RV-8 Landing Gear Issue

[sjsflyer]

I (like many others) have discovered uneven tire wear on my first annual CI so I
decided to take alignment measurements before moving ahead with any remedies. My airplane seems more squirrely than others as well.
I am now suspect of my right gear leg due to the results of the measurements below taken in 3-point attitude.

Left Gear:
1.0 degree toe-in
+2 degrees camber

Right Gear:
2.38 degrees toe-out (yes toe-out)
+2 degrees camber

Also the right gear is 2/10" further back (measured to the tail) than the right gear. As a note, I did not drill/install the gear on this aircraft.
Could the right leg be mal-formed? Is it too far out to shim?

[Kahuna]

Originally Posted by sjsflyer

I (like many others) have discovered uneven tire wear on my first annual CI so I
decided to take alignment measurements before moving ahead with any remedies. My airplane seems more squirrely than others as well.
I am now suspect of my right gear leg due to the results of the measurements below taken in 3-point attitude.

Left Gear:
1.0 degree toe-in
+2 degrees camber

Right Gear:
2.38 degrees toe-out (yes toe-out)
+2 degrees camber

Also the right gear is 2/10" further back (measured to the tail) than the right gear. As a note, I did not drill/install the gear on this aircraft.
Could the right leg be mal-formed? Is it too far out to shim?

Yes you can and should shim that. You can shim a LOT if the toe of that right gear and its very easy to do on the 8. You will see an immediate improvement in handling and longterm improvement in tire wear.

[sjsflyer]

Vans said the measurements are only valid with the weight off the gear in level attitude due to stiction/friction etc. So I should probably jack it and remeasure first?

[N661DJ]

My 8 was scary to land, once the mains hit the runway (3 point) it would dart either to the right or left, not as bad if wheel landing. I spent 2 days aligning the gear using a Laser, strings, grease plates. Vans 1/2 degree shims (easily installed). End result, I was able to get the left wheel 0 degrees toe in/out, the right was less than 1/4 degree toe in. The difference was amazing, could almost land with feet flat on the floor,(not recommended however)
Dick

[Michael White]

Originally Posted by sjsflyer

Vans said the measurements are only valid with the weight off the gear in level attitude due to stiction/friction etc. So I should probably jack it and remeasure first?

Yes.

(with extra letters added to fill the minimum requirement)

[scsmith]

I agree with the other experiences here. It took a fair bit of shim, (something like 1/2 degree on one side and 1-1/2 degree on the other).
It makes a big difference in handling, and also a big difference in tire wear.

But....


The tire wear only occurs with weight on the wheels. Lift the tail up to level attitude (like you were going to do a W&B) and roll the airplane forward several feet --this takes out any stiction effects. Then do the wheel alignment measurements.

It is true that the camber will be different when the gear is lightly loaded, like on a 3-pt landing, but in that case, there is no weight on the tires, so they don't wear.
And fortunately on the RV-8, because of the gear leg design, there is very very little toe-in angle change between unloaded and loaded, so the handling should be fine for 3-pt too -- as much as you could say the handling is ever fine at 3-pt touchdown on the -8
Lots has been written about that already.

[sjsflyer]

Measurement for toe angle were different with weight off wheels of course. Not that bad after all.

Left = 0.8 degrees toe-in (ordered .75 degree shim)
Right = 0.5 degrees to-in (ordered .5 degree shim)

Will install 1 degree shim both sides to reduce positive camber (light engine/prop combo).

Right gear still measured .2" aft of left gear (is what it is).