HBFP Brushless main motor
Substituting a modern brushless motor for the original brushed one should be fairly straight forward. Depending on your exact model you may not even have to change your 4-in-1.
There's a great hack for the E-Sky HoneyBee which just requires opening the 4-in-1 and tapping the main throttle output from the receiver before it goes into the speed controller. Here's one link showing the procedure: E Sky 4-in-1 brushless mod
For the Walkera #4 and the E-Flite Sabre things are not nearly so straight forward. The 4-in1 is much more integrated and it's very hard to find the main throttle signal as it crosses boards. I'm not even sure the signal is usable as input to a brushless ESC even if it could be found. The solution we went with was a full separates setup. I agree that's a bit of over kill for this old heli but in the interests of science here is how it went.
Parts List:
- Rx: Orange 6ch DSM2 compatible from HobbyKing
- ESC: 30A HobbyKing F series
- Brushless motor: P2632 Brushless Outrunner 3800kv
Battery: 2~3 Cell /7.4~11.1V
RPM: 3800kv
Max current: 32A
No load current: 11.1V/3.2A
Internal resistance: 0.036 ohm
Weight: 51g
Diameter of shaft: 2.3mm
Dimensions: 26mmx32mm - New Brushed tail ESC: GWS ICS-300
- Gyro: HobbyKing GA-250 Mini MEMS
After building the setup seen above, there were problems with the 30A ESC so the HobbyKing 10A ESC was tried and found to work better. This ESC starts motor much more smoothly than the 30A and will run it at much lower RPM. A much better fit for this application. Both motor and ESC remain cool during normal hovering flight. Max current seen driving this motor: approx 6A
The only settings available for this ESC are Battery type, Brake on/off, Direction of rotation. This ESC can be re-flashed with BL-Heli
Below, the tidied up configuration showing the gyro mount and the spacers required to lift the brushless motor up enough to allow proper engagement of the pinion with the main rotor gear. You can also see that the main rotor ESC has been changed for the HK 10A which is smaller, lighter and actually worked much better for a heli setup.