dunc
Active Member
- Joined
- Aug 1, 2016
- Messages
- 255
- Location
- Crawford, CO
- Aircraft
- AR-1C 915is, RAF/SH/SC
- Total Flight Time
- 5000
I am about to replace the upper mast with a SC unit. The lower attach bolt bushing has two holes in the blue anodized aluminum bushing. Understood.
However the upper mast attachment bolt went through a soft (degraded?) off-white plastic(?) bushing. The plastic was sticky and could be deformed/penetrated with a standard screwdriver. About the consistency of a wax candle but stickier, not as brittle. What is this stuff?? This bushing appeared to be one piece with extruded ends on both sides. How as could this ever be inserted? Is this "factory stock" or what should be used here? I destructively removed this for the photos. It just did not seem "right".
There are also two 1/8" thick nylon(?) or propylene(?) plastic shims on either side of the lower mast. This would seem to cause deformation of the upper mast plates. The uppers are built with spacers to have a 2" width, as is the lower mast. But adding these two 1/8" thick spacers would cause a 1/4" deformation of the upper mast side plates. Is this correct parts/assembly procedure?
However the upper mast attachment bolt went through a soft (degraded?) off-white plastic(?) bushing. The plastic was sticky and could be deformed/penetrated with a standard screwdriver. About the consistency of a wax candle but stickier, not as brittle. What is this stuff?? This bushing appeared to be one piece with extruded ends on both sides. How as could this ever be inserted? Is this "factory stock" or what should be used here? I destructively removed this for the photos. It just did not seem "right".
There are also two 1/8" thick nylon(?) or propylene(?) plastic shims on either side of the lower mast. This would seem to cause deformation of the upper mast plates. The uppers are built with spacers to have a 2" width, as is the lower mast. But adding these two 1/8" thick spacers would cause a 1/4" deformation of the upper mast side plates. Is this correct parts/assembly procedure?
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