T-Motor F40II Review

T-Motor, the leading manufacturer of brushless motors for drones, recently presented their new F40II 2305 motor. It is the successor of the great F40 motor, that I have reviewed few months ago. T-Motor made several changes in the motors design and personally I find it better than the old one. There are two versions of the F40II available:

  • F40II 2305 2400kv
  • F40II 2305 2600kv

According to T-Motor, the new F-Series motor is made of 7075 aluminum alloy. It has a high strength-to-density ratio and is used in the automotive and aviation industry. The motor is slightly lighter than the F40 v1 and weighs 28.9g.

The F40II is a 2305 type motor and has a 14mm long propeller shaft. Diameter of the propeller shaft is 5mm. Here is an overview of the specifications:

  • Dimension: Φ28.4×31mm
  • Stator Diameter: 23mm
  • Stator Length: 5mm
  • Magnet Poles: 14
  • KV: 2400 / 2600kv
  • Weight: 28.9g


I only ordered one motor for testing and it arrived in a small paper box including mounting screws and a lock nut. Just like the old F40 version there are sets of two motors available.

Manufacturing quality of the F40II motors is superior. Design is slightly changed, which should help for a better heat dissipation. The protection of the mounting holes is gone, maybe for making the motor more light weight. The mounting pattern is standard: M3 16mm x 19mm.

Thrust Tests

I decided to test my F40II 2600kv with the Aikon SEMF 30A BLHeliS ESC, because of its best results in my BLHeliS comparison. I fully charged my 16.000mAh 4S battery, mounted the motor on the RCbenchmark thrust stand and here are the results with three different propellers.


As you can notice I pushed the motor only to 80% throttle, while using the 3-bladed-propellers. And yes, it provided amazingly 1410g of thrust! The F40II got very hot, but it is normal for 750W electrical power. Surprisingly the Aikon SEMF 30A didn´t burned even the current was almost 50A 🙂

Update 2017: The complete thrust data can be downloaded here (private use only). I included also the results with the KingKong 4×4.5×3 propeller.

Summary: The motor runs very smooth, has great quality and provided more than 1.4kg of thrust with a 5″ propeller. I like the design and the light weight of the new F40II and I am going to get some more of these motors for my next FPV build. You can find the 2pcs/set at the official T-Motor webstore and separately here.

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  1. Kevin

    New to this sport, never flown or built before,I am sparing no expense in building two drones so I want to get this right. I am currently ordering parts to build my son a QAV 250r and I ordered a QAV x for myself. Below is what I have ordered for parts and I need some help with eCalc configurations to give me some specs on what I am building. I am looking for optimal prop size and pitch with the motor and size I chose along with optimal ESC to handle the motors on a 4s 95c 1300MAH Luminier battery.
    OEM Lumenier QAV X and QAV 250r will have PRO Tmotor F40 2600KV motors, Kiss 30 AMP ESC, 4s 1300 MAH 95c Batteries, 5045/3 Props. I seeking to get out of the 250r to 80-90 MPH and my QAV X to 95-100 MPH if not faster with decent fly time!
    My eCalc configurator shows that I am not even close to desired MPH and fly time for both QAV X and QAV 250r and shows my ESC’s, (KISS 30 AMP) are too small and I,need a bigger AMP ESC’s, it also shows my Pitch is way off and shows low MPH for both QAV’s. (I could be entering the wrong information based on lack of experience which is why I need your help)
    Can someone configure both QAV’s for me and let me know the following
    a) What optimal ESC and Prop size/Pitch would be for both build configurations and what prop would you sugest?
    b) What Max Speed will be for both QAV’s QAV 250r for my son and QAV X for myself?
    c)What is the fly time for each?
    d) What is your experienced opinion about the Motors ESC, Battery and Prop selection I choose for each the QAV 250r and the QAV X builds. Is there a more efficient, more powerful lighter better combination you would have gone with to make each QAV sick performing drones? if so what would you have chosen?Please email me product info and why you would have gone that route so I can research and change products before I build.
    e) What is it you would do to maximize each QAV with the Motor, ESC, Battery and Prop to get the most out of each QAV.
    I will be building these QAV’s this week and parts are arriving daily so time is off the essence and I need an experienced FPV Drone builder to help.

    • Sergey

      Hello Kevin, here is my advice for the drones that you are planing to build. I haven´t tested the new F40 “Pro” version of the T-Motors, but if you want more speed, you may need to go for the bigger F60 Pro or F80 Pro motors (F80 Review). It will allow you to use 6045 propellers on the 250mm type frame. The KISS 30A ESC is a bit outdated I guess. You may go for the KISS24A ESC or some BLHeliS ESC. I am using the new Aikon 30A 4in1 as well as ZTW Flash 30A on my quads.
      You will need a high-rated-C battery, as the one you have chosen. However you will damage all your batteries if you fly constantly with that high speed, which means a very high-current. Most 30A ESC can handle 40-50A current for about 10s, so its fine. While flying with high speed, you can forget about decent fly time. It is simply not possible by that high current.

      Here is a build-log of a QAV-X by Stef, which can help you with your build.

      I would friendly advise you, that as an inexperienced pilot you will most probably going to crash the first time you go out for flying. It is extremely difficult to fly in manual mode and I am not talking about high speed. Make sure you order some spare parts. Fly in an open area without people, so there is no risk of hurting other people. Last but not least: before setting your drone, the firmware, the software, REMOVE the propellers and keep your son away from you. These quads are powerful machines! And again REMOVE THE Propellers while setting your quadcopter.

      Cheers and welcome to the hobby! Best, Sergey