Building a replacement wheelpant

[MSFT-1]

I busted one of my wheelpants on my RV-10 a couple weeks ago.

I had resigned myself to buying a new one from Van's (something like $400).

The guy in the next hanger over from me has a Velocity RG that he built himself (beautiful airplane by the way). He scoffed at me when I said I was going to buy a new one. He said he would help me build a new one using the one from the other side as a mold. We would only need to build the front half.

I thought, What the heck, let me give this fiberglass stuff a try. How bad could it be? I kind have wanted to see what working with fiberglass was like anyhow.

Anyway he said I should go buy some materials (BID + West System). I went to AC Spruce to buy the stuff. The problem is that I don't know what type of bidirectional cloth is appropriate for making a wheel pant. I think we are going to do two layers and then fill and paint it. The shape is not particularly challenging in terms of the curvature. So can someone tell me what kind of bidirectional cloth is right for this application?

thanks.

[DanH]

Bruce,
Your neighbor is right; if you only need a front half it's not a hard job.

Given the extreme compound curvature, I'd suggest 7781 cloth (an 8-harness satin wrongly called crowfoot in the catalog). There's a fair chance 7781 plies can be worked into your female mold in one piece.

Yes, female mold. Clean your good wheelpant nose carefully. Place a small patch of clear plastic packing tape over each screw hole (important!). Wax it twice, then spray it twice with PVA. You now have a non-stick male form.

Drape dry 7781 over the form, smoothing it down with your hands and trimming off excess around the bottom as you go, which will help further with the draping. Leave a half inch or so of excess at the edge. The goal here is a seamless "liner" for your female mold. Saturate with epoxy, very wet, and make sure you have no trapped air bubbles. Now lay at least one more ply (two is better) just to stiffen the mold shell. Take care not to disturb the first ply.

When cured to the plastic stage, use a razor blade to trim the edge flush with the good pant. 24 hours later just squirt compressed air between the pant and the mold shell; the pant should fall right out. A lot of the PVA will be on the inside of your new mold, so wash it out, let it dry, then do the wax twice, PVA twice thing.

Lay up plies in your new mold as required. How many is right? Measure the thickness of the Van's glass. Figure roughly 0.010" per ply. For example, if the Van's glass is 0.040", you'll need four plies.

Have fun. It ain't rocket science.

[TSwezey]

How bad did you bust it where you can't repair it? My front one literally cracked in half and I was able to West systems it back together,Bondo it and paint in less than 24 hours and not a soul ever noticed. The original had such a thin wall.

[Toobuilder]

I toyed with building wheelpants for my airplane until I found the -10 parts (I have 6x6 wheels). When I got them out of the box though, I found them to be far too bulbous for the Hiperbipe (I'd never seen them in person before). So back to making my own... I built a male plug which produced a female mold. After about 100 hours of effort (from scratch, remember), I have essentially a production worthy "hard tooling" mold.

Anyway, I have pulled one part from it and it went pretty bad, which is the point of this story; Make sure you use plenty of wax on the mold with the West System epoxy - That stuff has some real "teeth"! I used 7 coats of wax and PVA and still pulled paint off the mold. I have spent the last few weeks refinishing the tool and am ready to try again.

Just don't rush it!