Cutoffs -- just listen to Brett; don't argue.

[Tim Wescott]

I'm not quite ready to say that Brett Buck is always right, but I experienced an event today that made me think of some long threads that he's been involved in here in past years.

It involves his cutoff switch rule for 'lectrics.  That's the one that says that if you're flying on electron power then your plane needs to be restrained any time the battery is connected to the rest of the system.

So, today, flying my newly-converted-to-electric plane, I suffered an event.  I'm pretty sure it's a loose connection, although it could be a heat issue or software or some interplay of the two.  My plane cut out early, and landed.  when I was about six feet away from it the motor started up -- I did the gentlest-ever tackle, and caught the plane.  It could have gone the other way -- in my case, the plane would have ended up in the blackberries, or in a tree.  At a contest it could have ended up wrapped around someone's head, or chewing a hole in their shins with that nice strong CF prop.

The timing was just right for a maneuver to have caused a loose connection to the timer's "on" switch to have cut out in the air, then have been jostled back into connection when the plane hit the ground.  If this did happen, then it came on again right after the 30-second wait for the pilot to get to the handle.  I happen to be flying a timer of my own design, but the wiring scheme is the same as the Igor Burger timer (i.e.: power on the timer, it handles things from there).

And -- Brett Buck was right.  Mysterious Forces can cause a 'lectric plane to start up unexpectedly.  As I recall, when he introduced the rule all the debate was about the possibility of a software fault; not one of us (again, as I recall -- it may have come up) considered a wiring fault.  So -- his point was that unexpected s**t can make a plane start up, and by golly, he was right!

Just food for thought, for anyone wanting to disagree with Brett's rule at this late date.

[Peter in Fairfax, VA]

The risk of an unintended start, either a bench start or a field start, has always been much greater for electrics.  Thanks for sharing.  I launch at contests for an electric user, and we have a protocol that I have to pull the disarming plug and hold it up for him and/or officials to see before he can release the handle.   Works for me.  And I agree that Brett does give info that is well considered and based on experience.

1970s era electric:  https://www.worthpoint.com/worthopedia/vintage-rc-astro-05-super-ferrite-1938116442

Peter

[Jim Hoffman]

I suffered an in-flight shut down recently.  The cause was an over temp of the Castle Creations ESC.

A review of the data logger confirmed that I had hit the ESC shut off temp threshold.  I relocated the ESC so as to improve its cooling, and the ESC peak temp was much reduced, and the problem was solved.

It was very disconcerting until I (with the help of  a Castle factory rep) figured it out.

[PJ Rowland]

Poor Atlantis, it saw her opportunity and ran with it.

Freedom !!!

Im not sure how any rule proposal would ammend having an electrical fault, lands mid flight then 6 seconds later restarted.
At a contest you must restrain the plane with either person or pilot at the handle. There was an electric shutdown at the US nats, and the plane landed on the other side, it took a while to retrieve the plane,  but it was always held by the pilot ( which is the rule anyway )


Granted, unlikely to ever happen with IC, but we need to be be vigilant anytime using planes.

Ive had an overtemp shutdown and they are typically not a problem.
Ive had an arming pin burn the wire, and fail.. now there was nothing stopping that wire from  "retouching" and rearming the system..

My point was,  in each of these cases once I landed. I stood with the handle for about 30 seconds, and gently rocked it to make sure it nothing else may restart..  then move really fast to the plane and disarm it..

Its impossible to make them 100% safe for 100% of the people. Ive had over 500 flights this year without an problem.

I like the knowledge that once the battery is in the plane there is zero % of it starting till I arm it and Im ready to take responsibility of the plane and the flight.

[Brett Buck]

I'm not quite ready to say that Brett Buck is always right, but I experienced an event today that made me think of some long threads that he's been involved in here in past years.

  I am most assuredly not. However, this was not a hard call, your computer, for instance, would crash 20x a day if it counted on low-level logic states to remain the same without help. So I was on pretty solid ground with this one.

