One Piece Air Foil Construction?

General Composites Discussions Composites Talk
#1

Im looking for help from anyone for a way to vacuum infuse or vacuum bag a air foil in one piece.
I started a project a couple weeks ago and I successfully made a 72" long 12" chord carbon air foil two piece mold. I decided to make my wing by infusing the two halves of the mold and then I used hysol to bond the two halves together.

Now I have a hanful of friend who also want me to make them a wing. The only problem is that infusing the two halves, trimming them, and then bonding together/trimming is very labor intensive. Since Im only doing this in my spare time, my one wing took me a week to complete.

Im now looking for a way to make the wing in one piece. When I first asked about wing construction a Canyon had posted a link to a method that Swift Engineering uses using silicone intensifiers/pre preg to make one piece air foils. Unfortunately, this construction method is beyond my means.

After looking around I came across a company called Kognition Designs that makes rear wings for race cars. They claim that they make their wings in one piece using vacuum infusion.

So I want to ask the experts on here, how would you infuse an air foil in one piece?
The only idea that I can think of is to wrap a foam core with carbon, put it in a two piece closed mold and then infuse from one end to the other?

#2

The easiest and cheapest way i can think of is just wrap a foam mandrel. If you want, you can dig out the foam later and bond in ribs/ends. Closed mold if you want a perfect surface and vacuum bag if you don’t care about he surface, and will finish it later by coating/sanding. Else, you will need some sort of internal mandrel you can pull out. Aluminum or presure bladder with closed outside mold.

#3

http://forums.bimmerforums.com/forum/showthread.php?t=1306900&highlight=CF+wing+DIY

I have seen this wing in person, he did a good job and it is holding up well.

#4

We make a lot of tubes and airbox ducting in split/2 piece female tooling and infuse it all in one shot.Like the one in the pic. Lay up two halves with “laps” + peel ply + perf + inf med put it all together with tubular bag and seal around end flanges of tooling then tacky tape over the seam line of the tool. Pretty straight forward.
You could do the wing the same but take your T/E laminate out onto the flange area so it’s over length (chord wise) and put a piece of plastic film between the 2 skins so the T/E isn’t actually bonded. When infused and cured remove all process materials and bond T/E with adhesive. Depending on loading of the wing, will it be strong enough without a shear web/ spar through the middle?.
Of coarse it would be easy to install one while the T/E is still open.

#5

Could u post more pics of the process looks really good just hard to visualize

#6

yeah, i’m having a hard time envisioning the process too

#7

If you want to infuse a closed box like a complete wing you can only do that with a core. If you have a open side you don´t need a core.
If you have the mould you can produce a core on your own by using for example 2k polyurethan foam. It does not need any air humidity to become hard.
But if it is a bigger part you have to drill and slot the foam to able the resin flow through the hole part.
Thats a simple way to make your own perfekt core. Use PVA when working with PU foam.