Number of Hinges to attach Flaps

[Casey]

My inboard flap is 23.6 inches. What is the minimum number of hinges I should use to attach it to the wing trailing edge?

[Perry Rose]

3 minimum. 4 is better.

[peabody]

Windy recommended four....two close to the outboard end.....

[john e. holliday]

What plane.   But me I do cloth hinges all along the edges.  Seals hinge line and easy to do.

[Mike Griffin]

I do what Doc does.

Mike

[Dave Hull]

I never understood the logic of a pair of plastic hinges at the tip of the flap. Anyone heard a reason that they believe?

Dave

[Randy Cuberly]

I Believe in using a hinge about every 4 inches apart and two hinges close together at the tip near the end of the flap.

My reasoning for this is that under load when maneuvering, especially in hard corners,  the flap can flex a small amount between the hinges and actually slightly stiffen the movement at the hinge and cause slight stiffening of the controls at a critical time.  It's only a theory of course but a sound one, I believe.  Also with less load on each hinge there will be less chance of any hinge failure.

Two are used together at the tip because that is the most likely place for destructive flutter to develop if the flap is not very secure!

Randy Cuberly

[EddyR]

The reason is simple . Many of us who have flown for many years have seen single hinges fail at the flap end. Many years ago most went to putting two hinges at the tip to stop failure.  There must be a lot more loads at the tip than one would think.
Ed

[Casey]

I am building a Genesis 46 Mark III. Powerplant is an ABC Super Tigre 51

[Dan McEntee]

I never understood the logic of a pair of plastic hinges at the tip of the flap. Anyone heard a reason that they believe?

Dave

   If you have ever witnessed a flap flutter and fall off, thus causing a crash, the you would understand why.  You probably would never see the flutter, but you may hear it.  Not very common but it does happen. Sparky lost one of his really nice Thunderbolts to this happening, and is the reason why he came up with the hinge that he uses now. I'm sure he has a video on it that you could find.
   MERRY CHRISTMAS and HAPPY NEW YEAR!
   Dan McEntee

[john e. holliday]

Does Sparky still make his hinges?

[Target]

Does Sparky still make his hinges?

He said no when i asked him about a year ago. He makes them for his planes but no longer to sell.

[Steve Fitton]

I used 5 hinges on my SV sized planes and just went to six hinges on the latest one.

[kevin king]

I've never seen a flap or anything else let go in the middle. If any two parts separate it usually starts at the ends. Not the centers.

[Shug Emery]

You may like watching Windy's hinging video. It changed the way I do it now.
Skip around in the video but some hinging at 1:38 in.
Shug