Wheel track and toe in question.

rodsmith

rodsmith

Well-known member
I know there is a maximum width for the wheel track that Bob specifies, but I can't find the reference. I believe it is measured between center of tread and 72" sort of rings a bell. With wings and engine mounted but missing a lot of empty weight mine is 69". Reason I am asking is because I need to adjust toe in. I am measuring 2 deg toe in both sides, wondering if I should try to spread the gear to 72" or Bob's max number and measure toe in again before adjusting it. I believe Bob states that alignment should be 0 to 1/2 deg toe out.
 
Hi Rod. As far as tire spread - Bob suggests 72" at "normal flying weights". So your 69" does not sound far off. No fuel/people etc.

I would spread to 72" and check the toe in. It might improve a bit. If not and you need to adjust - email me privately if you would like my 2 cents worth on how to adjust. Mark
 
Learned something about the Bearhawk wheel alignment that should have been obvious. The amount of toe-in changes with wheel spread. It has to because as the shock struts extend they are pushing the attachment point at the axle forward which reduces toe in. With my wings and engine on the fuselage my wheel spread was 69" and the toe in was obvious just standing in front of the plane and looking at the wheels. I had to jack the wheels apart to get to a 72" wheel track. My measured toe-in at that point was 1.3 deg each side versus the 2 deg that I had at a 69" wheel track. I adjusted the toe in using the procedure Mark shared with me. I had to buy a larger torch with a rosebud. I heated the axle cluster while a friend made the adjustment with a 10' piece of 1 1/2" schedule 40 pipe which has an ID of about 1.6". Calculated the distance the end of the pipe had to move for a 1.3 deg correction. We did pretty good. At 72" the left side is right at 0 deg and I have .1 deg toe out on the left side. I'm calling that close enough, would be hard to accurately make a correction that small and I don't want to heat the axle a second time. While researching this I found where Bob had changed the plans. Original plans called for a track of 72" with 1" extention of the shock struts. Current plans show 72" track with 1.38" extention of the shock struts. I need to adjust my shock struts when I get the weight back off the fuselage.
 
Sounds like you did good Rod. Even with the 1.3 degree toe in you probably would have had a fine ground handling plane. But getting it closer was worth the effort. Mark
 
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