6.4. Motors and related items

6.4.1. Motor

For more details see Section 30.2, “Motor selection guide” and Section 30.3, “Motor selection table” in the Chapter 30, Technical Appendix

6.4.1.1. Corona motors

Ideal Kv: 2700-3000 rpm/V - Main gear: 102T, 32 pitch

  • Graupner Speed 500 Race #6307 (brushed) mild

  • Kyosho Atomic Force (brushed) mild

  • Mega Motor ACn16/15/4 (brushless) mild

  • Mega Motor ACn16/15/3 (brushless) mild

  • Hacker C40-12S (brushless) powerful

  • Mega Motor ACn22/20/3HTDS (brushless, 8 cells/15T)

    Note: The Mega Motor motors are very good for duration flights in the Corona. 10+ minute flights are possible with some moderate wind.

Note: The Astroflight 020 has a high failure rate when used in the Corona.

6.4.1.2. FP Piccolo motors

Ideal Kv: 1800-2000 rpm/V - Main gear: 100T, 0.5 module

  • Astro Flight Astro 010 (brushless) mild

  • Team Orion Modified Elite (brushed) powerful

  • Hacker B20-36S (brushless) (8T pinion) powerful

  • Model Motors ACn1215/20 (brushless) powerful

Note: The Astro 010 is very good for long flights.

6.4.1.3. CP Piccolo main motors

Ideal Kv: 2700-3000 rpm/V - Main gear: 100T, 0.5 module

  • Hacker B20-36S (brushless) (10T pinion) mild

  • Astro Flight Astro 010/14T (brushless) mild

  • Team Orion Modified Elite (brushed) powerful

  • Astro Flight Astro 010/10T (brushless) powerful?

  • Hacker B20-31S (brushless) (8T pinion) powerful

  • Model Motors ACn1215/20 (brushless) powerful

  • Hacker B20-20L (brushless)

  • Hacker B20-18L (brushless) (8T pinion) powerful

Note: The B20-36S is good for duration flights.

The B20-18L is good for aerobatics.

6.4.1.4. Hummingbird FP/CP, GWS Dragonfly main motors

Century Hummingbird: 140T, 0.5 module

GWS Dragonfly: 120T, 0.5 module

Others: 0.5 module

  • HiMaxx 2015-4100

  • Model Motors ACn1215/16 (brushless)

The CP Piccolo is a similar weight and size, so all motors in the CP Piccolo section can be used also. Multiply the recommended pinion size by the difference in gear ratio to compensate (1.4 for the Hummingbird, 1.2 for the Dragonfly)

6.4.1.5. Piccolo, Dragonfly, Hummingbird tail motors

Main gear: 0.5 module

  • GWS EDF50-2 motor (brushed, can draw >2 amps)

  • Feigao 1208436L (brushless)(direct drive or geared use)

  • Feigao 1208430S (brushless)(geared use only!)

6.4.1.6. Hornet CP motors

Main gear: 135T, 0.4 module

  • HiMaxx HA3026-3600 (brushless)

  • Hacker B20-26S (brushless)

  • Model Motors ACn1215/16 (brushless)

  • Razor Micro Heli V2 (brushless)

6.4.1.7. Maxir SE motors

Main gear: ?T, 0.4 module

6.4.1.8. Zoom 400 motors

Main gear: 132T, 0.5 module

  • Himaxx HA2025-4200 (brushless)

  • Hacker B20-15L (brushless, 9-10T, 3S LiPo)

  • MiniAC 1215/20 (10T, 3S LiPo)

  • Eflight Park 400 4200 (8T, 3S LiPo)

  • Motor Max Motors 400DH (9T, 3S LiPo)

  • NeuMotors 1105/3Y (10T, 3S LiPo)

  • Do not use the Chili Pepper 3600 - it burns out

6.4.1.9. Align T-Rex 450X/450XL motors

Main gear: 150T, 0.5 module

  • Himax 2025-4200 (8T, 3S LiPo

  • Astro 020 4T (11-12T, 3S Lipo)

  • Mega 16/15/3 (13T, 3S Lipo)

  • Neumotor 1105/3Y (9T, ?S LiPo)

  • Lehner 1020/17 (11T, 3S LiPo)

  • Medusa Products MR-028-040-3400 (11T, 3S LiPo)

(Best low-cost choice is currently the Mega 16/15/3)

6.4.1.10. ARK X-400 motors

Main gear: 138T, 0.5 module

  • Mega 16/15/3 (?)

6.4.1.11. Voyager E motors

Pinion: ?

  • Hacker C40-10T (brushless)

  • Hacker C40-8L (brushless)

Note: The Astroflight 020 has a high failure rate when used in the Voyager E.

