[Struts1]

I thought i'll share how i'm making composite flaps for my S Connie model now days. My initial flaps were solid 1/2" x 3" x 20" sanded down to 1/4" thick and beveled it's one end into leading edge. It turned out that after glassing these solid flap panels they will become heavier and thickness of 1/4" will be too less then needed.

My newer flap panels are 1/2" thick with better LE and are built up types using self made fiberglass sheeting, individually cut balsa ribs, FG n CF rear spars and balsa leading edge.

Being fully composite they are a lot lighter then previous ones, these will be easy on servos to push them out and pull them in also.

Here are self explanatory pictures for all to see and if anyone have questions, pls ask.

[Struts1]

Leading edge made...

I used 1/2" x 1/2" hard balsa stock cut to size for 4 strategic locations on this flap panel, rest was built up with 1/16" balsa sheeting. I did it this way to save the weight where i possibly could since model will be powered by electric motors.

I couple of pics you will see top skin FG sheet on the flap's internal structure, it's just there for testing purpose n not glued on as yet. It dose gives a view how fully completed flap panel will look like.

[Cougar429]

Beautiful work. I always love to see how others solve problems they encounter along the way.

I've come up with my own method to build light and strong panels. I sandwich glass cloth between two thin sheets of ply, (number of bid layers determined by strength requirements) and then weigh the assembly down between plastic sheets and 1/4 plexi until the epoxy cures. All the ribs for my Harvard split flaps were made this way.

This same technique is also used when building layered firewalls or other structures where strength and/or weight are considerations as the end result is far stronger and stiffer than straight ply of comparable thickness.

[Struts1]

Thanks for liking my work Cougar. U juss gave me another idea for the composite ribs for my
2nd flap panel. I'm going to cut ribs form my fiberglass sheet n use them instead of balsa ribs. Prolly
it will be even lighter then this panel by few oz's!

[Cougar429]

Here are a couple of pics of some of the structure. The flaps and ribs were fabbed as described and I also added C/F rod to prevent twisting as the central control input transfers to both outer panels. All I can say is this kept my saw and dremel busy for quite a while.

[Struts1]

Very nice in intricate job done there, i really like how you used CF tube to take main load n also to give strength to the leading edge. I also like how you used brass tube to connect inboard and out board flaps....your flaps are far more complicated then mine build wise.

[Cougar429]

Actually the brass tube does not directly connect the panels. They are bonded to each panel and provide a sleeve which aligns the comparable OD dia C/F rod to slide through. Each rod is anchored to the outer panels immediately outboard of that sleeve and feeds into the brass sleeves in the inner panels. This allows for some sliding motion as the outer panels are not directly in line with the wing center section. As the flaps extend they spread apart a bit. It took a bit of experimenting to get the angle right.

The C/F rod was cut from both ends of one of my smaller heli Knighthead sets, (the braces that run from the lower frame out to the boom tube) with 2-56 blind nuts inserted into the flanges. The entire purpose was to allow the assembly to be tied together once the hinges were installed and also allow for removal of any panel without having to disturb the others.

[Struts1]

Its good that u mentioned in detail how you connected inner flaps with outer ones as i had hard time making those being fowler flaps on my model. It would have added to so much complexity that also would have added quite a lot of weight, so instead i went with semi-L1649's inboard style flaps on my model. On my next Ziroli DC 3 model i will tackle ur methods of connecting both inboard n outboard flaps as DC3's flaps are split pain flaps like AT-6s...

[Cougar429]

If you want I can try and take a closeup of the connection.

[Struts1]

Sure if you like, i'm sure other guys would be able to make use of this setup way before i could....