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RV-12 Wheel Camber

Vantastic12

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Patron
Greetings RV-12'rs:

Question please, I'm already having trouble severely wearing the outside of my new main gear tires after only 50 hours of taxi, take-off and landing time. In checking the KAI manual it only discusses toe-in/toe-out adjustment, nothing on camber. My toe-in/toe-out is neutral. In measuring the camber I'm seeing 6.9 degrees from vertical on the left wheel and 5.8 degrees on the right wheel, very obvious from just looking at the main gear on the ground. By comparison, my hangar partner's RV-8 tail-dragger only has apx. 1.5 degrees camber on both wheels.

Also, 28 PSI tire pressure per the manual seems low, also causing excess wear on the outside of the tires. I'm seeing no wear at all on the center of the treads yet.

How does this camber compare to yours and are you maintaining only 28 PSI in your tires? The only fix I can think of is adding shims B/T the lower gear legs and the axles to remove some of the camber, and increasing the tire pressure. Other ideas? I'd appreciate your response.
 
See photo below? I don?t have software tools but maybe someone can measure camber angle with respect to hanger floor. I installed Dresser 500-5 6 PLY AWBS RETREAD, ELITE PREMIUM 2 GROOVE (ELITE) 120 hours ago with lots of take off / landings on hard surface. Tires show very little wear.
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204e15.png
 
See photo below? I don?t have software tools but maybe someone can measure camber angle with respect to hanger floor. I installed Dresser 500-5 6 PLY AWBS RETREAD, ELITE PREMIUM 2 GROOVE (ELITE) 120 hours ago with lots of take off / landings on hard surface. Tires show very little wear.
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204e15.png

That is about 5 degrees with +/- 0.5 degrees error imho.
 
Also, 28 PSI tire pressure per the manual seems low, also causing excess wear on the outside of the tires. I'm seeing no wear at all on the center of the treads yet.

How does this camber compare to yours and are you maintaining only 28 PSI in your tires? The only fix I can think of is adding shims B/T the lower gear legs and the axles to remove some of the camber, and increasing the tire pressure. Other ideas? I'd appreciate your response.

Keep in mind that it is a light airplane.
There is quite a bit of difference in camber at light solo weights versus gross weight.

Higher tire pressure wont change the zone where your tire is wearing at all, but it will put you at a higher risk for airframe damage in real hard landings.
 
OneCNC CAD-CAM will trace an image by putting it on the screen and the user places points on the image as close to the desired image pickup points as possible. Imperfect at best but good enough for this. I used the exposed tire tread which was rather short but I thought better than the wheel pant side since there is not a flat area anywhere on it.

Unfortunately, the original image does not come with the OneCNC created .jpg image so you will have to take my word for it's accuracy.

camber.JPG


camber.jpg
 
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