torque values

[Rex Havis]

I am interested in knowing if the torque values are the same for wood as they are metals. I have removed the metal fitting on the wing spars and would like to confirm the torque values that I should use are the same for wood as for metal structures.

[flyguy]

Re: torque values

Apparently you just scared the hell out of the 54 people who viewed this thread.
So I will put it simply and emphatically for them. NO.
DC

[Pearson]

Re: torque values

I thought the bushings in the spar took all the compression of the bolts. If you are compressing wood, there is no way any sort of torque setting would maintain a set value with all the expansion and contraction.

[Rex Havis]

Re: torque values

Ok my question was answered, now can anyone tell me where to find the correct torque values that I should use for the different size bolts that are used for the spars metal fittings.

[Pearson]

Re: torque values

In the wing attach fittings the bolts are in shear, therefore a torque value is not needed. If the bolts were in tension, a torque value would be needed.

[mulwyk]

Re: torque values

Rex:
There's a torque chart in AC43.13-1B on page 7-9.
I know a guy who rebuilt an old Corvette. He did a great job. He torqued every single bolt on the whole car. Not because he had to, just because he wanted to do it right. You should be commended for wanting to torque your wing bolts.
But I'm not sure there are any bolts in the wing that would require torqueing and the ones that bolt through wood could do real damage if torqued too tight. In my wings anyway, there are only bushings in the front spar under the wing attach fittings. The other fittings use just plain holes drilled through the wood spar.

Are you rebuilding your wings? Got any pictures to post?

[Rex Havis]

Re: torque values

Thanks for the information Bob, in answer to your question, no I'm not rebuilding the wing, but I have removed all of the metal fittings and compression struts and have had them sand blasted and epoxy primered along with the airframe. At this point I do have pictures, but my computer skills are limited. I will post some of the pictures as soon as I get one of my computer savvy friends to show me how. Again Thanks and have a great fly day. Rex

[Guest]

Re: torque values

Do not use a torque chart for fittings attached to a wood spar.

It is not the correct procedure.

What did the A&P that is supervising you say to do? Or do you have a rating?

[astjp2]

Re: torque values

Just snug plus about 1/8 to 1/4 turn. any more and you break the grain and wind up doing repairs. Tim

[Robert Lees]

Re: torque values

I agree with the foregoing. Fundamentally, because the bolt is in pure shear, the nut's only job is to stop the bolt from falling off, so the minimum torque necessary to ensure a snug fit will suffice.