BMFA rules regarding starting electric planes

[Chris Barlow]

And even more dangerous if people don't call deadsticks, landings or passes...!

[Geoff S]

Peter, I agree with you but an armimg plug is even more dubious particularly in higher powered models. I've been involved in reviewing safety critical software (and very boring it is!) and really for our use it would be very expensive and far more than we need.. I also treat any model with a battery fitted as a potential hazrd so I take what precautions are reasonable and restrain the model when fitting the battery and thereafter. I also never used the esc switch that used to be common on brushed esc becuase I didn't trust it.

We're already relying on the transmitter software every time we fly and literally millions od succesful flights with no issues implies that it's as bomb proof as it's possible to get. Safety critical software is usually used in an environment where there are relatively few users and hence less testing in use.

I did a short course on structured software years ago and the lecturer was of the opinion that had modern s/w standards been applied to the Apollo programme Armstrong et al would never have left the planet let alone walked on the moon

Geoff

[ted hughes]

I think it is just a case of using common sense. Even the ESCs beep to tell you they are armed!

I don't arm my plane until I am ready for take off, switch Tx on first,and I also do a quick CofG and visual inspection before arming- force of habit from free-flight  I'm afraid. I keep body and fingers aft of the prop once the battery is connected.

I also do a look around for any obvious danger (people or animals standing around, I fly from a horse field) before taking off..

All common sense, such as not walking onto a live runway, etc.

Edited By ted hughes on 05/05/2015 00:59:10

Edited By ted hughes on 05/05/2015 00:59:33

[onetenor]

a jack socket adjusted to be in the closed (Switched on   condition is easily fitted to any model. Then when the jack is inserted it seperates the contacts thereby switching off. Pull it out to switch on. simple and neat

[Dave Hopkin]

Posted by onetenor on 05/05/2015 02:25:59:

a jack socket adjusted to be in the closed (Switched on condition is easily fitted to any model. Then when the jack is inserted it seperates the contacts thereby switching off. Pull it out to switch on. simple and neat

99% of jack plugs and sockets are designed for use in audio systems and as such rated for very low currents - when I see a pair of headphones rated for 60amps I might consider using its jack as an arming plug, till then I don't think so

[gangster]

Totally agree Dave. A so called safety measure if even more hazardous if it adds a weak link into the chain. An inadequate switch or plug that fails in flight whilst delivering high current to the motor will also kill the radio (assuming the esc contains the voltage regulator for the radio)

i still maintain that most of the radio related issues have always been down to poor battery and switch harness management. In spite of this modellers are still obsessed with interference or make A is better than make B I am also convinced that the number of people doing a range test on each model before the first flight is far too few.

[Dave Hopkin]

I am a firm believer in the "KISS" principal - "Keep it simple, stupid" - and the more components we place in the power/control chain the sooner we will have a failure - thats the law of probabilities in action

Almost all radios are capable of creating a "Power Kill" setting for the ESC, based on a switch throw on the XT, so immediately the electric model becomes safer than an IC which has to be kept running while the model is carried from the pits (and don't forget taxing out of the pits is an instant A Cert fail!)

Yes I could fall, knock the throttle kill switch, and push the throttle stick forwards and then stick my face in the prop arc - but then again I could get hit by a asteroid too!

[Engine Doctor]

Posted by Dave Hopkin on 05/05/2015 07:14:23:

Posted by onetenor on 05/05/2015 02:25:59:

a jack socket adjusted to be in the closed (Switched on condition is easily fitted to any model. Then when the jack is inserted it seperates the contacts thereby switching off. Pull it out to switch on. simple and neat

99% of jack plugs and sockets are designed for use in audio systems and as such rated for very low currents - when I see a pair of headphones rated for 60amps I might consider using its jack as an arming plug, till then I don't think so

Must agree .using a jack plug with hi amps is a recipe for disaster, failure will at least cause loss of power and control unless a separate battery for radio is used and at worse could cause a fire ! Dead man plug arming plug or whatever you want to call them is agood idea provided it can handle the current. They should be used when fitting and connecting a battery neccesitates working in the vicinity of the prop.Once armed model is potentially dangerous so has to be treated like a running I/C and restrained. Dont rely on saftey switches on Txs as radio ,although safer than some years ago can rarely go wrong with dire results.Re the carrying out of armed/live fixed wing models to the flight line; what plannnet are some of our coleuges from? I agree totally with what is said about helicopters ,you cant safely carry them when armed but fixed wing ? Come on they are easily and safely held or restrained while being taken out to the flight line as per ic ,you don't hold the prop do you?. No club that I know of starts their engines on the run way or flight line so why faf about plugging a battery or arming plug in on the runnway.I have been to one club that had a small and sometimes crowded pit area so starting etc was moved to a starting box between the pits and the runway .Fixed wing= arm it carry it out and fly it .Unrestrained taxying is probably the most dangerous practice . If a model is too big or heavy to carry it should at least be held back by the tail fin while taxied to prevent any problems or runaways. Let common sense prevail even if there is a world shortage of it. Its ahobby and as yet not governed or interfered with  by the HSE ,let's keep it that way

Edited By Engine Doctor on 05/05/2015 10:10:18

[Pete B]

I've been using safety arming plugs for several years with no issues whatsoever, originally using Deans and now XT-60s.

