E-flite Power 25 User Manual

Thank you for purchasing the E-flite Power 25 Brushless Outrunner motor. The Power 25 is designed to deliver clean and quiet power for 25-size sport and
scale airplanes weighing 3- to 5.5-pounds (1.4-2.5 Kg), 15-size 3D airplanes up to 3.5-pounds (1.6 Kg), or models requiring up to 600 watts of power. It’s an
especially good match for scale 25-size airplanes.

Power 25 Brushless Outrunner Features:

• Equivalent to a 25-size glow engine for 3- to 5.5-pound (1.4- 2.5-Kg) airplanes

• Ideal for 15-size 3D airplanes up to 3.5-pounds (1.6-Kg)

• Ideal for models requiring up to 600 watts of power

• High torque, direct drive alternative to inrunner brushless motors

• Includes mount, prop adapters, and mounting hardware

• Quiet, lightweight operation

• External rotor design, 5mm shaft can easily be reversed for alternative motor installations

• High quality construction with ball bearings and hardened steel shaft

• Slotted 12-pole outrunner design

Power 25 Specifications

Diameter: 35mm (1.4 in)
Case Length: 54mm (2.1 in)
Weight: 190g (6.7 oz)
Shaft Diameter: 5mm (.2 in)

EFLM4025A

Kv: 870 (rpms per volt)
Io: 2.4A @ 10V (no load current)
Ri: .03 ohms (resistance)
Continuous Current: 32A*
Max Burst Current: 44A*
Input Watts: up to 600
Cells: 10-14 Ni-MH/Ni-Cd or 3-4S Li-Po
Recommended Props: 11x8 to 14x7
Brushless ESC: 40-60 Amp

* Maximum Operating Temperature: 220 degrees Fahrenheit
* Adequate cooling is required for all motor operation at maximum current levels.
* Maximum Burst Current duration is 30 seconds. Adequate time between maximum burst intervals is required for proper cooling and to avoid overheating the
motor.
* Maximum Burst Current rating is for 3D and limited motor run flights. Lack of proper throttle management may result in damage to the motor since excessive
use of burst current may overheat the motor.

Determine a Model’s Power Requirements:

1. Power can be measured in watts. For example: 1 horsepower = 746 watts

2. You determine watts by multiplying ‘volts’ times ‘amps’. Example: 10 volts x 10 amps = 100 watts

Volts x Amps = Watts

3. You can determine the power requirements of a model based on the ‘Input Watts Per Pound’ guidelines found below, using the flying weight of the model
(with battery):

• 50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models

• 70-90 watts per pound; Trainer and slow flying scale models

• 90-110 watts per pound; Sport aerobatic and fast flying scale models

• 110-130 watts per pound; Advanced aerobatic and high-speed models

• 130-150 watts per pound; Lightly loaded 3D models and ducted fans

• 150-200+ watts per pound; Unlimited performance 3D models

NOTE: These guidelines were developed based upon the typical parameters of our E-flite motors. These guidelines may vary depending on other motors and
factors such as efficiency and prop size.

4. Determine the Input Watts per Pound required to achieve the desired level of performance:
Model: E-flite J-3 Cub 25e ARF

Estimated Flying Weight w/Battery: 4 lbs
Desired Level of Performance: 70-90 watts per pound; Slow flying scale models

4.0 lbs x 70 watts per pound = 280 Input Watts of total power (minimum)

required to achieve the desired performance

5. Determine a suitable motor based on the model’s power requirements. The tips below can help you determine the power capabilities of a particular motor
and if it can provide the power your model requires for the desired level of performance:

• Most manufacturers will rate their motors for a range of cell counts, continuous current and maximum burst current.

• In most cases, the input power a motor is capable of handling can be determined by:

Average Voltage (depending on cell count) x Continuous Current = Continuous Input Watts

Power 25 Brushless Outrunner Instructions

Average Voltage (depending on cell count) x Max Burst Current = Burst Input Watts

HINT: The typical average voltage under load of a Ni-Cd/Ni-MH cell is 1.0 volt. The typical average voltage under load of a Li-Po cell is 3.3 volts. This means
the typical average voltage under load of a 10 cell Ni-MH pack is approximately 10 volts and a 3 cell Li-Po pack is approximately 9.9 volts. Due to variations in
the performance of a given battery, the average voltage under load may be higher or lower. These however are good starting points for initial calculations.

