The great i.c. / electric finger chopping debate

[SIMON CRAGG]

I, and several others in the club use a physical tie back attached to the TX and the throttle stick. Seen to many horrors!.

[Former Member]

[This posting has been removed]

[Andy48]

Never had a problem. All my planes are electric, and most are fitted with an arming plug which doesn't get inserted until the plane is on the flight line, and is removed before leaving it.

The rest, small foamies have an almost foolproof arming switch on the transmitter which cannot be accidentally knocked on, like MattyB and Tim.

Electric can be made very safe with a bit of care.

[Former Member]

[This posting has been removed]

[John Stainforth]

Posted by Andy48 on 18/06/2020 14:59:03:

Never had a problem. All my planes are electric, and most are fitted with an arming plug which doesn't get inserted until the plane is on the flight line, and is removed before leaving it.

The rest, small foamies have an almost foolproof arming switch on the transmitter which cannot be accidentally knocked on, like MattyB and Tim.

Electric can be made very safe with a bit of care.

In the club I belong to in the US, it is mandatory to arm electric powered models on a special bench close to the flight line, and nowhere else.

I also think that wearing safety goggles should be encouraged, if not enforced, when starting larger engines, in case a prop should throw.

[Andy48]

Posted by John Stainforth on 18/06/2020 15:05:16:

In the club I belong to in the US, it is mandatory to arm electric powered models on a special bench close to the flight line, and nowhere else.

You still have to carry a live model from the bench to the flight line though.

[Nigel R]

"But just because you haven't seen it doesn't mean it can't happen. The ONLY completely safe electric motor is one where the power source is PHYSICALLY disconnected. "

Ok, talking brushless here (and happy to be corrected if anyone knows different)...

For an ESC to falsely detect a high throttle input, and to run the necessary software to drive the commutator and thus the motor, would be a fantastically improbable chain of events (if not actively impossible). However I would bet large sums on the chances of this happening are so vanishingly small as to be to all intents and purposes practically impossible.

The far more likely safety failure points are with physical accident on TX, the user doing something wrong, the TX setup being wrong or wrong model, failsafe set in reverse combined with signal loss, a memory corruption in the TX leading to open throttle being commanded, etc.

Most of the radio issues would present themselves on power on which makes the instant of arming (be that via arming plug, or just connecting the lipo) the absolute highest single risk moment. Radio checks would help avoid many of them, although a memory corruption problem is difficult to detect.

The physical accident mechanisms (whacking the TX stick) are a problem for the user to avoid - a difficult to knock arming switch or dial minimises the chance all of those. Voice alert coupled to the dial is a neat way of making sure the radio setup is still sane and working, if something becomes corrupted with a model memory, then there is a good chance the voice alert will also disappear.

[Tim Kearsley]

I agree with all you say Nigel and I'm sure a motor starting up because of an electronic problem in the ESC is a vanishingly small probability. It's just my personal discipline that makes me regard a motor with power connected as a potential danger, hence why, on larger models, I use arming plugs to only connect power at the last moment. Sticky throttle cut switches, which are simple to programme in the wonderfully versatile OpenTx system, are used on all models.

Tim.

[Nigel R]

Its certainly no bad idea to treat the connected power train with the same respect you would an idling IC motor.

[MattyB]

Posted by Nigel R on 18/06/2020 15:30:55:

"But just because you haven't seen it doesn't mean it can't happen. The ONLY completely safe electric motor is one where the power source is PHYSICALLY disconnected. "

Ok, talking brushless here (and happy to be corrected if anyone knows different)...

For an ESC to falsely detect a high throttle input, and to run the necessary software to drive the commutator and thus the motor, would be a fantastically improbable chain of events (if not actively impossible). However I would bet large sums on the chances of this happening are so vanishingly small as to be to all intents and purposes practically impossible.

In the days of brushed motors I saw a couple of incidents where motors sprung into life at the point of battery connection - one had the throttle stick raised and ran at full power til the stick was closed; the other gave a burst of power about 2 seconds long on arming even with the throttle stick down, a repeatable characteristic of that ESC and radio combination! Not terribly safe. Thankfully such behaviour seems a thing of the past with brushless ESCs.

