Firstly my thanks to AON Electric for supplying this motor for testing.
The AON is a 3500kv brushless motor and a new entrant in the brushless
motor market. It is at the heavy weight end of the spectrum for a T-Rex
motor with a weight of 98g.
Fitting the motor proved to be a rather fiddly exercise. The bottom two
main frame screws need to be loosened in order to stretch the frames apart.
This is the only way to get the large diameter motor and circular heatsink
into the motor bay.
I fitted an 11T pinion in line with the 3500kv motor rating. Having set
the Phoenix 35 appropriately I did a test spool up to measure headspeed.
The figures returned a touch over 2700 RPM, which is a fair bit faster
than I am used to as both the Align and Mega ran at or below 2450 RPM.
A quick test showed this to be a very powerful motor but without demanding
a huge amount in terms of amp draw. I'll be doing my usual full set of
graphs but as a preliminary indication of it's current consumption a full
throttle, full pitch climbout with the Align Carbon Fiber blades produced
a 20 amp loading.
I hope to get some flight time in on this motor before the week is out
as well as producing the usual bench tests.
I have had some opportunity to fly the AON today with the Align Carbon
Fiber blades. I've had to back the throttle off to 60% to get around 2400
rpm headspeed. This gives much better tracking with the Align Carbon blades.
The climbouts were quite rapid but the Align blades did load the head up
and there was some decrease in headspeed. Aside from this the power was
plentiful enough but I can't help but feel the motor would run happier
at a higher throttle setting but with a smaller pinion, possibly a 9T or
10T. I'll have to source a 3.2 mm pinion, the ECO 8 has a 10T that would
fit nicely.
The motor responded nicely to pitch changes and it was easy to hear the
different loadings on the motor whilst doing some gentle sport flying.
The Phoenix 35 kept the AON under nice control using the governor mode
throughout the flights.
I'm going to run two separate bench tests for the AON, one test using stock
wood blades and the other with the Align Carbon Fiber 325mm blades. Both
tests will follow the standard format as below. The tests were conducted
in an ambient 20 degrees centigrade, 68 degrees Fahrenheit. The pitch range
on the T-Rex being from +/- 10 degrees. As usual the power source was a
Tanic 3S 2220mah pack.
Time period
Activity
90 seconds
Spool up and hovering throttle/pitch (mid stick)
30 seconds
Full power / full pitch
30 seconds
Hovering throttle/pitch (mid stick)
30 seconds
Pitch pumping from full negative to full positive pitch
60 seconds
Hovering throttle/pitch (mid stick), spool down
First the standard wood blade test results :
The AON recorded the following maximum values :
18.5 amps
12.6 volts
184 watts
The recorded minimum voltage was 9.4 volts during the 30 second full throttle/pitch.
The motor temp at the end of the test was 62 degrees centigrade, 143 degrees
Fahrenheit. The lithium pack reached a max temperature of 48 degrees centigrade,
120 degrees Fahrenheit. All of this is well within specification and nothing
of concern.
During the 30 second climbout the headspeed dropped from 2350RPM to 2200RPM,
only a 150RPM drop in overall headspeed over a full 30 seconds of full
pitch. This is the most powerful motor I have tested so far, the Mega 16/15/3
being the next most powerful and only being able to maintain 2130RPM at
full pitch. It should be noted that had I run the AON at 2450RPM it would
still have dropped to the measured 2200RPM (I tested this just to be sure),
so relative to the Mega 16/15/3 it maintained an additional 70RPM over
the Mega's performance. This is excellent and confirms my thoughts and
observations on the power of this motor from flying it in the T-Rex over
the past week.
Where this motor shines is in the amp draw, the maximum value was only
18.5 amps which is below the draw on the Mega but delivering more overall
headspeed for that lower amp draw. Additionally the AON was cut back to
50% throttle on the Phoenix 35 governor mode in order to get the headspeed
down to a level that would be safe to use wood blades. On the correct pinion
I believe the AON would return even better results than the ones shown
here.
Just for comparison purposes I also ran a carbon blade test on this motor
as most people would probably resort to using carbon blades because of
the high headspeeds this motor produces on an 11T pinion.
Second the Align Carbon Fiber Blade test results :
For this second test the following maximum values were recorded :
22.3 amps
12.6 volts
212 watts
The recorded minimum voltage was 9.1 volts during the 30 second full throttle/pitch.
The motor reached a maximum temperature of 140 degrees Fahrenheit (approx 61 degrees C). The Tanic pack also reached a peak of 140 degrees Fahrenheit.
Headspeed was measured as 2400 in the hover and dropped to 1900 rpm at
the end of the 30 seconds at full throttle/pitch. This is pretty good considering
the loading from the Align Carbon Blades.
The AON is clearly not a motor that draws huge amounts of amps in order
to deliver it's power, which is good news as less amps equals longer flight
times and increased longevity of the lithium power source.
As a further test I also tried a 10T pinion as this should allow the AON
to run at closer to full throttle, which theoretically should produce a
more efficent run and allow the AON to run more freely at it's optimum
power. The following graphs are with stock 315mm wood blades. The results
are rather interesting :
he AON recorded the following maximum values :
17 amps
12.6 volts
173 watts
The recorded minimum voltage was 9.8 volts during the 30 second full throttle/pitch.
The motor temp at the end of the test was 63 degrees centigrade, 145 degrees
Fahrenheit. The lithium pack reached a max temperature of 45 degrees centigrade,
113 degrees Fahrenheit.
During the 30 second climbout the headspeed dropped from 2400RPM to 2020RPM.
Significantly more headspeed is lost in this test than with the 11T pinion.
Clearly the AON doesn't like running on the smaller pinion even though
it allows for higher throttle settings. The motor got hotter from running
at higher throttle but the overall amp draw was lower, resulting in a lower
overall battery temperature.
My conclusion from this is that the AON should run on the 11T pinion, even
though it needs throttling back significantly to get a reasonable headspeed
it means the AON has more to give when you load it up.
Overall I am very impressed with this motor and feel somewhat reluctant
to take it out of my T-Rex to make way for other motor tests. It runs relatively
cool due to it's large heatsink and the lower amp draws will allow for
more flight time before having to land to swap packs.
AON are certainly on to a winner with this motor and I'm very much looking
forward to trying out the 3000kv motor, which although reported to be less
powerful on a 3S pack with 13T pinion should prove very interesting on
4S as recommended by AON.
