ULSRS Electric Heli Accidental Motor Start

After a short motor run test of this heli, I unplugged one of the two LiPo packs expecting that the ESC would restart from a 'cold start' condition.

Little did I realize the small amount of electrical current flowing through the BEC on one side of the battery 'Y' lead was enough to keep the processor in the ESC 'hot' and it wouldn't have to start from cold.

To 'be safe' upon connecting the second pack and to take advantage of the Castle Phoenix ESC starter inhibit if the throttle isn't at zero, I placed the throttle stick at 50% before plugging the second battery pack into the 'Y' lead. This caused an almost instant start and caught me completely off guard!

Damage was minimal but eventually discovered that the autorotation (freewheel) clutch had slipped inside its hub.That's a bunch of torque available with 12S LiPo power and a 32-1 gearing from the Actro motor to the main rotor.Good thing the clutch slipped because something had to give!

Category:

Science & Technology

Tags:

• ULSRS
• RC heli
• low RPM rotor
• scale electric heli
• electric heli
• R/C heli

[TheLipRipp3r]

hahahahaha! Sorry to laugh! I really appreciate you sharing!

[StormyMaxPerry]

@TheLipRipp3r

It looks funny from the keyboard but scared the poop out of me when it happened! Notice where my hand was just as it started moving. Good catch indeed!

I wanted folks to see just how easy an electric heli can start and have the potential to do quick harm. Smaller e-heli's start much, much quicker and I know pilots that have been seriously hurt as a result. Always be vigilant, people...

[TheLipRipp3r]

@StormyMaxPerry

Throttle hold before energizing heli....every time here!! :-D

[StormyMaxPerry]

@TheLipRipp3r

Agree 110%! It's what I tell everyone but in this case I thought I could "outsmart" the ESC by not even allowing it to arm by plugging power in at roughly 50% throttle. Engaging T.H. *will* arm the controller; providing a throttle input higher than "idle" will inhibit arming. Regardless, I learned something that day!

[FoolDoolMoolDool]

That is scary. I always get wary of that happening whenever I power mine up. I know that normally it won;t happen but I always get a bit worried that some weird glitch will cause the motor to power up unexpectedly.

[TooSlow2Care]

whew. good catch on your part though.