Autorotation via TX ??

[Ben Kenobi]

How feasable is it to trigger rate changes using the momentary switch on the TX for auto rotation, i.e. pull the switch, throttle killed, maximum rates thrown at cyclic and collective, set maximum pos and neg pitch curve, set full negative pitch then release last minute to throw the pitch positive based on the throttle stick position.

In 'Normal' flight mode I set for -2 to +12, in idle up 1 I set for -5 to +12 and increase head speed, in idle up 2 I set -12 and +12. So clearly in modes 1 and 2 I wouldn't be able to maintain maximum headspeed during the 'fall'

Pulling the momentary would be much quicker than mucking about with many switches leaving right thumb free to steer as best possible while maintaining head speed until the last possible moment to flare out.

Just an idea.

[FailureToFly]

Few points.

You generally don't use full neg pitch for a whole auto (you also do not want to hold a set neg pitch) and you want to be able to gradually feed in the positive collective as you run out of HS; you don't want it to 'snap' to a positive pitch position.

You also want to do your auto in IU 2 (or your mode 2) so you can use as much neg pitch as required. I personally would advise you to get used to flying in IU 2 pitch curves (apply them to your other modes).

You basically just want to fly the heli using sticks as you regularly do during a move. There is no trick to autos as it's just another skill and you need finesse to accomplish it.

Differing ground speeds and wind conditions will dictate exactly how much of the controls you require. There is no setting to make it reliably happen via the TX.

[Ben Kenobi]

Partly answered what I was thinking, unless I'm in idle up 2 I won't have sufficient negative pitch. If I hit my mode 2 the motor speed is increased to between 100% and 85%, I absolutely don't want this on a tail rotor failure so I set my momentary to kill the throttle and set mode 2 simultaneously, I don't currently force the pitch one way or another.

I've been practicing auto rotation in the sim but only manage to land 2 out of three, depends on my detection of the failure coinciding with an altitude where any kind of attitude correction is possible and wind speed etc. I've set the simulator to trigger tail rotor and motor failure, tail rotor failure is easy to detect, motor failure not so easy I lose a lot of head speed before I figure it, it takes a lot of 'altitude' to get sufficient head speed back since the head has effectively stalled and sometimes I just don't have enough altitude - I was wondering whether to go past even the boundaries I have set - I've enough travel to get plus or minus 25 degrees if need be.

I'm just trying to figure the best way to set my TX and flight modes up to handle auto rotation requirements.

[ArchmageAU]

Originally Posted by Ben Kenobi

How feasable is it to trigger rate changes using the momentary switch on the TX for auto rotation, i.e. pull the switch, throttle killed, maximum rates thrown at cyclic and collective, set maximum pos and neg pitch curve, set full negative pitch then release last minute to throw the pitch positive based on the throttle stick position.

In 'Normal' flight mode I set for -2 to +12, in idle up 1 I set for -5 to +12 and increase head speed, in idle up 2 I set -12 and +12. So clearly in modes 1 and 2 I wouldn't be able to maintain maximum headspeed during the 'fall'

Pulling the momentary would be much quicker than mucking about with many switches leaving right thumb free to steer as best possible while maintaining head speed until the last possible moment to flare out.

Just an idea.

From memory (and previous posts), you are using a Taranis with OpenTX. This is VERY possible (and surprisingly easy).

In short, if you assign your hold switch to a custom switch, you can change anything (sticks, mixes, etc..) when the hold custom switch is activated. Sticks should control your cyclic sensitivities. Mixes should control your pitch curves (throttle curves and almost everything else ).

One of the things I love about the Taranis is that you don't have to program around anything. You tell it exactly what you want it to do and it does it. (However it's easy to tie yourself in knots, you don't FULLY understand it).

Post your .eepe and I will adjust, re-post and tell you where the adjustments are to increase cyclic rates on TH. Will only take me a few minutes. (Ideally in a new thread in the OpenTX Radios forum).

[Ben Kenobi]

I do indeed operate a Taranis, I use X8R receivers on all my birds. This is the best decision I ever made, I have yet to find anything that I can't do with it and as you say there's no need to 'work around' things, it does exactly what you tell it to, I'd recommend it to anyone.

I am now almost totally open source - am even considering replacing the 3GX with a Pixhawk / Arduino - but I'll need to learn a lot more about helicopter setup and flying before I do that.

I have started a thread in the location suggested.

To aid in reading the eepe I've put some descriptive text on the post.

I've tried to replicate the process used on the 'real' thing - bit like a cockpit drill, maintaining head 'energy' is number one priority, drop the collective, kick the nose into the wind if possible avoid using any cyclic if at all possible beyond keeping it coming down level and avoiding 'obstacles'.

I wonder if it would be possible to use some sort of 'governor' to control negative pitch and help maintain rotor speed and 'keep it in the green' whilst in autorotation ? is there anything available that can measure rotor speed that doesn't rely on the motor ?? - I may be able to add rotor speed to my TX / RX telemetry ...

[Aryemis]

You can tell the headspeed from the noise your heli makes (the noise on a RC heli is mainly from the drivetrain in an autorotation) fairly easily with some practice.

You could probably get an optical tachometer or such but you'd be better off learning from the noise your heli makes really.

[Ben Kenobi]

I prefer to practice in a way that doesn't involve a carrier bag, two hundred parts and a rebuild. I still crash one out of three in the sim, it depends upon the heli's altitude and attitude at the time of failure, some failures i.e rotor blade there is no recovery from.

I'm not prepared to try this with a real bird just for the sake of trying until I'm damn sure I can land it, if I get a failure fair enough but otherwise this isn't something that I have any intention of 'practicing' for real until I'm reasonably confident that it won't end in a carrier bag, the simulator is as far as I go.

[ArchmageAU]

Originally Posted by Ben Kenobi

I prefer to practice in a way that doesn't involve a carrier bag, two hundred parts and a rebuild. I still crash one out of three in the sim, it depends upon the heli's altitude and attitude at the time of failure, some failures i.e rotor blade there is no recovery from.

I'm not prepared to try this with a real bird just for the sake of trying until I'm damn sure I can land it, if I get a failure fair enough but otherwise this isn't something that I have any intention of 'practicing' for real until I'm reasonably confident that it won't end in a carrier bag, the simulator is as far as I go.

Get this to 19 out of 20 success rate in sim (with increased blade or drive train resistance), then you should be good to go.

If you configure autorotation bailout in your ESC (this also helps).

There are plenty of head speed telemetry systems that use optical or inductance to read the actual head speed.

Problem I see with telemery based is that rotor angle plays a big role in correct collective to maintain head speed (and upright is different to inverted too).

Best auto practice I have had is with clicky and that was with the attitude of no bailout.

I really need to do more auto practice IRL. Have not done enough recently.

[Ben Kenobi]

I'm with ya, I probably do this daily, I have realflight set to trigger various faults at random times, then fly expecting failure which I don't think is a bad thing but it does make you a tad overcautious - i.e. you don't put it at an altitude or attitude that would be hard to recover.

I'd be happy if I could get the head speed telemetry back on my TX, I could set an audio warning based on it being too low. At a guess you need around 1700 rpm for a decent flare out (with my copters flying weight) - but that's all based on simulator work , if the wind is gusty or you can't get the nose into the wind because of a tail rotor failure and you're spinning all bets are off.