Prop Testing - NTM Prop Drive 35-36A 1800Kv / 875w

February 19, 2014|fretsman

After watching the FliteTest episode called "Viewer Request Speed Challenge" I decided I was going to scratchbuild my own "FT Versa Wing" and use the same power plant the FliteTest crew used to get into the triple digit speeds of over 100mph. From the episode I know that they used the "NTM Prop Drive 35-36A 1800Kv / 875w" motor from HobbyKing with an 8x8 prop. What is hard to discern from the episode is what type of battery and speed controller they used. I also know from the video that using an 8x8 prop with the setup they used was not the most responsible thing to do. At the end of the show you see when David's plane bursts into flames... LOL

Next I set out to research the "NTM Prop Drive 35-36A 1800Kv / 875w" motor and I found that even though people were saying very good things about it, there was not a lot of information out there on prop sizes and battery combinations. Even the HobbyKing website says "Prop data coming soon".

I tested the motor with different props ranging from 7x6 to 8x6 using a 4 cell battery and from 8x4 to 9x7.5 using a 3 cell. I thought it might be helpful to post the results for anyone who is thinking about getting this motor. For the testing I am using the "HK-010 Power Analyzer" from HobbyKing. For a speed controller I am using the "Turnigy Brushless ESC 85A w/ 5A SBEC" also from HobbyKing. For batteries I used both a 4 cell "Turnigy nano-tech 2200mah 4S 45~90C" and a 3 cell "Turnigy nano-tech 2700mah 3S 65~130C". Every test was performed using a freshly charged battery and as you can see from the pictures I used my "Spektrum DX8" transmitter and a "Spektrum AR6115e" 6 channel park flyer receiver. Everything is bolted down to a 2 x 4 piece of wood and then I clamped the entire rig down to my work bench. For safety I also put on safety rated glasses when I do these prop tests. ( I always wear safety glasses when I do these prop tests and you should too. Safey first! )

Keep in mind that the "HK-010 Power Analyzer" I am using has a max current rating of 100amps. As you can see from the results below I maxed out the current using a 4 cell battery and an 8x6 prop. Even though this is way above the 65amp max rating on the motor I thought I would test it because I found a few posts where people claim they are using this size prop on a 4 cell.

Last but not least I also found a few YouTube videos of people using this motor with a 6 cell battery and small 5.5 x 4.5 props to get 150mph speeds on the HobbyKing "Rad Jet 800". Needless to say I will be ordering some 6 cell batteries very soon. Once I get them I will update this article and post the results using the 6 cells batteries as well. I will post links to YouTube videos I found below as well.

4 Cell Battery

7x6 APC prop = 78 amps / 1170 watts
8x4 APC prop = 80.5 amps / 1187 watts
8x6 APC prop = 100 amps (maxed out) / 1446 watts

3 Cell Battery

8x4 APC prop = 55 amps / 663 watts
8x6 APC prop = 72 amps / 804 watts
8x8 APC prop = 85 amps / 945 watts
9x6 APC prop = 86 amps / 960 watts
9x7.5 APC prop = 97 amps / 1056 watts

Video links I found on YouTube of this motor with a 6 cell setup using small 5.5 x 4.5 props:

http://www.youtube.com/watch?v=B85pvUKu5GE

http://www.youtube.com/watch?v=oXyNNqI2Hxk

http://www.youtube.com/watch?v=_tXda2pT-xY

Well I hope that someone who is planning on purchasing the "NTM Prop Drive 35-36A 1800Kv / 875w" finds this information useful. Like I mentioned before, once I get the 6 cell batteries I will update this article with prop testing data for those batteries as well. I am also planning on posting an article/video of my scratchbuilt "FT Versa Wing" running the motor and batteries listed in this article. Stay tunned for that...

Rock ON!
fretsman

Some close up pictures of my testing rig:

"NTM Prop Drive 35-36A 1800Kv "
Specs:
Model: NTM Prop Drive 35-36A 1800
Kv: 1800rpm/v
Max current: 65A
Max Power: 700W @ 12v (3S) / 875W @ 15v (4S)
Shaft: 4mm
Weight: 120g
ESC: 70A
Cell count: 3s~4s Lipoly
Bolt holes: 18.9mm & 25mm
Bolt thread: M3
Connection: 3.5mm Bullet-connector