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Old 05-14-2021, 04:14 PM
Eveningflyer is offline
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Big prop low pitch or smaller prop higher pitch, what to choose for 3d?

I have an Ef Edge 540 74" with a Hacker A60 8S motor on it. Going to run it on 12s but not certain what propeller to choose.

Currently I have a 22x13 and running 10s. I like the sound and calmness of having a big propeller and also how it feels like it has loads of torque to pull out of stall flight.

For the 12s setup I'm choosing between 21x10 or 22x8 which will give about same wattage from the motor.

What's considered best in 3d flying bigger or smaller props. What are the advantages of each? I can see how a smaller propp will spin up faster but also how a larger will have more grip and get air flowing over a bigger part of the wing.

Very curious what you guys think.
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Old 05-14-2021, 04:29 PM
The Hodge is offline
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Its very Subjective, The Trend has gone to more pitch for speed as the 3D style has evolved.

Its very much something you need to try for your self. it is true the Bigger prop less pitch creates more thrust, But you loose speed , So if you like to do big air things like huge loops you will find you are going full throttle but the plane wont be moving real quick. Liek being stuck in 2nd gear and revving. at 7 k.

For that size model , I had tried a 20x6 and 19x8 and the 20x6 was thrusty but slow i the airspeed, Ie it would top out on uplines.

The 19x8 gave lots of vertical pull. I would use the 22x8 as the 10 & 13 pitch's i feel are too much on size model unless you like lots of speed.

Hope that helps.
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Old 05-14-2021, 04:47 PM
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Interesting thoughts!
I do have a 22x13 running on 10s right now and it's very fast. Going level flight I feel like I'm flying on idle, but it's very nice for big loops and large movements.

Will a 21x13 propeller give the same speed as a 23x13 or how does the pitch to speed work? Assuming that revs will be the same even though I'd guess it would be lower with the big prop.
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Old 05-14-2021, 05:12 PM
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Quote:
Originally Posted by Eveningflyer View Post
Interesting thoughts!
I do have a 22x13 running on 10s right now and it's very fast. Going level flight I feel like I'm flying on idle, but it's very nice for big loops and large movements.

Will a 21x13 propeller give the same speed as a 23x13 or how does the pitch to speed work? Assuming that revs will be the same even though I'd guess it would be lower with the big prop.
The 21x13 Vs the 23x13 The 23, Will load the engine more and assume it will be lower rpm (unless the Elec setup can spin it), So there will be less speed.

Most of the 30c-38cc class models the 20x8/21x8 are common props that work well for mixed flight , 23 i think you will run into ground clearance issues.

I feel drop down the A60 in cell count and use a 20x8 or 21x8 get the 7-8k rpm thats plenty of prop for a 25% Model. and it will cause less issue with ground clearness and P-factor. Gyroscopic force ad so on. and the model will be lighter
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Old 05-16-2021, 06:58 PM
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Try the prop calculator spreadsheet and enter known RPM with the prop you have now and record the watts and or HP. Then enter the new prop and fudge the RPM until the watts are the same. It will show you the thrust and speed, and noise limit.
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Old 05-17-2021, 10:11 AM
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I put pitot telemetry on my 11.5 pound Sebart Funtana with a Hacker C50-14XL with the 6.7:1 gear box... 10S x 5000 mah LiPo....
top speed...
55 mph....

VERTICALLY!!...

Horizontal top speed about 85 mpg at 6500 RPM's,,, prop... Falcon 22 x 10...

if you like the full throttle 3d popular today... prolly higher pitch...

the beauty of RC... you can try a whole slew of different props!!
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