# Airbike Composite Wing

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#### kendavistoo

##### New Member
A few years ago some fellows developed an interesting method for constructing wings for an airbike. What do you all think of this method? It is described at

Airbike Project by MG&BB

Look under the section "Building A/B", "April 17, 2003 - Wing almost done + engine"

#### WurlyBird

##### Well-Known Member
I am equally interested to see what those that know more about composite design have to say about this. I think taking an internal structure and simply adding a stressed skin can greatly impact the structure itself. I am working my way through the books to figure it out exactly, but it does not seem to me that it should be to hard to design and build a composite wing or structure once you understand the fundamentals.

#### cluttonfred

##### Well-Known Member
HBA Supporter
Interesting...if you go through to the most recent video, you see that they are glassing the wings in the end rather than typical fabric covering. I'd be very interested in seeing some numbers on this type of construction, especially the weight and impact on overall wing strength vs. fabric-covered plywood ribs (which I think are typical for the Airbike) or even fabric-covered foam and plywood ribs.

EDIT: One variation on this technique, which I would want to use if I tried it, would be to lay out the glass on an acrylic or similar plastic sheet, squeegee out the excess resin, then slip that sheet and glass into some female profile molds to take the rough shape of the wing. That way, the skin would already be glass smooth on the surface and you could bond it to the foam in one step.

#### wsimpso1

##### Super Moderator
Staff member
Log Member
Wooden spars, foam filled, glass covered... Um, that was introduced with the KR's in the 1970's.

Fabric covered wings involve building a bunch of ribs, getting them all installed, straight, laced diagonally, and whatever other reinforcements are needed then the fabric covering, tapes, rib stitching, etc. To skip most of that and install foam and glass is physically easier and perhaps quicker, but fabric covered wings in this wing loading and speed range will usually be lighter at the same strength.

Weight you do not need is payload sacrificed and reduced performance.

Billski

#### Hugh Lorimer

##### Well-Known Member
Some photos of a wing construction made thus.............

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#### sachaknoop

##### Well-Known Member
Thanks! love to see constructions of wings! more picks are always welcome.
Sacha

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#### sachaknoop

##### Well-Known Member
Ah, Thanks again Hugh!
I am curious how the main wing is finished I see a foam outer layer? So the wing is, except from the 2 spars, almost entirely built out of foam?
Hope you can describe how the wing is finished..

Regards
Sacha

#### Himat

##### Well-Known Member
Thanks for sharing!

#### Hugh Lorimer

##### Well-Known Member
Hi Sacha, the outer panels are 0.5 inch extruded polystyrene covered with 290t glass cloth with West System 105/205 epoxy resin. Because epoxy dries with an oily surface I de grease the surface with a strong detergent and after a quick rub down I found white undercoat paint best, the pinholes don't matter because the speed is low and will not affect performance.

Hughie.

#### sachaknoop

##### Well-Known Member
So That does the trick! Seems like a really simple way to build a wing, but do I understand that the glass skin is not directly connected to the spar? Is that strong enough?
When I want to finish a glass surface I always cover it with peelply, so there is no need for using detergents. The pinholes I fight by putting on highbuild epoxy undercoat, and squeegie that into the pinholes. Then sanding and spray finish.

I was thinking of making wing skins, but with a sanwhich of glass/foam/glass. I would cover one side of the foam with glass, and put the glass side on the wing when wet, so it would bond with the ribs and spar. Then use maybe mild vacume or probably just weights for curing. After that there is a chance for smoothening the surface, and wrapp the wing in the outer layer of glass. Do you think this would work, or does this just asks for a lot of new problems ????

Reg.
Sacha

#### sachaknoop

##### Well-Known Member
Huhg,
Just asking; are you building something at this moment???
Seems like you are the kind of guy that always has something new to build on, or am I wrong???

Sacha

#### sachaknoop

##### Well-Known Member
I would like to post a small rhino drawing here, but have no clue how to post it???
Sacha

HBA Supporter
Export to PDF?

#### wizzardworks

##### Well-Known Member
sachaknoopp, In Rhino4 go the the view menu and down to capture. Select JPEG and give the picture a name. Then add the picture as an attachment which is the fourth icon from the right in the reply toolbar here. For 3D use the perspective window and render the view. Save the file in the rendered view as JPEG in the save as file menu.
wizzardworks

Ok, lets try:

#### sachaknoop

##### Well-Known Member
that's a bit small ehhhhhh.
I'll try again later, but thanks for now

#### Pops

##### Well-Known Member
HBA Supporter
Log Member
Back in about 1960, an article was in the EAA Mag about a homebuilt that was built by making skins from fiberglass on sheets of aluminum and using the fiberglass sheets as plywood in covering his wings and fuselage sides. I think the airplane was called "Old Iron Sides"
I started hot wiring model airplane foam wings and covering them with balsa about that time. Dan R.

#### Hugh Lorimer

##### Well-Known Member
Hi Sacha, I am afraid I now suffer from Parkinsons so I am a has been.But I am still interested. I hope the attached helps to explain the construction of the spar joint treatment. I sandwich the lower closing plate from root to strut hang point to act as a drag spar.

Hughie

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#### sachaknoop

##### Well-Known Member
Hi Hugh, that is sad to hear, but nice you are still interested, and hopefully you can help us which we highly appreciate.

I am working on the design of a wing according to a list of demands (which I have to specify further). In short it should be a wing ment to build an airchair like Mike Sandlin is building. The wing should be made of mainly composite materials, with most parts CNC cut out of foam (needs further specification). The idea is easy fabrication, the spar will be pultruded carbon with a glass, or carbon web. I want the wing skin to be sandwhiched in between an outside/inside layer of glass. The previous drawing shows the connection with the spar (ignore the front and back of the wing please). The inside of the wing consists of foam ribs. There will be a rear spar as well, just learning to draw, so this is a little excersise for me . First practical thing for me to find out is, if I can laminate the inside of the foam, and then get it wet layed on the ribs to close the wing. The first skin will be visible from the other side, but the second closing skin goes on uninspected.
I am curious if any experience or opinion you, or others have.
Thanks!