rv7charlie
Well-Known Member
What chain drive are we talking about? Most of the Yamaha drives I've seen are gear; either custom boxes or adapters that mount one of the commonly available drives like the Rotax C.
Cruise rpm kinda depends on the a/c type/mission. A lot of the stuff flying the engine now is STOL, flexwing trikes, etc, and they're probably running 50%-60% rpm (& maybe half throttle) in cruise because the airframe hits an aerodynamic wall and there's no point in wasting fuel. But a slick cross-country a/c would run at 75% *power* up at altitude, and up around 8k feet, 75% power requires the same rpm (at wide open throttle) as full power at sea level.
Charlie
Cruise rpm kinda depends on the a/c type/mission. A lot of the stuff flying the engine now is STOL, flexwing trikes, etc, and they're probably running 50%-60% rpm (& maybe half throttle) in cruise because the airframe hits an aerodynamic wall and there's no point in wasting fuel. But a slick cross-country a/c would run at 75% *power* up at altitude, and up around 8k feet, 75% power requires the same rpm (at wide open throttle) as full power at sea level.
Charlie