Damaged Wheelpants

Ever wonder what happens if you don't leave enough clearance for your wheels when you trim your wheelpants? I found out after a rather firm landing in Sandia, NM.



I thought it was interesting that the damage on both sides was nearly identical. The tires contacted the rear/inside corner of each wheelpant. I think the reason is that the tires are distorted to the rear and to the centerline by the camber and the direction of travel when the plane touches down. If you're building its probably a good idea to give the wheelpants plenty of clearance in this area.

John

Open the gap

John, good on you for raising this critical issue with photographic proof of what is likely to happen when there is insufficient clearance around the tires.

A guy I know had insufficient clearance and when the wheel fairing of his RV disintegrated on touchdown it threw a piece of fibreglass up through the bottom of his fuel tank creating a sudden and massive loss of fuel. He was extremely lucky he didn't end up in a Concorde type fire.

I've been judging aircraft for many years so I've inspected hundreds of RVs and the vast majority have totally insufficient clearance around the tires. On many of them you can't get your little finger into the gap. It's just crazy.

I advocate that builders should aim for a minimum of 3/4" all round (front, back and sides). In actuality most of them are less than half of that in some areas.

Jup - I have that T-shirt as well

Measuring Clearance

Maintaining or checking a clearance seems simple - use an apropriate size dowel under various tire pressures, loaded and unloaded, etc? Any scenarios to check from those of you who have had experience?
Thanks.

jpowell13 said:

Ever wonder what happens if you don't leave enough clearance for your wheels when you trim your wheelpants? I found out after a rather firm landing in Sandia, NM.

Click to expand...

I realize some models have a gear shimmy problem, and the popular "fix" is moderate to low tire pressure. However, a firm arrival really does spread the tire sidewall a lot.

Want to run lower pressures, and wonder about how much you should open up the wheelpant? Remove the front half of the pant, then deflate the tire while checking the clearance. Copy the clearances on the front half.

http://www.vansairforce.com/community/showpost.php?p=888474&postcount=31

Rule of Thumb - I want to be able to stick my thumb in the gap all the way around....

(with 3 RV's, I've repaired more than my share of wheel pants)

Paul

New tires and wheel pants

Also, be sure to recheck the clearance if you change the tires. The Monster Retreads I just installed are bigger than Aero Classics requiring even more trimming.

Ironflight said:

Rule of Thumb - I want to be able to stick my thumb in the gap all the way around....

(with 3 RV's, I've repaired more than my share of wheel pants)

Paul

Click to expand...

That is exactly how I sized my gap.

For those who think they are loosening a lot of speed by keeping the gap small, think about this. If you gain 10 knots by adding the gear leg fairings and 5 by adding the wheel pants, how much speed are you really going to loose by opening up this gap?

Also, when planning you paint scheme, try to use only one color on your wheel pants because matching a fancy paint scheme and color when you repair your pants is a challenge.

Paint

Good point about the paint Bill. My original paint was no longer available, but the grey was easy to match and I kept the repaired area as small as possible. Because of the simple paint scheme and the location of the damage I was able to touch up the paint with a brush.

At least they are easy to repair - just done a pair for some chaps in UK.

They are carbon now - they won't be breaking anytime soon

I finally ended up going with a solid inch all the way around. I cracked my pants several times before paint. I have used some questionable strips in the past and operate off of grass often. I witnessed rub marks on the edges even with 3/4 clearance. During my repairs, I beefed up the area around the opening with several layers of glass. I made the sides about 1/8 thick and the aft part to include the rounded corners about 3/16 thick. I also reinforced the perimeter of dam with fiberglass tape. Periodically I woud find it loose. I haven't had any issues in the last 400 hours since reinforcing them. I thought the edges were a little flimsy to start out with.

Jerry Esquenazi
RV-8 N84JE