6.4.1.12. Robbe Eolo motors

Ideal Kv:

3.17mm shaft motors: 3000-3300 rpm/V

5.00mm shaft motors: 2700-3000 rpm/V

Pinion: 0.7 module

The available pinions are 14-18T for 3.17mm, shafts, and 19-22T for 5mm shafts.

  • Hacker C40-9L (brushless) (8 cells/18T)

  • Hacker C40-8L (brushless)

  • Mega 22/20/2 (brushless)

  • Kontronik Twist 3700 (brushless)

  • Aveox 27/39/1.5 (brushless)

  • Lehner 1930/6 (brushless)

6.4.1.13. ECO 8 motors

Aerobatic flight - ideal Kv:

3.17 mm shaft motors: 2300-2600 rpm/V

5.00 mm shaft motors: 1800-2000 rpm/V

Duration flight - ideal Kv:

3.17 mm shaft motors: 2100-2300 rpm/V

5.00 mm shaft motors: 1500-1800 rpm/V

Main gear: 180T 0.5 module

The ECO 8 has a 180T main gear, and the available pinions are 10T-17T for 3.17mm shafts, and 13-24T for 5mm shafts

  • Magnetic Mayhem (brushed) mild

  • Mega 16/25/3 (brushless, 10 cells/13T) mild

  • Hacker C40-13L (brushless) mild, good for duration

  • Aveox 27/30/1.5 (brushless) ???

  • Mega 22/20/4 (brushless, 10 cells/19T) mild

  • Aveox 36/15/1.5 (brushless) ???

  • Ikarus X-250-4H (brushless) mild, discontinued

  • Hacker C40-14S (brushless, 8 cells/9-10T) mild

  • Hacker C40-12L (brushless, 8 cells/12-13T, 10 cells/10-11T)

  • Aveox 27/39/1.5 (brushless, 10 cells)

  • Aveox 36/15/1.5 (brushless, 10 cells)

  • Ikarus H8 (brushless, 8 cells 22-24T, 10 cells 21-24T, 12 cells 20-24T) ???

  • Hacker B50-22S (brushless, 10 cells/16T, 12 cells/13T)

  • Hacker B50-18S (brushless, 8 cells/14-19T, 10 cells/13-15T) powerful

  • Hacker B50-15L (brushless) powerful

  • Hacker C40-10L (brushless) powerful

  • Mega Motor ACn22/20/3H (brushless) powerful

  • Kontronik 500-19 (brushless) (8-10 cells, 13-15T) powerful

  • Hacker B50-13L (brushless) very powerful

  • Plettenberg Orbit 15-14 (brushless, 10 cells/24T) powerful

  • Lehner Basic 2400 XL (brushless) ???

  • Lehner Basic 2800 XL (brushless) ???

  • Hacker B50-11L (brushless) insanely powerful(requires very good matched batteries)

6.4.1.13.1. Best inexpensive motor for ECO 8

Mega Motor ACn22/20/3H

6.4.1.13.2. Best overall motors for ECO 8

Hacker B50-15L

Plettenberg Orbit 15-14 (10 cells/23-24T)

Note: The C50 motors will NOT fit in an ECO frame.

The smaller motors (C40, etc) may overheat in warm weather (70+F) so be careful.

6.4.1.14. ECO 16 motors

The ECO 16 has the same main gear and pinions as the ECO 8.

  • Mega 22/30/4 (brushless, 16 cells, 17-20T)

  • Ikarus H16 (brushless, 16 cells, 20-24T)

  • Plettenberg Orbit 20-16 (brushless, 16 cells, 22T)

  • Mega 22/30/3 (brushless, 16 cells, 13-15T)

6.4.1.15. Viper 70 motors

The ECO 16 has the same main gear and pinions as the ECO 8.

  • Mega RCn 400/15/5 (brushless, 3s lipo, 17T)

  • Mega ACn 16/15/4 (brushless, 3s lipo, 10-12T

6.4.1.16. Logo 10 motors

5.00 mm shaft motors: 1800-2000 rpm/V

Pinion: old models: 0.5 module, newer models: 0.7 module

The main gear is 200T, and the available pinions are 13-23T for 5mm shafts.

Pinion:0.5 module

  • Aveox 36/24/2 (brushless) ???

  • Kontronik Fun 600-15 (brushless) powerful

  • Hacker C50-15L (5s3p, 13T)(brushless) powerful

  • Mega ACn 22/30/3 (brushless) (5s3p, 13T)

  • Astro 040 (brushless) ???

