Graham Selick has graciously allowed me to share the way he has combined his RDT (Radio DT) with a Texas Timer. RDT is a good way to keep your plane on the field in case the drift is more than expected or to keep you from setting down in a bad location.

This is the working part of the RDT and Texas Timer installed on an AB Spacer using GH .19/.23 engines. . Not shown is the battery and receiver for the radio system  located under the hatch on the bottom of the fuselage and the antenna. Under normal DT by the timer, the ring is released by the post falling down, and the stop limit travel is limited by the rubber tubing hitting the place in the fuselage where the line to the stab enters it.

If the flier calls for DT by pressing the button on his handheld  radio transmitter, the servo arm will rotate, releasing the lever wire held under it, and the other end will lay down. The line will pull through the ring on the timer post, until the rubber tubing on the limit stop reaches the fuselage. The same way it did with a timer initiated DT. The force multiplication from the lever takes almost all pressure off the servo arm.

In both cases, the same wound spring provides the line tension to hold the stab down under power.


This clearly shows the ring on the timer post that links the timer and RDT to the stab DT sysmtem.

You can see how the servo arm will release the line that runs through the ring on the timer post.

RDT used with a timer on a High Thrust T-Bird

This is similar to the other installation, but different in a significant way. This an OS MAX III .35 powered T-Bird with the timer and RDT mounted on the pod. You can see a very different way of releasing the radio dt line. (See photo below) As before, it uses some tubing as a shock absorber on the travel limit.

Here, the servo arm is used to pull a pin that releases the radio dt line. Cleaver, eh?


This is a standalone RDT with a burning rope fuse. Boooooo Hisssssss.

The engine time is set by a Texas Micro I timer on this 1/2 A plane. Now, does the rope back up the RDT or vice versa?