About Mark Miles
more to come...
A practical approach to RC planes
Today I found some time to test three NTM Propdrive motors from Hobbyking. I’ve started to used these 28 sized motors for a bunch of my scratch builds. They are well build and hold up well. But the real test will be to see if they are true to the specs on the HK site. Standard disclaimer applies. These are the measurements I got on this date with these conditions. Your findings and mileage may vary. Please only use as a guideline. Ok with that out of the way let’s begin! For each motor I tested a number of props ranging from under spec right up to the limit. Each test is a 100% throttle measurement of watts, amps, and thrust. I used fully charged 20c Zippy 3000 mAh batteries and a Dynam Detrum 60 amp ESC. The images below show these rating for each motor. Watts and Amps are color coded to the 80% rule (below 80% green, 80-100% yellow, and over 100% red). Thrust is color coded from highest thrust (dark green) to lowest (white). As a good rule of thumb we’re looking for a prop with an 100% throttle reading at just about 80% of the motors watt/amp ratings and of course high thrust. For your use I have put together Prop reference guide linking to all props used during testing.
Review/notes: I plan on using a pair of these motors on my modified TwinStar 2 project I have in the works. I plan on running a set of Durafly Spitfire/P51 replacement 4 blade props on a three cell. From the testing I can see that this setup will be pretty good. Right in line with 80% of the max amps and well below max watt rating. While it’s not the most beneficent setup, a 4 bladed prop never is. And with this motor prop combo I’ll not have the option to setup up to a four cell. I tried it and fried the motor. But that was to be expected as these little motors have a low watt rating. If I had to recommend a prop for both 3 and 4 cell use on a high-wing plane, I’d go with 10×3.8 electric slow fly from APC. All around balance between power and efficiency.
Review/notes: The 1000 Kv motor is a perfect pair with many of the 30-40 inch scratch built war birds. I have plans on using this motor on both my P51 and FTracer. Fitted with a 9x6e prop these birds will have super long flight times, tons of power, and still come nowhere near the limits of the motor. If your new to low wing war birds this 9×6 1000kv pairing will make learning to fly them easy. And stepping up to the four cell will turn your olf bird into a rocket with unlimited vertical. Now with that said the above testing realy doesn’t reach or even push the limits of this motor. Looking at this data I’d like to follow up with some testing of 10 inch props. I really think this little guy could handle it.
Review/notes: For a long time I had been using motors from HobbyPartz.com for my F22 foamie builds but this time around I decided to give this HK motor a try. It looks like the 7x4e APC prop I’ve been using in these airframes will work great with the NTM 28-36 1800. Using a 4-cell battery yields 1600 grams of thrust on a 1000g plane. Now that will be a rocket. 🙂 I’ll just have to step up the ESC to cover the 50+ amp draw. I’ll defiantly post some videos once it is mounted comparing the two motors.
Overall not a bad day of testing. And once again I can’t stress enough how great having the thrust rig is. It helps illustrate such a clear picture of a motor’s performance. Which in turn helps pair the right motor and prop to an airframe. If you’d like to see a motor tested or have any questions about building your own thrust rig, please post them below. We read and respond to every post. And if you like what you see let us know. Thanks, -Miles