I have a question about the difference between a pusher configuration and a tractor configuration with the same HP on airframes with equal clean configuration drag.
Assumption: Inflow to a tractor propeller is mostly unaffected by the airframe. For example, flap deployment, elevator deflection and retractible landing gear position all redirect some of the airflow, thus increasing drag. That slows the aircraft, but does little to affect the efficiency of the propeller. In contrast, a pusher aircraft, with the same HP, has disturbed propeller inflow that, when the gear is extended, or the control surfaces deflected, or the angle of attack changed significantly, affects the inflow much more than the tractor configuration.
A random data point: the prototype Twin Velocity was able to maintain level flight on one 160 HP engine with the landing gear retracted, but was unable to do so with the gear extended.
Does anyone have any data that might be used to quantify the difference in thrust available between otherwise equal clean configuration drag aircraft with a pusher propeller verses a tractor propeller?
Thanks,
BJC
Assumption: Inflow to a tractor propeller is mostly unaffected by the airframe. For example, flap deployment, elevator deflection and retractible landing gear position all redirect some of the airflow, thus increasing drag. That slows the aircraft, but does little to affect the efficiency of the propeller. In contrast, a pusher aircraft, with the same HP, has disturbed propeller inflow that, when the gear is extended, or the control surfaces deflected, or the angle of attack changed significantly, affects the inflow much more than the tractor configuration.
A random data point: the prototype Twin Velocity was able to maintain level flight on one 160 HP engine with the landing gear retracted, but was unable to do so with the gear extended.
Does anyone have any data that might be used to quantify the difference in thrust available between otherwise equal clean configuration drag aircraft with a pusher propeller verses a tractor propeller?
Thanks,
BJC