The safety advantages vastly outweigh the extremely remote possibility that the plug will fall out of the socket in flight. This is particularly so when the battery bay is under the fuselage as there is then no need to rotate an inverted, armed model. The peace of mind in being able to safely connect the battery within the bay, turn the model upright and then insert the arming plug at a suitable time is very worthwhile.

I don't see any more reason for the plug or its solder joints to fail than any other connector in the system as it will have the same current rating as those other connectors. It's also down to the constructor's ability with a soldering iron.

There have certainly been many more reported instances where Rx pack harness switches have failed than arming plugs failing as the quality of the switch contacts seeems to be the weak point.

I also use a throttle cut switch on the Tx as a secondary safety measure. The use of both features make the setup just about as safe as it can be, IMHO.

Pete

[Geoff S]

Posted by onetenor on 05/05/2015 02:25:59:

a jack socket adjusted to be in the closed (Switched on condition is easily fitted to any model. Then when the jack is inserted it seperates the contacts thereby switching off. Pull it out to switch on. simple and neat

I sincerely hope you aren't doing that on any model drawing more than a few milliamps. Even big jack plug sockets aren't designed to cary large currents and using one to do so can only end in tears.

Geoff

Edited By Geoff Sleath on 05/05/2015 10:46:49

[Martin Harris - Moderator]

ED - I agree with your thoughts 100%...

Just to expand a little, a programmed arming switch is another level of safety but must be regarded as fallible - for instance, how many are used with switch contacts in the closed condition? A switch can develop faulty contacts or mechanical problems leading to open or short circuits. Do you even know whether your switch is open or closed in the safe programmed position?

The simple application of common sense is the best precaution - use additional safety measures by all means but handle the model like a running IC and there's little chance of an accident.

HSE? Perish the thought - we'd only be allowed to fly ducted fans unless a propeller guard could be developed!

[Andy48]

Posted by Geoff Sleath on 04/05/2015 23:23:16:

Posted by Andy48 on 04/05/2015 22:31:58:

Frankly its simplicity itself to wait until there are only one or two flyers on the field, walk out with the model, check with other flyers its OK to take off, arm the model using a safety plug, and then check the control surfaces before taking off. Less than a minute to do all this. There's no fiddling, if something is wrong, remove the safety plug and leave the field with the model.

Where is this safety plug fitted? The only safe place to put it is in the battery circuit which means all the current is passing through it (60 plus amps in many cases). It's an extra point of failure (most faults in electrical systems are down to connectors and switches) and also increases the battery to esc wire length which is best kept as short as possible. Whlist it seems a good idea at first sight it isn't so good on closer examination.

Agreed its an extra point of failure, but one that is easily checked on routine model examination. The point about increasing battery to esc wire is hilarious. Just how much difference do you think adding a couple of cm of silicon wire will actually make? Try doing the maths. Since when do MANY electric models run at continuously more than 60amps? In any case, you fit a safety plug capable of carrying the current load.

[Andy48]

Posted by Martin Harris on 05/05/2015 00:08:03:

Posted by Dave Hopkin on 04/05/2015 22:59:37:

Posted by Andy48 on 04/05/2015 22:31:58:

Why can't it be safe "to fiddle around on the runway"?

Erm Deadsticks...... low passes........

One of the changes that I'm happiest about in the last few years is what seems to be a fairly common move away from people walking out onto the runway to stand behind their models for take-off. I made a conscious decision to teach learners to stand in the pilot's box for take-off from the start when I started instructing and it seemed to catch on quickly with other instructors. Since then, the BMFA have echoed my thinking by making this a requirement for the A test - which I thoroughly endorse.

As an example of how people on the runway can cause problems to other pilots, some years ago, I had to dump a dead-stick model (not even mine, which made it worse) in an adjoining field due to a hugely experienced but not over-skilled pilot who was incapable of taking off from the side, wandering about aimlessly on the runway after taking off - either unable to hear, understand or respond to my dead-stick call.

I fly at two fields. Neither has a designated "runway", neither has a designated pilot's box. On both field the position for pilots and take-off is determined by wind, sun etc. and rarely does anyone stand behind their model.

