Broken flap hinge wire

Bubblehead · #1 01-04-2011, 09:17 PM

The last few weeks I have been working on replacing the flap tape on my -8. It's been a real chore but with some help from Jay Pratt I finally got the second one done. We ended up taking it off the plane to work on the very determined tape.

Jay suggested putting the new tape on the underside of the wing skin instead of on the flap, so last night I pulled the right flap off so I could clean the underside of the wind skin well and position the tape accurately.

Unfortunately the hinge pin bent end broke off! I ended up disconnecting the aileron push rod inside the wing so the aileron would drop a little lower allowing me to get a good grip on the broken end and pull the wire out of the hinge. Now I need to find a replacement.

According to the plans the hinge is 56" long so I need a length of wire approx 60" long. Is there a source for that in the Dallas-Ft Worth area? I suspect the wire is relatively inexpensive but shipping will be expensive.

fehdxl · #2 01-04-2011, 09:34 PM

John, There's a technique out there to remove one hinge tab in the middle of the flap and insert 1/2 of that long hinge outboard, the other inboard. That way you don't have to fool with the aileron getting in the way. Maybe with that technique you can reuse what you have. If not, two shorter pieces are easier to ship than a long one. Worst case, buy a new hinge and just use the wire. Hope that helps. -Jim

Bubblehead · #3 01-04-2011, 09:51 PM

Jim - That helps a lot. Perhaps someone else will chime in with more specifics but that seems pretty straight forward. 36" pieces of piano wire should be available locally or like you way, I may be able to reuse the broken one.

Ironflight · #4 01-04-2011, 09:58 PM

If you're looking for experience one way or another, I have the split pins on all three airframes at our house, and find them easy to install and remove. Not saying anything bad about the single pin, just that the dual pin works well.

Hinge is REALLY cheap from van's BTW (compared to many aircraft parts...). And they often send it rolled up in a hoop to make a smaller package - they know just what the allowable bend radius is.

Paul

rocketbob · #5 01-05-2011, 07:24 AM

Why split the hinge. Just drill a small hole in the aileron bracket so you can run the pin in, then put a screw and a nut thru the hole to keep the pin from backing out.

Bubblehead · #6 01-05-2011, 01:41 PM

Paul - great info. Thanks. I'll order a replacement this afternoon. Do you have a couple of pictures you can direct me to that show the missing tab? Just one in the middle?

Bob - the hole is already there to put the pin in. In fact, that's how I got the pin out!

The problem is the pin comes out very close to the aileron and it is hard to grab the pin with a pliers without dinging the aileron. Once the bent end was broken off it was impossible without getting the aileron out of the way more, and that required disconnecting the pushrod.

WenEng · #7 01-05-2011, 07:31 PM

Take 1 loop off one side of the hinge and 2 off the opposite side of the hinge. I put a nut plate on the flap spar (some put it on the flap brace) and rigged up a hold down clamp from surplus hinge. Slip it over the two bent hinge pin ends, fold it back to the nutplate and screw it down. Even if the screw backed all the way out, those hinge pins are not going anywhere. I've seen others just safety wire the bent ends to the brace. I'm sure there are many ways to secure the pins.

kevinh · #8 01-05-2011, 08:32 PM

Yep - I split the pins and used safetywire to the support. The other benefit of splitting the pin: half the friction when you go to get it out/put it in.

JonJay · #9 01-06-2011, 07:44 AM

Quote:

Originally Posted by rocketbob

Why split the hinge. Just drill a small hole in the aileron bracket so you can run the pin in, then put a screw and a nut thru the hole to keep the pin from backing out.

No screw or or nut, just bent the rod slightly so it will not find the hole again if by chance it ever moved. Four years, 350 hours, has not budged.
If I ever need to remove it I will be careful not to break it off.
While we are on this discussion, I would be curious to hear from Mel/other top experts on oiling of the hinge pin, Yes/No, if Yes, with what, frequency?
I have never touched mine.

Bubblehead · #10 01-09-2011, 06:25 PM

Saturday I modified both flap hinges for two hinge pins. I still need one new one from Vans to have both pins made, but the left aileron turned out great. It is so much easier to get the hinge pin in and don't have to risk dinging the aileron.

Mine looks pretty much like kevinh's. Just safety wire around the two L's.

My thanks for all the ideas and pictures. This is a definite improvement.