Dave’s R/C Electronics Servo Speed Reducer

There are often model airplane functions that require the speed of the servo to be changed from the normal rotational response to something slower. Scale flaps are what come to mind here. With computer radios, some have programming that allows you to adjust the speed of your servos, but for modelers using basic radios, a simply plug-in device can provide an inexpensive solution. To fly your model smoothly and consistently, the motion of your flaps need to be slowed down, and that’s where a Servo Speed Reducer (SSR) comes in handy. If you simply add the flap function to a two- or three-position switch, the flaps move quickly and this produces a sudden change in pitch, which has to be corrected during your landing approach.

Available from Dave’s R/C Electronics, this SSR is compact and lightweight, and simply plugs into place between your flap servo and your receiver. Installation takes only seconds. It also provides adjustment for the servo’s speed with a potentiometer (pot) on the circuit board.

Setting up your model is easy. After you install the SSR, make sure the receiver is off. If the unit detects power but not a signal, the indicator LED will slowly flash on and off. With the receiver off, turn the pot full clockwise and then turn on the transmitter, followed by the receiver. The LED will come on (without flashing), indicating that the servo will operate at normal speed without any speed reduction. To make an adjustment to the speed, you turn the receiver off, make the adjustment to the pot, then turn the receiver back on. This way, the device’s circuit memory will accept and retain the new setting, and the LED flashes rapidly.

Some fine-tuning is required with some test flights to dial in the proper amount of servo speed reduction. By taking several seconds to lower the flaps, the abrupt change in lift is minimized and gives the plane time to settle down, smoothing out the flight path. Priced at $15.00, this simple plug-in device works great and provides modelers with precise control over their servo’s speed and performance without needing a more expensive programmable transmitter.—Gerry Yarrish davesrce.com

With no soldering required, the Servo Speed Reducer comes fully wired and is simply plugged in between your servo and receiver.