MAKING WINGS

[roam]

to anyone who has made wings for their car, a few questions
- did you vacuum bag your carbon? If so was it for any reason other than to creat a stronger join between the carbon and foam?
-were the sides of the wings glassed independantly from the effective surface area(ie leading edge to trailing edge). How did you make a bond between the sides and the effective surface area(eg carbon tape?)
- How did you get the 3mm radius on the trailing edge?. Any advice etc would be greatly appreciated

[roam]

to anyone who has made wings for their car, a few questions
- did you vacuum bag your carbon? If so was it for any reason other than to creat a stronger join between the carbon and foam?
-were the sides of the wings glassed independantly from the effective surface area(ie leading edge to trailing edge). How did you make a bond between the sides and the effective surface area(eg carbon tape?)
- How did you get the 3mm radius on the trailing edge?. Any advice etc would be greatly appreciated

[Scott Wordley]

Check the past threads on wings lots of info there.

Vacbagging the carbon with the foam in one operation is very hard as any slack will bunch at the leading and trailling edges and require trimming and additional carbon in this area. If the trailing edge is not 3mm rad you cut off the carbon and relay it till it is. Scruitineers are very strict on this. So think at least 3 separate vac bags PER element. Then you have to finish the surface to a reasonable level, think filler, primer and paint or if you want carbon look, brushing on resin. Did i mention lots of sanding?

Or you look at making good quality plugs, then moulds then wing halves and then join them together using some internal structure. Better surface finish, stiffer and can be lighter but even more work overall.

Vac bag everything you can to keep the weight down and improve the smoothness of the product.

Its May so I'd get started if I were you guys.

Check out the pictures on our website, follow the link below

[imajerk]

Monash's 2003 wings, which Scott slaved away at, are fantastic (with the aid of beerhttp://fsae.com/groupee_common/emoticons/icon_smile.gif. Scott's second suggestion is really the way to go.

Or, you could find some nice companies in China http://fsae.com/groupee_common/emoticons/icon_smile.gif which have aluminium extrusions of a few common aerofoils. However - best to find a local distributor if there even is one. Or, get a good engineering shop and they can press a profile with a soft radius tool and then weld the halves together. If you do this, you can slot some holes along the surface so you can weld some internal stiffeners from the outside, which greatly increases load capability. You can then hand grind with a polishing disc or set-up the profile on a horizontal grinding machine and make a few very precise runs. That's how I do it. The main advantage here is you can press lengths of 6m or more at once... you'll end up with heaps of left over but you can give them to other FSAE teams.

But, needless to say aluminium wings don't look as flash as Scott's 'slave away for a long, long time' method.

[roam]

to scott,

agree that moulds are the best way. How long did it take to make your moulds, cause the way i have should take round 3 days. Also what did you use as the sideplates after ou joined the two halves together?

[James Waltman]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by roam:
- did you vacuum bag your carbon? If so was it for any reason other than to creat a stronger join between the carbon and foam?
<HR></BLOCKQUOTE>

roam,
Vacuum bagging improves consolidation and removes excess resin. These two factors give a better volume fraction (ratio of reinforcement volume to matrix volume). Better volume fraction means stronger, lighter parts. It should be illegal to lay-up carbon fiber without a vacuum bag or some other form of consolidation.

What do you mean by "stonger join(t) between the carbon and foam"�? Are you thinking about making a foam core/plug and laying carbon fiber over it? How are you planning on making it? Three days is a very short time to go from nothing to complete part.

I agree with Scott and imajerk. Plug/mold/part is the way to go – unless you skip the plug step by machining the molds.

[Scott Wordley]

To make all 8 of my plugs and moulds took at least 2 months. And thats working on them nearly every night.

[Jon Huddleston]

At UTA we use a 4 element wing that was designed and cut from Renshape to form the buck or "tool". Then we laid up a fiberglass mold on that surface. We stack a few layers of prepreg carbon on the mold. Takes about 1 hour per wing element. The elements are then autoclaved (must be vacuum bagged or else.)(Ugly,and heavy with resin!)to form taco style shells. Then carbon-nomex endcaps of the wing profile are epoxyed with toughened adhesive and larger elements with "ribs" and "spars" to strengthen them. Then the wing shells are clamped together with the internals in place and toughened adhesive on the trailing edge. The radius rule is achevied by clamping a 1/4 inch wide honeycomb between the trailing edge with more toughened adhesive.

Lots of expensive toughened adhesive used. About 40 dollars for 200ml (thank our sponsors for not making Us pay.) But once the tooling is done it really only takes a two from start to finish. Great looking wings! Maybe next year...