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Electric Flight Safety

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Greybeard19/10/2013 16:13:43
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726 forum posts
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We had a discussion at my club on ways to improve the safety of electric flight systems in the pits and transit to and from the flight line, in particular methods to prevent inadvertent starting of the motor. We already follow the requirement that the models failsafe should be set to stop the motor on loss of a proper signal.

One idea is simply to delay the connection of the battery until the model is on the edge of the landing strip and to disconnect it there immediately on landing. This is fine if the connection plug and socket is readily accessible or if a suitable arming plug is fitted as has been discussed in other threads.

As an alternative we have a proposal to rely on a spare transmitter switch mixed through a spare channel so that it inhibits the throttle channel thereby preventing operation of the throttle. The idea is that the throttle can then only be brought into use by moving this switch to the “on” position so that the throttle channel becomes operative. This, it is felt, will allow the batter pack to be connected in the pits and the model to be safely carried to the flight line without any possibility of the motor starting even though the motor and ESC is live.

Yet another proposal suggests turning the transmitter off prior to delivering or collecting ones model from the strip so that its receiver goes into failsafe and thereby ensuring that the motor cannot start.

I will welcome others thoughts on these proposals in order to help me clarify my thought as at the moment I have some unease with the latter two ideas.

malcolm woodcock 119/10/2013 16:24:39
401 forum posts

I usually fly alone so I always have the tx off and failsafe activated except when ready to go. Thank God for 2.4 Ghz.

ken anderson.19/10/2013 16:26:34
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hello GB ........whats the reason behind the proposal? .....we have at the moment 112 members and I think that it would be a hard rule/change to police.....could you not have an interim start/finish box..between the pits and runway for the arming and disarming of electric models? ....

ken Anderson ne..1. proposal dept...

Greybeard19/10/2013 16:30:46
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We want to adopt the best safe practice so are investigating all proposals hence my request for input from those here.

ken anderson.19/10/2013 16:34:28
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8634 forum posts
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ok GB....I would have thought a half way box would be the way to go.....keep the models and pilots away from the runways when they are connecting/ disconnecting the batts.....as there is nothing worse than someone on or near the strip messing around with a model when other flyers are attempting to land / takeoff.....

ken Anderson.....ne...1 .......proposal dept..

Greybeard19/10/2013 16:46:28
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Posted by ken anderson. on 19/10/2013 16:34:28:

ok GB....I would have thought a half way box would be the way to go.....keep the models and pilots away from the runways when they are connecting/ disconnecting the batts.....as there is nothing worse than someone on or near the strip messing around with a model when other flyers are attempting to land / takeoff.....

ken Anderson.....ne...1 .......proposal dept..

I agree but that does involve carrying a live model which is something we wish to avoid. Your input is appreciated.

Tony Bennett19/10/2013 16:55:06
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5082 forum posts
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sorry but you carry a live ic powered model with the prop turning round out to the flight line.

though an arming plug is a good idea.

WolstonFlyer19/10/2013 17:00:41
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2104 forum posts
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I have a throttle cut mix set up on all of the models in my Spektrum DX8, it has worked very well for me so far.

Bearair19/10/2013 17:35:05
386 forum posts
22 photos

I would rather rely on my sense of not getting near the prop or moving the throttle stick. Using an arming switch or similar just makes it more complicated in my opinion. From the moment the model has the battery connected I think big, sharp spining object and treat the model and tx accordingly. If some people really have an issue then make everyone walk with the model with the prop gently turning, they wont forget then!.

Wingman19/10/2013 17:41:06
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1145 forum posts
405 photos

Tony and Bearair have it right - if you're that scared of electric flight don't do it - also only include those who actually fly electric in any discussion about electric flight safety matters,angry 2

John Privett19/10/2013 18:41:01
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6039 forum posts
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Greybeard, what is the actual problem, or perceived problem, you are trying to regulate against? If everyone treats an electric model in the same way they'd treat an ic model with the engine running then is there actually any problem? I can't help wondering if you're trying to devise a solution without knowing whether or not there's even a problem, or what it is.

The ideas about fail-safes are ok up to a point, but won't work for the folks still using old 35MHz PPM gear. You also risk causing more accidents than you prevent when somebody activates their fail-safe because you say they have to and then discover it's been inappropriately set...

Bill_B19/10/2013 18:44:24
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1145 forum posts
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Posted by Wingman on 19/10/2013 17:41:06:

Tony and Bearair have it right - if you're that scared of electric flight don't do it - also only include those who actually fly electric in any discussion about electric flight safety matters,angry 2

Whole heartedly agree! yes

Greybeard19/10/2013 19:19:50
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726 forum posts
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I’m not afraid of electric flight, neither is anyone else that I know of, but the medium has an inherently higher risk over i.c. engine insomuch that an apparently benign motor can become active unexpectedly by for example catching a throttle stick with a lose neck strap or simply because the operator forgot that the model was armed. I for one have seen enough of other people’s body parts together with associated blood and flesh flying around a pit area not to want to see a repeat performance.

The point of my question was not to find out who suffers from an electric flight phobia but rather to glean sensible ideas or experience of the points I raised in the opening post. I would like to know, for example, if it is possible for a powered but shut down ESC to fail to an active state such that the motor will run. In other words could the motor start with the receiver in failsafe mode?

