I have 140 fun flying hours to date in my WindFire helicopter.
It's powered by a Subaru EA81 engine short block, rebuilt by Ron @ RAM Performance with an excellent Simple Digital Systems ECU (EM5). 5 gph average fuel burn of non-ethanol premium auto fuel.
MGL Voyager screens and V10 com radio, controlled and tuned by buttons on cyclic control. Microprocessor-controlled fans on radiator, front cabin heater and finned oil pan, keep engine cool even during long ground maneuver practice on warm days. Cabin and cowls are carbon fiber. Tail cone is a one-part uni carbon prepreg, and the fuel tank a one-part carbon-kevlar lay-up.
Time consumed fabricating and assembling parts: thousands of hours! More than I kept track of.