Posted by Nigel R on 18/06/2020 15:30:55:

...The far more likely safety failure points are with physical accident on TX, the user doing something wrong, the TX setup being wrong or wrong model, failsafe set in reverse combined with signal loss, a memory corruption in the TX leading to open throttle being commanded, etc.

Most of the radio issues would present themselves on power on which makes the instant of arming (be that via arming plug, or just connecting the lipo) the absolute highest single risk moment. Radio checks would help avoid many of them, although a memory corruption problem is difficult to detect.

The physical accident mechanisms (whacking the TX stick) are a problem for the user to avoid - a difficult to knock arming switch or dial minimises the chance all of those. Voice alert coupled to the dial is a neat way of making sure the radio setup is still sane and working, if something becomes corrupted with a model memory, then there is a good chance the voice alert will also disappear.

Yes, completely agree. In recent times the only incidents I have seen have been for the reasons you suggest - the most common have been leaving a model armed whilst switching on another one, and switching on with throttle cut disabled and the throttle stick up.

The reason I pointed out the sticky throttle cut was because I don't understand why most canned mixer based systems don't offer it as an easily selectable or default option; the amount of code need is minimal, and I can't see any obvious disadvantages to doing so (the system works well for the ignition on petrol engines too, though I would always slave that to a dial rather than a switch to prevent accidental disablement). Maybe there is a use case it doesn't work for, but for electrics I personally can't think of one.

Edited By MattyB on 18/06/2020 15:49:27

[John Stainforth]

Posted by Andy48 on 18/06/2020 15:10:12:

Posted by John Stainforth on 18/06/2020 15:05:16:

In the club I belong to in the US, it is mandatory to arm electric powered models on a special bench close to the flight line, and nowhere else.

You still have to carry a live model from the bench to the flight line though.

This area close to the flight line includes the (mandatory) starting benches and bays for i.c. and turbine powered aircraft, and has a model taxi track down the centre. This track has a big red line across it, on the side away from the flight line, saying "NO TAXY BEYOND THIS POINT" and then continues to the covered work bench area, which is 20 yards away. So the whole start-up area and taxy way are regarded as a "live" area where only pilots and helpers are allowed and extra care should be taken.

[Richard Clark 2]

Posted by Steve J on 18/06/2020 14:55:34:

 

Some of us who don't use OpenTx find the fact that some OpenTx users feel the need to ram their radio choice down our throats at every opportunity boring.

 

 

Absolutely. They can never stop 'plugging' the things. Worse than Apple fanboys.

Edited By Richard Clark 2 on 18/06/2020 16:01:53

[Keith Miles 2]

With standard gear, I would argue that it is VERY easy to fire up an electric motor accidentally, by accidentally catching the transmitter and/or switches. I’ve done it. I’ve seen others do it.

You have to physically start an IC engine. It will NOT fire up on its own nor it will restart on its own if it stops.

It is also standard, if not necessary, practice of IC operators (or certainly should be) to restrain or tether the model in some way, a much less common practice, and often not practical, when handling electric models.

Any inference, or argument, that might be put forward that electric models are less potentially hazardous than IC is an unsustainable argument, in my view, and even before we get into a further debate about the respective likelihood of explosions or fires created by operational errors or faulty or damaged equipment!

All electricity is a silent assassin ready to catch the unwary!

[Keith Miles 2]

Posted by Steve J on 18/06/2020 15:03:10:

Posted by Keith Miles 2 on 18/06/2020 14:51:06:

My simple “safety device” on my DX9 is a rubber band between switches H (throttle cut/hold) and G providing just enough tension to keep switch H in safe mode until I’m ready to go.

I use G (a rotary control) as the safety switch with voice alerts.

Edited By Steve J on 18/06/2020 15:08:15

Sounds like a good idea. Not tried that.

On the DX9, the rotary switch is marked “R-KNOB”. Switch G is a 3-position toggle switch.

Apologies if I misunderstood.

[cymaz]

I’ve found it’s never the engine that gets the fingers, it’s always the prop.

