On our first flights back in 1996 with Jesus Artes we used a Kavan fuel pump and a speed controller for a brushed dc motor from a RC car. We had a adjustable bypass valve to adjust the maximum fuel flow at full power. No RPM meter, we checked just the compressor pressure and adjusted the maximum before each flight. Idle power was adjusted by trim, and acceleration and deceleration was adjusted by the "servo slow" function on the TX.
We flown using this setup from summer of 1996 (17 years ago!) to June of 1998 when I did the first flight with a fadec controlled engine.
Some footage of our beginnings, put together by a fellow friend. Turbine footage begins around minute 4, includes our early experiments in 1993-1995. The plane on the final minutes on the video weighted 7,8Kg at take off, for a thrust of 3,5kg of the engine, but on first two flights we flown with 2,6Kg thrust, about 1/3 of thrust/weight ratio