    In this case, it sounds like an intermittent open, which was not the original idea, which was to protect the rest of the world from single-event upsets/logic state changes. Nonetheless, it illustrates the potential for disaster.

   Since this topic first came up, people have told me about, and I have seen, maybe 30-40 cases of incidents of unexpected behavior from electrics. That's not all that bad, given that they have essentially no protection against these sorts of problem. But in the same time, I have heard maybe 2 incidents of IC engines starting unexpectedly. That, too, is much more common since the development of ABC/AAC engines, but still very rare and you still have to do something to make it happen, like, dribble fuel in the venturi and flip it.

   Ultimately, there was no real objection to the underlying idea, it seemed to be about the penalty. To be honest, no one was ever able to articulate what their issue was, aside from finding me personally objectionable (which is hardly a new or unique situation), so I couldn't explain it beyond that.

    Brett

     

[Howard Rush]

Whenever one’s electric aeroplane stops early, one should hold onto the handle until either somebody else pulls the arming plug or the intended time expires.  I’ve had one land after a minute, then take off again and finish the set duration.

[Brett Buck]

Whenever one’s electric aeroplane stops early, one should hold onto the handle until either somebody else pulls the arming plug or the intended time expires.  I’ve had one land after a minute, then take off again and finish the set duration.

  Do you status LEDs show you stuff like that, like, "I am armed and I am still counting" VS "I am armed but have timed out"?

     Brett

[jerry v]

Safety first.

All safety rules are written in blood.
Person is not allowed to work alone in construction, machine shop, automotive garage, etcetera .
It’s a good idea to not fly alone. Most of RC clubs require to have model restrained with a rope to the stake in the ground. With or without helper holding the plane to start the engine.
If CL pilot flies alone, then IC powered model is restrained by the stooge. Electric powered model should be on the stooge too. One more piece of equipment is required: a large screwdriver or a T- stake. To hold the safety strap of the handle before and after the flight. If pilot flies alone, then safety thong on the stake/screwdriver helps retrieve the model to the starting area without kinking the lines.

I think the arguments about arming plugs and procedures of arming/disarming electric systems will continue, because people believe in the 100 percent reliability of cheap electronic components.

Jerry

[Dan McEntee]

  Do you status LEDs show you stuff like that, like, "I am armed and I am still counting" VS "I am armed but have timed out"?

     Brett

   I don't fly electric, but the status light option sounds like something I would like on a model. You would need 3? Armed, timer running and active, and then timer off/shutdown. Especially if you have to fly by yourself. If you have a shut down, just that simple bit of information could avoid an incident like Tim's. An overtemp shutdown on an ESC could trigger some kind of sequence of the three that tells you that condition?  Knowing what kind of power we are talking about here in these batteries and such, yeah, I would like something like that.

    Type at you later.
     Dan McEntee

[Scott Richlen]

  I am most assuredly not.   

Wait?   What?  How could that be??      

Years ago I had a SIG Akrobat with an FSR 40 that started unexpectedly.  The battery was not attached, I had choked it and was flipping it through and it started!  So, I waved at the judges and proceeded to fly.  I'm not sure they realized that the battery wasn't attached when the engine started.  A bit out of order, but I was flying Intermediate and the judges probably figured "oh well, he'll learn to signal properly one of these days...."

It did this twice at various contests.

[Tom Luciano]

A few years back flying alone on grass, I had a prop strike on spool up(Nose over). As I started walking to the plane I thought, this is a bad idea. I proceeded back to the handle and about 5 seconds later the motor spooled up. Stock Igor setup, no indicator light.  Lesson learned as Howard suggests, wait until timer shuts down with your stop watch.

I have experienced the following
1. Overheating shutdowns
2. Bad battery shut downs
3. Uncharged battery shutdowns
4. prop strike shutdowns
5. launched battery shutdowns
6. Complete powertrain separation from airplane due to  ground interruption.