Johnny Kirkham19/10/2013 20:21:36
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180 forum posts
49 photos

I had a close one myself when i first bought my foamie wot 4 (my first electric model) by knocking the throttle stick whilst carrying it out to the flight line this prompted me to do a throttle to throttle mix assigned to one for my switches to kill the throttle stick. So far its worked ok for me.....and its easy to do too

Johnny

Bearair19/10/2013 20:37:28
386 forum posts
22 photos

Greybeard I do have lots of experience of electric flight, lots with models (6 and 10 cell) that will do you lots of harm to you if not treated with respect. I also have experienced how people set up models, even with something as simple as a rate switch I have seen people who set them up with different settings between models. IE on one model full rate is down on another full rate is up! That is why I think involving a separate switch is a no go. You can be sure someone will set up there inhibit switch as down for arm on one model and up for arm on another, then between flying sessions forget which is which.

My suggestion to set up models so the motor is never completely stopped would in my opinion be about the easiest and safest way to do it. As you have said it is the fact that the propeller is not going around that causes people to be stupid.

As for things like the escape failing and causing the motor to roar into life, yes it could happen in exactly the same way as a throttle servo could go wrong and open the throttle wide in fact I have seen this happen.

I still believe the only safe way is for people to get it in their head that once the battery is connected the prop is dangerous, maybe your club could come up with a S.M.A,R.T. like saying. Battery Armed Prop Spins type thing! And then grind it in to everyones brain!

Roger

Edited By Bearair on 19/10/2013 20:38:11

Masher19/10/2013 20:47:14
1106 forum posts
79 photos

"I would like to know, for example, if it is possible for a powered but shut down ESC to fail to an active state such that the motor will run. In other words could the motor start with the receiver in failsafe mode?"

Although it is very unlikely, I'm afraid it is possible if a fault develops in the receiver/ESC circuitry. The only certain way to be safe is not connect the battery.

We have these discussions at our club and one bloke made a good analogy I think: If you think of a loaded shot gun being carried around "broken" so it can't go off - is there a way you could fall, close and shoot the gun? - unlikely but yes not impossible - the only safe gun is an unloaded one

Martin Harris19/10/2013 21:14:04
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9262 forum posts
245 photos

Simple answer - make sound and smoke systems compulsory and active from battery connection...

Well it works for IC models!

But seriously, drum into people that a model with its flight battery connected must be regarded in exactly the same way as an IC model with its engine idling. We have a start/park line (and preparation benches) at the front of our pits. Whether IC or EP, you start or connect your model in front of that line and carry it to and from the flight line from there. At the end of the flight you disconnect the flight battery before taking the model past that line.

You are still free to have whatever additional safety device that you wish. I have an inbuilt throttle lock (defaults to a soft key) in my transmitter which I opt to put on a dedicated switch but I still regard the model as if it were live (which it's only ever a switch fault or error on my part away from). The only safety device that you should ever rely on is to never get complacent and always bear in mind the worst case scenario.

Edited By Martin Harris on 19/10/2013 21:17:05

Joe Beavis19/10/2013 21:54:31
101 forum posts

I have a slightly different slant on the matter. I have drilled the casings of my DX6i and Futaba 6J transmitters so that I can fit an 'R' clip (made from a coat hanger) across the front of the throttle (mode 2). The rudder is still operable for checks, but the throttle cannot be moved. Apart from being easier for people like me who are better at drilling holes than doing clever electonic wheezes, it is plain to everyone around that the throttle is disabled. I leave the pin in until blast-off, and refit it before I pick the model up. Care is required to avoid drilling through the throttle trim switch! It might possibly be frowned upon by the manufacturer, though!

Joe Beavis

Max5020/10/2013 08:19:12
178 forum posts
8 photos

If you arm the model at the flight line; how do you restrain the model, while holding the transmitter and plugging in a safety connector. I wouldn't like to put my tranny down on wet grass while restraining the tailplane and plugging in a connector. If you had a restraint at the flight line then that would take one action away, but i would think a condition hold on your transmitter in the pits would be better, and be part of your SMART checks.

As an i/c flyer i was wondering what steps you electric guys take in arming, as an electric motor wants to still keep turning whatever is in the way.

What do the competition F3A people do with their mainly electric planes?

Quite interested to know?.

Also if you're taking your 'A' or 'B' test with an electric; what is the examiner looking at with this action of arming, and where the arming should be done?

Greybeard20/10/2013 08:30:03
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726 forum posts
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Posted by Max50 on 20/10/2013 08:19:12:

If you arm the model at the flight line; how do you restrain the model, while holding the transmitter and plugging in a safety connector. I wouldn't like to put my tranny down on wet grass while restraining the tailplane and plugging in a connector. If you had a restraint at the flight line then that would take one action away, but i would think a condition hold on your transmitter in the pits would be better, and be part of your SMART checks.

As an i/c flyer i was wondering what steps you electric guys take in arming, as an electric motor wants to still keep turning whatever is in the way.

What do the competition F3A people do with their mainly electric planes?

Quite interested to know?.

Also if you're taking your 'A' or 'B' test with an electric; what is the examiner looking at with this action of arming, and where the arming should be done?

We have a model restraint stand near the flight line which has a transmitter stand incorporated.

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