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EX-5VA1 Fuel Servo Mixture lever hitting bottom cowling

S

scrockard

Active Member
Has anyone had the mixture lever hit the bottom cowling while using a Silver Hawk EX-5VA1 servo?

I have an IO-320 with vertical induction O-360 bottom cowling (the one with the snout off center apparently designed for the traditional carburetor).

Vans says switch the current mixture lever out for the straight one. That should help out a lot...
see http://www.precisionairmotive.com/silverhawklevers.htm

How much clearance did you achieve in this area and did you have to modify the cowling around mixture lever area to give better mixture lever to cowling clearance?

Thanks,
Scott
 
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I talked with Precision Airmotive yesterday and I'll get the replacement mixture arm that is a straight version.

The default one was a bent version. The bent one caused me to have to put a spacer between the arm and the mixture rod end bearing. Now the mixture rod end bearing will be in about the same position as it always has been but the arm will be tucked in and away from the interference with the cowl problem. The bent one had a .938" offset so you can see the difference that could make.

I still have to put that modification into the airbox itself to allow this lever to descend down below the airbox mounting plate.

I'm not sure if I want to change the lever direction at this point since the cable is pointed in the down direction for normal mixture cable push/pull.

Finally, I'll try to measure the clearance distance from the cowl with this arrangement. If I don't get that 3/4" or more distance, I might end up modifying that cowl too. At this point I may not need to do this however.

Thanks,
Scott
 
As a follow up to this:

The straight arm version of the silverhawk throttle arm is kind of installed with some temporary hardware for fit checking purposes. It didn't line up the rod end bearing quite as nicely as I had hoped it would. My throttle rod end bearing is now at a slight angle in relation of the hole axis of the rod end bearing. I had to add an AN960L-10 and a 5702-75-60 "steel washer" between the rod end bearing and the new straight arm mixture to keep the rod end bearing clearing the straight arm throughout the full range of it's motion.

I'm attempting to find guidance right now on what the policy is for rod end bearings with regards to allowing some slight offset angles on the installation. I didn't find anything in AC43-13 yet... I know this is the purpose behind a rod end bearing in the first place but I'm not sure that is a good practice to count on that ability for the bearing to rotate at odd angles?
 
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