Funny now, but it could have been a lot worse

[ted hughes]

Is it possible, in a few words, to describe what failsafe is and how you set it?

I came to electrics after a 20 year break from flying, all was new to me, and I have managed to get my brushless planes to fly, but that's about it.

[The Wright Stuff]

Martin, sorry to confuse - I was replying to the same post as you were in the bit I quoted, rather than your response specifically - I just deleted too much of the text...

Agree that the failsafe is activated by the receiver and the receiver alone upon loss of signal. However, the OP was claiming that the transmitter couldn't be used to set the failsafe position. I was just pointing out that even if that was the case, it still fails to comply with the CAP. Like I said - just a technicality...

Ted. Short answer: if the receiver loses the signal from the transmitter, or the signal is too corrupted to be clear (e.g. interference), then the receiver automatically sets all controls to a pre-set position. The recommendation is that the throttle (be it IC servo or electronic control of a motor) be set to stop or idle, so that the model doesn't fly away. The other controls can be set in any way you feel appropriate. To test, simply switch off the transmitter and see what the controls do in the absence of a signal (while restrained, if a motor is running). The failsafe positions are set from a computer transmitter usually, but the exact process is dependent on brand...

[Don Fry]

Discussing fail safe it strikes me that arguments I used to hear in the 80s and 90s have never been resolved. I fly from standard sites, and work on the basis that once on the public side of the aircraft in pits area, you need not keep an eye out for hazard. The rules keep you safe.

A fail safe, clue in the word, is not a device to keep the aircraft safe in the event of a system failure, it it there to bring it down, for example cut the moter (cut not idle) shallow banked turn, rudder assist), or variations, to crash the aircraft in the dead ground in front of the flight line. A fail safe that allows an out of control aircraft to maintain flight in the hope the pilot gets control back, could be said to be a hazard to bystanders, and so in contravention of the ANO.

The ancient arguments went that crashing the aircraft, because it hit faster COULD be more dangerous that a glided decent, always to my view hinted at wishful thinking,in compromising safety for your pride and joy.

[Jack Banner]

I wouldn't include any elevator, rudder or aileron in a fail safe. Any change from a level flight path risks increasing air speed and that increases the potential for greater kinetic energy transfer when it eventually hits something. Just my opinion / preference of course. In reality all bets are off when you have no control and, as long as your fail safe cuts the engine, you have done what you can.

[jrman]

Anything other than reducing power is probably pointless. If the model is halfway through a roll or loop etc when it goes into failsafe what good is setting anything else?

[Andy48]

I don't agree with either of the previous posts. A little rudder will turn the plane in a gentle circle, which might, just might bring it back into range, and hence be recoverable. The increase in speed/kinetic energy will be very minimal. If one is in some roll or turn then of course the outcome is unpredictable. 

Edited By Andy48 on 21/06/2016 11:00:58

[Biggles' Elder Brother - Moderator]

CAA have been very clear on this matter - more so in CAP 722 than in CAP 658 admittedly - the only purpose of a failsafe is to reduce (preferably eliminate) the possibly of a fly away and the aircraft becoming a danger to other aircraft. It is, believe it or not, not particularly about protecting people/property on the ground. Its about protecting airspace. So, anything other than what simply brings the model down in as quick and safe a manner as possible is superfluous to requirements.

For a fixed winged aircraft - reduce throttle to minimum/idle and centre all control surfaces.

For an MR - set throttle at 40% and all steering controls to centre.

BEB

Edited By Biggles' Elder Brother - Moderator on 21/06/2016 11:09:44

[Martyn K]

Posted by jrman on 21/06/2016 10:56:36:

Anything other than reducing power is probably pointless. If the model is halfway through a roll or loop etc when it goes into failsafe what good is setting anything else?

I set my throttle to idle and all other control surfaces to hold - for that reason.

My experience of a failsafe cutting in (on a Futaba) was performing an inverted low pass and I 'lost' the down elevator that I was holding. Fortunately, the Futaba receiver reset was very quick and I recovered the model at about 2-3m altitude.

The Rx got binned.

