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Wing Strut Length

Jim Miller

Registered User
Normandy TN
When wing rigging is done and to specs is it common to have the forks showing a different number of threads from one wing to the other?
The reason I ask is I have made one side of the struts trying to keep minium number of exposed threads and now may have to make the other
siide struts shorter due to the fact the first two were made long to the limit and too long to work on the opposite side.

Thanks
JM
 
Crusier
That will be a lot of help later-I saved the link. What I was asking now is it common for needed strut length to vary from side to side making one fork screwed in
more than the fork on the opposite side?

Thanks
JM
 
Alot of the older cubs that have been rebuilt will have a difference in thread count showing. Just so you can have at least 7 turns into the strut if memory serves. Someone correct me on the threads if I'm wrong.

Dave
 
not common if fuselage is square.....

so if you find its crooked, some ways to work around it....

but it ALL depends on what you call/use for level point side to side on fuselage..... for unsquare fuselages, best choice is to put tail stabilizers & fly wires on and get even slop on jack screw then level it bassed on stab rear hinge line and call that your level position... in this position then level dash and turn & bank...... now rig to this position.....

a variation on the above if cabin is NOT square and like you say you end up with Allot out on one front fork and none on other doing the level under leading edge at struts, is get your 3" dihedral height, and then move in fork thats out allot say 5 turns, and move other side IN same 5 turn... and call this your level point, level the dash and T&B now.... down side to this method, it will fly great, but... the wing tips will not be same height off ground a little, and tail will probably not be in line with wings side to side, but that will not affect flight....
 
Alot of the older cubs that have been rebuilt will have a difference in thread count showing. Just so you can have at least 7 turns into the strut if memory serves. Someone correct me on the threads if I'm wrong.

Dave

From my Clyde Smith notes: Stock Super Cub with no damage started out with 4 threads exposed on the front struts.

My experience has been a square fuselage has the same threads showing on each side but seen many repaired frames with no threads on one side and a lot on the other.
 
It looks like if I make the left struts 1/2" shorter than right I will be OK and have two or three threads showing on both sides. With a old front spar on frame
I measured from tailpost to the wing/strut attach point and both sides were nearly the same 16 feet and 9 inches varying from left to right by 1/2 inch. This
was encouraging and Mike and Steve how does this compare to what you see in the field?

Jm PS What is the max number of threads that can show above the fork jam nut?
 
The tailpost pad on my jig has no holes, just a pad. There are never two frames the same. Wayne Mackey confirmed the same.
 
not common if fuselage is square.....

so if you find its crooked, some ways to work around it....

but it ALL depends on what you call/use for level point side to side on fuselage..... for unsquare fuselages, best choice is to put tail stabilizers & fly wires on and get even slop on jack screw then level it bassed on stab rear hinge line and call that your level position... in this position then level dash and turn & bank...... now rig to this position.....

a variation on the above if cabin is NOT square and like you say you end up with Allot out on one front fork and none on other doing the level under leading edge at struts, is get your 3" dihedral height, and then move in fork thats out allot say 5 turns, and move other side IN same 5 turn... and call this your level point, level the dash and T&B now.... down side to this method, it will fly great, but... the wing tips will not be same height off ground a little, and tail will probably not be in line with wings side to side, but that will not affect flight....

Mike,what exactly do you mean here. I'm installing some new sealed struts and plan on rerigging the plane but I like this idea.

Jeff
 
I level across the cabane attach bolts. make sure the heads are turned in the same direction. if the cabin is bent it will be bent above these points. Rig wings and tail to this reference. Easy and works. Total dyhedral is 3 degrees (1 1/2 degrees per wing). This method will leave the aircraft sitting level on the ground and tailfeathers will be level.

John
 
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