Thanks. It got messy again today, since I have a track day next week and I had to throw together a replacement wing for the car on short notice.
Here's the old one, in use:
Why? Well, the thing melted. It was made of Spyderfoam, which is a fairly rigid foam that's used for making surfboards. I didn't imagine that a surfboard material would have a low melting point, but while I was working on the deck I left the car outside on a hot day and didn't roll a window down. The wing was still inside, since I'd packed it there for the drive home from the track. It must have gotten above 150° in the car? I don't know for sure, but the wing's heat-shrink coating bubbled off and the foam itself melted.
The carnage:
So, I'm back in the wing building game.
The goal for this one was to have it cost no money at all -- which was possible, since I already had a lighter-weight foam core that I planned on eventually vacuum bagging with carbon fiber or fiberglass. But there was no time to teach myself that today.
So the first step was to get the old hardware off (and out) of the damaged wing. The brackets, end caps, Gurney flap and inner spar tube were all still useable. I just had to go at them with a wire wheel to get rid of the old adhesive. I had a half a tube of the structural adhesive left over, which I hoped would just be enough to adhere the stuff to the new EPS core. Here it is setting for an hour, which is all I needed with the 3M DP110 adhesive.
EPS is the stuff Styrofoam beer coolers are made out of.
To cover it, some RC guys use heat-shrink coatings or packaging tape when budget is an issue. I had some leftover adhesive and also some vinyl tape that I'd used to cover the padding on my roll bars. I figure if it sticks to the EPS, then it ought to stay put in the heat, since it was on the roll bar in the hot car and didn't come loose.
Here's the first piece of tape put in place. It seemed to make sense to do it perpendicular to the direction of the wing's travel, but it was more straightforward to do it parallel, like this. Much easier to get around the brackets for the uprights, for example. And if it does come loose, wind won't pocket in the same way as it would with a perpendicular edge.
More tape:
And done. Quick and cheap. The longest part of the project (aside from letting the adhesive set) was putting on the tape, which took about half an hour.
It's not going to win any beauty contests, but it ought to give me the downforce I need when I go out next Wednesday.
