Foward Motor mount reinforcement

Questions, best practices, and general info regarding getting your hands dirty

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lourubin
Posts: 4
Joined: Sun Apr 16, 2023 3:32 pm

I recently had a motor mount fail in several areas due to a violent nosewheel shimmy caused by a collapsed strut . I purchased a new mount and added reinforcement according to the Lancair SB. I've noticed on several ES aircraft including mine the forward mount attach metal donuts had a tendency to expand from the left donut to the right donut. This is quite evident from the elliptical pattern of the lord mounts instead of being concentric as they are on the rear mounts. Id be interested to hear from other owners if they have expanded forward mounts. I'm not sure if the Legacys, 360s, and 4s have the same mount configurations? if they do I'm sure the same problem could be evident.
It appears the bracket bolted to the engine is preventing the mount from expanding to failure and cracking however, I believe its putting a serious sideload on the engine mount itself. If you look at the rear of the engine mount there is a lateral tube running left to right reinforcing the rear donuts however there is nothing on the front. I believe there is a design flaw, and the front needs to be reinforced as the rear is. I'm currently making modifications on the front mount and will send pictures when its completed.
George Wehrung
Posts: 183
Joined: Tue Nov 22, 2022 3:56 pm
Location: KMRH

Lou are you speaking of the welded plate gusset scythe front of the engine cradle?


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lourubin
Posts: 4
Joined: Sun Apr 16, 2023 3:32 pm

No I’m talking about welding another reinforcement bar on the foward donuts
The gussets does reinforce the foward mount but I’ve seen lateral movement in the foward donuts on Sarah’s plane and mine She had the gussets installed.I didn’t
George Wehrung
Posts: 183
Joined: Tue Nov 22, 2022 3:56 pm
Location: KMRH

I will take a pic tomorrow. I pull the cylinders tomorrow. Today I got the Emags, fuel pump, starter & adapter, and the prop governor pulled.


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