REFLECTOR: RG Questions

[Laurence Coen]

Mack,

I agree that nylocs shouldn't be exposed to high temperatures.  Dave Dent solved this by inserting the bolt from the firewall side, placing the nut out of harms way.  My concern was that if the area where the Nyloc melted got that hot it was also hot enough to soften the epoxy supporting the aluminum bushing.  I suspect that is why the bolt bent.  If the bushing is held rigidly, the load on the bolt is carried in shear with very little bending moment.  Steel on steel bearings are a bad idea which is why the aluminum bushings had a oilite insert.  This would indicate the bolt was supposed to rotate on that bearing.  If the factory has altered the design since my kit I am unaware of it.  Despite some pretty ugly landings, my grade 5 bolts are not bent.  I also keep hearing about folks adding carbon fiber wraps to their gear legs which will make them stiffer and transfer greater loads to the gear pivot bolts.  I think that the carbon fiber wraps are appropriate for the XL which also uses a 5/8" bolt instead of the original 1/2".

Larry Coen
N136LC
  ----- Original Message ----- 
  From: MMurp16900 at aol.com 
  To: reflector at tvbf.org 
  Sent: Wednesday, April 11, 2007 3:26 AM
  Subject: Re: REFLECTOR: RG Questions


  Hi Larry
  I would like to discus main gear  installation.
  AC4313-1B  par f states"nylon self-locking nuts are not installed in areas where temperatures exceed 250 F"
  So I recommend that all nuts on engine side of the fire wall be metal locknuts or castellated nuts.
  The standard Velocity pivot bolt should 1/2 inch grade 8 and the XL should be 5/8 inch also grade 8.
  Aircraft grade bolts are grade 5 and very expensive. 
  Yes the bolt should be tight and should not rotate.It should be GREASED each 100 hours..
  The factory agrees steal bushings pressed in the gear leg rotates on the secure bolt.
  The factory is considering a change in this design.
  Regards
  Mack Murphree A/P I. A. EAA technical consular 






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