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!

Subject: Great Planes Zlin 526

The Great Planes Zlin was designed by Great Planes R&D airplane designer Mark Hampe and builder/writer Steve Beros with George Rodriguez as the product manager. This same team developed the "Sequence", which I have flown extensively, written about on a RCU thread in the electric pattern section and just think is incredible!

Repairing/attaching the ARF ailerons-

The pre-hinged/glued ailerons were cut away from the wing and the factory applied Monokote was removed. The goal is to have the new wing (wing #2) be lighter with the modifications and additional servo/linkage than the the stock wing #1. I will save weight in the following areas:

- The wing tube will be replaced with a 1/8 light ply brace reinforced with carbon fiber matt (see earlier thread for using modern materials to strengthen and save weight) and glue panels together with a 4" glass cloth and epoxy. The aluminum wing tube weighs 78 grams.

- The root rib will be lightened by removing all but a 3/16" edge and 3/8" around wing tube. This saved 7 grams per panel...1/2 ounce!

- Lightening holes will be placed in the outer portion of wing panel (outside of servos) using a 2" - 2 1/2" Forstner bit in a drill press. I estimate that each hole will save 7 - 9 grams for an additional 1/2 ounce.

- The color scheme will be simplified on the bottom (all blue like the full-scale), the colors will be overlapped by 1/8" with an estimated savings 16 - 20 grams per panel...another ounce!

- The landing gear will be shortened 1" - 1 1/2", an aluminum axle (Central Hobbies) will reduce the weight of the wire and replace (2) wheel collars and an 210mm aluminum hubbed wheel for weight savings and low drag. I initially intended to use retracts and the more I thought about it, I decided to shorten the gear to reduce drag and weight. A new wire leg will be bent out of 5/32" music wire. I estimate that the new parts may save between 30 and 40 grams!

The process/photos-

Photo 1, 2- The new spar, aileron template (about 15% more area by using the full-scale hinge line) and axle/wheel.

Photo 3, 4, 5- Baseline weights of wing, wing no covering, wing with mods and (2) servos...no lightening holes.

Photo 6, 7, 8- Ailerons reinstalled after removing trailing edge of wing and leading edge of aileron and replace with 3/8" soft balsa sheet attached with Titebond. A razor plane and sanding bar squared each edge after the pieces were cut with xacto knife and long straight edge.

After the glue dried, the area was sanded using a long sanding bar to match contour of wing.

A cardboard template was created using a 3-view found on the internet, confirmed all measurements using a digital micrometer and ruler to proportion the dimensions. The new surfaces were drawn on both sides of wing and (2) lines added allowing for the 1/4" soft balsa trailing edge and 3/8" soft balsa aileron leading edge. The flap/ailerons were cut-out using a straight edge and xacto adding 1/8" soft balsa caps to flap and ailerons with Titebond.

The stock servo plate was glued using thick CA after hardwood corners were removed (see previous threads regarding sing #1).

Flap/aileron control horn will be 6-32 stainless steel screws threaded into 5/8 dowels. The dowels are glued using 30-minute epoxy. This method provides infinite adjustablility to match the throws of each surface with via proper geometry rather than ATV. It is also very strong, simple and cheap! The holes have not been drilled or marked for the screw and has not been final sanded.

The new wing brace is sticking out of a wing half also showing the removed plywood on the root rib. A Dremel (old school) router bit/router attachment was used to make the cut-out.

I am pleased so far and expect to have it completed before Santa comes...now if the weather would cooperate!

Rusty Dose
Team Futaba