Wing bolts

[Rene Bubberman]

Hello group,

Does anybody have an advise on the correct torque value for the Large wing bolts? If I apply the torque value for a AN7 bolt this seems/feels quite heavy.

 

[jrvssgl]

Wing bolt torque

Great, Posted in july of 07 and still no answer. I was torqueing the big wing bolts tonight and the same thought crossed my mind. The torque seemed quite heavy and my better sense told me to back off. I was using the same torque as required for an7's, so set my wrench to 40 ft/lbs. Is this right? Anyone?

 

[jthocker]

That sounds about right to me.

 

[mcencula]

Bolt torque isn't intuitive

I recall reading an article years ago that indicated the relationship between bolt torque and tension is roughly a cube (iirc) function. However, humans tend to ramp up force linearly with bolt size. The result is that for bolts torqued without the benefit of a torque wrench (just done "by feel"), small bolts tend to be over torqued, and large bolts tend to be under torqued.

By way of example, this article describes the torque for a 1/4-28 bolt to be 15 ft-lb whereas a 1/2-20 bolt needs to be torqued to 131 ft-lb. Doubling the bolt diameter increased the torque required by more than eight times. (Please note these values are not valid for AN series bolts)

Of course there are other factors...the torque required to impart a certain bolt tension can be greatly affected by bolt material, plating, and lubrication.

 

[jrvssgl]

Well the wing bolts are torqued to 40 ft lbs. Sure does seem tight though. Thanks. Two more days and I can do a test run. Yeehah!!