This is an enhanced version of the SDG1 unit and was developed to meet the additional needs of competition glider flyers, though sport fliers may find certain of the additional features are desirable. It is an upgraded version of the now discontinued SDG2.


As with the SDG1, the timer drives a D/T servo to terminate the flight, the DT periods being set by a simple push button / LED interface, but the SDG3 has additional features:-

  • Maximum duration extended from 5 to 10 minutes
  • Improved duration setting procedure which minimises button pushes
  • Timer may be interrogated to display current duration setting
  • Option for D/T timing to start only when the glider leaves the towline - there are reports (SAM35, Sept 2015) that under certain conditions "hi-start" gliders can reach D/T time whilst still attached to the towline/bungie. This feature is aimed towards competition fliers and requires fitting the glider with a set of towline operated contacts which communicate with the SDG2 Timer.
  • Supports "circle towing"
  • An optional piezo sounder can be connected to the timer which emits regular "beeps" following D/T to allow fliers to more easily locate models landing in tall grass/crops or on the far side of a boundary hedge etc. Typically an SDG2 equipped model can be heard up to 50 metres away (Sticks & Tissue #103) 
  • A battery monitoring function to detect dangerously low battery voltage. This causes an immediate D/T, which can prevent a fly-away if the model is aloft or prevent a launch should the model be on the ground.  
  • A battery 'health' indication - in standby, the LED flickers at a rate proportional to the battery voltage - fast when fully charged and progressively slows down as the charge declines.


Key Features:

  • operates from a single 3.7v Li-Po battery (50/70mAH suggested)
  • d/t duration:-adjustable 10 seconds to 10 minutes, set in 10 second increments
  • optional (bleeping) piezo sounder assists model location after D/T
  • option to commence timing period after towline release
  • supports "circle towing"
  • low battery voltage (3.3v) cut-out - operates D/T for safety
  • piezo resonance set-up routine to optimise volume of the sounder
  • push button immediately cancels the flight at any time
  • duration setting is saved in memory – so a single button push serves to repeat a flight



Length 27mm | Width 17mm | Height 9mm | Weight 3g


Plug and Play Options:

  • piezo sounder
  • towline release contact set

The timer is supplied with a comprehensive instruction manual and users guide.



INSTRUCTION MANUAL - E-Zee Servo Operated D/T for Free Flight Gliders SDG3

This item is exclusive to:-   

in the UK and in the USA