[Dave Hopkin]

Andy48 - the "Pilots Box" doesn't have to be a pre-defined zone, its simply a term for the area where pilots can stand close together so they can all hear each others call outs - it can be moved round the field as required for the prevailing weather etc

A designated runway - is the one we are using today, it will vary with the prevailing wind

The point being that you dont want people controlling from anywhere on the field and not communicating, you want them in a group (collective noun "a stick" maybe?)

Neither do you want people taking off from any old bit of grass you want them taking off and landing in the same area

So I would suggest you do have a "pilots box" and a "designated runway" on any given day - either that or your saftey officer wants a rocket

[Cuban8]

As part of a normal flying session, I don't believe any pilot should be standing behind their model to take off. If you don't feel confident, get someone else to do the take off for you! The only exception I'd make is perhaps on a maiden test flight when other flyers have agreed to cease flying for a while.

[Andy48]

Posted by Dave Hopkin on 05/05/2015 12:05:02:

Andy48 - the "Pilots Box" doesn't have to be a pre-defined zone, its simply a term for the area where pilots can stand close together so they can all hear each others call outs - it can be moved round the field as required for the prevailing weather etc

A designated runway - is the one we are using today, it will vary with the prevailing wind

The point being that you dont want people controlling from anywhere on the field and not communicating, you want them in a group (collective noun "a stick" maybe?)

Neither do you want people taking off from any old bit of grass you want them taking off and landing in the same area

So I would suggest you do have a "pilots box" and a "designated runway" on any given day - either that or your saftey officer wants a rocket

Perhaps if you re-read my post you will see that we do have a well organised flying field. I was commenting on the bit about "fiddling on the flying field". Surely everyone does that when you take a model out? Don't you at least point it in the direction you want to take off in? The only difference with a safety plug is that there is the few seconds while the safety plug is inserted, and that is close to the flying box usually- well it is in the case of our flying fields. If anyone is trying a dead stick or a low pass there, then it is too close to the pilots and decidedly dangerous.

People wandering about in the flying field should not really be a part of this discussion, unless there is the incorrect assumption you have to do that to insert a safety plug.

Edited By Andy48 on 05/05/2015 12:50:20

[Dave Hopkin]

Posted by Andy48 on 05/05/2015 12:49:34:

Posted by Dave Hopkin on 05/05/2015 12:05:02:

Andy48 - the "Pilots Box" doesn't have to be a pre-defined zone, its simply a term for the area where pilots can stand close together so they can all hear each others call outs - it can be moved round the field as required for the prevailing weather etc

A designated runway - is the one we are using today, it will vary with the prevailing wind

The point being that you dont want people controlling from anywhere on the field and not communicating, you want them in a group (collective noun "a stick" maybe?)

Neither do you want people taking off from any old bit of grass you want them taking off and landing in the same area

So I would suggest you do have a "pilots box" and a "designated runway" on any given day - either that or your saftey officer wants a rocket

Perhaps if you re-read my post you will see that we do have a well organised flying field. I was commenting on the bit about "fiddling on the flying field". Surely everyone does that when you take a model out? Don't you at least point it in the direction you want to take off in? The only difference with a safety plug is that there is the few seconds while the safety plug is inserted, and that is close to the flying box usually- well it is in the case of our flying fields. If anyone is trying a dead stick or a low pass there, then it is too close to the pilots and decidedly dangerous.

People wandering about in the flying field should not really be a part of this discussion, unless there is the incorrect assumption you have to do that to insert a safety plug.

Edited By Andy48 on 05/05/2015 12:50:20

No I dont "fiddle about on the active area" - I call on "on the runway" - place the model into wind and retire to the pilots box - while I have already done control surface checks in the pits, I do waggle the sticks as I walk back from the model just to make sure.... then take off - to ensure that I am in the "active area" for the least possible time and that my model is sat on the runway for the least possible time - and because I plugged in the battery with the model restrained - I dont have the worry of a model suddenly going to full throttle unrestrained on the runway when its not restrained either

[Vinegar Dave]

From what i have seen more pilots who fly IC planes fiddle about on the runway than electric and some IC's will cut out and i have seen quite a few get down the strip to conk out but i have never seen an electric cut out or stay there reving up the motor as they sence a problem as usually there is no middle ground with electric the power is there or not .

I also am wondering that we are sacrificing safety to being 'held up' on the strip because the danger lays from passing others and walking with the aircraft. From what i understand the pilot should warn others he is entering the strip to take off so i see much more danger having the plane armed while walking than starting up on the runway . If a pilot has problems on the runway its common sense to walk back off the runway within a reasonable amount of time

As i said i may disagree with a club who thinks opposite to me but obey the rules or leave and that's fair enough.

Just my two pennies worth

[Daves42]

I have a Futaba 8FG and fly only electrics. I was concerned about safety right from the start so used the TX programming to set up a kill switch for the motor, which worked just fine. Then taking it one stage further, I was concerned that I might accidentally flick the switch while transporting to the flight line (and back) so, I changed the assignment from the switch, to one of the rotary knobs, which is almost impossible to move by accident.

