So, the GK 976cc engine weighs 42kg (92.6 lbs), John's redrive might(?) weigh another 5 kg (11 lbs), then maybe a gallon of water/coolant (8 lbs), some oil (2 lbs) and we'd have about 114 lbs. Extras would be the exhaust system and engine mount, prop, maybe the radiator isn't in that weight, etc.

It could be an attractive alternative for planes now using the VW Type 1, at least by weight and HP--the PSRU would get the prop up high so maybe it would even work with stock VW cowlings. The standard Ace 1:1.8 PSRU ratio would turn the prop at 3611 RPM at the engine's 6500 RPM top speed, so even a stock VW prop designed for 75 HP at 3600 RPM wouldn't be a bad starting point, though we might find we need a bit more blade to absorb slightly more HP.

Initial unknowns are cost, total system reliability (at high output, for hours at a time), and availability of parts.

It could be an attractive alternative for planes now using the VW Type 1, at least by weight and HP--the PSRU would get the prop up high so maybe it would even work with stock VW cowlings. The standard Ace 1:1.8 PSRU ratio would turn the prop at 3611 RPM at the engine's 6500 RPM top speed, so even a stock VW prop designed for 75 HP at 3600 RPM wouldn't be a bad starting point, though we might find we need a bit more blade to absorb slightly more HP.

Initial unknowns are cost, total system reliability (at high output, for hours at a time), and availability of parts.

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