  • Kontronik Fun 600-15 (brushless) (12 cells, 14-16T)

  • Aveox 36/24/2 (brushless)

  • Hacker C50-14L (brushless) (5s3p, 13T)

  • Hacker C50-13L (brushless) (12 cells, 14T, 14 cells, 13T)

  • Kontronik Fun 600-17 (brushless) (12 cells, 15-19T)

  • Kontronik Fun 600-18 (brushless) (12 cells, 14-18T)

  • Plettenberg Orbit 15-16 (brushless, 1070 rpm/V) ???

  • Plettenberg Orbit 15-14 (brushless, 12 cells, 17T) ???

  • Mega ACn 22/30/2 TDS (brushless) (6s3p, 10T)

  • Hacker B/C50-11L (brushless) super powerful (requires very good matched batteries)

Recommended:

  • Plettenberg Orbit 15-14 (12 cells/17-21T)

  • Plettenberg Orbit 15-16 (14 cells/17-21T)

  • Hacker C50-13L (12 cells/13-17T)

6.4.1.17. Logo 14 motors

5.00 mm shaft motors: ?

There are two main gears included with the Logo 14: 200T/0.5 module and 140T/0.7 module.

  • Hacker C50-13XL (5s4p, 11-13T)

  • Hacker C50-14XL (6s3p, 10-12T)

  • Hacker C50-15XL (7s3p, 10-11T)

  • Hacker C50-16XL (8s3p, 10T)

  • Hacker C50-17XL (8s3p, 10-11T)

  • Hacker C50-18XL (8s3p, 10-11T)

  • Hacker C50-19XL (8s2p, 10-11T)

  • Hacker C50-12XL (6s3P, 13T)

  • Hacker C50-11XL (5s4p, 13-14T)

  • Hacker C50-10XL (5s4p, 13T)

  • Plettenberg HP 300/30/A2 Heli (5s4p/15T)

6.4.1.18. Logo 20 motors

5.00 mm shaft motors: ?

138T main gear for the older model, 98T main gear for the newer model

6.4.1.19. Quick EP 10 motors

The main gear is 120T, and the available pinions are 10-14T for 5mm shafts.

  • Aveox 36/20/2 (brushless, 12 cells, 11-12T)

6.4.1.20. Quick Sweet 16 EP motors

The main gear is 120T, and the available pinions are 10-14T for 5mm shafts.

  • Aveox 36/38/3 (brushless, 20 cells, 12-13T)

6.4.1.21. Summary

If you choose a brushless motor, then an autorotation gear is highly recommended. Most brushless motors have extremely high torque so when the motor spools down, the "braking" effect will be very strong. This will very likely break the main gear teeth if you do not have an autorotation gear. The only exception to this is the Corona; the main gear on it is very tough and can handle a brushless motor without an autorotation gear.

The older sensored Aveox motors (12xx and 14xx series) are only rated to 20,000 rpm, and the JETI motors are only rated to 15,000 rpm. You must be careful not to exceed these rotational speeds otherwise the rotor may eject a magnet (i.e. "throw a magnet"). Therefore, I do not recommend these motors for helicopter use. The better motors such as the newer Aveox, MEGAs, Hackers are typically rated for 50k-70k rpm, which makes them a better choice for helicopter applications.

The Model Motors 2814/10 is not recommended for an ECO 8. The motor seems to have problems with the rotor wobbling and touching the stator windings which burns out both the motor and the ESC. There are also some reports that the magnets are not epoxied very well to the rotor and may shift position. Also, these motors are not very efficient, and run very, very hot when used in a helicopter.

Most of the HiMaxx motors are not very efficient and therefore are not very good for larger helicopters because they generate large amounts of heat. There was one report of an HB 3615-2100 used in an ECO 8, and it became "too hot to touch". The HiMaxx seems to work okay in microhelis such as the Hornet CP and Zoom. The choice of a motor with a proper Kv for a collective pitch helicopter is very important, because most motor ESCs are not efficient when running at much less than 90% throttle. If you run an ESC continuously at low throttle, the ESC will probably overheat. Therefore, you should select a motor + pinion combination that will allow the motor ESC to run at 90-95% throttle for best efficiency.

Pole counts for motors are unfortunately difficult to find, and are necessary to program some ESCs correctly. Here are the pole counts that I have managed to find:

  • 2 pole: Hacker, Kontronik, Lehner, some Plettenberg

  • 4 pole: Aveox, Neumotor, some Plettenberg

  • 6 pole: Mega 16 and 22 series, some Plettenberg

Also see Tohru Shimizu's helicopter brushless motor page at: www.dokidoki.ne.jp/home2/tohrus/motorindexE.html

[Note]Note

Check the length of your motor mounting screws before mounting!

