Hi John,
Thanks. The problem as always is the availability of a sufficient engine for the four seater. There are some convienient options for a high powered 2-seater that improve the per-seat payload. At 1250kg, you a right up against the power limit for a naturally aspirated conventional piston engine. You could solve it with a turbo engine, but they are ALOT more expensive.
The turbo engine would get you another 150kg of AUW, but cost another $50K and burn more fuel. Is it worth it? My original design point was attempting to keep purchase and operating costs as reasonable as possible.
Thoughts welcome?
CRAN