if done this way, I would still put glass cloth and epoxy over that center section.  I would not trust the balsa alone.