Model IV-1200 factory tube landing gear alignment discussion

[GWright6970]

I have done a search on here and in the internet regarding toe in and toe out. I checked my gear out per the excellent photo procedure on here, and found that my 1993 factory tube gear has BOTH sides with a toe in of about 1/2 inch to the aircraft center line, on 8 inch wheels and 21 inch Nanco tires.

There are at least 3 of us builders in search of your experience and knowledge!

Before I embark on disassembly and attempting to bend these axles, I wonder just how necessary this is. I can put up with the tire wear on the outsides. My questions revolve around if people are successfully landing aircraft with this much toe in, or any amount of toe in? Did you ever measure the toe in loaded, and in the 3 point attitude? Have those with positive camber (tire top is outward from the fuselage) had to ever adjust the camber also? How did you successfully correct the toe in or camber? Did bending the axle result in having to make modifications to the brake calipers, etc?

It is my hope to have this thread be dedicated to factory tube gear experiences. Thank you!

FYI.. my Kitfox is now registered, and after I address this issue, I will be proceeding to the Airworthiness Certification process... super close!

[avidflyer]

Here is my take on it. If you are running right down the runway straight and level, then the tires will be scrubbing themselves off more or less the same amount with the toe in you have. But then you start a swerve to the right, weight will shift to the left wheel somewhat, and maybe the left wing goes down some as well. Both of those things will add more weight on the left wheel, and less on the right wheel. Where is that left wheel pointing (considering the toe in you have)? I would say it's trying to steer you more into the swerve rather then neutral or the other way, which toe out would do. That's why I would say neutral or just a slight bit of toe out is the way to go. I'm no expert, but like everyone else, I have an opinion, and this is it! :-) JImChuk

PS when I measure the toe in/out, I make a mark in the center of the tires, and measure off that mark when it's straight ahead to a center line or the other tire. Then rotate the tires back 180 degrees and measure from the same mark again. That should be way more accurate then measuring off the sidewall of the tires.

[GWright6970]

Jim,
Thank you. I agree with all of your response. I measured as per your procedure, from center of tire to center of aircraft line that was determined by a set of plumb Bob's off the center of the prop, and the tailwheel spring attachment bolt.

I wonder what those who are flying with toe in can add to this discussion?

Thanks Jim!

[efwd]

Believe I recall you said you have a toe-in condition. If that's correct, then the handling characteristics you describe are precisely what you would expect with a toe-in condition from what I have read. I believe it is recommended to be neutral or slight toe-out for this reason. I bought shims from Kitfox. They aren't the cheapest peices of aluminum (less $$ than Grove) but my airplane tracks true down the runway. I believe I did the deed with two shims.

[rv9ralph]

On my Model 3, I had toe in on the left and neutral on the right. On landing the aircraft wanted to divert to the right so hard the I could hardly keep it straight... it was a struggle.

To measure I used a straight edge (6 foot level) on the rim of the wheel. To get an accurate line, I used 3/4" nuts as stand-offs from the rims to the straight edge.

By whatever means, make both neutral.

The method of correcting by putting a pipe on the axel and tweaking to straighten in not intended to bend the axel, it is intended to twist the landing gear.

Ralph

[Slyfox]

On my Model 3, I had toe in on the left and neutral on the right. On landing the aircraft wanted to divert to the right so hard the I could hardly keep it straight... it was a struggle.

To measure I used a straight edge (6 foot level) on the rim of the wheel. To get an accurate line, I used 3/4" nuts as stand-offs from the rims to the straight edge.

By whatever means, make both neutral.

The method of correcting by putting a pipe on the axel and tweaking to straighten in not intended to bend the axel, it is intended to twist the landing gear.

Ralph

but if you have the grove gear, I think you can get shims from kitfox to kick the wheel in or out.

[Auster]

You were also asking about tyre wear with positive camber e.g. top of the tyre further out than bottom. I have the standard grove gear and wheels with 8" Air Trac tyres on my S5 Outback. After a little more than 400 landings, almost all of those on tarmac, there is very little tread on the outside of the tyres and plenty remaining on the inside. This weekend I will swap the tyres around and start wearing the other side.

Does my experience match others with this set-up?

[GWright6970]

Ralph,
What method did you use to correct your alignment?

Excellent information, thank you!

[GWright6970]

Auster,
Good idea on rotating your tires to compensate for wear. Have you ever measured for toe in or out?

Thank you for relating your experience!

[Auster]

Auster,
Good idea on rotating your tires to compensate for wear. Have you ever measured for toe in or out?

Thank you for relating your experience!

We did measure back when the plane was built. about ten years ago, and I think it was neutral but I will check again tomorrow when it is in the workshop. It isn't the easiest plane to keep straight on take-off or landing but I just put that down to it being a Kitfox and that I have to work a bit harder than in other taildraggers. Will report back.