Two flap hinge questions

So I've mounted the first flap, and it came out better than I expected. Trailing edge with the aileron is dead on, and the gap between the flap and aileron is an even .2" all the way down. That said...

I used a pnuematic squeezer to rivet the hinge on (dimpled the skin, counter sunk the flap brace, only drilled the hinge). About every third rivet when I set them the aluminum in the flap hinge would get little white "blotches" around the rivet. Kind of like when you take a piece of plastic or metal and bend it, all the little microscopic cracks turn white? Did I explain that well enough? Should I be worried about the structural integrity? I tried hand squeezing some but got the same thing. Other than that, it looks great.

Second question, I went with the "hole in the aileron hinge" method, as I didn't want to cut loops for inserting the wire. I also left one last loop on the outboard side that I drilled a small hole in, and used safety wire to keep in place. On the inboard I'll make a small bend, but how do you bend it back perfectly straight again if you need to remove the flap? Is it easier just to install a new wire every time?

No one?

Sig,

The stars as you are calling them on the flap hinge are normal.
There is a thread on that in the Spar section I think.

The hole in the hinge method you are talking about is where
most people drill the hole about a 32nd below even with the
hinge hole and then bend just the end of the hinge pin, with
no safety wire. The offset should keep the pin in.

I hope this helps

Sig600 said:

Second question, I went with the "hole in the aileron hinge" method, as I didn't want to cut loops for inserting the wire. I also left one last loop on the outboard side that I drilled a small hole in, and used safety wire to keep in place. On the inboard I'll make a small bend, but how do you bend it back perfectly straight again if you need to remove the flap? Is it easier just to install a new wire every time?

Click to expand...

I'll give you an opinion based on my experience....I originally decided to use the single pin method, drilled the hole in the aileron bracket, and installed my flaps on the wing rack the first time. When i went to remove them for some reason, it took HOURS to get that dang pin out - as long as it is, just a little bit of friction makes it quite hard to pull, even if you do get it ined up with the hole. At that point, I realized that I would be installing and removing the flaps DOZENS of times before the plane was finished - you'll have to put them on and off while trimming the inside edge during wing installation - and I decided to go with the split hinges - much less friction on half a pin length, and very easy to insert. The "loss" of two or three loops is insignificant from the standpoint of strength.

I know many use the single pin, and like it. I found that the ease of installing the dual pin made life simpler.

As I said - my experience.

Paul

Paul, tried cutting two loops out and you're right, getting the two halves of wire in/out are easier. Question though, I've only tried installing it from the bottom. The wings are standing up right in the stand. I'm guessing that you'll need to let the flap hang at about 90 degrees and go in from the inside? Doesn't look easy. I'm posting this before doing some searching...

Flap hinge pic

Alright, here's my final product. Paul you convinced me to not go the single pin route. Only thing that's going to be a pain is not scratching the paint taking the flaps on/off... once it's painted.

I'll drill a hole through the brace and safety wire the whole thing once it's time to secure it. I used some opposing pieces of piano hinge to make the slide to secure the pins. Counter sunk the back side and used some flush rivets, so it sits flat. Here's another tip for anyone in the future, use a file to round off the end of the pin. Taking the edges off makes it slide in MUCH easier.

Looks like a good solution. You'll find that hanging the flaps down at 90 degrees for installation/maintenance is no big deal. Tape on the flap or under the skin will prevent scratching the paint.

Paul

Any possibility of safety wire sawing it's way through the flap brace over time?

Sig600 said:

Any possibility of safety wire sawing it's way through the flap brace over time?

Click to expand...

I drilled two small holes in the flap brace for the safety wire so that it wasn't pulling across the edge at too sharp of an angle, and it hadn't moved or worn at all when I have the flapos down at about 1200 hours (to change the anti-rub tape).

Paul

Sig600 said:

Click to expand...

Old thread revival because it is the best picture I have seen of this mod. Better to search than start a new thread.
I am at this point on my QB 8 wings and plan on doing the split pin modification. Couple of quick questions.
1. How many loops did you remove from the hinge halves. It looks like three sections. Two from one half and one from the other. Do I see that correctly?
2. Do I see that you used a couple sections of hinge material to secure the ends of the pins?

xblueh2o said:

Old thread revival because it is the best picture I have seen of this mod. Better to search than start a new thread.
I am at this point on my QB 8 wings and plan on doing the split pin modification. Couple of quick questions.
1. How many loops did you remove from the hinge halves. It looks like three sections. Two from one half and one from the other. Do I see that correctly?
2. Do I see that you used a couple sections of hinge material to secure the ends of the pins?

Click to expand...

1. Yes

2. Yes. Two pieces flush riveted together. After this pic I drilled a hole through the middle and through the flap brace, mounted a nut plate to the back side of the flap brace (flush riveted), and then used a button screw to secure the whole thing.

Sam,

I just did this install on one of my flaps. It should be 3 sections. It does depend a little on how you positioned the hinges when you mounted them. I just used one section of the hinge for the retainer. From this picture it looks like the clips are riveted on. Must just be the picture. I installed a nutplate and put a screw through retainer to hold it in place. Works pretty slick.

rapid_ascent said:

Sam,

I just did this install on one of my flaps. It should be 3 sections. It does depend a little on how you positioned the hinges when you mounted them. I just used one section of the hinge for the retainer. From this picture it looks like the clips are riveted on. Must just be the picture. I installed a nutplate and put a screw through retainer to hold it in place. Works pretty slick.

Click to expand...

The rivet heads you see in my picture are just for the two pieces of hinge riveted together. If you rivet the whole assembly to the flap brace, you'll never get them off again! Like you said, drill hole through it and the flap brace, nutplate, screw to secure.