Setting up fail safe

[toto]

I will be setting up some basic settings on my Arising Star which will be using a Spektrum AR 620 receiver.

 

The default for this receiver on fail safe is the throttle gets cut to zero and all surfaces go to neutral.

 

I intend to keep all surfaces at neutral with the intention that if fail safe kicks in, the model should revert to straight and level flight. However, I would intend setting it so the throttle is slightly above idle in order to allow the model to keep moving.

 

Does this sound right? 

 

I cant see any reason that you would want to incur a change in direction or height. If I have this wrong or am misunderstanding something ..... feel free to chip in.

 

Toto

[GrumpyGnome]

Yes, you want throttle at idle and all other surfaces at neutral.

 

This rx has 2 failsafe modes - one will do the above, and the other will set throttle to low and set the control surfaces to the last 'good' position.

 

Follow the manual carefully to make sure you select the correct one, then test it as described in one of your other threads, i.e. push both sticks to a corner (a top corner), switch off the tx, and see what happens.

 

 

 

 

[Frank Skilbeck]

Bear in mind the failsafe has to be set so the model can't fly away and endanger any other aircraft, so the throttle has to be set to bring the model down, note this is a legal requirement.

Plus if you manage to set the failsafe to keep the model flying straight and level chances are you'd be very lucky to see it again, as opposed to a short walk to collect the bits. 

[Rich Griff]

As mentioned in the "chirp" thread, super 60 and farm yard 😀

[GrumpyGnome]

There have been lots of threads about failsafe settings, and there are lots of opinions.  

 

I very much doubt that an Arising Star, with engine at idle, will fly out of sight, so a slow, natural descent resulting in a 'gentle crash' is safer, IMO, than trying to deliberately bring it down - a situation where there is no control of the impact zone or speed. 

 

Also, neutral controls, plus idle, will allow an easier regain of control if the signal is re-established. 

 

As toto gets more specialist models, he may well choose to add, say, some 'up', or flaps, or rudder or whatever. But for now, neutral plus idle is probably most sensible.

[leccyflyer]

As GG said there are diferent opinions on best failsafe settings. The role of failsafe is to prevent a fly-away, not to somehow save the model. There's a good case to be made for setting the controls to put the model into a flat spin, with the aim of bringing it down as close to the point where contact was lost, reducing the chances of a fly away and also reducing the vertical speed at impact. That's actually more difficult to accomplish than it sounds in practice. I used to be firmly of the opinion that is the way to go, so had up elevator, rudder and aileron set to put the model into a spin. Since then having experienced two instances -one where failsafe cut in and the model spiralled to it's death at quite a high impact speed and one where failsafe did not cut in, because all power was lost, but the model gently circled to a perfect landing with minimal damage and no threat to life and limb, I've changed my approach. Closing the throttle is the most important thing for a power model and I now go with the other controls set for neutral, such that, if contact is re-established (which telemetry suggests can happen after momentary loss of contact) then there is a better chance of getting the model safely back to the strip, or landing out safely.

[Nick Cripps]

As mentioned on your other thread, the AR620 and other Spektrum receivers have 2 types of failsafe: smartsafe and preset failsafe. The "default" setting if you use the simple bind process is smartsafe, ie, throttle closes and the other controls hold their position. They do not go to neutral.

 

Extract from the AR620 manual:

[Cuban8]

Personally, I set failsafe to throttle idle (stop for leccy models) and then set aileron and elevator to give the very gentlest of left turns - essentially giving one a decending free flight model, which in failsafe it has become. Obviously, one can't guarantee when a model might go into failsafe or what attitude it'll be in at that instant.  However in IMHO  it does offer the best chance of preventing a distant fly-away should the radio link not be regained. 

I reckon a trainer at a decent circuit altitude will still cover a considerable distance with controls neutral so attempting to keep the model circling fairly nearby is worth a try. 

Edited September 15, 2023 by Cuban8

[Rich Griff]

Hi nick,

 

Although I do not have any spectrum kit, usefull info none the less.

 

Please may I ask, what does the Rx info sheet say about Rx being in close proximity to metal objects please ?

 

Probably similar to futaba 3008 Rx but interesting to know...

 

Thanks.

[Jon H]

I shoot for idle engine (i.c) and a small amount of up elevator. The idea being the up elevator will hopefully prevent the model diving at Vmax into someone or something and offer a more shallow dive. The sound of an engine, even at idle, might be enough to make any bystander look up and see the model coming towards them. 

 

Also, if the radio comes back again its going to be a safer job overall if i still have engine power to return the model either to the field, or at least in the general direction of the field. 

 

I actually had a situation some years ago when i pulled up into a steep climb and lost the radio on my flying test bench model. The engine went to idle but had just enough pull with my up elevator to allow a very graceful wing over. The model then settled into a shallow dive, slowly recovering as the speed increased. About 3 seconds from impact the engine returned to full throttle and i once again had full control. Upon landing i discovered a split fuel tank bung had filled the front fuselage bay with fuel and my steep climb poured this fuel all over the RX. It was a 35meg jobby, and i assume the fuel grounded the antenna somehow and i got control back after enough of it had evaporated.  i do not know for sure but it was the only logical explanation i had at the time.

[Nigel R]

1 hour ago, Rich Griff said:

what does the Rx info sheet say about Rx being in close proximity to metal objects please ?

 

https://www.horizonhobby.com/on/demandware.static/-/Sites-horizon-master/default/dw7382b6a5/Manuals/SPMAR620-Manual-EN.pdf

[GaryW]

I have a DX7S and with the failsafe set as standard/default setting when binding the RX... ALL my models , Electric, Glow & Diesel, when failsafe kicks in , it kills the Motors dead & none of my glow/diesel engines go to idle failsafe also completely cuts them dead the same as the throttle/engine cut function would   so if failsafe kicks in my models wont get very far and descend to the ground... As for my Quads/Drones both are Blade 350 QX3's ,, when failsafe kicks in they automatically return home, land and kill the motros

 

RX's Im using

AR500

AR6100e

AR6200

AR6210

AR6710

Edited September 15, 2023 by GaryWebb

[GrumpyGnome]

Does your rth functionality avoid houses, trees, pits, car park etc.?  Or just fly aitonymously in a straight line ?

[Rich Griff]

Thanks Nigel, will inwardly digest later, much appreciated, thanks

[GaryW]

1 hour ago, GrumpyGnome said:

Does your rth functionality avoid houses, trees, pits, car park etc.?  Or just fly aitonymously in a straight line ?

 

Straight line,, however both are always flown within the clubs field perimeter and never over pitt area or parked cars / car park area