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

#1
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 guys used on this episode 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 the 4 cell "Turnigy nano-tech 2200mah 4S 45~90C" and the 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 radio and a Spektrum AR6115e 6 channel park flyer receiver.

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...

I also posted an article with pictures of my testing rig on the FliteTest website but it is pending approval. Once it gets approved and posted I will update this post with the link.

Rock ON!
fretsman
 

Walkerr

Junior Member
#4
Thank you very much for this well worked through and structured post. This is good reading. I've done almost exactly the same analysis of the mentioned FT episode trying to understand the specs of the gear David used. Winding it back and forth trying to see if I could get some more data.

And of course: I also ended up buying the NTM 35-36A 1800kv. But I still haven't made use of it.

Now your test results bring answers to some of my questions. Thanks :) Looking forward to your next post!
 
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willsonman

Builder Extraordinare
Mentor
#5
Well thank you sir! I have had this motor in a plane for nearly two years. I had been running things just fine on a 3S battery and a 7x6 prop. I decided to try a 4S but only purchased the battery. I never got the nerve to actually fly it. The plane is very fast even on 3S. This is encouraging data. While I think my full-throttle may be a bit heavy handed I think I will be in a safe zone to at least give a couple high-speed runs and see if the plane disintegrates!
 
#6
Fretsman, thank you for the in depth testing. It very much matches what I found when I built a 30" span delta last year using 2mm coroplast for this motor.
Build thread with plans
Flight video
The best prop I found on 4S that didn't draw too much power from the motor was an APC 7x5. On 4S the 7x6 drew too much power even with an extra heatsink on the ESC. I used an older HK watt meter for testing. It flies approximately 100mph (calculated) with unlimited vertical and a nice "happy prop" sound. :D You can sort of see in my build thread how I added an external Turnigy heatsink to the Plush 60A ESC.

Now that you have it tested you'll have to get it flying! :)
 
#7
Thanks for posting this. It is always good to get real world test data for as many motor / lipo / prop combinations as possible. Interesting that the only result within the specified safe limits was the 8x4 on 3cell. I'm sure that combination would be a screamer...

I'm always wary of people who post combinations out of spec as running just fine. Yes, it may have been for one flight or for 30 seconds on the bench. That is a long way from being a reasonable option. if it burns up after two dozen flights, that isn't really safe. And it could be weeks before one has even that relatively small number of flights under the belt. I assume that those results get posted a let less often. always a big 'YMMV' and 'common sense applied here' badges should go with any posted results, especially anecdotes without real data like the bench test posted here. Thanks again. imho.
 

willsonman

Builder Extraordinare
Mentor
#9
Thanks for the reply there on the heat. I may take this motor and swing in onto my viggen. My 64mm EDF gets it going but is just not as fast as I want.
 
#10
Thanks for the reply there on the heat. I may take this motor and swing in onto my viggen. My 64mm EDF gets it going but is just not as fast as I want.
Thanks willsonman!

As I mentioned in the comments section of my article. I have this motor on my scratch built FT Viggen. I am running it with two setups detailed below. It flies great with both setups since this plane has such a huge flight envelope. The only thing to keep in mind is that you will need to use fairly large batteries pushed way up into the nose in order to get the proper center of gravity. If you don't use nice sized batteries you will need to add some weight to the nose in order to counter the weight of this 120 gram motor.

My FT Viggen setups:
A) 3 cell setup = Turnigy nano-tech 2700mah 3S 65~130C with an APC 8 x 4 prop
B) 4 cell setup = Turnigy nano-tech 2200mah 4S 45~90C with an APC 7 x 6 prop

I will also be posting a new article soon of my scratch built FT Viggen running this motor with the setups I detailed above. In the article I will post a video with flight footage and I will also post detailed links to all the parts I used. Stay tuned for that!

Rock ON!
fretsman
 

nerdnic

nerdnic.com
Mentor
#12
I am doing some bench testing and I get 70.9a/781w on a 3S 8x8 APC. I'm not sure why our numbers aren't even close to matching, maybe I'm doing something wrong?
 