Whenever Mrs C or another is helping, communication is key. I say “ignition live” or “ clear”...anything to warn and remind myself

[Former Member]

[This posting has been removed]

[Keith Miles 2]

Posted by Steve J on 18/06/2020 17:25:37:

Posted by Keith Miles 2 on 18/06/2020 17:04:35:

On the DX9, the rotary switch is marked “R-KNOB”. Switch G is a 3-position toggle switch.

You are quite right. For some reason I have spent the last five years thinking of the knob as being G, but it is isn't. How strange.

Very easy mistake to make, I must admit!

[Peter Miller]

On myold Spectrum DFX7 there is no kill switch unless in helicopter mode. It was one of the very first.

On my Hitec Aurora 9 one presses a symbol on the touch screen. THis symbol also changes the touch screen which is a bit of a pain but at least it works

[Former Member]

[This posting has been removed]

[Chris Bott - Moderator]

Whilst I agree that an IC engine is not dangerous while it's not running, and that it only takes the combination of a couple of mistakes for an electric motor to start unexpectedly, that's surely not the end of the debate.

IC prop strikes dominate, in my experience, and that's because engine adjustments or removing the glow clip can require you to put your fingers perilously close to the prop. A moment's lapse in concentration can see you reaching through the prop too. I've even seen a loose tether cause someone to put their hand out to stop the model as it took up the slack and travelled towards him when he'd just started it.

[Peter Miller]

Posted by Nigel R on 18/06/2020 14:44:09:

The Spad had the pilot as well as gun in a tiny pod in front of the engine. It looks, frankly, terrifying. Wonder how pilots enjoy it?

Not quite

The pilot sat in a normal position. The gunner sat in the front nacelle and prayed that the pilot didn't nose over on landing.

Don't try to offer the pilot a sweet or chocolate bar!!!!!

[Dwain Dibley.]

I would also say, that while someone is starting (IC) or preparing (D.C.) a model for flight, keep your trap shut, as there is nothing more distracting than a club mate asking dumb Q's, talking about his bunions, or asking you to look at the latest pile of scrap he's bought from the swap-meet, while you are trying to concentrate on starting your 50 cc engined, 24" propped, beast of a plane.

D.D.

[john stones 1 - Moderator]

Posted by Dwain Dibley. on 18/06/2020 21:13:33:

I would also say, that while someone is starting (IC) or preparing (D.C.) a model for flight, keep your trap shut, as there is nothing more distracting than a club mate asking dumb Q's, talking about his bunions, or asking you to look at the latest pile of scrap he's bought from the swap-meet, while you are trying to concentrate on starting your 50 cc engined, 24" propped, beast of a plane.

D.D.

Someone with bunions upset you D.D ?

[Geoff S]

Posted by Steve J on 18/06/2020 15:03:10:

Posted by Keith Miles 2 on 18/06/2020 14:51:06:

My simple “safety device” on my DX9 is a rubber band between switches H (throttle cut/hold) and G providing just enough tension to keep switch H in safe mode until I’m ready to go.

I use G (a rotary control) as the safety switch with voice alerts.

Edited By Steve J on 18/06/2020 15:08:15

I've always used a toggle switch as first, a throttle cut on ic engines (on my Mux3030) and now I'm almost exclusively electric as a throttle disable on my Horus etc. Having read this about using a rotary control (much harder to operate inadvertently) I've just altered one model to use the 6 position rotary switch rather than the toggle. Always have voice warnings, too.

I've not only found a use for the 6 pos switch but freed up a toggle switch for something else

Geoff

[cymaz]

Posted by Dwain Dibley. on 18/06/2020 21:13:33:

I would also say, that while someone is starting (IC) or preparing (D.C.) a model for flight, keep your trap shut, as there is nothing more distracting than a club mate asking dumb Q's, talking about his bunions, or asking you to look at the latest pile of scrap he's bought from the swap-meet, while you are trying to concentrate on starting your 50 cc engined, 24" propped, beast of a plane.

D.D.

Agree, you need to concentrate. And can easily get side tracked.....dangerously