What to do?

[Glyn44]

Hi,

I have read many times, in articals, and forums, that as soon as a lipo is connected into the model the pilot must be aware that the aircraft is then “live” I understand this, and agree one should be alert.

My query is what do I do if the worst happens and the motor fires up unexpectedly. I cannot remember seeing a best course of action that should be undertaken. On many models it is not easy to access the battery and connectors with a stationary prop never mind one that has now become a lethal weapon. So has anyone experienced such an event (no one at my club has) and what was the method to kill the motor?

Regards, and festive wishes, Glyn.

[The Wright Stuff]

The most likely scenario by far, is that you accidentally knock the stick, or otherwise open the throttle unexpectedly (perhaps because the throttle channel is reversed, for example). In all of these cases, you can stop it with the transmitter, once you have worked out the issue, of course.

If you are talking about a failure of the ESC which forces full throttle, then I've never heard of this ever happening, but I agree it is theoretically possible.

In which case, your options are:

• Disconnect the battery.
• Cut the leads with pliers.
• Wait it out until the battery depletes.
• If not alone, scream for help.
• If all else fails, aim the model at the undergrowth with down elevator and watch it destroy itself without damage to property of people.

Edited By The Wright Stuff on 20/12/2017 12:23:00

[Ben B]

Grab the tail of the plane (assuming not a pusher plane!!) and lift to smash the prop???

[Cuban8]

It is very rare for an electric motor to simply burst into life because of a fault - more than likely it's a case of finger trouble on the tranny, not having a arming/kill switch and knocking the throttle up. I suppose keeping the model restrained as per IC practice is a good idea, but it's unusual to see many larger electric models tied down properly at the field. Setup is another issue and either remove the prop or secure the model firmly.

As you said, be prepared for the worst, keep fingers, arms etc clear of the prop arc at all times and arm the model only when about to fly so you're not carrying a potential weapon. Should the motor start at full chat with no control from the tranny, then unless the battery can be disconnected safely whilst the model is secured or firmly held by a friend, then short of waiting for the battery to discharge, I'm not sure there's much else you could do safely.

[Frank Skilbeck]

Just about all ESCs have a safety feature where the throttle shouldn't arm until it sees the low position from the transmitter so an unexpected start up will only happen if you do something on the Tx, the only time I have seen an electric model runaway was when somebody had not set their failsafe for low throttle and had switched off the Tx before disconnecting the battery, fortunately the model shot off and was stopped by the hedge.

I always make sure that when I am connecting the battery that the model is restrained and pointing away from other people, and then treat it like an IC model with the motor running.

[The Wright Stuff]

The conclusion I'm coming to is that if the plane is big enough or of long enough duration that you couldn't restrain it by hand until the battery died, then it should be physically restrained when the battery is plugged in.

[Dave Bran]

It happened to me or at least right by me, when a flying buddy plugged in. He hung desperately onto the plane, I turned the Tx on that he'd just thought he'd turned on but had turned off! (And yes, no fail safe set!)

On another occasion a plane on a nearby table powered up, Futaba wrong model, just bad luck it powered up on a glider model memory with throttle not reversed............. it went between cars in the pits and tangled itself to a standstill without any lasting damage.

Our club (now!) has a rule that EP models have to be restrained in the pits, though flying wings and the like are not obviously able to be loop or rod in ground held.

[Denis Watkins]

A switch or arming plug is a pretty safe option

Though we are put off doing this on lightweights

Most TX allow a "motor off "setting, or button or switch

And failsafe setting is paramount

As above, my club too insists on tethering

[Ron Gray]

Our club rules are just like yours Dave, all models have to be restrained when started up, flying wings and 'planes without U/C have to be held and pointed away from the pit area. We also now check each others kill settings for each model, just to be sure that if a Tx is inadvertently switched off before Rx the motor does kill, this gets over the 'I forgot to do that' situation.

[The Wright Stuff]

Posted by Ben B on 20/12/2017 12:26:00:

Grab the tail of the plane (assuming not a pusher plane!!) and lift to smash the prop???

I'm not sure I'd want to risk getting hit by high velocity prop fragments at close range, but you are right: it is an option if all else fails.

With an I.C. engine, it would most likely stall if you did this. Which raises an obvious question:

Why, then, do all ESCs not include a replaceable fuse which would blow and cut power, if the motor encountered an obstruction to turning (i.e. prop hits something). This would increase the current beyond 'normal' levels, right?

[Glyn44]

I was indeed thinking of a component failure, as opposed to a tx being knocked. I have to say that speaking to people no one seems to have considered this to be a likelyhood.

I think it would be good practice to have a plan in mind beforehand, as I’m sure there would be a considerable panic and headless chicken syndrome occurring in the heat of the moment. Anyway thanks for your thoughts. Your varied replies seem to indicate why I have not seen much in print on a recommended course of action.

Let’s all hope we never have to deal with it!

[The Wright Stuff]

Indeed Glyn.

