Gear Alignment (allowable Toe Out)?

[LSaupe 123]

I am checking my gear alignment and find I have some toe out.  Is there a criteria for this (max allowable)?

 

Model III Kitfox with Cabane gear.

[Av8r3400 1179]

Well, you've just asked the proverbial Ford versus Chevy, on the top or on the bottom question.

 

The optimum situation (I think everyone would agree) would be to have zero toe in/out.  IMO a slight amount, less than 1/4", of toe out would be acceptable on a tail dragger.

[MarkD 53]

My experience with Toe Out on a RANs S6s, with tri cycle gear  with Matco brakes was not good.  The toe out condition caused the brake to not seat in properly and chatter.  The chatter got progressively worse until it caused the fatigue of the fasteners that held the piston side of the brake to the static side and the brake assembly failed on the runway.  Fortunately, it did not cause a wheel lock up and I was able to recover the parts that shed off.  I talked to George at Matco and discussed the situation thinking I had a faulty brake assembly but he was fairly adamant that the wheel alignment was the cause.  After jacking the airplane up and removing both main wheels I found the right wheel/axle had a slight toe out condition.  I applied shims to the right axle to get a neutral alignment, replaced the disc and caliper, reinstalled the wheel and re-performed the break in procedure.  The brake seated in and no more chatter. 

 

Conclusion:  Neutral alignment at a minimum,  Slight toe in if applying the brakes will flex the gear so the wheel will be neutral under heavy braking.  The RANs had a steel gear leg that would flex a considerable amount.  The tire will scuff if the toe out is more than a few degrees.

 

MarkD