If they go too deep into the motor they will short out a winding which will damage the motor. Even worse, if you try to run a motor with a shorted winding, it will burn out the ESC. So test the screw length by screwing it into the motor with your fingers before mounting in the frame.

6.4.2. Pinion

For more details see Section 30.4, “Pinion selection guide” in Chapter 31, Glossary

Most helicopter manufacturers supply a range of pinions for their helicopters. You may require pinions with more teeth for some reason. The most common reason is for running outrunner motors which usually have a fairly low Kv and therefore require a pinion with a higher tooth count.

Some helicopters use metric pinions, and some use English pinions.

The smaller brass press-on pinions (1 and 1.5mm) can be very difficult to remove from motors. I do not recommend the GWS pinion puller for these - I have personally destroyed two GWS pinion pullers trying to remove this type of pinion. The Maxx products pinion puller (ACC650) is much sturdier than the GWS pinion puller. Also, many brass pinions can be pulled off motor shafts by using heat since brass has a high coefficient of thermal expansion.

The best way to remove these brass pinions is to clamp the motor in a vise, then press a hot blunt tip soldering iron on the end of the pinion (for maximum heat transfer), wait about four seconds to allow the pinion to become hot and expand, then pry off the pinion using needle nose pliers. Do not skip the soldering iron step, because otherwise you will pull the shaft out of the motor.

The best way to install a brass pinion on a motor is to use a vise. Put the motor and pinion between the jaws, and screw the vise shut to push the pinion onto the shaft. Be sure the back end of the shaft is pressed against the jaw otherwise you may damage the motor bearings.

When selecting pinions, be sure to check your helicopter manufacturer's pinions first. The pinions from the helicopter manufacturer usually work best for most models.

6.4.3. Motor connectors

The standard connector for nonmicro helis is the 3.5mm bullet-style connector. These work well for up to 70 amps and are supplied with Schulze controllers.

For the main motor of FP micro helicopters and for tail rotors of micro helicopters, the most commonly used connector is the crimp pin from a D-sub connector. These are good up to about 4 amps and are available from Jameco Electronics; the female pins are part #43369 and the males are part #43377

For the main motor of CP micro helicopters there really is no standard. I personally use the MP Jet 1.8mm gold connectors, which are available from Aircraft World.

6.4.4. Main motor ESC

(See Chapter 31, Glossary for a definition of ESC)

If you plan to use a brushed motor, you will need a brushed motor ESC. If you plan to use a sensored brushless motor (like the X-250-4H) then you can use either a sensorless or sensored brushless motor controller. For the sensorless brushless motor controller, the sensor wires (connector) from the motor will not be connected to anything because the sensors are not required by the controller.

The sensored brushless motors may need to be sent back to the motor factory to reverse the motor direction if your rotor head is spinning in the wrong direction. Therefore, I recommend avoiding sensored brushless motors unless you already know the timing is for the desired direction of rotation.

If you plan to use a sensorless brushless motor, you will need a sensorless brushless motor controller. This motor type is not usable with a sensored brushless motor controller (such as the older Schulze Booster-40b).

An ESC used for main motor control must have the following characteristics are required (or must be programmable):

  • No brake. If the ESC has a brake, then the motor may strip the main gear when the throttle is reduced.

  • No reverse. A helicopter rotor should never spin in reverse.

  • Slow start-up. If the ESC does not have a slow startup, the heli may spin when throttle is applied, tip over, or strip the main gear.

  • No low voltage cutoff or programmable very low voltage cutoff. (As low as possible, must be less than 0.7 volts/cell for Nicad/NiMH or less than 2.5 volts cell for LiPo.

Most airplane ESCs are not suitable for helicopters because they have low throttle resolution, include a brake and have a fairly high low-voltage cutoff.

For the micro helis, the following are poular as main motor ESCs:

  • Pixie-7P (brushed ESC, 7 amp)

  • Schulze Future 11.20e (brushless, rather heavy)

  • Castle Creations Phoenix 10 (brushless, very light)

  • Piccoboard/Piccoboard Plus/Piccoboard Pro

  • GWS ICS-100E (brushed main motor ESC, 5 amp)

  • Cool Running H-12 (brushless, 12 amp)

  • Cool Running H-25 (brushless, 25 amp)

For the Corona, the following work:

  • Castle Creations Pegasus 35 (brushed)

  • Castle Creations Phoenix 35 (brushless)

  • Hacker Master 40-3P (brushless, do not use the BEC on this ESC because the ESC will overheat on 3 servos?)

