Classic Tutorial...seperate flaps and ailerons added to an ARF!!

Hanno Prettner chose to use flaps, spoilers, combination spoiler/flap, elevator/flap mixing and seperate aileron servos in his Curare models from 1975 - 1977...without our magical radio systems!

I am interested in testing these devices as well as "crow"-flaps down and aileron up for significant drag...maybe for slowing a down line? The Futaba 14MZ can handle many, many nifty combinations or conditions activated by switches or stick positions or both...with trim at each condition...limited only by your imagination. The full-scale Zlin 526 used ailerons and flaps with the same OR different deflection angles (see previous photo of a Zlin in a vertical line with a flap with a different deflection the the aileron). I am only guessing that the variable geometry would behave like differential? An added benefit of using only the outer ailerons, leaving the flaps fixed, is the ailerons will not block/disrupt the air flow over the stab/elevator...a detail Hanno used on his WC Calypso.

The recently released Great Planes Zlin is the perfect subject to "kit bash" to test these ideas. Thank you for your interest!

More details of the execution

Symmetry- Try to make each surface left-right should be identical. I like to complete one half of the wing then transfer the measurements to the other side. When I was kid, I was a terrible measurer, never really learned "how" to use reference marks, sharp pencils and patience...nothing may be more important than a little patience.

I chose a 25 degree angle for the flap and ailerons. I expect to use 20 - 22 max, leaving a couple of degrees of deflection available. The dowels have been drilled to accept the 6-32 stainless steel screw.

The wing panels have been glued together using 30 minute epoxy applied to the 3/16" remaining edge of the plywood root ribs and the 1/8" light plywood/carbon reinforced spar brace. The spar brace fits snugly in the epoxy wing tube and may be strong enough without the 3" glass cloth to be added.

The 3" nylon cloth (Sonic Tronics) is applied after drawing lines on the top and bottom of the wings. The joint has been carefully sanded, the halves have been test fit PRIOR to gluing them together. Adhesive is applied to each wing half, spar brace and the whole assembly after it is squished together. The excess glue was wiped away with a paper towel then 2" wide painters tape is added to the leading edge and trailing edge, checking for the halves pushed tightly together and the alignment of the halves.

After the wing was dry, a series of (3) 2" holes were bored 1" apart on the bottom trailing edge of the wing with a 2" forstner bit and drill press. The drill press "stop" was adjusted to not drill too deeply and the wing was held by hand. Other then the huge mess, the holes turned out very smooth with no additional sanding required. The weight savings was (20) grams for all of the holes...less than I had hoped...it took less than ten minutes to complete.

Zap finishing resin was mixed (about 10cc at a time) to apply to the 3" nylon cloth. The cloth is easier to cut if masking tape is applied to the cut line. The rear 1/4" of the tape is attached to the wing with thin CA and kicker and the epoxy is brushed on with a disposable nylon brush inside the lines. The cloth is then replaced over the wing and another coat of the unthinned epoxy is applied to the cloth from rear to front. A squeegee then removes all of the excess epoxy with a few passes and set aside for curing. The blue painters tape protects the wing hold down hole and will be removed with an xacto knife.

Final picture shows a flap placed on top of wing #1 to show the larger size and shape.

Just need to cover, hinge, add servos, control horns, push rods and progrtamm the radio...wow that could take (10) more hours...

Rusty Dose
Team Futaba