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Lumenier "JohnnyFPV" 2207-8 2400kv
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The updated design and mid-Kv edition of the JohnnyFPV 2207 motor from Lumenier.

Check out the full list of motors in this series here

Summary

Published: Nov 29, 2018 by quadmcfly

Lumenier

Tested KV:2500kv
Weight:31.2g
Stator W:22mm
Stator H:7mm
When the original JohnnyFPV motors from Lumenier released almost exactly a year ago, I was impressed but voiced some minor complaints with the design. Since then Lumenier and Johnny have taken the opportunity to make some revisions and release some additional Kv variants.  This motor is the 2400kv variant with the updated design features. Much of the core design is the same, but the base has been modified to 16x16 with an open base design, following the trend of most of the recent Lumenier releases. In addition the circ-clip on the shaft has been swapped for retaining bolt. My only minor complaint about this revision is that the bolt is using a 1.5mm hex drive, though it makes up for it by using a high carbon 12.9 steel.  I was able to remove the bolt without issues, and 12.9 is clearly stamped on the bolt.  The flux ring has also included a lip to prevent stress from forcing magnets to slip.  In addition, this design has added a positive inflection knurling on the top of the bell, which makes a large difference in the torque needed on the prop nut. The changes have brought the weight down to just over 31g as well, which is very reasonable for the stator size. In general this motor feels much more polished than the intial JohnnyFPV motor while not loosing the heritage of the Lumenier brand.

Results

One of the surprising things here is that the Kv tested about 100Kv higher than stated, coming in at closer to 2500kv than 2400kv. This isn't necessarily a problem though, given the rest of the results.  Even with the higher Kv, the internal design choices such as air-gap and magnet size and strength combine with the Kv to the desired results. The lightest prop is just shy of 1300g of thrust at the top end, with very reasonable efficiency numbers, with larger props, with the heavier 5" props coming in just shy of 1500g.  As with the other motors in Lumenier's line-up, this motor focuses more on smoothness than abosolute reaction times and top power.  The difference is particularly noticeable on the heavier props when directly compared against a similar size and Kv motor with a tighter air-gap and heavier magnets. The 2207 stator size here still delivers plenty of torque even for the heavier props and the slightly higher Kv will have a slight speed advantage in forward flight over higher torque but lower Kv motors. The final outcome is primarily a slightly flatter throttle curve with a bit less of that "turbo charger" feel at the top end and a bit less of the "jumpy" feel in general that high torque 2207 motors tend to deliver.  For a certain type of freestyle pilot this motor will hit exactly what they're looking to accomplish while still providing enough torque and efficiency to work well on a large range of props and flying weights.