I have a routine now built into my procedure to ensure that the assigned rotary knob (it is always the same for all of my planes) is in the safe (fully anticlockwise direction) before plugging in the lipo. The rotary knob has to be rotated beyond its midway position before the motor becomes active.

I assume that most computer radios would be able to be programmed in the same way.

In the pits, the rule is that all props should point outwards away from any people. All take-offs are made from the pilots box except for exceptional circumstances.

[The Wright Stuff]

Posted by Daves42 on 05/05/2015 14:28:38:

I have a Futaba 8FG and fly only electrics. I was concerned about safety right from the start so used the TX programming to set up a kill switch for the motor, which worked just fine. Then taking it one stage further, I was concerned that I might accidentally flick the switch while transporting to the flight line (and back) so, I changed the assignment from the switch, to one of the rotary knobs, which is almost impossible to move by accident.

I have a routine now built into my procedure to ensure that the assigned rotary knob (it is always the same for all of my planes) is in the safe (fully anticlockwise direction) before plugging in the lipo. The rotary knob has to be rotated beyond its midway position before the motor becomes active.

I totally agree, I do exactly the same on my 6J with the throttle kill button. My main concern about this in terms of failure points is that it is model-specific in the memory, so it would still be possible for the ESC to unintentionally arm itself if I had the wrong model selected.

To mitigate this the best I can, I ensured that (a) the throttle was reversed on all model memories, and (b) the throttle kill was enabled on all memories - INCLUDING those 'spare' model memories not yet in use.

[Chris Bott - Moderator]

My models fall into two categories.

Type 1 - Has any sort of easily opened hatch that gives access to the battery. With this type of model I "Arm" them by plugging the battery directly into the ESC.

Type 2 - Requires some sort of disassembly to get at the battery. With these, I have an external arming system. Usually a pair of 4mm gold plugs shorted together that will plug between two 4mm sockets on the model.

This way, every model can be armed wherever is most practical and safe.
Sometimes in the pits if there is a clear and safe way to get model and transmitter to the flight line. If it's a larger model then this would require a helper. The model is treated just like an IC would be treated once the engine is started.
Sometimes, it's more sensible to carry the model, unarmed, to the flight line. Especially if there's a queue and a bit of waiting to do. it only takes a second to either plug in the battery and close the hatch or just plug in the arming plug.

There's a few threads on arming plugs. This one, for example.

[Chris Bott - Moderator]

Posted by The Wright Stuff on 05/05/2015 16:00:06:

I totally agree, I do exactly the same on my 6J with the throttle kill button. My main concern about this in terms of failure points is that it is model-specific in the memory, so it would still be possible for the ESC to unintentionally arm itself if I had the wrong model selected.

To mitigate this the best I can, I ensured that (a) the throttle was reversed on all model memories, and (b) the throttle kill was enabled on all memories - INCLUDING those 'spare' model memories not yet in use.

I too use a throttle cut switch.
It's set so that the motor won't start if the throttle stick is up when the switch is operated too.
I also use a brand where the throttle channel dosen't need reversing for electrics, and individual receivers only respond to the model memory they're bound to.

[gangster]

So what is the difference between ic and electric in terms of safe practice,no difference.

both must be restrained in the pits ,the electric must be restrained all the time it has a battery in whereas the ic will not burst into life

so once we are ready to head for the strip the ic is running and is just as likely to speed up as the electric,for exactly the same reasons.

The only difference is we have a warning that it is dangerous from the smoke,noise and spinning prop but

the peace and quiet of the electric can lead into a false sense of security. That's where the safety switch comes in be it on the model or the TX

Both are equally dangerous at this point and must be carried firmly and carefully. I believe the danger comes in when being quiet and benign we do not have the same grip on an electric as we would on a fire breathing ic model.

hold it tight as if it was running,dare I suggest we should carry it out on "tickover". Yes I expect to be ridiculed on that point but it raises the question of what's the difference between ic and electric in terms of carry out to the strip

and before someone reminds me that the electric is unstoppable yes but the ic bite is not to be trifled with either

just a point to be aware of when carrying out either ic or electric model don't let your tranny swing on the neck strap. I did this the other day and it did unleash the full fury of the motor cos it hit both the override and the throttle . Total stupidity but let he etc etc

Stupid? Yes ,dangerous ? Yes ,consequences? I felt a prat,quite deservedly so but that was all cos I had one hand on the wing and one one the back of the fus. It went nowhere

lesson learnt

Edited By gangster on 05/05/2015 17:31:29

[Vinegar Dave]

I think some of us me included are knit picking a bit as i am sure that everyone in this thread is as safe as safe can be it was a good discussion mevertheless and thankyou for all your comments.

[gangster]

A discussion worth having Dave it's good to think of these things and share practice