Foam wing Lay Up
 

Has anyone tried to do a foam quickee wing, without the balsa skin?

I saw a great how-to video by Phil Barnes who primarly works on Sail Plane wings. He showed construction of fiberglass / carbon fiber / kevlar without skinning the foam initially with balsa.

Could this technique be used in quickee while retaining the strength and lightness of a conventionally built foam / balsa wing?

RE: Foam wing Lay Up
 

Dave:
I’ve seen this done several times. Actually I think it’s called a “Bagged Wing”. I witnessed Brian Burass do a quickee wing in less than an hour. The next day cut the control surfaces, put in the linkage in it and away you go. I don’t believe he had three hours in it. (He knows what he’s doing). While all this sounds good it does require a level of expertise in bagging I don’t have to get it to come out right. Another problem is white foam is not strong enough so he used pink which resulted in a slightly heavier wing. He also built a couple of Q40 wings this way. They all worked fine.


Barry

RE: Foam wing Lay Up
 

I don't have the skill at this point either, but watching this video sure made it look easy. I would think you could put some sort of spar in a white foam wing, and still keep the weight in tact while not compromising the strength.

I really think this could speed up the process of making a q500 wing, without expensive cnc cut molds if we borrowed some of this glider technology.

I'm not even thinking about q40 wings at this point, but quickee wings gotta be doable this way.

RE: Foam wing Lay Up
 

Dave,
Brian Buaas did a bagged carbon over blue foam Q500 wing for me, that I used at the 2002 NATS (well, for two rounds). It came out heavy (20 ounces with servo), but the fuse was light enough that the plane was less than 2oz over weight.
The problem with bagged Q500 wings is that in order to make them light enough, you need to be extremely careful, as they dent very easy. I wouldn't even think about trying one with white foam. The blue foam/carbon wing I had was marginal as far as ding resistence. If the wing was layed up lighter, or had lighter/softer foam, it would have been even worse.
Q40 wings are better suited to this technique as there is a lot more weight margin to work with, plus the wings have a lot less area.
GS

RE: Foam wing Lay Up
 

I did it once with white foam. By the time I had inserted spars, balsa L.E. etc. it came out very heavy. The wing had a finish like a golf ball. I could have used the mylar procedure but then none of the excess resin would have ben soaked up. As has been said before it was very susceptible to denting with just finger pressure. So now I had a dented golfball.

Ed S

RE: Foam wing Lay Up
 

Thanks for the replies, my question now is, why the heck are the glider guys using this procedure???

I can't imagine they would want a heavier, dent prone wing when other options exist...

RE: Foam wing Lay Up
 

Dave,

The glider guys use unidirectional carbon fiber cloth (CF uni-cloth, for short), which is more dent-resistant but also brittle. About 10 years ago I experimented with this on some F3D and Formula 1 wings. My crowning achievement was an F3D Swee'Pea wing that weighed 17 oz. (not too bad for 450 square inches) and was stiff as a surfboard. Unfortunately, the sparless construction didn't hold up very well under vibration, the top skin separated from the foam & it collapsed with a bang on its third test flight. Later versions had a full-depth spar and a thicker top skin, but it was next to impossible to keep the spar from forming a "bump" right at the high point of the airfoil. By the time I'd solved all those problems, it was heavier and much more expensive than a balsa-sheeted wing.

Ed probably remembers my black-and-silver Q40 Stinger that I flew at the Black Hills, SD contest in 2001. That airplane had blue foam cores, full-depth spar, 2-oz. glass on the bottom, 1/16" balsa and 2-oz. glass on top. It was built in a smooth fiberglass cradle that I waxed and laid up the bottom skin on -- sort of halfway between the CNC aluminum mold method and the conventional method. Looked good, came out light, went fast, but every time I picked up the airplane I put fingertip dents in the bottom skin. Now I'm back to balsa skins. Live and learn!

DHG

RE: Foam wing Lay Up
 

:)
Duane has now tried a new and technological method for wings, shoot this works for the whole aircraft, I do not think he has ever tried it before, but I am looking forward to seeing if he goes faster with it...
Its a complete molded model from Bruce DE Chastle
its called a PoleCat!!!

PoleCat
 

I am sure he will like it. Mine just arrived last week. Now if we can just get them to arrive painted...

RE: PoleCat
 

Add an elliptical wing and you'd have something there. ;)

RE: PoleCat
 

Is That the polecat with the illegal removable cowling?

Ed S

RE: PoleCat
 

Its all a matter of perception Ed. Its really not any different than using tape around an engine like I've seen the Canadiens use for the past couple of years. Just a little cleaner.

RE: PoleCat
 

Done properly with some interesting techniques, one can actually build a light and strong wing this way. The amount of resin can be controlled and Phil does utilize some methods to soak up resin before bagging. Technique is the key for the most part... The thing too is that the mylar methods are a fast way to do a clean wing without making a set of molds. Probably why they do it that way.

Michael

RE: PoleCat
 

Michael,

Aha, that must be my problem. I was pouring out 3 gallons of resin in the bathtub and submerging the foam cores in it for 2 weeks or until all the resin was soaked up, whichever came first. It did promote good adhesion of the skins, but might have been a trifle heavy.

That darn Ed! He swore it'd work great! [:@]

RE: PoleCat
 

I'm not going to give a wing a try at this point, but I do think I'm going to try a tail bagged on painted mylar to see how it turns out. Sounds like a decent way to work the fiberglass hinge and finishing onto a surface in a quicker manner.

RE: PoleCat
 

Until recently, I pretty much overdid everything on my models to ensure that they were strong. Mind you, the methods were not exactly scientific, but of the form TLAR - That Looks About Right. Now, I've built some interesting UAV's where weight is a critical issue. It is amazing how one can optimize the layup for a given model. I totally look at plywood in an entirely different light now... and I thought lite ply was light!

Dave, I first tried the mylar method on a 1/2a ace simple series model. Came out pretty good.

Michael

RE: PoleCat
 

Ok, not quite Q500, but we race these with bushing .40's. I hear how light some of the foam wings are here, my first one I cut my wing, and put a few spars, some CF, and glassed it, I probably used too many layers (.75 cloth), too thick epoxy, but it came out almost 27oz. I re-built a crashed stocker from another member, and the stock foam sheeted wing is 24oz (these are complete with servo) I'm building another stock kit now, so I may be able to make them lighter, but its glued together, le, and te on, no ail or servo, and it's at 15oz. How do you guys build the light foamies? Maybe the glue they use is heavy, the airfoil is thicker (like a E473?) so I know it will be somewhat heavier. The sweep is another problem (glue joint adds weight) and they use 1/4" balsa for wing tips. Any tips you give give me are greatly appreciated! And also any for the entire plane too... for a pic of them see click on this.. http://racingrookies.tripod.com/rookies_005.htm