Although I'm making a bit of fun at my own expense the last two are really the only two you can leave the handle before the timer expires.

[Elwyn Aud]

When I hear cut-offs my mind goes to abrasive cutting disks or Daisy Duke.

[Dave_Trible]

Gee Whiz Elwyn I was looking for the Daisy Duke photos.......

Dave

[Scott Richlen]

Gee Whiz Elwyn I was looking for the Daisy Duke photos.......   

And, of course, you mean "back then", not now....(she's probably older then us!!)   

[Brett Buck]

And, of course, you mean "back then", not now....(she's probably older then us!!)   

    Time is extremely sexist, and life is unfair.

   Brett

[Gary Dowler]

And, of course, you mean "back then", not now....(she's probably older then us!!)   

Catherine Bach is……67.

[Dave_Trible]

Catherine Bach is……67.

Exactly my age...HHMMMM..

Dave

[Ken Culbertson]

When I hear cut-offs my mind goes to abrasive cutting disks or Daisy Duke.

My first wife lived in cut-offs.  Sort of liked them but I still can't figure how they will stop a runaway motor.

Ken

[John Rist]

I have brought this point up many times.  It is not necessary to put an electric airplane on a stooge.   In the first place if flying alone you have to walk to the airplane after you lay the handle down to disarm it at the end of a flight.  So a stooge may help on takeoff but is of no use on landing.  The correct way to fly electric alone is to stake the safety thong on the handle.   Most all safety thongs are attached to the down side of the handle.  So if the motor starts when it shouldn't the  secured handle jerks the down line.  Aircraft noises over stopping the prop and hopefully shouts things down.  I fly KR timers and they do a pretty good job of doing this. Admittedly the KR timer during the first second or so of startup will not stop the motor in case of a prop strike, but for only a second.

Any way photo attached shows how I stake my handle.  The handle is secured as I walk to the airplane.  I am old so give myself a full minute to get to the handle.   Once I have landed I once again stake the handle as I walk to airplane to disarm it.  I have never had a false start but it can happen and I want to be safe.   

[Dave Harmon]

My first wife lived in cut-offs.  Sort of liked them but I still can't figure how they will stop a runaway motor.

Ken

So did mine....but the motor didn't run away....SHE did!   

[Ken Culbertson]

So did mine....but the motor didn't run away....SHE did!   

Same Here!

[Dwayne Donnelly]

I have brought this point up many times.  It is not necessary to put an electric airplane on a stooge.   In the first place if flying alone you have to walk to the airplane after you lay the handle down to disarm it at the end of a flight.  So a stooge may help on takeoff but is of no use on landing.  The correct way to fly electric alone is to stake the safety thong on the handle.   Most all safety thongs are attached to the down side of the handle.  So if the motor starts when it shouldn't the  secured handle jerks the down line.  Aircraft noises over stopping the prop and hopefully shouts things down.  I fly KR timers and they do a pretty good job of doing this. Admittedly the KR timer during the first second or so of startup will not stop the motor in case of a prop strike, but for only a second.

Any way photo attached shows how I stake my handle.  The handle is secured as I walk to the airplane.  I am old so give myself a full minute to get to the handle.   Once I have landed I once again stake the handle as I walk to airplane to disarm it.  I have never had a false start but it can happen and I want to be safe.   

As someone who's dealt with a motor spooling up before I made it to the handle this is a great idea and easy to do if flying off grass, my luck though I'd trip over it. 
In the meantime I don't care what anyone says, use a stooge!!!

