Splitting Jam Nuts

[jasimmons]

Suppose you run out of rear strut fork threads on a covered airplane. Is splitting the jam nut a safe option? Are there other options that are non-invasive, inexpensive?

Thanks.

[jgerard]

You mean you are bottomed out and want to cut the jam nut in half to shorten the length of the strut even more?

Some thing is not right...any pictures?


Jason

[jasimmons]

Correct. Bottomed out and need to shorten the rear strut further. Following the digital level method of rigging with Mark Englerth's help (great guy by the way!) Dihedral is set to 0.8.

This is a PA-11.

[Steve Pierce]

I don't see any problem. The jam nut is not there to keep the strut or fork to keep from rotating. It does pull any slop out of the threads of the strut or fork. Unfortunately needed to rig some wings on slightly mis-aligned fuselages.

[n40ff]

Question. Are you just setting things with a smart level or are you also test flying to see what you really have.

I've rigged several biplanes with smart level and had a handfull in the air. You got to do what you got to do to make them fly hands off/straight. (hopefully both)

[cubunltd]

How are the front strut threads in relation to each other? If they are close and it's only the rear thats off that far then you've got a problem somewhere. usually if the frame is off then both struts will be affected since they mount in the same location. Who's struts are you using? do the rear struts measure the same length. Are the attach fittings in the wing mounted the same. lots of possible problems here.
John

[12 Geezer]

I ran into the same problem on my 12. Fuselage was correct in a jig, and the struts are Univair, so it "should" be right, but the rear struts are just a tiny bit too long. I compensated by increasing the dihedral a couple of turns, and that worked out fine.

[n40ff]

I know of a homebuild whose builder made a 1" mistake(in 74") when installing strut attachment on one wing. So when making struts he shortened one of them. Project was sold(original builder died) and new owner discovered error only when doing final rigging. Bottom line, dihedral is about 1.2 degrees different between wings. Airplane/pilot simply doesn't know the difference, it flys straight/ball centered(I suppose .6 degrees off?), stalls straight ahead and spins the same right or left.

I would suggest to those who "cut" an inch when using a tape a common practice.....I've had to pick up another 2X4 a time or two, I suggest when working on spars that measure twice/cut or drill once is more than good advice..

But again, airplane doesn't know it's a little odd....