(Micro Brushless Outrunner Motors)
An APPLICATION REVIEW
This article is launching a new RC MICRO WORLD series, which we are calling “Application Reviews”. It will primarily concentrate on motors, ESC’s, batteries and chargers. The key throughout these reviews is how the product works and what is its specific application. If a motor, we expect to tell you the power levels, recommended prop size, battery capacity and then tell you what weight plane it can fly. What we won’t do is copy catalog and website information which is available to anyone.
For our kick off review I’m going to tell you about two new Horizon Hobby E-Flite micro size outrunner brushless motors.
E-Flite PARK-180 motor at the left and the PARK-250 on the right
PARK-250 motor at top and PARK-180 motor at bottom
Motors under test at top, ESC in center and both battery packs at the bottom)
The first is their smallest, the PARK180 which is described in detail at this exact website: http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFLM1120.
It weighs 8.5 grams and is claimed to run up to 30 watts input power. Price is just $41.99 or about half of what we paid for a similar size motor only a year ago. So the key items here are the size, weight and price. The second motor in this series is slightly larger. It is the E-Flite PARK-250, also a brushless outrunner type. It is well described at this Horizon Hobby website: http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFLM1130.
It weighs 14 grams and is claimed to run up to 55 watts power input. Price is also very reasonable at $44.99. Having introduced both of these micro gems, let me get into my detailed evaluation and testing.
E-FLITE PARK-180
This micro size brushless outrunner motor is intended mainly indoor RC aircraft and has a claimed Kv of 2200, is said to fly model aircraft up to 6 ounces total weight, has a continuous current rating of 2.6 amps and can supposedly run at power inputs up to 30 watts. The recommended prop range is 3 x 3 to 6 x 3 for two Li-Poly cells and 4 x 4 to 4.5 x 3 for three-cell operation.
Included with this motor, for the stated price, are a conventional prop adapter and a metal motor mount. The bare weight of the motor is stated as 8.5 grams (0.3 ounce). After installing the prop adapter, a typical prop and the metal motor mount the total weight was measured at 12.5 grams (0.44 ounce), which is still very light.
The 180 is also very small in size. You won’t realize this from the photos, but when you hold it in the palm of your hand you will see what I mean. The outer barrel of the motor is only 5/8-inch diameter. The distance from the rear of the prop to the rear of the motor mount (at the firewall) is 1 1/8 inches. The metal motor mount has only two mounting holes that are spaced 13/16 inch apart.
If you install this mount on a firewall at approx. a 45-degree angle, the firewall size can be as small as 13/16 inch wide by 1 inch in height. This metal mount is quite strong and is recommended when you have a conventional built-up fuselage. For profile fuselages the rear of the motor can be slipped over a short length of carbon fiber or aluminum tubing (like from KS Engineering).
The three wires that exit from the motor are reasonable in size and durable. It is not the extremely thin and frail wire that comes with some of these micro motors. The wires are color-coded and terminate in individual gold plated pins. This makes it easy to swap wires to achieve the proper motor rotation. When soldering up the mating gold plated pins to the wires of your ESC make sure the pins are completely covered with heat shrink tubing. Failure to do this could allow the pins to short out during flight and stop your motor.
The 180 motor shaft is just 1.5 mm in diameter. This is a lightweight shaft and therefore must be treated carefully for fear of bending it. If you bend it accidentally while installing the prop adapter or as a result of a plane crash, the motor will likely not be repairable.
When you install that prop adapter you should not grab the outer barrel of the motor. The best way to do this is mount your motor to the firewall. Then install a prop on the adapter. Next slip the adapter over the end of the motor shaft. Holding the prop, tighten the setscrew on the adapter. This way no bending motion is imparted to the delicate motor shaft.
For my testing purposes I used a Castle Creations Phoenix-10 brushless ESC that can handle up to 10 amps motor current. I like this particular ESC because I can program many different parameters into it by using the Castle Creations software and their PhxLink (ESC to PC) cable. The Phoenix-10 weighs 6 grams (0.21 ounce).
