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wheel alignment on RV-6,7,9

scsmith

Well Known Member
For the RV-8, it is possible to shim the attachment of the axle to the gear strut to adjust the wheel toe-in.

For an RV-7, or any of the the other round strut RVs, is there any way to adjust the toe-in/toe-out on a completed airplane? Somebody with a fixture that can twist a gear leg?

I don't see anything in the archive after a quick search
 
The -7 and -9 gear legs come pre drilled from the factory and should be aligned. (I'm on my third engine mount, don't ask, using the original gear legs and have not had an issue.)

The early -6 gear legs have to he aligned and drilled by the builder.

I know one guy that bought a -6 with miss-aligned gear legs. He had the holes in his legs welded shut and redrilled them. I have flown his plane and it tracks as well as mine. Which is to say it tracks straight.
 
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When I first started flying my 7A in 2012, I went through the first set of tires in no time at all. I was SURE my gear legs were misaligned. I spoke to vans and they sent, (loaned), me a little device to check alignment and they were perfect. Over time I've learned the plane. I guess it was my techniques that had caused the excessive tire wear. I use to brake a lot more on landings. Now I land and just let it roll applying minimal braking as needed. Seems rolling is much easier than braking on the rubber. I think I've changed the mains only once since that first time. The current ones are still in good shape.
 
My -6's finish kit was probably delivered in 1999. The gear legs were pre-drilled in that kit.

Thanks Kyle. I added the word "early".

When I bought my 2nd and 3rd RV-9 engine mounts, there was some concern that my legs were not drilled at the factory. That has always made me wonder if some of the newer kits needed to be drilled.

In the 3rd mount, which was custom made to fit my plane and cowl, it had to go from the fabricator to Van's to he drilled in their jig, and then be sent to the powder coaters.
 
Thanks guys. I was asking for a friend who just bought a nice -7 and the tires show very uneven wear. So I was just wondering.

We will do the measurements, but the expectation based on what you have said here is that his wheels are straight.
 
Thanks guys. I was asking for a friend who just bought a nice -7 and the tires show very uneven wear. So I was just wondering.

We will do the measurements, but the expectation based on what you have said here is that his wheels are straight.

What symptoms is he seeing? Torque will cause you to scrub tread off of the left main unless you counteract the torque with aileron on takeoff.
 
Realignment is possible

I checked the alignment of a friend's 6 who had a loss of directional control incident by clamping pieces of angle iron to the brake discs and measuring to a center line fore and aft. It was way off so I removed the bolts, turned the legs in their sockets til they aligned then filed and taper reamed the holes for taper pins. I went home and checked my project the same way and wound up doing the same to my airplane.

Ed Holyoke
 
I checked the alignment of a friend's 6 who had a loss of directional control incident by clamping pieces of angle iron to the brake discs and measuring to a center line fore and aft. It was way off so I removed the bolts, turned the legs in their sockets til they aligned then filed and taper reamed the holes for taper pins. I went home and checked my project the same way and wound up doing the same to my airplane.
Ed Holyoke

When doing this, be sure that all weight of the airplane is off the gear while measuring.

By design, this style gear will always have an amount of toe-out with the airplane on the ground.
 
Thanks guys. I was asking for a friend who just bought a nice -7 and the tires show very uneven wear. So I was just wondering.

We will do the measurements, but the expectation based on what you have said here is that his wheels are straight.

Steve, I did bend a gear leg by DROPPING my RV in from a pretty good height during a BFR. It was enough to crack the gearleg fairing, bend the right gear leg, and crack the engine mount. (Thus died engine mount #2.) I flew it for about two years before the engine mount crack showed up and although the gear leg was bent, it was still find during taxi, landing, and takeoff. The right tire did wear a bit odd but I made excesses and kept flying.

Here is a picture of the bent gear leg. Surprisingly I was able to get it straightened and it has been working fine ever sense.
 
I've seen a technique to change the rotation of the leg in its socket. It involves making a fixture, attached to the leg below the socket that will align the drill bit with the hole in the leg. Sectioned tubing (basically a bent oval or disc) is welded over the original holes in the socket. Then the leg is reinserted and rotated to proper alignment/depth, and the new holes are drilled in the welded-on patches using the fixture. A longer bolt is required because of the extra thickness of the patches.

I suppose the fixture could be eliminated if you slot the holes in the socket, assemble the leg/patches into/onto the socket with the longer bolt, and tack weld the patches to the socket. Remove the leg and finish the weld.

Charlie
 
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