It finally happened to me: spin up on the workbench

[Montana]

I've always tried to be super double extra careful when working on the heli when the blades are on and a battery is in. I super double extra check the hold switch and throttle stick. Turns out that isn't good enough. I accidentally changed the throttle travel endpoints and the heli spun up. Of course I didn't realize what had happened- I thought I was adjusting the gear channel- so I jumped away from it and luckily when it fell of the table the blades got pinned up against the table leg and stalled the motor, so I was able to approach it and unplug the battery.

So after that I started taking out the upper jesus bolt but then I thought that won't stop the tail rotor so that wasn't a good plan. I don't want to take the whole head off every time I plug in the battery. I decided to take a 550 boom strut and stick it in front of the blade grip, in front of the swash antirotation pin, down through the body, and through the main gear.

Well, sure enough, later on I messed up again (in a different way, I'm having a bad day I guess) and the strut kept the motor from spinning up. Maybe it works because I have the ESC set for a low startup rate with low motor power that nothing strips or bends.

I guess the lesson I am trying to share is that no matter how careful I was I ended up having an accident with the motor spinning up.

[Bob O]

What about just unplugging the motor?

[Montana]

In the past I had shrink tubing over those connections,... but I suppose that would be the more obvious solution, wouldn't it?

But really, my point in sharing was just to say no matter how careful I thought I was being it still happened.

[Larry227]

When I do setup work on my 500 I usually use a 3s pack instead of 6s. That way if I do anything to make it spool up it's nice and slow if it even turns at all.

[pzadach]

I put in another plug between the BEC and battery so I can power up just the electronics without the motor.

[wouterd]

Typically I back-off the motor-pinion from the mean-gear when I work on the heli. Especially when working on pitch settings (as there is only 1 safety left then, the TH switch).

That also gives the added advantage that you would still notice that you are doing something really wrong (when the motor does spin up) without risks (in contrary to unplugging the motor, which is even more complicated in my case as connectors are hard to reach). Your wake-up call so to say!

I have never really needed it so far... but I realize that one day I will... just a matter of time I guess. Better safe than sorry.

Another possibility is taking off the pinion, so typically if you can remove the pinion, the motor is already backed-off from the gear.

Sometimes I do feel somewhat uncomfortable in the (public) preparation-zone at the club field, where we typically fully-connect-up our helis before we walk it out to the flying zone. Are there clubs where you have to wait to connect your heli till you are in the flying area i.e. away from the public?

[Bob O]

Originally Posted by wouterd

SNIP
Are there clubs where you have to wait to connect your heli till you are in the flying area i.e. away from the public?

I was at a fun fly last year at a neighboring club, and they had a rule that there were to be no engine starts in the pit area. This was new to me. Engine starting was only allowed at the pilot's station, which was well away from everyone else and their aircraft. Didn't make much of a difference to me, nothing to complain or whine about anyway, just not what I was used to at my own club/ field.