It really comes down to hanging onto your transmitter (as well as the model) if at all possible. Ensuring you have a free hand to get at the transmitter is a good reason to restrain models 'hands-free'.

Like Pascal's wager: either it's a problem that can be fixed from the transmitter, or it isn't. If it can, then great, you have the transmitter. If it can't be fixed from the transmitter, then there's not much you could do, anyway.

Final thought, the likelihood of the problem occurring is just as significant as the consequences, in risk assessment. So if it's so remote that no-one has ever encountered it, then let's relax and enjoy our hobby.

What happens if I get abducted by aliens, whilst flying? It's theoretically possible, after all?

[ken anderson.]

I've heard tales of people nearly kapowing their patio doors and shredding members of their families....the thing is to try and get into a fixed routine and stick to it,its easy to get distracted when arming a model(electric)..and once an electric motor is going-nothing will stop it as long as it has a battery connected-IC normally stops once it hits something solid(parts of us!)...........I've seen a few nasty messes with prop's over the years.........

ken Anderson...ne...1..... .routine dept.

[Former Member]

[This posting has been removed]

[The Wright Stuff]

Posted by Steve J on 20/12/2017 16:12:56:

Posted by Glyn44 on 20/12/2017 13:09:56:

I think it would be good practice to have a plan in mind beforehand, as I’m sure there would be a considerable panic and headless chicken syndrome occurring in the heat of the moment.

To protect myself from my own models, I have a throttle lock on my transmitter (rotary control so that it cannot be knocked) and either have them restrained or positioned such that the prop cannot rotate when I connect the battery.

All good practice Steve, but I think the OP was specifically talking about hardware failures that could occur spontaneously (e.g. ESC failure resulting in full throttle whilst walking from the pits to the strip). Neither transmitter throttle locks nor restrains would be any use in that event...

Edited By The Wright Stuff on 20/12/2017 16:18:23

[Keith Evans 3]

Hi all .I don't fly much in the way of electric models but with this situation is there a business opportunity for a fluid clutch arrangement as some cars use . I remember I could stop a radiator fan by a smart grab with no problem ! ! !

[Former Member]

[This posting has been removed]

[The Wright Stuff]

Posted by Steve J on 20/12/2017 16:38:44:

...such that vulnerable bits of your body are nowhere near the prop.

Now there's a mental image I could've done without!

[PatMc]

The esc can't power the motor unless it's receiving a signal from the Rx.

Assuming that the model is being operated on 2.4GHz.The failsafe should be set, as per legal requirement, so that the motor will cut or reduce speed to idle on loss or corruption of signal.
Therefore, AFAICS, the best immediate course of action is to switch of the Tx. Then investigate the why the motor had burst into life unexpectedly.

 

Edited By PatMc on 20/12/2017 20:05:01

[J D 8 - Moderator]

While not the same thing, a few years ago a club member was starting his 40 2 stroke when it threw its prop and went for a shaft run! Gawd knows what the revs were but the noise was unbeleivable.

The owner operated throttle cut but the thing kept going. I guess just enough fuel/air was still getting through, not much needed with no load.

Of those around some like myself stood there wondering what to do,others ran, but a young fellow who was prepairing his aircraft alongside just reached over and pinched the fuel tube shut.

[Denis Watkins]

Plan B

Usually there is a rag,

Block the exhaust outlet firmly, using thumb and rag over hole

Prior to being unkind, remember it is Peace to all men season

Edited By Denis Watkins on 20/12/2017 20:35:27

[John F]

As JDB says I've seen this runaway motor more with IC than with electric!

For me, all models, irrespective of motor type, are properly secured before I insert batteries / start engine.

Edited By John F on 20/12/2017 21:27:44

[The Wright Stuff]

Posted by PatMc on 20/12/2017 20:03:56:

The esc can't power the motor unless it's receiving a signal from the Rx.

Pat, I think this is the OP's primary concern.

Is it possible that a severe (and unlikely) failure - perhaps involving smoke and molten solder - could cause a ESC to fail in a 'closed-circuit' state?

[PatMc]

Posted by The Wright Stuff on 21/12/2017 08:33:53:

Posted by PatMc on 20/12/2017 20:03:56:

The esc can't power the motor unless it's receiving a signal from the Rx.

Pat, I think this is the OP's primary concern.

Is it possible that a severe (and unlikely) failure - perhaps involving smoke and molten solder - could cause a ESC to fail in a 'closed-circuit' state?

The the motor wouldn't burst into life in that case.

[Bob Cotsford]

Posted by PatMc on 21/12/2017 09:58:29:

Posted by The Wright Stuff on 21/12/2017 08:33:53:

Posted by PatMc on 20/12/2017 20:03:56:

The esc can't power the motor unless it's receiving a signal from the Rx.

Pat, I think this is the OP's primary concern.

Is it possible that a severe (and unlikely) failure - perhaps involving smoke and molten solder - could cause a ESC to fail in a 'closed-circuit' state?

The the motor wouldn't burst into life in that case.

unless it was a brushed motor?