How do I keep the wheel pants from falling off my 4*120? I lost one on the second flight, and the other one was loose too. Now I fly without them because I haven't found the one that fell off yet. It's somewhere out in the corn along with my T-34 canopy.

Although now without wheel pants, the plane doesn't bounce when it lands.<br type="_moz" />

From the sound of it, maybe you're happier with the wheel pants off.

Without seeing the actual wheel pant construction, about all I can give you is a general guide. (1) Mount a 3/32" or 1/8" birch-ply block above the axle inside the wheel pant on the strut side. You can sand it to match the inside curve if you want, or just slather on a bunch of epoxy or PU glue and clamp it in place. Mount the wheel pant, and drill a couple of 1/16" pilot holes from the inside of the landing gear strut into the wheel pant and the ply-block. Drill the pilot holes on the strut out to 3/32", then use two #2-1/2" wood/sheetmetal/socket head screws to hold the wheel pant onto the strut.

If you're flying off pavement the wheel pants should work well. The rougher your field, the greater their tendency to twist off, just from getting knocked around by weeds/rocks/rough landings.

The pants had threaded holes in them, and the screws felt tight, but looks like the rough ground loosened them.  There isnt much clearance that I remember to get screws inside it, but if so, by putting bolts from the inside, epoxy the heads so they dont move, and then a nut on the inside of the strut, would that work?  The screws were rather short and small too.  If I remember I will get a picture of the parts I still have posted, pictures are worth a thousand words as they say.

Especially in this case.

Your idea about installing the bolts from the inside would work, although I find trying to tighten small nuts kind of a pain.

What surprises me is that you have such tight clearances. With a 4*120, you're flying with what? 3.5 or 4" wheels? So I'd think your LG setup would be an aluminum strut with a bolt-through 3/16" axle? If that the case, the normal sort of lineup from inside to out would be strut, wheel pant side, wheel collar, wheel, another collar, and the outside wheel pant side. So you should have 1/4" to 3/8" of clearance between the side of the wheel pant and the wheel hub.

I'd try something like this: epoxy as thick a wooden plate as possible, probably 3/16" or 1/4", to the inside of the wheel pant. Then drill the pilot holes as mentioned before. Instead of using wood screws, put in a #4 or #6 blind nut on the inside of the plate. Then drillout the holes in the strut to take a #4 or #6 socket head cap screw, trim the screws to the length you need, and then you can bolt the wheel pants to the struts. This should give you more strength in the mount. If you're worried about rough landing destroying the wheel pant, use a nylon bolt on one side of the strut so it can shear off and let the wheel pant rotate.

Wish I could draw this, but you'll have to take the 1000 words

When building ARFs I'll usually forgo the mounting block already in place, remove it if possible and make my own.

The idea is to move the pants UP so that you have as much ground clearance as possible while still retaining the looks of the plane.

I will also use small blind nuts and bolts to put them on.

I have had no problem with the wheel pants coming loose on ARFs. The "secret" is to use blue LockTite on the mounting bolts before screwing them in the pants. You can get it at many places including Tower Hobbies.

Bruce

I didn't think the loctite would work on the fiberglass.  I gave the blind nuts a thought too after posting. The clearance issue isnt with the pants, but getting to the inside of the pant to tighten the screw or nut as the opening is pretty snug around the wheel.  If or when I find the lost pant I will give it a shot with thicker ply inside and blind nuts.

Try using Sig's wheel pant attachment (SIGSH727 )....they have never failed me and I used to fly off grass!

Why wouldnt they be part of a SIG kit that has wheel pants? The question had to be asked! LOL

I pulled the one pant I still have off the shelf. It has 3/16" of block for the bolts, but its all fiberglass, so blind nuts wont work very well.  When I get the other one back and flying season is over I will get them to stay put.

Let us know how you come out.

Just in case you didn't know Sig has replacement wheel pants for their
4*120 part number SIGSH744 $25.99 + S&H. These are the ones for
the kit built plane, if yours is an ARF they might have them also, give them
a call.

Red.......SIGRPWP265ARFR
Yellow....SIGRPWP265ARFY

In addition to the above suggestions, add another block inside the OUTER half of the pant, with a hole the diameter of the axel drilled into the block . Center the hole so the axel plugs into it when the pant is secured using one of the above suggestions. This arrangement should eliminate much of the up-and-down flexing of the pant which has been part of your problem.

Jack

Thanks for the tips!

And here is one more tip to add to the many good ones already suggested. Use a FG cloth and epoxy to extend over the new plates installed inside the pants. Lather the epoxy on good over the cloth. Extend the cloth another 1/2" OR MORE beyond all edges of the plates. If you don't do this you will find that your pants WILL eventually crack at the weak point which is at the edges of the plates. I absolutely love wheel pants and most of my planes have them. No matter how perfect you might always land, the pants take a beating and do eventually crack somewhere. Jon

Doing this takes almost all the flex out of the wheel pants because they are held in place from both sides which is 99% of the battle.