The Align 400S is a 2800kv brushless motor. It is probably the most common
power source for the T-Rex currently and offers a reasonable level of performance.
Certainly there is enough power for mild 3D maneuvers like flips or piro
flips. The climbout on this motor is certainly not what I would call fast
but it is more than adequate for a beginner, sports flyer or somebody just
getting into 3D. The motor weighs in at 71g which is close to the heaviest
motor currently viable as a power source for the T-Rex.
The motor does run quite hot, the addition of the shown heatsink is deemed a necessity if you are to extract a reasonable service life from the motor. The motor is not particularly efficient but given the price for these motors I feel they should be considered quite a bargain considering the reasonable amounts of power they produce.
The motor reached a temperature of 190 degrees Fahrenheit during this test with ambient temperature of 70 degrees Fahrenheit.
The lipo reached 100 degrees Fahrenheit, which is nothing to be concerned
about, the Tanic 3S 2220mah is well over specification for the amp draw
on this motor.
Headspeed at zero pitch using the 13T pinion and 90% throttle was 2220
rpm.
During the full throttle, full pitch climb out the motor bogged and the
head speed dropped to 1870 rpm. A loss of 350 rpm, this backs up my initial
thoughts on the motor being OK for mild 3D but continual hard 3D would
result in a loss of headspeed and the required responsiveness of the model.
Bear in mind that this test does not factor in the potential further loading
of the motor from large cyclic inputs whilst pulling large amounts of pitch
as would be typical of many 3D maneuvers.
The following graphs show the performance of the motor on the test bench and were produced using the Medusa Power Analyser Plus. The graph can be split up into phases, the initial minute or so is just spool up and hovering throttle. This is followed by a thirty second full throttle, full pitch climb out. Then there is a further period of hovering followed by pitch pumping from full positive to full negative pitch for 30 seconds. This is then followed by another period of hovering before spool down.
The following table summarises the test :
Time period
Activity
90 seconds
Spool up and hovering throttle/pitch (mid stick)
30 seconds
Full power / full pitch
60 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
The recorded maximum values for the duration of the test were the following
:
17.9 amps
12.6 volts (I should hope so)
182 Watts
0.748 amp hours
8 Watts/hour
The recorded minimum voltage was 9.8 volts during the 30 second full throttle/pitch.
Based on the above data and using the Tanic 2220mah full capacity then
a theoretical flight time of 13minutes and 20 seconds would be achieved
if the flight profile above was repeated until the pack was out of capacity.
In summary this is a respectable level of power based upon the price of
the motor, efficiency is probably the largest factor in the recorded theoretical
flight time and more power would be required to make this motor capable
of serious 3D. This motor would suit a beginner, sport flyer or someone
just entering into the realms of 3D.
