SP series Props
11-08-2005, 01:49 PM
#1
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SP series Props
I understand that RCV recommends very high pitch props (12-13) for the SP series engines due to the 2:1 gearing.
My question is, can inches of pitch be replaced with inches of length?
i.e. can I reduce the amount of pitch required by increasing prop length?
My question is, can inches of pitch be replaced with inches of length?
i.e. can I reduce the amount of pitch required by increasing prop length?
11-15-2005, 11:26 AM
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RE: SP series Props
Hi
The minimum pitch that RCV recommend for the SP series engines is 10, but 12 is preferable. The 2:1 output means the prop is turning at half the rpm of a conventional engine and the pitch combined with the rpm on any engine will decide on the speed the engine will move forward.
If you use a pitch of less than 10 this will have a limiting effect on actual speed.
eg. a conventional engine running at 10,000rpm on a 6" pitch will achieve about 60mph
To achieve 60mph, the RCV needs to turn 5000rpm on a 12 " pitch = 60mph
The maximum rpms you should run an RCV is around 5500, which would would mean you would need a minimum 11" pitch prop to achieve 60mph.
You would therefore need to find out the minimum speed your plane could fly, to see if you can reduce the pitch at all. But either way you would need to be sure not to over rev the engine.
I hope this helps
Best regards
Laurenne
Nb. Our CD series engines use conventional size props
The minimum pitch that RCV recommend for the SP series engines is 10, but 12 is preferable. The 2:1 output means the prop is turning at half the rpm of a conventional engine and the pitch combined with the rpm on any engine will decide on the speed the engine will move forward.
If you use a pitch of less than 10 this will have a limiting effect on actual speed.
eg. a conventional engine running at 10,000rpm on a 6" pitch will achieve about 60mph
To achieve 60mph, the RCV needs to turn 5000rpm on a 12 " pitch = 60mph
The maximum rpms you should run an RCV is around 5500, which would would mean you would need a minimum 11" pitch prop to achieve 60mph.
You would therefore need to find out the minimum speed your plane could fly, to see if you can reduce the pitch at all. But either way you would need to be sure not to over rev the engine.
I hope this helps
Best regards
Laurenne
Nb. Our CD series engines use conventional size props
