Actuator and rudder design used by Aeronutz

for one and two cell electric planes.

Can also be used for Co2 or rubber power machines

          see sketches lower down ...
 

NOTE! Mark's Mig 3 had a high frequency fin/rudder side to side wobble. This was due to the fin being butt glued to the top of the fuselage, so just extend one of the two 0.5mm Depron plates down into the fuselage, a bit like a mast in a ship!!
This does not seem to be a problem on the smaller Corsair or "57" machines.
29th Dec 2001

The basic principle is that you have the magnet positioned in the middle of the coil.
When the current flows through the coil it makes one end of the coil magnetically North and the other South.
This makes the magnet want to rotate about its own centreline, to line up with the magnetic north and south.
The magnet is directly fixed to and supported by the rudder so as long as we have the centreline of the magnet inline with the hinge of the rudder,  the rudder moves left and right - simple!
If the magnet is not on the centreline of the rudder hinge it will be inefficient and your little bit of power will be lost.

Here is an easy way to get all these parts together successfully, this method has been used in
several successful models.

The fin and rudder are made from two plates of 0.5mm Depron with hinges in the middle. The hinges are made from the clear plastic wrapper around cigarette packets. I have found that two 5mm wide strips are strong enough to hold the rudder and flexible enough for the coil to move it left and right. You only need to fix the hinges one of the Depron plates with double sided tape. Then glue the other plate on to the first, but make sure you don't get glue on the hinges otherwise the mass of calculations that arrived at the 5mm wide strip of hinge will be no use at all!!
Make the rudder and fin a little bit bigger than required and then cut to size with scissors. Paint the parts before gluing together, its easier.

 There is no centring of the rudder, it is blow in inline by the breeze.
We do not have or feed feedback like a servo
The hinge of the rudder / fin must be very flexible so we don't waste the power of the actuator pushing against a stiff hinge
         Quick, light and cheap!