For the ECO 8/16, the following work:

  • Schulze Future 12.46k

  • Schulze Future 18.46k

  • Hacker Master 40-3P Heli

  • Kontronik Jazz 55-6-18

For the Logo 10, the following work:

  • Schulze Future 18.46K

  • Kontronik Jazz 55-6-18

Do not use the SMILE 40-6-18 in the Logo 10 - it tends to burn out!!!

The Hacker Masters seem to burn out in the Logo 10 as well due to ESD problems.

The JETI Micoprocessor (red label series) is not suitable for helis because the throttle control is not smooth and is rather "steppy". The Advance (blue label series) is supposedly better, but nobody I know has tried this.

Some ESCs have an optocoupler (usually called OPTO) instead of a BEC. The optocoupler electrically isolates the ESC from the control signal which reduces the possibility of interference from the external BEC.

The Kontronik ESCs have a good soft start and governor mode for use on helicopters. However, they do not have thermal overload protection.

The Schulze ESCs also have a good soft start and governor mode, and they do have thermal overload protection.

The Castle Creations Phoenix works fine in the Piccolos and the Corona but does not work well in the ECO 8/Logo 10 and larger helis. The current version of the firmware has a problem in three areas:

  • The soft start doesn't work properly. It may kick your heli around 180 degrees and/or tip your heli over.

  • The governor mode doesn't work properly with a heading hold gyro. The RPMs will go up and down even when hovering, which makes the tail wag back and forth.

  • The controller seems to have less glitch filtering than other ESCs. When the Phoenix is used in a heli, it requires a receiver which has a fail-safe mode or glitch filtering, such as a PCM receiver or a Berg DSP receiver.

Therefore, the Phoenix is not suitable for larger helicopters until these firmware bugs are fixed.

If you are mounting the Phoenix ESC with double-stick tape, be sure to put the tape on the BEC side and not the FET side. The FET side generates the most heat, so it needs to be exposed to free air.

Phoenix 35 ESC showing the BEC side

The FET side is the side with the regular pattern of identical chips. The BEC side has a random collection of chips. Do NOT use a switch between the battery and ESC. Most switches will not handle the current and will become very hot. Also, if the battery is plugged into the helicopter, you should consider it live for basic safety reasons anyway.

6.4.5. Tail motor ESC

(See Chapter 31, Glossary for a definition of ESC)

You will only need a tail motor ESC if the heli has a tail motor, obviously.

For the tail motor ESC, two characteristics are important:

  • High throttle resolution (256 steps or more)

    Many airplane ESCs have very low throttle resolution (typically 32 steps) because airplane radios typically have a ratchet on the throttle stick which limits the throttle resolution anyway.

    If a heading hold gyro is used with an ESC with low throttle resolution, the tail will "wag" as the gyro tries to find the correct throttle position to hold the tail still.

    If a yaw rate gyro is used with an ESC with low throttle resolution then the tail will creep left or right because you will be unable to set the tail throttle to the perfect value with the revo mix.

    The GWS ICS-50E and probably other GWS ESCs are known to have only 16 steps of throttle resolution

  • High switching rate (>50 khz) (for brushed motors)

    Many micro helis use metal brushed tail motors. Theses are easily recognizable because there are two types:

    • The popular "N20" style motors all use metal brushes.

    • The IPS-style motors with grey endbells use metal brushes.

    These metal brushes are very fragile and are easily destroyed by the high current surges generated by low switching rate ESCs. Therefore it is desirable to use a high switching frequency ESC to extend the operating life of the expensive tail motors.

    The IPS-style motors with black endbells use carbon brushes which are less fragile, but they will still last longer with a high switching frequency ESC. IPS motors (both grey and black endbell) are rated for about 2 amps max current.

    The GWS ESCs are described as "high frequency" but they're only 2.8 khz. It's high frequency compared to the 50 hz control signal but it is not high frequency compared to the the TREC and other high frequency ESCs.

    Some people are using the Feigao 1208436L brushless motor + Phoenix 10 ESC for tail control, but this combination has wagging problems and does not work as well as a standard brushed motor + high frequency ESC. See also Section 30.1.7, “How gyros work” for more info on tail motor ESCs and mixing options.

    The following ESCs are usable as tail motor ESCs

    • JMP HF100 (brushed 100khz switching, 256 steps, 1.5 amp)

    • Schulze Slim-105He (brushed, 100 khz switching, 256 steps, 5 amp)

    • Dionysus Design TREC ESC (brushed, 78 khz switching, 256 steps, 5 amps, low voltage LED)

    • Castle Creations Phoenix 10 (brushless, 10 amp, ? steps)