Model: E-flite J-3 Cub 25e ARF
Estimated Flying Weight w/Battery: 4.0 lbs
Total Input Watts Required for Desired Performance: 280 (minimum)

Motor: Power 25
Max Continuous Current: 32A*
Max Burst Current: 44A*
Cells (Li-Po): 3

3 Cells, Max Burst Power Capability: 9.9 Volts (3 x 3.3) x 44 Amps = 435 Watts

Per this example, the Power 25 motor (when using a 3S Li-Po pack) can deliver up to 435 watts of input power, readily capable of powering a scale 25-size
electric ARF with the desired level of performance (requiring 280 watts minimum). You must however be sure that the battery chosen for power can adequately
supply the current requirements of the system for the required performance.

Battery Choices:

We recommend either E-flite or Thunder Power batteries and list some possible choices for the Power 25 Brushless Outrunner motor, all depending on the
airplane application. Battery technology is constantly changing and manufacturers are improving and updating older packs with new ones so the list below may
generally have new substitutions.

THP33003SP30 3300mAh 3-Cell/3S 11.1V Pro Power 30C Li-Po EFLB32003S 3200mAh 3S 11.1V 20C Li-Po, 13 AWG
THP33004SP30 3300mAh 4-Cell/4S 14.8V Pro Power 30C Li-Po EFLB32004S 3200mAh 4S 14.8V 20C Li-Po, 13 AWG
THP38503SP30 3850mAh 3-Cell/3S 11.1V Pro Power 30C Li-Po
THP38504SP30 3850mAh 4-Cell/4S 14.8V Pro Power 30C Li-Po

Examples of Airplane Setups:

Please see our web site for the most up-to-date information and airplane setup examples.
NOTE: All data measured at full throttle. Actual performance may vary depending on battery and flight conditions.

3 Cells, Continuous Power Capability: 9.9 Volts (3 x 3.3) x 32 Amps = 316 Watts

E-flite J-3 Cub 25e ARF

Option 1:

Motor: Power 25
ESC: E-flite 40A Brushless (V2) (EFLA312B)
Prop: APC 12x8E (APC12080E)
Battery: Thunder Power PRO LITE 4200mAh 3S2P (THP420003S2PPL)
Flying Weight w/Battery: 4.0 lbs

Amps Volts Watts Input Watts/Pound RPM

36.8 10.8 397 99 7410
Expect very strong performance providing plenty of power for full aerobatics. Average duration is approximately 12-15 minutes depending on throttle

management.

Option 2:

Motor: Power 25
ESC: E-flite 40A Brushless (V2) (EFLA312B)
Prop: APC 12x8E (APC12080E)
Battery: KAN 1800mAh 4/5A 10-Cells
Flying Weight w/Battery: 4.15 lbs

Amps Volts Watts Input Watts/Pound RPM

29.6 9.8 290 70 6780
Expect good flight performance with ability to do rolls and loops. Scale flight at half throttle was smooth and responsive. Average duration is approximately 5-7

minutes depending on throttle management.

Accessories and Spare Parts:

See our web site at
on our web site so you can compare the different motors we offer.

EFLA110 Power Meter (measures power output in amps, volts, watts, and capacity)
EFLA241 Gold Bullet Connector Set, 3.5mm (3)
EFLM1925 Prop Adapter w/ Collet, 5mm
EFLM40102 X-Mount/Hardware: Power 10/15/25
EFLM40251 Shaft: Power 25 BL Outrunner
EFLA1040L 40A Lite Pro SB Brushless ESC
EFLA1040 40A Pro SB Brushless ESC
EFLA1060 60A Pro SB Brushless ESC

Operating Instructions:

1. This brushless motor requires the use of a sensorless brushless speed control. Failure to use the correct speed control may result in damage to the
motor and/or speed control. Please be sure the timing and PWM switching frequency is set properly on your controller.

2. When mounting the motor, be sure the correct length of screws are used so damage to the inside of the motor will not occur. We suggest you use the
mounting hardware included with your motor. The use of long screws will damage the motor.

3. You may connect the three motor wires directly to the controller with solder or use connectors such as gold plated brushless bullet connectors
(EFLA241), which will also need to be soldered properly to your wires. The three motor wires can be connected in any order to the three output wires

www.E-fliteRC.com or www.horizonhobby.com for our complete line of brushless motors. We have posted a specification comparison sheet