I had a glow plug heater installed on a 1/4 Scale Aeronca Champ, with a 1.20 O.S. 4 stroke. It was very simple, when the throttle servo went to low, it bumped a micro- switch and turned on a single cell Ni-Cad battery and heated the glow plug. The engine always had a very reliable idle with it and I could start the engine just by turning the system on and proping the engine or by using my starter. It unit came with a little charger and I mounted the charge jack in the cockpit. Overall, I was happy with the system and might do it again just for a safety factor on a plane I was wanting to protect from engine flameout, if I was concerned. I know they have expensive electronic systems now, however what I had was as simple and as reliable as you could ask and it was relatively cheap.