Wednesday, February 6, 2008

Dualsky XMotor Review

When looking for a new power source for my RC Bug , I ran across a very unusual motor from Dualsky . This tiny outrunner contains a 6 amp brushless speed controller in the motor housing. That means you get a matched motor and ESC with no hassles of soldering bullet connectors or checking which way the motor spins, and less wire clutter when installed. Read on for our review.







Specifications



Diameter
28 mm


Length
18 mm


Weight
25 grams


KV
1780


LiPo Battery
2 to 3 cells


Max Amps
10A for 15 seconds


Max Watts
80W for 15 seconds


Street Price
$55 USD




The Dualsky line is distributed in the U.S. by 2DogRC , who sent along this motor for review. The XMotor 2812RTR comes in two versions: 33 windings for a KV of 1470 , and 27 windings for a KV of 1780 , which is the unit I received. Both motors are also available in more traditional form without the ESC if you prefer to use your own controller.










My first task was to figure out how to best use this power system. I had been flying with the LightFlite blue motor (1100 KV) and ESC that come in the Bug combo. These gave very good power with a GWS 10x6 prop on 2S, and ballistic power on 3S.

Mark at 2DogRC was very helpful when picking which XMotor to choose, how to prop it, and what battery to use. We decided to go with the 1780 KV version, which meant dropping down to a GWS 8x4 prop. For those keeping score, that means the ability to fly one inch lower than with the old prop. Both 2S and 3S batteries would work, although he cautioned me that I might see heat problems on 3S if I held a hover for a long time, due to lack of airflow over the motor. I'll get ahead of myself a bit here and mention that no matter how hard I pushed this motor on 3S, it never overheated.

Since the motor-ESC connection is internal, the XMotor only has two connectors exiting the case. The power leads came with a JST connector, which I replaced with a Dean's micro to match my batteries. The other wire is a standard servo connector for throttle and receiver power, which runs to channel 3 as usual. It takes a little getting used to seeing these connectors coming directly out of the motor, but I really like how it simplifies the installation.



The RC Bug comes with a plastic tube mount, which allows the blue combo motor to be directly inserted, or to mount a different motor on a circular plate. The plate which came with mine was too small for the XMotor, so I contacted Ron at LightFlite who was happy to send a larger one.




At a minimum this plate required drilling two holes for the mounting screws, but I also wanted the ESC at the back of the casing to have as much ventilation as possible. Therefore I drilled a number of large holes in the mounting plate and cleaned up the surface with a Dremel. I could have cut down the outside of the plate to reduce drag and weight a bit but decided to leave it.

The LightFlite motor and ESC weigh a total of 32 grams, whereas the XMotor is 25.7 grams. That's a nice savings, but the XMotor puts all its weight at the front. This was easy to compensate for by moving the battery back a bit. I already had a strip of velcro running down the fuse so I could change the CG for different size packs.

The XMotor came with the prop saver already attached, a couple of step-up rings, and a couple of rubber O-rings. The GWS 8x4 props have a hexagonal cutout on the back, so I had to make it a bit rounder and use one of the step-up rings, which subsequently popped out in a light crash. I have since flown without it, which gives the prop a little side-to-side wobble when off, but flies OK with perhaps a small hit to efficiency.



Flying with the XMotor has been great. I've put about 20 packs through it as of this writing. On 2S the Bug floats around beautifully but still has enough power to go vertical forever. On 3S, it's a screamer: a full power snap happens basically in place, and an inside loop takes only a little more room. Fast level flight is also possible, but since the Bug has no airfoil it takes a lot of elevator management not to climb or dive.



With hard use the motor comes down fairly warm but never uncomfortable to touch. I typically get 10 minute flights on a 2S 460 mAh battery, and 8 minutes using a 3S 300 mAh pack.

I'm quite impressed with the Dualsky XMotor 2812RTR . Packing an ESC inside a brushless outrunner motor is a great idea, both for convenience and weight savings. It's a great example of integration which still lets you choose between 72 Mhz and 2.4 GHz receivers, unlike the 4-in-1 units on some micro helicopters. I'm happy to recommend the XMotor for your next foamie or indoor plane.

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