Flaperon Question

[SuberAvid 617]

I've been doing a lot of thinking about my new wing build lately but no building as of yet, but looking at the post Larry made of the STOL competition at Osh, I got to looking at the videos.  The one of Kazoom was pretty interesting, besides the NOX (which I may get around to one of these days), it showed they had extended the flap chord with just a full length aluminum sheet tab along the trailing edge.  It looked like about a 2" extension.  What do you guys think that would do on the inboard section (say 40 to 60%) of our flaperons for slow flight?

[akflyer 1427]

hmmm.. I like where your going with this!  I can see roll forces getting heavier, but it could add some benefit too on the flaps.  I am still tinkering with the idea of splitting them so I can have flaps 40 and full aileron.  Not sure if I really need it though once I get the dadgum 800 in it.

 

[EDMO 1078]

Randy,

      I would be a little cautious about the single sheet of aluminum sticking out of the flaperon because of possible flutter.  I would think that if you used 2 sheets, one on each side of trailing edge, and riveted together at their trailing edge, you would have a much stiffer setup.   I think you could go 100%.

      Have you thought about rechecking balance?  And maybe, reinforcing rib ends?

EDMO

Edited 17 Jan 2014 by Ed In Missouri

[SuberAvid 617]

Thanks for the thoughts; always good to bounce this off of others.  Flutter would certainly be a concern since they are flaperons and not separated flaps.  If they were only flaps I would not be as cautious in experimenting with this.  Maybe not the best thing to experiment with unless we could test them in a wind tunnel first.

 

Makes you wonder if you were to experience some flutter when you pulled full flaps if by letting off on the flaps the flutter would stop quickly? 

 

I guess this would be a strong argument to have separated flaps.  The Kazoom has extended flaps plus the lengthened flap chord and they deploy to 80 degrees; but it sounds like they only drop them to that right at landing to help slow the plane.

[lostman 198]

At 80 degrees of flaps you might as well be able to tilt the wing! That's some serious barn door hanging down at that rate. I'd like to see pictures of that.

[akflyer 1427]

I think Kazoom also has a flap dump button on the stick so the pilot can get to within a foot or two of the ground then hit the dump button and the flaps come off without him having to reach for the flap handle.  Some type of electric release on them.  Isn't Kazoom the plane that Ed Doyle was flying at Valdez?  I know it has made an appearance there a few times... I also think it was the one that was featured in several news articles where Ed had fuel issues and stuffed it into a hell hole on a beach surrounded by HUGE piles of drift wood.. and only folded a gear leg that had broken a few days prior and had a hasty field repair done to it so they could fly it in the competition.

 

 

 

Edit, yep, did a little digging, here is where he broke the gear the first time, and you can see the flap dump... that lead to the plop down, that folded the gear leg.... sumbitch ifn he didn't get it in short though!  they had a 9-12 MPH head wind blowing that day.

 

And the news article showing the Valdez win... then the crash... The gear folded twice in a week, but look at the mine field he set if down in on that beach!!!

http://www.alaskadispatch.com/article/aircraft-wins-valdez-competition-then-becomes-another-alaska-plane-crash?page=0,0

 

 

[EDMO 1078]

Randy,

       I don't think that flutter with flaps is a big issue if the controls are holding them tightly when retracted - Flaps don't even have to be balanced - On the other hand, ailerons and even more, flaperons, float and move in the wind, and have more of an issue with flutter - I know that on my Ercoupe the TCDS listed how much movement (play) could be in the aileron control mechanism so to prevent flutter - It didn't have flaps.

       80 degrees !!!!! and the FAA said that to license the L-19 Cessna Birddog you had to reduce the flap angle to not more than 40 or 45 degrees from the original 60......so I was told.  Experimental is Wonderful.....

EDMO 

Edited 21 Jan 2014 by Ed In Missouri