Martyn

[Don Fry]

Fair enough, but does not 138 apply, aircraft endangering people. Saying a moter going to idle is the best you can do protects the aircraft, but does not minimise the risk that it leaves a safe area. And arguments about loops is irreverent. Another control movement for a fail safe is full up elevator, full rudder, and full opposite ailerons.Ain't going to fly then, and pretty predictable it goes down.

I am by the way not advocating a change to our practices, but am asking if we are aware that we are making an informed risk assessment and accepting risk to non participants, for the people of protecting a or aircraft

[The Wright Stuff]

Posted by Donald Fry on 21/06/2016 11:56:15:

Fair enough, but does not 138 apply, aircraft endangering people. Saying a moter going to idle is the best you can do protects the aircraft, but does not minimise the risk that it leaves a safe area. And arguments about loops is irreverent. Another control movement for a fail safe is full up elevator, full rudder, and full opposite ailerons.Ain't going to fly then, and pretty predictable it goes down.

I am by the way not advocating a change to our practices, but am asking if we are aware that we are making an informed risk assessment and accepting risk to non participants, for the people of protecting a or aircraft

Totally agree, but remember that CAP658 only specifies a minimum requirement. Beyond throttle to zero, the 'best' or 'safest' settings of the control surfaces are probably very context specific: depends on the model, depends on the site, depends on the radio. Is the most likely scenario a momentary glitch or a permanent loss of signal? All of these factors should be considered by the pilot when assessing whether the flight can be safely completed - so yes, I agree with you that it is implicit in the guidelines.

[john stones 1 - Moderator]

You've taken all reasonable precautions to ensure you can carry out the flight safely, where it lands should failsafe kick in is in lap of Gods, stop it flying away is only thing you can reasonably ensure. There is no way to guarantee anything 100% other than don't fly.

John

[kc]

Could we get back to the original subject here? The subject was hovering and a structural failure which caused damage to a model that was presumably parked in the 'pits' area. Yesterday I asked " In a club flying environment how far away from other pilots and models should hovering vertically be done? And upwind or downwind of oneself and others? "

I don't think we have really discussed that enough . So where should one hover? ( I believe it's vertical hovering we are concerned with here)

[Jack Banner]

Anywhere where all pilots on the flight line have agreed is OK.

[The Wright Stuff]

Posted by kc on 21/06/2016 19:56:33:

Could we get back to the original subject here? The subject was hovering and a structural failure which caused damage to a model that was presumably parked in the 'pits' area. Yesterday I asked " In a club flying environment how far away from other pilots and models should hovering vertically be done? And upwind or downwind of oneself and others? "

I don't think we have really discussed that enough . So where should one hover? ( I believe it's vertical hovering we are concerned with here)

If the hovering is down close at ground level, then I would imagine that the same separation rules apply as with take off and landing - i.e. at least 30 metres.

[Keith Simmons]

Sorry chaps, In this instance, I can't see how the fail safe helps as the motor has detached itself from the model including the wire connections and the signal connection itself is still strong and active with the rx and battery via the ESC. (Unless the ESC becomes detached with the motor from the model).

The model therefore is no longer in powered flight so it would return to Earth tail heavy and so is likely uncontrollable.

 

Edited By Keith Simmons on 22/06/2016 09:22:57

[The Wright Stuff]

Posted by Keith Simmons on 22/06/2016 09:20:23:

Sorry chaps, In this instance, I can't see how the fail safe helps

Precisely why we're now desperately trying to return to the original point of the thread!

[kc]

The first comment about failsafe was just a jest. Later comments were sensible but not the point of this thread.

[Keith Simmons]

Everything we do in life carries a degree of risk.

Even staying at home and not going out is risky due to lack of exercise and that damages health.

I would argue that we as members of model fliers do accept risk simply by being at the field and that we all attempt to minimise risk as much as possible by playing safe and follow rules.

This is an unforeseen event and we may check the structure of the model by exerting forces greater than experienced in flight, we could unfortunately damage the unseen weak glued areas under the covering.

We don't normally strip the newly brought ARTF model's wing or rear fuselage to check the structure to see how well it's glued. (Unless that particular model has a structural failure & owners would want to check if theirs don't carry the same deflect)

[Richard Harris]

Could it be that there was a vibration issue, out of balance prop/ bent motor shaft perhaps? This could easily exert forces way beyond what the components are designed for?

