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Lumenier "Bardwell" JB2407 2500kv
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A very specific freestyle motor produced for Joshua Bardwell by Lumenier.

Check out the full list of motors in this series here

Summary

Published: Jan 22, 2019 by quadmcfly

Lumenier

Tested KV:2520kv
Weight:36.2g
Stator W:24mm
Stator H:7mm
Lumenier has long been one of the biggest producers of pilot-specific motors made to fairly narrow specifications, and this release for Joshua Bardwell is another in the same line.  The motor quality is up to Lumenier's typical standards, with excellent finish and build quality. Obviously with a 2407 stator size, weight will be an issue here, but Lumenier managed to get the weight down to a very reasonable 36g at the 40mm wire length that I use for testing. The screw that retains the steel shaft is also a 12.9 steel M3 screw with a 2mm hex drive, which is a huge plus for motor maintenance. My only real negative on this design is the use of a negative inflection prop grip under the prop shaft. I would have liked to see something with a bit more holding power, but that isn't necessarily a deal-breaker depending on your needs. 

Results

Given the relatively high Kv of this motor for the large stator size, it puts it right on the line between mid-Kv and high-Kv. I decided to classify it as mid-Kv even though the thrust output is on par with some higher Kv motors because the large stator size allows for a range of prop loading and the current draw is just low enough to allow for some light weight 6" props. In addition, though the maximum thrust numbers on static load are high, the lower relative Kv (2520 as tested) means that as the motor unloads the RPMs are likely to be lower than a higher Kv counterpart even with the high torque production.  The highest current draw and largest thrust production will happen under near-static or past-static conditions, such as hard 180 degree turns and dive recoveries. That being said if the current draw had been a few points higher or 6" props were unfeasible, then I would have bumped it up to a high-Kv classification. It's definitely right on the line.

The power and efficiency here is solid, though the large stator pushes hard enough under the mentioned conditions that it will definitely draw down some power even on robust batteries. With throttle management though, the larger stator size will provide some excellent responsiveness even on high torque load props.  The ideal setup here will likely be heavier tri-blade props or very light loaded (low pitch) dual blade 6" props on a high-quality higher capacity battery. Based on the results this motor sits on par with several similar motors in the size class, such as the T-Motor F80 Pro.  I would actually make the argument this motor would do quite well on lighter props given the thrust generation, as 36 grams is actually not that heavy compared to some of the older generation 2207 motors that came in at around 35g (the Cobra CP2207 for instance, which weighs essentially the same and has done very well on 5" props, not to mention the original T-motor F60 Pro.) Overall a power-house motor at a very reasonable weight point for the stator size.