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RV7-A model: Access to torque landing gear mount hardware

Draker

Well Known Member
Looking ahead in the plans, us -A builder eventually need to install the WD-721 landing gear mounts against the F-704 center section bulkhead with bolts on the top and bottom of the mounts. Once the bottom skin is riveted on, getting good access to those bottom nuts will be challenging:

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I will be able to get a long skinny wrench down there, but not any torque wrench I've seen. Before I button these bottom skins up, is there anything I can do to make this task less of a P.I.T.A. later? Is it acceptable to measure/set the torque on the bolt sides instead of the nuts for these?

I decided to install the F-663 control column mounts to the bulkhead before riveting the skin for this reason. But I don't think it would be possible (or wise) to install the gear mounts early too.
 
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bolt/nuts can be tightened from either side. Washer goes on the end that will be rotated when tightening.

Larry
 
What Larry said. Some have to be torqued from the back side of the spar. Add the drag torque to the required torque. In same cases, a large flat screwdriver is all you can manage to hold the nut stationary.
 
Yep these were somewhat of a pain but not terrible. Don't forget that rogue hidden washer on the one on the right too.
 
Cool idea on that crow foot socket, maybe I'll try something like that. Good to know it's no problem torquing from the bolt side if I don't manage to get the socket down there. Wilco on the hidden washer, was reminded of that guy a couple of times so far.
 
Modified Tool

While at that point on my 9A, I took a ratcheting box wrench and added a flat piece of steel, secured together with duct tape. This was the only wrench I had that didn't have too much of an angle to fit in there. I then torqued from the bolt side. I went a little tighter than normal due to the bold drag.
 
Look, look again

Screwdriver, crows foot, duct tape, I?ll add long extension to the mix. I tended to look at those on the -9, with some forum prewarning, and usually had enough threads to washer both sides, which helped give the option of either nut or bolt turning. Turning the bolt against a stationary nut is sometimes all you have. Practicing against your torque wrench is a good idea to calibrate your hand, there will be one or two you?ll be stuck with feel.
 
Don't forget that if a crows foot is extended forward of the torque wrench that a "torque compensation" calculation needs to be performed (see AC43.13) and the value to be read on the wrench compensated accordingly. (If the crows foot is 90 degrees to the wrench handle then compensation is not required.)
 
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