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New MultiRotor Motor

Tritium

Amateur Extra Class K5TWM
#2
I received the MR2814-KV800 motor from Value Hobby Today.

It was carefully wrapped in foam and packaged in a more than usually sturdy box.

The leads are about 11.5" long of high quality flexible silicone jacketed wire strain relieved where it exits the motor housing, terminated with pre-installed 3.5mm gold plated male plugs, each is insulated with a different color of shrink tubing and the ESC side female connectors are included.

The motor is VERY noticeably different from the standard Chinese cheapy motors I have bought in the past.

The rotor is made of stacked laminated steel used in high quality transformers which contains the magnetic flux very well.

The motor is machined extremely well and uses over sized bearings of high quality.

There is absolutely no end play of the rotor as exist in almost every RC Timer / MyRCMart motor I have ever purchased.

The magnets are nickel plated and of a high quality.

There were no chips from machining or assembly (as I have found in cheaper ones) inside the motor.

There is no protruding shaft on this motor as it uses a bolt on threaded prop adapter which will accept a standard nylon insert locking nut to secure the propeller without the fear of loosening up during flight.

The bolt on prop adapter is available in RIGHT and LEFT hand threads to prevent the above mentioned use of a locking nut but I use locking nuts anyway on my builds.

My first impressions is this is a quality motor for about $22 US including the prop adapter and mounting kit (which is about what the DJI 2212-950's retail for although the Value Hobby motor is a lot beefier than the stock DJI's). It is MUCH better fit and finish than the Hobby King NTM series motors and for a couple of bucks more probably a better buy.

Prop test data shows 12X6 to 13X6 props and a max current draw of 29A (4S battery) although this is about 3A over specified max amp draw. Battery's from 2S to 4S are specified for this motor. A 30A esc should be sufficient for most uses but a 40A will give ample "wiggle" room for any flying style.

I would like to see at least 3 or 4 different KV ranges for this series from 800KV for aerial photography to 2200KV for Hot Rod Acro Mode (stunt) craft.

Electrical and performance testing to follow although at this time I may go ahead and order Value Hobby's pack of 4 (plus 1 since I have a spare Hex frame) so I can actually build a multi with it when my electrical testing is done.

$130 for quality motors for a hex copter is a bargain in my book.

Thurmond
 

Tritium

Amateur Extra Class K5TWM
#4
Initial very limited testing today with my own precision current shunt and Fluke meter indicates 22.5A full throttle with a freshly charged 2200mAh Turnigy 35-45C battery Hobby King Blue 30 ESC and an 11X4.7 Turnigy (Gemfan) Slow Flight Prop.

Balance of the motor alone is very good.

Balance with the prop saw one harmonic vibration just before full throttle which I attribute to prop backwash since the test was 2" above a flat surface.

As soon as I can secure a 13" and 14" prop I will get some numbers with them.

Thurmond
 
#5
So one motor with an 11x4.7 prop is pulling 22 amps? Spinning three or four of those will suck down a battery pretty quickly. Did you get thrust measurements too?
 

Tritium

Amateur Extra Class K5TWM
#8
No I have not completed my testing apparatus for thrust measurements yet.

Most flyers average somewhere just above 1/2 throttle in normal flying so the average amp draw would be around 50A.

It is worth mentioning though that any quad with more than minimal motors needs a 40C battery minimum IMHO!

Thurmond
 

Tritium

Amateur Extra Class K5TWM
#9
New data: 13X4 APC style glass filled nylon prop 22.5A (only a half amp more than the 11X4.7 slowfly). Surprised me.
14X7 APC style glass filled nylon prop (from Value Hobby as well) data 29A at full Throttle on a 3S battery.
Perfect for my Hexcopter.

Also the nut included with the prop adapter is drilled and threaded off center :mad:. Toss it and replace it with quality nylon insert locking nuts.

Now I have to find the 14X7 in a reverse rotation model.

Thurmond
 
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#11
Looking at these to possibly replace the DT700s I have on my quad. Are they rated for 4s lipos? Also will these be big enough for like a ATG 650 size frame?

Finally, what is the deal with the standard and reverse spin shaft? I thought any motor could be reversed if you just switched the leads why the shaft difference?
 

xuzme720

Dedicated foam bender
Mentor
#12
It's only the threads in the prop adapter that are reversed, so the rotation doesn't unscrew the prop nut. It's not actually the motor.
 

xuzme720

Dedicated foam bender
Mentor
#16
I'm sure you must have seen these CF 14x5.5 at Rctimer.

Very close to 14x7 and stiff as steel and not too crazy expensive.
No, I hadn't checked RCtimer yet. I was just over at Heads Up getting some wire when I checked for the larger size in pusher.

I like the style and that's not bad price at all for CF props! Not sure I'm quite ready for CF though as I still land my multi's a little harder than planned occasionally. Yes, that should read: crash! So I have denial issues....
 

Cyberdactyl

Misfit Multirotor Monkey
#17
I've noticed with CF props the jello pretty much disappears. The buzzy vibrations can see be seen if everything is not balanced or the cam is not isolated from boom thump, but jello from flex pretty much is solved.
 

Tritium

Amateur Extra Class K5TWM
#19
I was looking at these:

http://www.himodel.com/plane/14x7_Carbon_Fiber_Propeller_Set_CW_CCW.html

The Hex is about 32" or 810mm motor shaft to motor shaft. Weight is yet to be determined when loaded but it is planned to carry several batteries, FPV and Video recording equipment along with a telemetry radio autonomously (APM 2.5).

I have also built a wooden quad frame that can use props 14" in size too.

Hobby King has some 14X7R APC style props but they are only at the HK warehouse so that is another possibility.

Thurmond
 

Tritium

Amateur Extra Class K5TWM
#20
It's only the threads in the prop adapter that are reversed, so the rotation doesn't unscrew the prop nut. It's not actually the motor.
Correct but I will only order the right handed threads from now on since the nuts they ship with are no good and I will use nylon insert locking nuts and I haven't find them in left hand threads in metric sizes so far.

Thurmond