T-Motor F40 Pro III Review

T-Motor, one of the top Chinese brushless motor manufacturers, released a new version of the popular F40 Series motor – the F40 Pro III. It is the third generation of the “Pro motor”, targeted at FPV racing pilots. We have been reviewing and testing the F-Series motors since the first F40 version back in 2016 and we are really interested to see how this new F40 Pro III is performing compared to the previous generations.

We will first start with a quick comparison between the F40 Pro III and the F40 Pro II and then review the thrust results.

Design and Packaging

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The box containing the motor and the mounting screws are the same for both the new F40 Pro III and its predecessor. Only the printed label on the front of the box was slightly changed.

The design of the motor itself was also slightly changed. Mainly the top part of the motor is different, while the stator of the motor looks the same.

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The anti-slip design for the propellers has a different pattern, but I haven´t experienced any problems with the previous version as well. The windings of the motor are “high temperature resistant silver winding” and should resist up to 240C, same as in the previous F40 Pro II generation.

Specifications

The specs of F40 Pro III and the previous Pro II generation are very similar. However, the newer model is slightly bigger and heavier. Below you could find the differences:

  • F40 Pro III weighs 29.7g compared to the Pro II, which is 27.5g
  • The length of the new motor was increased by 1mm (33mm vs. 32mm)

The F40 Pro III is offered in two different versions: 2400kv and 2600kv. We have kindly received the 2400kv version from Banggood for our tests and below you could find the trust results.

Thrust tests

We have tested the motor on the RCBenchmark 1520 Tool with an Aikon 35A BLHeli32 ESC. The SkyRC power supply was set at 16.8V (4S LiPo). The first test was done with an HQ 5” tri-blade propeller. The maximum thrust achieved was 1487g at 37.29A.

Throttle (µs) Thrust
(gf)
Voltage
(V)
Current
(A)
El. Power
(W)
Efficiency
(gf/W)
1300 112 16.66 2.99 50 2.26
1400 342 16.62 5.15 85 4.00
1500 491 16.57 7.84 130 3.78
1600 647 16.51 11.34 187 3.46
1700 840 16.42 16.48 270 3.11
1750 967 16.36 19.89 325 2.97
1800 1056 16.31 22.98 375 2.82
1850 1176 16.25 26.46 430 2.74
1900 1295 16.18 30.44 492 2.63
1925 1399 16.13 32.95 531 2.63
1945 1416 16.12 33.89 546 2.59
1965 1464 16.08 35.69 574 2.55
1985 1492 16.06 36.93 593 2.52
2000 1487 16.05 37.29 598 2.48


Interesting is to see how the new F40 Pro III is performing compared to the previous generations of F40 Pro motors. Below you could find a comparison with the first generation F40 Pro and the second generation F40 Pro II. The setup was the same.

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As you can see on the picture above both the new F40 Pro III and Pro II are performing much better than the first generation. Up to 60% throttle we could see F40 Pro III is performing better. In the upper range between 60% and 100% throttle, the Pro II is always a bit ahead of the newer version. The biggest gap is at maximum throttle: F40 Pro II provides 60g more thrust.

Finally, we decided to make a test with a 6-inch propeller as there is none of the website of the manufacturer. We have used a KingKong 6” prop.

Throttle (µs) Thrust
(gf)
Voltage
(V)
Current
(A)
El. Power
(W)
Efficiency
(gf/W)
1300 131 16.66 3.70 61 2.14
1400 374 16.61 6.22 103 3.62
1500 532 16.55 9.70 160 3.32
1600 688 16.47 14.38 237 2.91
1700 932 16.36 21.11 345 2.70
1750 1077 16.29 25.23 411 2.62
1800 1213 16.21 29.80 483 2.51
1850 1329 16.13 34.13 551 2.41
1900 1455 16.05 39.17 628 2.32
1925 1525 16.02 41.38 663 2.30
1945 1559 15.99 43.11 689 2.26
1965 1589 15.96 44.75 714 2.23
1985 1616 15.93 46.22 736 2.20
2000 1631 15.90 47.10 749 2.18

With the 6 inch propeller, the motor achieved 1631g of thrust or about 140g more than with the 5” tri-blade prop. The motor was very hot, but luckily it didn’t burn out.

Conclusion

There is nothing so much new in the F40 Pro III compared to the previous generation. We personally like the slightly changed new design. The performance is similar to the F40 Pro II and for the most pilots, the slightly better performance in the range up to 60% throttle should be perfectly fine. Those pilots pushing their drones to the absolute limits may be still better with the previous version.

The price of the new and previous version is the same – 26.9$/pcs. As of today, if you get a set of 4pcs on Banggood, the price per piece is 24.51$. My order was shipped with priority airmail and delivered within 8 days per DHL in Germany.

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