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Fail safe best practices

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Old 02-11-2018, 09:49 AM
  #1  
kman527
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Default Fail safe best practices

In the last couple of years I have seen several accidents when control of gassers were totally lost for unknown reasons. (There was not much left so any post-mortems were not possible.) Luckily no one was injured. All three planes crashed away from the field - one was about a mile away.

Putting aside good practices to prevent signal loss, what do you all do to minimize the chance of your airplane disappearing into the distance completely out of control?

I have set up my receivers so that if there is loss of signal the controls default to engine idle (or ignition cut off), some up elevator, left aileron, and right rudder with the hope that the plane might sort of forward slip to its demise in the local area.
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Old 02-11-2018, 04:14 PM
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Have your 'tried' those control throws while flying?
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Old 02-11-2018, 04:31 PM
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kman527
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Not yet but I have fiddled around a bit with Real Filght.
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Old 02-12-2018, 04:38 AM
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Hi Kman, I believe that attempting to setup some sort of deliberate slip is virtually impossible. Also I setup fail safe on all my airplanes but do it differently according to what type of airplane, for example: The vast majority of my various sport airplanes large and small I set all the controls to default to neutral and the throttles to idle cutoff. This even applies to my turbines (which by the way are required by AMA regulation to use fail safe) which I always set for idle cutoff, I do not want those airplanes to go far and they don,t .

Now back in my racing days (pylon) after witnessing an incident in Los Angeles I became a believer in fail safe and I set all my of racers for idle cutoff and about 25% DOWN! An OSS (out of sight) loss of one is completely unacceptable with any loss of control I want it to crash BEFORE it ever leaves the race course.

That incident I referred to was some years back and a fellow competitor was on the course during a practice session and he experienced a complete loss of control and he yelled out the dreaded warning. That airplane was seen to be traveling in a straight line at about a hundred feet and a hundred and fifty mph. It passed over our heads back in the pits and vanished over the giant old oak trees.

A search proved fruitless until a someone brought a chunk of the wing back to the field, It was covered in tire tracks. Well where that airplane decided to hit at terminal velocity was in the middle of the #605 freeway interchange with the interstate #10 freeway which was about three quarter of a mile away. At the time that interchange was gridlocked typical for that time of day.

The fellow who returned the chunk of wing said the airplane hit vertically between the lanes some distance ahead of him and as he reached the spot he just opened the door a grabbed that wing chunk.

I never heard of any repercussions and apparently a very nasty situation was avoided just by pure luck, Any way it made a believer out of me about using fail safe.

John

Last edited by JohnBuckner; 02-12-2018 at 04:44 AM.
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Old 02-12-2018, 05:51 AM
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Default How do you test your Fail Safe

Okay -

Fail Safe is important. But how do you test Fail Safe after setting it up on a plane? Let me guess:
1. Place you plane on a stand if possible. If it's too large for a stand immobilize it by some other means such as tying a rope between the tailwheel and a post in the ground.
2. Turn on transmitter.
3. Turn on receiver.
4. Verify control inputs are working and do a range check.
5. Start the engine if it's gas or glow.
6. Run up the motor to full throttle.
7. Give right (or left) aileron and up elevator.
8. Turn off the transmitter.
9. Verify the control surfaces and throttle move to their Fail Safe positions.
10. Turn on the transmitter. Verify normal operation.

Or you can fly your plane, turn off the transmitter, verify it enters Fail Safe mode, turn your transmitter back on, and resume normal flight. But I'd rather not test Fail Safe by actually flying it. What if something goes wrong and it should decide to go berserk?

What do you think?

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Last edited by oliveDrab; 02-12-2018 at 06:02 AM.
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Old 02-12-2018, 09:10 AM
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Yes indeed that would be the long form. However it not need be so involved if one chooses as I do and includes full idle cut off with all types and with the racers down elevator:

To confirm failsafe enabled, no need to run engine just turn on Tx and Rx then turn off only the Tx and watch/listen throttle has closed. That's it.

In the case of a turbine just lite up and after ramp up and running indication on the GSU just turn the Tx only off The engine will shut down if failsafe is enabled.

Many Contest Directors in pylon now require a simple demonstration as above during tech inspection that the throttle barrel closes when the Tx only is switched off.

John
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Old 02-12-2018, 11:13 AM
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Default an what about electric?

Originally Posted by JohnBuckner View Post
...
To confirm failsafe enabled, no need to run engine just turn on Tx and Rx then turn off only the Tx and watch/listen throttle has closed. That's it.

In the case of a turbine just lite up and after ramp up and running indication on the GSU just turn the Tx only off The engine will shut down if failsafe is enabled.
John
Okay thanks John.
What about electric? uummm.... Maybe actually need to throttle up the electric, turn off the Tx, and watch the motor spin down.
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Old 02-12-2018, 02:03 PM
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Yup that will get her done with electrics.