Luckily no one was hurt, well worth adding this to your pre flight checks in future, I know I will !

Rich

[Don Fry]

Richard, a small reality check here, a small foamy broke up, a small motor and bits detached, and by small chance punctured a bit of profilm. The pilot box in inhabited by consenting adults.

A big petrol unit detaching, different ballgame. Everyone has a voice in the pilot box, or withdraw as appropriate.

[kc]

The reality is that if that prop had pucntured someone's eye instead of just a model it would have been very serious whether it was just a foam model or not.

As for saying "consenting adults" ...... rubbish. There is a duty to fly safely. So the question remains What is an apropriate distance for hovering and should it be upwind or downwind?

[Don Fry]

Harold would have agreed all those years ago. But flying contains risk, and sometimes the bad end of a distribution curve bites. I would point out that the much enjoyed low flat out beat up of the strip involved standing in front of the prop as it comes past. Try the hover a bit further out.

[Biggles' Elder Brother - Moderator]

I think this is one of those "common sense" things that at one and the same time are so easy to do but quite slippy and difficult to define!

Take two extremes:

case 1: its a very busy Saturday afetrnoon at the club, lots of people down at the strip. The club allows 4 planes in the air at any one time. Three are already up when one one member takes off with a 6 foot wing span, 10Kg, 3D model of an Sbach and starts constantly hovering over the mid-point of the strip - right opposite the pilots' box, 6 feet out.

case 2: is a quiet Tuesday afternoon. There are only two people flying. One of them puts up a 30" span foam Extra and does a few Harriers etc and an occassional hover well out away from his mate as part of his general flying round.

Most of us would say case 1 is a safety problem - an accident waiting to happen. The guy flying the Sbach is anti-social (in club terms), probably rather dim and frankly potentially dangerous. He's a pain and a hazard to everyone around him. But the second guy with the foam Extra? No big problem right?

The problem is of course 99% of real cases are somewhere between these two. Also big plane doesn't necessarily mean big problem - just as small plane doesn't always mean "safe"! Where do we draw the line?

Personally I think its a got to be a case-by-case basis. If there is a general view among the pilots present that Bully's hovering is a nuisance and a potential danger, then the club - either through the committee or the safety officer - needs to "have a quiet word" with Billy about him changing hos ways.

But if, on the other hand, the general concensus is that, while Billy's interest in hovering baffles most traditionalists and leads to tut-titt's and comments about "If the Wright brothers had wanted planes to do that they would have invented the helicopter", the fact is Billy is quite thoughtful about his flying, gets in no one's way anymore than the rest of us, is skillful and quite safe - then why not leave him alone to have his fun his way? "Lve and let live" eh? Each to their own.

The point is - I don't think you can make hard and fast rules about this - or that it is particularly helpful to try to do so. Experoenced flyers know what's safe and what isn't and in this case I think theor collective judgement is the best yeardstick.

BEB

BEB

[Don Fry]

BEB, I admire your typing skills, very good, but to quote " If there is a general view among the pilots present that Bully's hovering is a nuisance and a potential danger, then the club - either through the committee or the safety officer - needs to "have a quiet word" with Billy about him changing hos ways."

I have had the privilege, or burden, to have belonged to clubs where the verbal skills of the pilot box need little recourse to safety officer or committee.

My present (French) club had a dreadful accident. My regular flying mate and I came to an agreement, on safety issues, you say what you like, the recipient is obliged to listen without comment.

[Owdlad]

A pilot should always act in a safe manner as not to endanger othes or property

It doesn't matter if the pilot is highly competent and can hover at the end of his ariel without issue! The problem is if something goes wrong that is not of the pilots fault and the time span it takes the model to come back on the pilot line. The further out the greater the reaction time for others to duck.

Personally if I was flying and some half-whit decided to hover at the end of my nose I'd tell the offender to pack it in, if the pilot continued and took no notice I'd land and take matters into my own hands. ( Words chosen carefully as this forum doesn't subscribe to violent conduct )

This is another reason I shy away from clubs.