#13
Bearings!!! Be Carefull!

******Please Keep checking your bearings. These are extreme motors. They eat bearings!!!

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 guys used on this episode 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 the 4 cell "Turnigy nano-tech 2200mah 4S 45~90C" and the 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 radio and a Spektrum AR6115e 6 channel park flyer receiver.

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...

I also posted an article with pictures of my testing rig on the FliteTest website but it is pending approval. Once it gets approved and posted I will update this post with the link.

Rock ON!
fretsman
 
#14
I am doing some bench testing and I get 70.9a/781w on a 3S 8x8 APC. I'm not sure why our numbers aren't even close to matching, maybe I'm doing something wrong?
Its been a while... Have you determined the best combo for this motor for speed? Planning to put it in my resurrected nnMig3... thanks nic!
 

nerdnic

nerdnic.com
Mentor
#15
2200 60c 4s with a 7x7 is what I run on my 800mm planes. I haven't clocked it yet but the 800 nnMiG does at least 120 on this setup. I don't suggest this motor for the full size (40") planes.

The NTM 3548 1100kv with a 10x10 is what you want. Does about 80 on 3s and about 100 on 4s.
 

stwilkie

Junior Member
#16
Hi I am new here but have a bit more info on this motor for you.

This motor is my goto motor for the HobbyKing EFX models. I run it on 6s with a 6x5 aeronaut carbon prop. this gives me an amp draw on the ground of 63.5 amps. Worth noting is that the max amp rating on this motor is only 65 amps. I have burnt one out so far having full throttle on for about 10 secs.

Whilst the tests on the first page show results up as high as 100amps you would have to use throttle control here to stop you burning through the motors.

Also I now prefer the YEP controllers over the plush ones from hk, they pair very well with this motor and seem very very good for the price point.

Airspeed using the 6x5 on 6s is enough that in a full power dive the wing tips flattern out and act like ailerons.

But hell it sounds fantastic, https://www.youtube.com/watch?v=VSD11Kmplq0

My latest efx will run this motor using the 6x5 but on 5s, which should see amp draw drop to mid 50's.
I will loose a small amount of speed but at least the tips should not deflect, and i should get a little more airtime as I can fit 5s1800's instead of 6s 1500.

I also have a Ripmax Laser Arrow delta whose motor has let go of all the magnets, so I am going to replace it with another of these running an aeronaut 7x7 carbon prop on 4s. Should give me a nice performance range. Will let you know the amp draw figures once she is all back together.

Steve
 

Sero

Well-known member
#17
I just received V2 of this motor and ran some tests:

4S
TGS 7x4 prop - 55 amps - 811 watts
Master Airscrew Electric 7x5.5 - 76 amps - 1146 watts.

Installing it on my Racer; forum link here
 
Last edited:

Sero

Well-known member
#18
Got a few more props in to test out:

4S
Master Airscrew 7x6 Scimiter - 61 amps - 930 watts
EF Extra replacement 7x6.5 - 69 amps - 1010 watts

I was surprised of the above results so I ran the 7x5.5 from the above post again to see if something else had changed but the results were the same.

I will eventually get in an 8x6 Scimitar to see how that holds up as that's my preferred prop size for this plane. Given that the 7x6 drew 61 amps I'm hopeful that the 8x6 will still be under 80 amps
 

Arcfyre

Well-known member
#19
I know this post is ancient, but I use this motor on a 5' modified versa wing with a red brick 100A ESC and an 8x6 APC with a 2200 3S. Full power draws over 80 amps, so bursts only. It still rips at 3/4 throttle even on 3S.

 

Sero

Well-known member
#20
I know this post is ancient, but I use this motor on a 5' modified versa wing with a red brick 100A ESC and an 8x6 APC with a 2200 3S. Full power draws over 80 amps, so bursts only. It still rips at 3/4 throttle even on 3S.

Nice! Are those numbers while the plane is flying or static?