[yankee-flyer]

I saw this mentioned in a much earlier thread but didn't see a definitive answer. When turning AN-3 bolts into the nutplates for the Vertical Stab rudder attach brackets and stabilator control horns the listed 20-25 inch-pounds doesn't appear to do much more than snug them down, if that. A query to Van's produced the reply "Estimate the drag of the elastic and add that to the torque values". Did anyone come up with a realistic setting for a torque wrench? My best guesstimate would be adding 15-20 pounds to the published torque values for the nutplate nolts? The rudder attachment brackets and control horn brackets seem like pretty important pieces-- I don't want to over-torque their bolts but neither do I want to leave them too loose. What did you more experienced builders do (this is my first time, and as an aero engineer I may be over-thinking things, but all my experieces is in design, not practical assembly).

And did anyone get the ELT bracket yet?

Thanks

Wayne Moyer N143WM

 

[Mel]

There is NO "standard" drag torque!

You need to measure the "drag" torque of each bolt/nut combination. There can be a lot of drag variation between locking nuts; especially the all metal "crimped" style.

 

[Mich48041]

Torque

Wayne,
I think it is better to not add any additional torque than to arbitrarily add 15-20 inch pounds. Assuming that you have a dial type torque wrench, watch the dial to see how much torque is required to turn the bolt before it starts to tighten up. Add that amount to the published torque value. Torque wrenches have a long handle compared to to a 3/8" open end or box end wrench. If you grasp the torque wrench handle at the same distance from the bolt as if you were using an open end wrench, then you will get a better feel of the applied torque. A nut driver will give even better feel. When tightening nuts or bolts, more is not necessarily better, and could be worse. If a bolt is stressed to near its breaking point, then it could break when flight loads are added. If you can not measure the additional torque required by a locking type nut, then I would just tighten to the maximum published value.
Joe