Toe-in/Toe-out "That's the question!

I have a question for the "All Knowledgable" master builders on the forum.....so that I have sufficient part available. How many, and what degree alignment shims have you used to correct toe-in/Toe-out?

I'm sure I aren't the only one pondering this question....like the duuu question of where to place balancing weights on nose wheel.....or why the tube valve stem washer is to thick to start threads of nut on valve stem protruding thru wheel assembly. "Read all the info"!!!

I'm not Yoda, but I would wait to see if they are needed. They are $50 per so not cheap. I ended up with two 1/2 degree and two 1 degree wedges. After some jumbling around, I got one axel straight and one with just a hair of toe-out. Couldn't get them both perfect.

Remember, toe-out rather than toe-in although on these airplanes, they are not as sensitive to toe as the other Wittman-style gear leg models.

Wittman

It is spelled Wittman, but thank you for giving the proper credit to the inventor and original patent holder of both the flat and round spring landing gear.
The round gear is only in "alignment" for one weight and angle of fuselage to ground. The round gear is not very sensitive to toe in-toe out on lighter airplanes. As the weight increases I would expect the toe to become more critical.

With my eagle eye....I am the thickness of a string off with both axels requiring a shim to toe them in. How many degrees is the thickness of a string? is this a trial and error exercise until it looks just right or is a string thickness close enough? Can you return the shims you do not use to VANS?

I confess that I just put the wheels on and didn't try to measure the toe-in/out. 160 hours later my faith in Vans has been rewarded with even tire wear. Proving once again it is better to be lucky than good!

1 DEG = .017 Gap in 1 INCH

1 DEG = .017 Gap in 1 INCH

Note:
A little math .017 X12" = .204 X 300' = 61.2 " run in or run out

Personal opinion a 1/2 deg toe in is better then 1/2 deg toe out

The drag of the tire and the drag of the brake will flex the gear back and negate the toe in.

My View

QUOTE=ben barron;868795]With my eagle eye....I am the thickness of a string off with both axels requiring a shim to toe them in. How many degrees is the thickness of a string? is this a trial and error exercise until it looks just right or is a string thickness close enough? Can you return the shims you do not use to VANS?[/QUOTE]

Had

joedallas said:

1 DEG = .017 Gap in 1 INCH

Note:
A little math .017 X12" = .204 X 300' = 61.2 " run in or run out

Personal opinion a 1/2 deg toe in is better then 1/2 deg toe out

The drag of the tire and the drag of the brake will flex the gear back and negate the toe in.

My View

QUOTE=ben barron;868795]With my eagle eye....I am the thickness of a string off with both axels requiring a shim to toe them in. How many degrees is the thickness of a string? is this a trial and error exercise until it looks just right or is a string thickness close enough? Can you return the shims you do not use to VANS?

Click to expand...

[/QUOTE]



I believe Joe is on the money with this. I checked mine, found they were toed in slightly and left them alone. Had I found them to be toed out, I would have toed them in slightly. The auto industry used toe in for years because of this reason. 300 hours and going strong on the original tires.

Pitch attitude or block position on the axle affect the toe-in determination

I liked Scott's use of a straightedge alongside the tire. I used a level with a laser to put the dot on cardboard at 120 inches and to set a "centerline" from the tail to each side of the nose gear. The difference in measurements at the gear and at the cardboard determine the amount of toe-in.

With the airplane sitting on the tail, pitched up about 10 degrees, the total tow-in was 4.3 degrees. Setting level on the nose wheel tire, the toe-in was 0.75 degrees. The amount of camber and "caster" (forward rake of the main gear legs) make the toe-in calculations very sensitive to the pitch attitude of the airplane.

If you are using the wood blocks, make sure they are on the 90-degree positions of the axle (parallel to the airplane axis). Off-position affects the block/string method as pitch affects the straightedge method.