[Dan McEntee]

    If an electric model unexpectedly decides to spool up and run, and the model is not restrained securely, even if the handle is allegedly anchored, it is still capable of accelerating out and doing some kind of damage to you, other people or property. Imagine you being half way out to the handle and it takes off, and wraps around you like something out of a cartoon? If the model is in a stooge, it can't get away, and it moves forward when you and your brain are ready for it. Why take the chance of damaging a good model, at the very minimum? At the end of the flight , it's another matter. The timer should have things turned off, then restraining the handle on the ground has a better chance, and the battery has been nearly depleted. But in the beginning of the flight, with a freshly charged battery, which is armed and the time is activated, That is too risky. There is too much power in one of those battery packs for me not to have the model restrained, and 6 minutes is a LONG time in an emergency situation.
  Type at you later,
   Dan McEntee

[John Rist]

    If an electric model unexpectedly decides to spool up and run, and the model is not restrained securely, even if the handle is allegedly anchored, it is still capable of accelerating out and doing some kind of damage to you, other people or property. Imagine you being half way out to the handle and it takes off, and wraps around you like something out of a cartoon? If the model is in a stooge, it can't get away, and it moves forward when you and your brain are ready for it. Why take the chance of damaging a good model, at the very minimum? At the end of the flight , it's another matter. The timer should have things turned off, then restraining the handle on the ground has a better chance, and the battery has been nearly depleted. But in the beginning of the flight, with a freshly charged battery, which is armed and the time is activated, That is too risky. There is too much power in one of those battery packs for me not to have the model restrained, and 6 minutes is a LONG time in an emergency situation.
  Type at you later,
   Dan McEntee

One should never walk in front of the lines.  Admittedly if flying in grass lines could get snagged and airplane do strange things.  On the subject of a stooge, how many stories have I read about people getting tangled in the stooge lines.  Also if you don't stake the handle how do you get the aircraft back to starting point for the next flight.  Stooges are not the cure all, end all.   I don't think a stooge is worth the hassle if you stake the handle.  I fly on a paved surface making setting up a stooge a hassle.  With no grass to snag my lines I am sure that the aircraft ain't going anywhere with the stake pulling on the down line.  At the end of the flight the setup is safe while I walk to the aircraft to unplug the battery.   

[Gerald Arana]

    If an electric model unexpectedly decides to spool up and run, and the model is not restrained securely, even if the handle is allegedly anchored, it is still capable of accelerating out and doing some kind of damage to you, other people or property. Imagine you being half way out to the handle and it takes off, and wraps around you like something out of a cartoon?

Dan, The "Simple" solution is to walk on the other side of the lines.......

I had an incident with my stooge a loooong time ago. It wrapped around my ankles and I stayed calm (Unusual for me) and went inverted. Unwrapped the line and walked away from it.

Cheers, Jerry

[jerry v]

    If an electric model unexpectedly decides to spool up and run, and the model is not restrained securely, even if the handle is allegedly anchored, it is still capable of accelerating out and doing some kind of damage to you, other people or property. Imagine you being half way out to the handle and it takes off, and wraps around you like something out of a cartoon? If the model is in a stooge, it can't get away, and it moves forward when you and your brain are ready for it. Why take the chance of damaging a good model, at the very minimum? At the end of the flight , it's another matter. The timer should have things turned off, then restraining the handle on the ground has a better chance, and the battery has been nearly depleted. But in the beginning of the flight, with a freshly charged battery, which is armed and the time is activated, That is too risky. There is too much power in one of those battery packs for me not to have the model restrained, and 6 minutes is a LONG time in an emergency situation.
  Type at you later,
   Dan McEntee

There is the reason to have a safety strap connected to the bottom of the handle. If safety strap is restrained by the stake, how much will model roll in full power and full “down “ elevator? Will it take off? Damaged model is the least of the problems compare to property damages and human casualties.

Jerry

[Paul Walker]

There is the reason to have a safety strap connected to the bottom of the handle. If safety strap is restrained by the stake, how much will model roll in full power and full “down “ elevator? Will it take off? Damaged model is the least of the problems compare to property damages and human casualties.

Jerry

I believe they are talking about staking it after it has landed..

No one would be so stupid to not use a stooge with an electric powered model. Right??

[AMV]

No one would be so stupid to not use a stooge with an electric powered model. Right??