Quite a few years back now I was doing some cross country flights just during the period when fail safe started to become avalible on some radios. On one route it required travelling under two railroad underpasses which caused blocked line of sight for perhaps two seconds having done this before using simpler radios no problem. But this time I had to make sure that I set the fail safe to cruse setting not idle cutoff It proved no problem and we of course tested the reaquisition time with the tranny off then on method timing it.
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Old 02-12-2018, 06:49 PM
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Originally Posted by JohnBuckner View Post
Hi Kman, I believe that attempting to setup some sort of deliberate slip is virtually impossible. Also I setup fail safe on all my airplanes but do it differently according to what type of airplane, for example: The vast majority of my various sport airplanes large and small I set all the controls to default to neutral and the throttles to idle cutoff. This even applies to my turbines (which by the way are required by AMA regulation to use fail safe) which I always set for idle cutoff, I do not want those airplanes to go far and they don,t .

Now back in my racing days (pylon) after witnessing an incident in Los Angeles I became a believer in fail safe and I set all my of racers for idle cutoff and about 25% DOWN! An OSS (out of sight) loss of one is completely unacceptable with any loss of control I want it to crash BEFORE it ever leaves the race course.

That incident I referred to was some years back and a fellow competitor was on the course during a practice session and he experienced a complete loss of control and he yelled out the dreaded warning. That airplane was seen to be traveling in a straight line at about a hundred feet and a hundred and fifty mph. It passed over our heads back in the pits and vanished over the giant old oak trees.

A search proved fruitless until a someone brought a chunk of the wing back to the field, It was covered in tire tracks. Well where that airplane decided to hit at terminal velocity was in the middle of the #605 freeway interchange with the interstate #10 freeway which was about three quarter of a mile away. At the time that interchange was gridlocked typical for that time of day.

The fellow who returned the chunk of wing said the airplane hit vertically between the lanes some distance ahead of him and as he reached the spot he just opened the door a grabbed that wing chunk.

I never heard of any repercussions and apparently a very nasty situation was avoided just by pure luck, Any way it made a believer out of me about using fail safe.

John
When I started thinking about this I thought if I could get the plane into some kind of forward slip it would not impact the ground at a high speed even though it would probably meet its expiration date. I'll experiment a bit more with Real Flight and repport back.
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Old 02-12-2018, 06:52 PM
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Originally Posted by JohnBuckner View Post
Yes indeed that would be the long form. However it not need be so involved if one chooses as I do and includes full idle cut off with all types and with the racers down elevator:

To confirm failsafe enabled, no need to run engine just turn on Tx and Rx then turn off only the Tx and watch/listen throttle has closed. That's it.

In the case of a turbine just lite up and after ramp up and running indication on the GSU just turn the Tx only off The engine will shut down if failsafe is enabled.

Many Contest Directors in pylon now require a simple demonstration as above during tech inspection that the throttle barrel closes when the Tx only is switched off.

John
John - do you know of any clubs that routinely check whether the members use fail safe on models a certain size or just on everything?
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Old 02-12-2018, 07:42 PM
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The only problem with setting control surfaces we assume the plane will be in level flight....
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Old 02-12-2018, 10:46 PM
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For most practical purposes, no matter how you set it, the only thing Fail Safe does for you is change the place where you crash.
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Old 02-13-2018, 12:08 PM
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Originally Posted by EloyM@twc.com View Post
For most practical purposes, no matter how you set it, the only thing Fail Safe does for you is change the place where you crash.
And, while that is true, you have to look at the other side of the coin:
A plane without an active fail safe is going to continue on at the last control setting until something stops it, being something, someone or the ground.
A plane with an active fail safe, unless you lose the batteries, is going to respond in a planned, predictable manner and will probably come to a stop in a location that is much easier to find and get to if you don't regain control of it first
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Old 02-14-2018, 11:59 AM
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My feeling is that no power, and full up elevator
will give a low impact speed, with the only
possible exception being to enter failsafe
from low level inverted flight.
To further reduce the speed, add
a lot of drag by giving full ailerons to one
side and full rudder to the other side.
If you have each aileron on its own channel
make them both go full deflection either up or
down. If you have flaps use crow configuration.

On a combustion engine plane, you want the
engine stopped, even though an idling engine
makes more drag. You don't want it running when
it hits someone's leg.. On an electric, you want the
propeller wind-milling without power.

With these settings, your plane will come down
pretty quick with a minimum of collateral damage,
which could prevent lawsuits and field loss.
You could find yourself repairing planes more
frequently from momentary glitches, so if it is
possible, set the failsafe to kick in after a couple
of seconds of signal loss.

Jenny
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