Subject: Motor Mounts
From: ACRE NL
Date: 7/1/2001, 9:16 PM

Ken Powell wrote:

Paul,
   As you know a RV-4 is very narrow (24.5" at its widest) and I would like to use the following:
22001-13  -  right front mount  140 lb axial load rating
22001-14  -  left front mount   260 lb
22001-13  -  single rear mount  140 lb
   Note that the 22001 uses a 3/8" bolt.  The front mounts will be ~21.5" apart center to center and will be mounted directly under the rear oil pan rail (PSRU end of engine).
I would like to use the 22001 rather than the 22002 because I can gain an inch in radiator width because the 22001 is 1.31" dia and the 22002 is 1.88" dia, so I gain .57" on each side for a total of 1.14".  This would  help on the RV-4.
   Is the axial load for these mounts OK?  Is the 3/8" bolt ok?

Thanks,

Ken Powell
kenpowell@aristotle.net

The axial loads are fine. The problem might be a bit of vibration
isolation in the radial direction as the Barry 22001 rubber 
bushing mount does not have a lot of rubber between the bolt spacer 
and the hole in the bracket. I also think the radial loads
are not up to the expected thrust loads. 

You will have up to 500 pounds of thrust in certain conditions. 
Average is lower than this of course. At about 200 MPH or 300 
FPS and 180 HP net out of the prop thrust is about 330 pounds. 

The 3/8 bolt will take the load no problem. 

Paul Lamar
 
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