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        Discussion 22xx-24 direct drive in IMAC model?

#1 Magne Mar 06, 2013 03:13 AM

22xx-24 direct drive in IMAC model?
 
Hello Steve.

I am considering motor options for a 35% IMAC model operating on 12s.
(2600mm/102" wingspan, 13 kg/28 lbs)

Although I have used set-ups with both the P42 and the P62 gearboxes in the past, I would prefer a direct drive system.

Are the 2220-24 2.5Y or 2225-24 2Y viable options in a direct drive system?

Is the 8mm output shaft strong enough to take the load from a 24-26" propeller operating at 6500 rpm?

Thanks and regards,
Magne

#2 sneu Mar 07, 2013 10:57 AM

The 22XX motor is really for higher RPM than you are looking at--one of these would make more sense: http://www.neumotors.com/Site/3200_36_series.html

#3 Magne Mar 07, 2013 12:57 PM

Thanks for the reply, Steve.

Maybe I am misinterpreting the data on your website, but I find this a bit confusing.

For my application I would be looking at something like 7 kW power, for IMAC.(Advanced class)

The 3210/2Y (kv=165) would be in the ballpark when it comes to rpm, and is rated at 4 kW peak.
(Assuming 165x44x0.86=6200 rpm loaded.)

On the other hand, the 2220-24/2.5Y (Kv=172) has a similar Kv, but is rated at 6 kW peak.
Further I would expect the 2225-24/2Y (Kv=180) to be in the ballpark 8 kW peak.
(data missing from table)

For applications requiring 4kW peak power (as quoted for the 3210), why would not the 1924/2.5Y (Kv=165), rated power 6 kW peak be a better option?

Really not trying to be difficult here, but seriously interested in finding viable options that would work reliably without a gearbox!

Regarding the 3210:
Is the motor front mounted only? (no rear supports required?)
I have previously operated the 1527/P42 combination to levels significantly exceeding the stated Surge power. After sorting out some initial cooling/baffling problems, this seemed to work fine.
Do you think this would be possible with the 3210 also? (i.e overloading)
4 kW Surge is a bit low for this particular project.

Thanks a lot,
Magne

#4 sneu Mar 07, 2013 04:45 PM

Quote:

Originally Posted by Magne (Post 24352120)
Thanks for the reply, Steve.

Maybe I am misinterpreting the data on your website, but I find this a bit confusing.

For my application I would be looking at something like 7 kW power, for IMAC.(Advanced class)

The 3210/2Y (kv=165) would be in the ballpark when it comes to rpm, and is rated at 4 kW peak.
(Assuming 165x44x0.86=6200 rpm loaded.)

On the other hand, the 2220-24/2.5Y (Kv=172) has a similar Kv, but is rated at 6 kW peak.
Further I would expect the 2225-24/2Y (Kv=180) to be in the ballpark 8 kW peak.
(data missing from table)

For applications requiring 4kW peak power (as quoted for the 3210), why would not the 1924/2.5Y (Kv=165), rated power 6 kW peak be a better option?

Really not trying to be difficult here, but seriously interested in finding viable options that would work reliably without a gearbox!

Regarding the 3210:
Is the motor front mounted only? (no rear supports required?)
I have previously operated the 1527/P42 combination to levels significantly exceeding the stated Surge power. After sorting out some initial cooling/baffling problems, this seemed to work fine.
Do you think this would be possible with the 3210 also? (i.e overloading)
4 kW Surge is a bit low for this particular project.

Thanks a lot,
Magne


Hello,

The ratings for the power levels are based at operating the motors at or near their maximum RPM rating. The 22XX @ 6200 RPM is only operating at just over 1/5th its maximum RPM--which means the available power with have to be reduced to 1/5th also.

The 32XX at 6200 is running at almost 2/3 of the maximum RPM so the derating is less.

We will also be making a longer version 3215 which would easily handle the power you need.

The published ratings are on the safe side--you can push things harder than suggested.

Steve

#5 Magne Mar 08, 2013 02:38 AM

OK, that is interesting.
I suppose that this means that the motors for all practical purposes don't have a power level limitation, but rather a current (Amp.) limitation. (I mean, is anybody operating these model airplane motors at up to 125 or 166 Volts? Certainly not legal here in Europe.)
In my opinion it would make the specification tables easier to read if the Max. Amp. level was quoted in the table. (Suggestion.)

Back to the 32XX motor.
The 3215 is interesting. Do you have any details such as various Kv's, and motor weight and length?
(And max. Amp!)
Is the motor front mounted only?

Thanks for your support,
Magne


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