Prop sizing for efficiency
07-13-2012, 08:04 PM
#1
Thread Starter
Prop sizing for efficiency
Background....Converted nitro Cermark Javelin. Full throttle performance is very good for pattern flying. AUW 6 lbs. Motor is Leadershobby 9394001223655. 4s lipo 3800 ma/40C. Flight times 3 to 3.5 minutes. Lipo very warm after flight. Static amps are 82 at full throttle. (About 1100 watts). Running the recommended (motor mfr) 13/10 prop. If my tach. is correct 5,200 static rpm. My gut tells me too much prop. The full throttle amps should drop when flying...how much?. I do not want to exceed 60 amps flying. My esc does not log data. Fire away!.......
07-14-2012, 06:38 AM
#2
RE: Prop sizing for efficiency
Here is a good online calculator program. You can run different props and see what they do to the amp draw and EFF.
http://www.s4a.ch/eflight/motorcalc_e.htm
I ran the numbers and it looks like you are on the upper edge or just over it with that prop. I then ran a 13X8 and it was out of the red. Then ran a 14X6, better EFF number.
Buzz.
http://www.s4a.ch/eflight/motorcalc_e.htm
I ran the numbers and it looks like you are on the upper edge or just over it with that prop. I then ran a 13X8 and it was out of the red. Then ran a 14X6, better EFF number.
Buzz.
