Rc Timer motor for multicopters

I don't have performance data on those motors, however, anecdotal information and my general calculations suggests:

* the BC2836-9 is likely to have a slight edge in endurance for hover using this prop at this AUW

* the first optimization you should consider is finding a better prop for this AUW. You can expect this prop@auw@hexa to take ~690watts to hover (~115 watts per motor) this does not include the APM, BEC heat loss, external sensors, RX, or VTC, which will be fixed irrespective of your propulsion choices.

* your ideal motor/prop combo will deliver ~614gT and 115watta at around the 1/3 point in the motor power curve, where the motor efficiency will approach 82%.

* your ESCs are overpowered for this motor/prop combo at hover speeds and 4S. You might save weight by dropping to 20A ESCs. However, you could also locate a more efficient prop, which may require the 30a ESCs at higher speeds (which you'd want to control with a throttle curve)

* After finding a better prop for this weight, find a more powerful motor to drive it (or a more oowerul motor to drive this prop, if you are really comitted to these, which i do not recommend) You dont need more than 2.2x weight to thrust ratio for acrobatic, 1.5 or 1.6 is more than enough even, the point of finding a more efficient/powerful prop/motor combo is to keep the hover rate at closer to the 1/3 point of the motor power curve. Yours is around 60% with both of these motors with this prop. These motors are likely to be running around 77-68% efficiency at hover with these props.

Questions?

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Michael Pursifull June 6, 2012 at 8:20pm

One more thing: if you can get the weight of the additional two arms, motors, and ESCs within a reasonable limit (<240g) moving these props and motors to an octo will be as much as 29% more efficient (because these props push the motors outside of their most efficient range to hover this weight.)

Of course, the best thing you can do for increasing efficiency is to drop the weight. 3kg is a heavyish vehicle in this class for 10x4.5SF.
Moderator

Michael Pursifull June 6, 2012 at 8:10pm

I don't have performance data on those motors, however, anecdotal information and my general calculations suggests:

* the BC2836-9 is likely to have a slight edge in endurance for hover using this prop at this AUW

* the first optimization you should consider is finding a better prop for this AUW. You can expect this prop@auw@hexa to take ~690watts to hover (~115 watts per motor) this does not include the APM, BEC heat loss, external sensors, RX, or VTC, which will be fixed irrespective of your propulsion choices.

* your ideal motor/prop combo will deliver ~614gT and 115watta at around the 1/3 point in the motor power curve, where the motor efficiency will approach 82%.

* your ESCs are overpowered for this motor/prop combo at hover speeds and 4S. You might save weight by dropping to 20A ESCs. However, you could also locate a more efficient prop, which may require the 30a ESCs at higher speeds (which you'd want to control with a throttle curve)

* After finding a better prop for this weight, find a more powerful motor to drive it (or a more oowerul motor to drive this prop, if you are really comitted to these, which i do not recommend) You dont need more than 2.2x weight to thrust ratio for acrobatic, 1.5 or 1.6 is more than enough even, the point of finding a more efficient/powerful prop/motor combo is to keep the hover rate at closer to the 1/3 point of the motor power curve. Yours is around 60% with both of these motors with this prop. These motors are likely to be running around 77-68% efficiency at hover with these props.

Questions?
Moderator

Michael Pursifull June 6, 2012 at 5:33pm

What is the weight of your aircraft?

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Rc Timer motor for multicopters

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