NorthwestJack
Well-Known Member
Im in stuck with a problem:
I purchased an Aerotwin engine 4 cycle 4 years ago. Two inline cylinders, turbocharged that puts out 65 continuous and 75 for a brief period of time.
the problem is that their reduction drive is not working , and its been under development for years. ( so I dont have a working engine)
I was considering removing the redrive and going direct drive. What kind of penalty am I looking at:
max continuous RPM at 65 HP is 4100.
Ive been using Raymers book on propeller sizing and using his notes on not exceeding prop tip speed beyond Mach .8
If my cruise is at 3600 RPM should I design the prop size for mach .8 at 3600, and let it overspeed for takeoff and climb?
How much am I loosing by going from a 68 " diameter prop to a 54" prop.)
Jacq
I purchased an Aerotwin engine 4 cycle 4 years ago. Two inline cylinders, turbocharged that puts out 65 continuous and 75 for a brief period of time.
the problem is that their reduction drive is not working , and its been under development for years. ( so I dont have a working engine)
I was considering removing the redrive and going direct drive. What kind of penalty am I looking at:
max continuous RPM at 65 HP is 4100.
Ive been using Raymers book on propeller sizing and using his notes on not exceeding prop tip speed beyond Mach .8
If my cruise is at 3600 RPM should I design the prop size for mach .8 at 3600, and let it overspeed for takeoff and climb?
How much am I loosing by going from a 68 " diameter prop to a 54" prop.)
Jacq
