A unique light weight large stator motor BoltRC sent over for testing.
Check out the full list of motors in this series here
Published: Jun 10, 2017
Bolt RC has long been a producer of quality frames, and has brought several OEM motors to the market that were matched to their frames. The latest motor is a bit unique in that regard. While the previous motors were simply custom color and labelling, this new motor is a completely unique design. The motor mounts are designed specifically to complement the ultra-light BoltRC Kraken Worx frame, and all the extra fluff has been removed from this motor for the sake of weight. The BoltRC team put a good deal of work into this motor to make it as light as possible while losing as little strength as possible. As a result this motor has some design features that aren't very common. The bell uses an interesting T-beam structure with increased surface area around the outside where impact is the most likely, allowing for a very low mass bell. In addtion the motor mount only has two mount points, further reducing weight. When I said this motor was light, I meant light! With 45mm wires it comes in at just under 29g, which for a 2207 is absolutely insane. The other construction elements are very solid. Parts of this motor are a hybrid between the Returner R3 and R4, inheriting the 0.15mm stator laminations and insanely tight air gap from the R4, but drawing the 3mm internal shaft and bell-integrated external prop shaft from the R3. BoltRC has definitely added it's own flair in this itteration though, and the design looks nothing like either of it's ancestors despite its internal resemblances. Overall excellent work from BoltRC.
The results here are about what I expected to see given the heritage of this motor. Results are almost identical to the Multicopter Builders 2207 2400kv, though KV is slightly higher at 2425kv as tested. This shows in the results, where the BoltRC matches thrust at the top end, but shows a bit of a lead at 50 and 75% throttle. Expect the throttle curve on these to demonstrate the slightly higher KV, weighted a bit more to the low and mid throttle. The extremely light build for which this motor was designed will have some insane response with the size of the stator, while staying relatively efficient do to the low KV and low loading. Even on a heavier build these motors will peform well, though tradeoffs made to reduce weight may not be as applicable. Overall excellent performance, especially in the 28g weight range.