Wingtip Bow Repair/Replacement advice sought

[Glenn Farrant]

Thanks Hank. Once I saw it uncovered today, I feel that pulling the wing may be excessive noting the direction of the damage. I'll sleep on it.

Thanks for the note about the lens. Sounds like some more hard-won knowledge.

[N96337]

It is easier to work on, when it's off. But, I can agree that it's maybe excessive. I agree with Rob about stresses induced. This was the best you could get. I wish you had just slit the fabric along the bow instead of cutting it all away. You made more work for yourself, but that's ok. Straighten that bow out, get your Ceconite manual out ( https://4dc8cf9a-0bab-40d5-bd6e-ca9b...bb4787e540.pdf ), turn to the repair section, and get to work. Enjoy!! If you have questions, you can ask here and someone will be able to help!!
John

[Glenn Farrant]

Thanks John.

I had resigned myself to fabricating a new bow and having to remove even more fabric to get to the leading edge where the bow connects.

Thanks for the ceconite manual. Thankfully the guy who did the damage is also quite experienced in this area and will be doing the fabric and paint with but I will be supervise that piece closely.

Any thoughts on how to straighten it? I'm concerned about straightening it when it's installed due to the forces involved. On the other hand, doing it whilst installed would be convenient for minimizing extra fabric work and also acting as a "jig" whilst it's straightened. Without starting the process, I don't have a sense of how strong that 4130 tube is.

Best regards
Glenn

[PA1195]

Are there sufficient inspection covers to examine the spars and lift strut fittings (both ends)? Telescoping mirrors, bendable light source, and a quality borescope might help.

Gary

[N96337]

Glenn, try a C clamp and some iron or better yet, wood blocks that are profiled to the radius. It shouldn't take that much. If it doesn't want to go, a little heat wont be a bad thing. It's far from a structural piece, but be VERY careful, as dope is quite flammable!
John

[Glenn Farrant]

Hi Gary. Yes there are sufficient covers. We used then when we did the Pre-buy.

I'll be removing them all tomorrow and checking with a light.

Straightening went well today:

[Hank Jarrett]

Please tell me you didn't drop the glass light dome!

Hank

[Glenn Farrant]

No Hank. It's in one piece in a very safe place.

[PA1195]

That part of the wing should be easily deformed by design to save the rest of the assembly. Why transfer loads to other structures in event of a minor bump or bend? Ground loops were a common event before steerable partially locking tailwheels.

Gary

[Glenn Farrant]

Thanks Gary. It's a good design. Just strong enough, but not too strong.

[Scott]

Should check the tension rod/wire that runs between the spars at the bow attachmnet points. The bow dirives much of its stregth from the tension on that rod. It will have been stressed during the deformation of the bow. Check for "necking" at the threads and re-tension once your happy with your bow reforming. Note that tension on this rod can affect the alinment of the outboard aileron hinge... so you want tension but it's easily over done.
S

[Glenn Farrant]

Thanks Scott. That's great input. I had been wondering about that piece. I have inspected it and didn't notice any damage but I'll take a closer look today and check tension.

[Glenn Farrant]

A quick "thank you" for all of the input and advice. I especially appreciate the advice on the repair considering that many people are reticent to recommend such things in a semi-public forum.

The bow is in silver now and will have color later this week

The annual was started last weekend and all of the airframe checked out great. We just need to finalize some things (paperwork and engine) and perform a run-up and it'll be ready for flight.

Thanks again

Glenn

[Hank Jarrett]

OUTSTANDING!! You need to post some photos of the repair.

[PA1195]

Good news Glenn!

Gary