Foolproof procedures are impossible because fools are very extremely supremely creative.

[Dan McEntee]

There is the reason to have a safety strap connected to the bottom of the handle. If safety strap is restrained by the stake, how much will model roll in full power and full “down “ elevator? Will it take off? Damaged model is the least of the problems compare to property damages and human casualties.

Jerry

      You won't know that until it happens. All it takes is a simple line snag, and the model turns and it coming at you at full power. It can get airborne, fly to the other side of the circle and if it doesn't come loose from the stake, the lines can snap, or bell crank ripped out, and then still be airborne under full power. If it manages to come loose from the stake, how far it will fly is dependent on factors of luck. You are assuming only one small accident scenario. Stranger thimgs have happened.
  Type at you later,
   Dan McEntee

[jerry v]

      You won't know that until it happens. All it takes is a simple line snag, and the model turns and it coming at you at full power. It can get airborne, fly to the other side of the circle and if it doesn't come loose from the stake, the lines can snap, or bell crank ripped out, and then still be airborne under full power. If it manages to come loose from the stake, how far it will fly is dependent on factors of luck. You are assuming only one small accident scenario. Stranger thimgs have happened.
  Type at you later,
   Dan McEntee

Dan, accidents happen all the time. Stunt is the most peaceful way of flying. Racers, speed and combat pilots can tell you more  dramatic stories. And I personally witnessed some of them. I described my opinion on flying gas and electric stunt in earlier post here #7. My opinion is the same : it’s not a good idea to fly alone. If rules are written for competition with all the procedures like pull test, line size, safety plug, safety strap, helpers holding armed model , etcetera - if pilots always follow this rules, in competition or in the practice in the own backyard, then we will eliminate a lot of accidents.
And for Paul Walker remark to my earlier post - we will continue to have arguments about arming procedure on the electric setups because people believe in the 100 percent reliability of cheap Chinese electronic components. Paul, those believers are not smart or stupid. They just don’t know anything better.

Jerry

[Brett Buck]

we will continue to have arguments about arming procedure on the electric setups because people believe in the 100 percent reliability of cheap Chinese electronic components.

  I would note that the problem I was originally concerned with (low-level logic flips from SEUs) has nothing to do with the it being cheap or Chinese. I have seen this incessantly with the highest-end military electronics, and your Intel processor from Silicon valley - maybe made about 5 miles from where I currently sit - probably has 20 of them a day, the higher tech and more modern it is, the higher the frequency. It keeps working only because it also has protection against it, being utterly unusable otherwise.

    We do a lot of dangerous things, we get away with them primarily because of low rate of activity and a minimal set of basic principles - like *not arming your airplane and hoping nothing goes wrong as you walk to the handle*. Absolutely anything could happen after you walk away, only one of those things (nothing happens) is good.  By definition, flying with a stooge means flying alone, you are *probably* (although not certainly) the only one that might be endangered, so I wouldn't try to write a rule (in this case, a safety code modification, not a competition rule) about it, because it is indeed up to the individual.

    But I strongly suggest everyone follow Paul's advice, I have seen the results of people getting cut up with lines and have seen CL airplanes flying free, lines or otherwise, and it is not good, and not worth the risk to slightly reduce the convenience.

     Brett

[jerry v]

Brett,
You are right, none of the electronics is 100 percent reliable. I just give the name “cheap” to it because in most cases contract to make something will be won by the lowest bidder))
Maybe my description of flying alone is not perfect. During pandemic C-19 it was practical to use stooge and keep the helper 6 feet or more away, and not allowing him to touch the model or the handle.

Jerry

[AMV]

But I strongly suggest everyone follow Paul's advice, I have seen the results of people getting cut up with lines and have seen CL airplanes flying free, lines or otherwise, and it is not good, and not worth the risk to slightly reduce the convenience.

I cannot fly alone because my brother keeps the lines to my airplane at his house under lock and key