RCX 1304 4000kv
RCXs medium kv, mid-weight micro motor.
The 4000kv version of this 1304 suffers a bit in efficiency compared to the 5000kv build, particularly at higher rpm, but otherwise performs as you would expect compared against it's higher kv sibling. Prop load matching is typical for this class, with 2.5" and light 3" loads ending up right in the ideal place to take advantage of unloading, 2" props shooting right through the middle of the sweet spot leaving them at a slight disadvantage when unloading kicks in, and heavy 3" loads suffering in efficiency compared to an ideal loading by perhaps some 10-20%
calibration report - most recent dyno calibration at the time this test was run