wing spar wiggle giggle

[James733]

Thanks Robert. I'll check there as well.

[Mark Bowden]

Tcrafters, to requote Forrest above, don't yank and lift on the outboard wings. You will over stress the wing past what it was designed for. You are using a 18 foot lever on a 750 lb object, it will move and move a lot.

If you need to rock the aircraft only do so at the outboard strut to wing attachment by grabbing on to the struts (at the tie down ends). Then be GENTLE, very gentle you can rock the main gear with two fingers.

When you do this at the tip you are introducing very high G-loads into the wing. You are also rocking all three landing gear points. Tailwheel will move and flex, main gear will pivot and the bungees move along with those heavy cables that hold the gear when the bungees break.

All kinds of noise sources when you do this. You could very well be hearing noises coming from the gear movement, bungee covers, bungee stretch, etc... Countless noise oppertunties in the wing, too numuerous to list, you could be moving the free aft edges of the leading edge, poping the wing/fuselage fairing strips, moving rib nails, fabric stretch on the lower surface...it is endless.

An IA made my Dad remove and recover a wing once due to "noises" to find nothing.

I'm not saying you don't have an issue, you may have. You have triggered a noise with your actions and asked a question about it. Thus you must with your IA 's oversite and likely a couple other eyes and ears take a methodical, over the top annual inspection process in a quiet hangar to get an answer.

With the inspection covers off, upper surface aileron cover if you have one, check how loose they are, do they slide around? Then some suggestions (not a full list) I would suggest the main things to check are along the spar spans for cracks especially on the upper and lower edges and at the strut and wing root attach fittings. Delaminations of the plywood at the attach fitting locations. Check compressoin struts for attachment at fwd and aft spar faces.

Any loose rib nails into the spars?

Ensure good adhesion of the fabric to the leading edge and all rib surfaces. Do a tap test on each bay, upper & lower surface, run your fingers along those surfaces for loose spots.

Attach hardware is likely brand new new but make sure things are tight. Check that the jury strut wing attach lock nuts are tight. Check that the jury strut spar clamps are tight and don't move, shouldn't be steel on steel either. Check that the entry step is free to swivel with some snugness. Check for play in the 3 strut attach bolts by touching them while someone gently lifts on the struts, do the move and click?

Check for cracks at the fuselage strut attach weld assembly, this is an AD location. Agian Bruce just restored her so unlikley an issue. Check the wing / fuselage fairing for security and tightness and the aft tension bolt. Remove the fairing and inspect the fueslage attach fitting for cracks and do the same strut lift test while touching the bolts for movement.

You are also bending the wing about the aileron hinge line so you could be moving the aileron, aileron rigging, hinges and the actuator rod, all of which have nearly no cable tension and free play in the linkage. Look at it too.

The diagonal wires you mention are Drag, Antidrag wires and are used to Trammel the wing. Each wire might not have the same tension as they are adjusted during trammeling.

In essence you must satisify your IA, and yourself, it has passed annual.

[Scott]

A flat sheet of aircraft aluminium is flexible, but form it into a leading edge and it becomes very rigid. Lap joint it with other formed lengths with screws or rivets and you have a long rigid 'C' section attached to a relatively flexible structure.

Now shrink fabric over the whole thing and force a twist along its length (wash) and it it's very likely areas of oil-canning will result. Minimized to some degree if the wing is set to the wash angle while the leading edges are installed, but even then not unusual for localized oilcanning especially if the leading edges are of a harder alloy like 2024T3.

Locate the the source(s) by sight, sound and feel. Once confirmed, don't worry about it.

Common around the strut attach area, especially if the short angle between the ribs adjacent to the strut attach was not installed.
S