Radio Gear for RC Flying

The radio gear for the Twinstar had to be purchased separately.

The chosen radio was the Futaba 6EX, 6 channel FM radio, combined with 4x Hi-Tec HS-81 servos. This radio would give 4 channels to control the plane, 1 channel in case flaps or spoilers were needed and another channel for retractable undercarriage (or to activate the camera).









The choice of this radio was based on several features.

  • It had 6 channels, which could all be used as explained above.
  • It had flap/spoiler mixing possibilities (see below).
  • It had adjustable servo travel, which would be useful to press the camera button.
  • It had a free mixing channel, which could be used to mix rudder and ailerons for easier learning.
  • It was Mode II (see below)
  • It had dual rates (see below)









Some general information about radios.

Here is some more information on radio features.


Most people fly with either a Mode I or Mode II transmitter. This number just refers to the layout of the main controls.

Mode I has the primary controls split between the left and right stick. Right stick for ailerons and throttle, left stick for elevators and rudder.

Mode II has the Primary controls all on the right stick and the left stick just does the throttle and rudder.

Which mode you use is a matter of preference but you need to make sure the radio you purchase is in the correct mode or is convertible.












EPA - End point adjustment

Sets the amount of travel of a servo.

A servo arm normally sweeps trough about 90 but this can be too much for some functions (pressing a camera button for example). EPA allows servo travel to be set as a percentage of the normal sweep. This means that you still make full use of the whole of the lever travel on the transmitter but the servo moves a reduced amount.

Dual-Rate switch

Used to reduce servo movement

This is similar to the end point adjustment except that it is a 2-position switch, which is used during flight. With the dual rate switched off, the servos use full movement (or the movement specified with the EPA setting) but with the dual rate engaged the servos move a percentage of this movement.

This feature can be used to give sensitive control at slow speeds (for landing for example) but less sensitivity at higher speeds.

On the Futaba 6EX dual rate could be set on the 4 main channels.

Free Mixing

Used to combine 2 channels to work together

This feature allows mixing of 2 channels. Possible uses include the mixing of rudder with ailerons for example, or adding some down elevator in with the throttle so that the plane stays level at full speed.

Even when channels are mixed they can still be controlled individually.

Flaperons, Spoilerons, Ailerons and mixing

Use Ailerons as spoilers or flaps

This feature allows the ailerons on a model aircraft to act as spoilers or flaps. A real aircraft wing has separate control surfaces, which act as spoilers, ailerons and flaps, but with model aircraft the ailerons can be made to do all of the tasks.

Mixing is used to achieve this. Instead of having both aileron servos connected to channel 1 so that they are always working opposite to each other, the left hand one is connected to channel 6 (flaps) but they are mixed together. So when channel one is activated the right aileron will move and the left one is mixed to do the opposite. But when channel 6 is operated then the left aileron drops like a flap and the right one is mixed to move the same way.

When flaps are activated the ailerons are still operational. Effectively the neutral position of the ailerons has been off-set downwards, but the surfaces are still controllable by the aileron stick.














RC Flying