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  #11  
Old 12-28-2020, 12:24 PM
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Erimo Erimo is offline
 
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Location: Marcoussis, France
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There is also this positive camber on my 14, but the tires are very little and symmetrically worn after more than 250 landings (Michelin Pilot).

Could this rapid wear not also come from a lack of parallelism ?
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  #12  
Old 12-28-2020, 12:30 PM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
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Had one customer come in with persistent tire wear similar to yours but not as dramatic. Did all kinds of trouble shooting to figure out the cause, nothing. One day I was riding with him & noticed he tended to yaw the plane in flare, every time. He didnít realize he was doing it, essentially scrubbing the tread off his left tire every time he landed.

I donít think this is the problem here though. I notice the sawtooth pattern around the tread outter edge. From my days in a tire shop long ago, weíd say you probably have a Toe-in problem compounded by the camber issue.
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  #13  
Old 12-28-2020, 12:31 PM
Mikeavny Mikeavny is offline
 
Join Date: Apr 2018
Location: Port Jefferson, NY
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I am presently building a 14A and happen to be working on Section 40A which states that shims are available for order on the Van's website if you too much toe in or out camber. This is determined using a string and is documented in the instructions.
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  #14  
Old 12-28-2020, 06:47 PM
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f1rocket f1rocket is offline
 
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Just FYI, your problem is not caused by the camber. Itís caused by too much toe in. Get a laser tool, level the airframe and measure the actual amount of toe in/out of each wheel. Then order the appropriate spacer for each axle to get you as close to zero toe as possible. If itís close, very slight toe out is preferred over toe in.

These are just my opinions based on 30 years of building 6 airplanes and a lot of experimentation on gear configuration, especially on my Rockets.
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  #15  
Old 12-28-2020, 08:28 PM
RonS RonS is offline
 
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Quote:
Originally Posted by f1rocket View Post
Just FYI, your problem is not caused by the camber. Itís caused by too much toe in. Get a laser tool, level the airframe and measure the actual amount of toe in/out of each wheel. Then order the appropriate spacer for each axle to get you as close to zero toe as possible. If itís close, very slight toe out is preferred over toe in.

These are just my opinions based on 30 years of building 6 airplanes and a lot of experimentation on gear configuration, especially on my Rockets.
I will check the toe-in. Do you know if this can be done with the airplane resting on the gear or do I need to jack it up?
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  #16  
Old 12-29-2020, 06:01 AM
RV6-KPTW RV6-KPTW is offline
 
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I too have camber but did add shims to address a toe out on one side. No sign of tire wear at 80 hours. Look at 40B-06.
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  #17  
Old 12-29-2020, 06:07 AM
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Quote:
Originally Posted by RonS View Post
I will check the toe-in. Do you know if this can be done with the airplane resting on the gear or do I need to jack it up?
No you don’t need to Jack up the airplane but I would measure the toe with the airplane in the landing configuration, weighted to your typical operational weight, with the mains on grease plates.

It’s a lot of work but pays off in better tire wear and improved handling at high speed. I actually changed shims on my Rocket three times before I was happy with it.
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Paid through 2043!
Lund fishing Boat, 2017, GONE FISHING
RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
F1 EVO - partially completed, Sold
F1 Rocket - Completed 2005, Sold
RV-7A - Partially completed, Sold
RV-6 - Completed 2000, Sold
Long-EZ - Completed 1987, Sold


Last edited by f1rocket : 12-29-2020 at 06:09 AM.
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  #18  
Old 12-29-2020, 01:48 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by f1rocket View Post
Just FYI, your problem is not caused by the camber. Itís caused by too much toe in. Get a laser tool, level the airframe and measure the actual amount of toe in/out of each wheel. Then order the appropriate spacer for each axle to get you as close to zero toe as possible. If itís close, very slight toe out is preferred over toe in.

These are just my opinions based on 30 years of building 6 airplanes and a lot of experimentation on gear configuration, especially on my Rockets.
Since shims in very small angle increments are available, suggesting any toe out is bad advice in my opinion.
If a builder has to accept any amount of mis-alignment, slight toe in is preferable to toe out because all of the different landing gear loads (braking, rolling drag, tire spin up, etc), will generally add a toe out change.

Builders should also note that adjusting for neutral alignment is only valid with the wheels on the ground (and on grease plates) and the airplane loaded to an average percentage of gross weight.
If you follow the build manual and adjust the gear alignment while assembling the landing gear, the specified toe in value should be used.
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  #19  
Old 12-29-2020, 03:03 PM
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When I wrote my response I KNEW that Vans recommended slight toe in. I could not disagree more. We could rehash all the engineering logic but thereís no point to it. To each their own. Do what works for you.
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Paid through 2043!
Lund fishing Boat, 2017, GONE FISHING
RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
F1 EVO - partially completed, Sold
F1 Rocket - Completed 2005, Sold
RV-7A - Partially completed, Sold
RV-6 - Completed 2000, Sold
Long-EZ - Completed 1987, Sold

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  #20  
Old 12-29-2020, 06:25 PM
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rjcthree rjcthree is offline
 
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Default Grease plate alternate

And if you donít know the poor racers (As in most SM racers) grease plate trick...a clean heavy duty garbage bag folded over a couple time on a smooth surface is very camber / toe / suspension settling friendly. The will allow the tire to slide all around while taking weight.
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