aileron efficiency

When you look around at our models, (excluding scale) you will notice that practically all the aircraft have strip ailerons, that is, full length from the tip to the centre of the wing, with one central servo activating both ailerons via wire torque rods.

Being a person that appreciates improving efficiency in our hobby, I decided to experiment with my Tucano trainer wing. With a span of around 1.7 metres, my strip ailerons did exhibit a measurable amount of flex from the centre of the wing to the tip. I cut the aileron length by nearly one half, but kept the same width. I fixed the centre portion of the ailerons to the trailing edge, and used "Pic" filler where necessary to flair in before re-covering.

Of course an additional servo must be used in this setup, and being a foam wing, I was able to lay the servos on their sides in a recess cut in the foam. A balsa platform was fitted between two wing ribets to enable each servo to be adhered into position using Silicone after neutralising the servo arms. Two short pushrods were used to connect each servo to their respective aileron horn. Don't forget to face both servos either outward or inwards, otherwise you will finish up with a great set of flaps!

A conventional four channel radio will require both servos to be connected through a "Y" lead. If your wing is foam, a neat recess groove can be formed for the leads by gently running the tip of a soldering iron along the foam, and under each riblet. If you have a multi channel computer radio, you may connect each lead separately to the receiver. This will give you the added advantage of differential and/or flaperon positions, and exponential if required. (Refer to your R/C manual for the correct setup procedure).

When completed, the difference in weight was negligible. Being only half-length ailerons, I initially set them up to give more throw than before. Now for the real test, let's see how it performs in the air.

Immediately after lift-off, it was obvious that I had far too much aileron throw. I quickly switched my rates down to 50% and still too much! It was interesting to note that following further adjustments on the ground, the final aileron throw was far less than that of the original strip aileron wing to obtain similar results.

The aircraft felt good. The elevator and rudder felt more responsive, particularly when banking. This would be due to the "clean" air over the tail area, which also produced minimal height loss on tight turns. Knife-edge performance was also noticeably improved.

I guess to summarise, I would have to say that the main impressions noted would be the general improvement in stability, and accuracy of all controls.

A great flying aircraft made even better. Try it, you will like it!

Ray Dixon. CFI