Flybar

Is it possible to use a neo or evo just as a tail gyro on flybared helicopter? I'm considering a scale hiller HT2 which is a flybar full size helicopter.

Hi,

NEO and EVO can do that. Set up as usual, but set main rotor gain to zero—this will disable the main rotor stabilization, but you still have all the other advantages of a VBar, swash plate mixer, tail gyro, governor, even Rescue could be used.

Kind regards

Eddi

Born to fly ...
forced to work.

Thats great. thanks

Hi Eddi,

I have a question to this topic too.
What tuning parameters remain effective when turning the gain down to zero?
- Expo? I assume yes
- Style? Probably not
- Agility?
- Paddelsim? (I do not know if it is called this way in the english setup)
- Nick precompensation?
- Pitch pump?
- Optimizer?

I do ask because I am a bit confused. When I use the Neo with gain turned on (any value) and I tune down the agility then the maximum deflection of the servo is less than with a high agility value (work bench test). When I use the Neo with gain turned down to zero it seems that the agility value does not effect the deflection of the servo at all (again work bench test) the servo always moves to the maximum that was set with 8 degrees cyclic setup. Do I have to set the agility to the desired value and the perform a flight with the optimizer turned on before the agility tuning works for flybar helis? Currently I limit the agility by setting the 8 degrees to lower value e.g. 6 degrees.

Many thanks and best regards
Christian



1 mal bearbeitet. Zuletzt am 20.06.2024 22:08 von x-mess.

Hi,

I did some testing for you, on the bench:

- Expo? yes I notice a difference when holding the stick at 50 % elevator for example, and moving Expo from min ... max.
- Style? Probably not correct, it's part of the (here disabled) control loop.
- Agility? no even though I'd have thought, yes, because you might want or need some way to adjust the agility (like dual rate) per bank. A bit weird ... bug or feature?
- Paddelsim? can't seem to notice a difference ... wouldn't make sense after all, because why simulate the parcticular effects of a flybar with paddles (accentuated acceleration and deceleration) when it is actually there
- Nick precompensation? no it's also built into the flybar that it counters the force from the blades, at changes of angle of attack, would also be a double, or interfere with the mechanical control loop
- Pitch pump? yes I notice a difference when changing that
- Optimizer? I'm pretty sure that no, this is a ratio (remotely comparable to Bell/Hiller, on the flybar), for the stabilization control loop, defined by the overall gain

So I _guess_ the only way to set the maximum servo throw is by using the cyclic (8°) setting, to whatever maximum swash plate deflection and resulting agility you want. All other parameters have to be set mechanically (again), by length of flybar, size, shape and weight of paddles, and the options given by any number of mounting holes you have on the levers.

Kind regards

Eddi

Born to fly ...
forced to work.

Hi Eddi,

Many thanks for your testing and answer. The point is that I do not use zero gain with a flybar heli but with flybar less helis for different reasons:
- fun, I actually like the feeling of flying unstabilised especially when doing certain manoeuvres like slope landings and resting the heli on one skid
- testing of rotor heads and rotor blades
I used to set one bank to unstabilised but gave it up since there is a weird quick reaction of the heli when switching back to a stabilised bank. So now I use two different setups which I load to the Neo for the different scenarios.
I thought of going for a different FBL but the concept of VBar Control and Neo/Evo is currently the only offering me all possibilities I need: stabilised and unstabilised flying, horizontal mode for both, attitude trimming in horizontal with just a click on a button and all this with full setup possibilities via the transmitter - that is really great!
The only drawback for me is the missing of the bank related adjustment of the servo deflection when gain is at zero.
The ultimate thing would be the possibility to switch between unstabilised and stabilised mode during flight (I-discharge, fade-in of stabilisation…?) but I guess that this will be a too complex if not impossible matter. But a solution for tuning the servo deflection with zero gain could be something for a wish list … ;-)

Thanks again, the support from all of you is unbeatable! Keep it up!

Hi,

what could work—unstabilised!—(just bench-tested, and with one servo on one channel only):

. make macrocells on physical outputs CH1 (2, 3) a multiplexer cell each, selector bank switch, inputs yet unused macrocells 31, 32, 33 (CH1) 34, 35, 36 (CH2) and 37, 38, 39 (CH3).
. make cells 31 (2...9) a mixer cell with input CH1 (2, 3; this is the calculated servo output which would usually go directly to physical CH1 (2, 3)), and dial in a ratio in each (like, 50, 75, 100) -> this should act as dual rate

When switching between stabilized and unstabilized, the stabilized bank should just have the it's own output as an input (multiplexer, high, CH1 instead of a one of the macrocells created above). You wouldn't want to dial down the control loop with yet another factor.
This will still not help with the jump when the control loop kicks in, but it could help with the fully unstabilized setup.

Kind regards

Eddi

Born to fly ...
forced to work.



2 mal bearbeitet. Zuletzt am 21.06.2024 11:50 von Eddi E. aus G..

I will test this. Thank you!

Hi Eddi,
Just a feedback on my testing.
Your suggested solution with the macrocells works fine for the cyclic but it also affects the collective ways and complicates the things more.
So in my opinion the only sensible solutions could be:
1. Having the „agility“ factor an effect on the maximum servo deflection
2. Insert a way to limit the cyclic deflection in the transmitter before they are sent to the Neo/Evo
3. Insert macrocells on the signal entrance side in the Neo/Evo resp. create the roll and nick processor inputs as outputs for the macrocells.

Maybe one of these solutions could work for future updates?

Best regards
Christian

Hi Christian,

well, if it, or something of it, can be done without too much effort, why not?

But said effort has to be put into perspective
You can put it to use to bring forward progress, for the majority of customers, or you can put it o use for retro projects, for some inidividual users

—Eddi

Born to fly ...
forced to work.

I know and I fully understand, it is more meant as a reminder if it is possible in anyway with little effort so that it does not get forgotten… ;-)

I'm sure Rainer and Uli read this, too

Born to fly ...
forced to work.

Hi,

small update:

We will look into the agility setting, per bank, so there will be no need for macrocell tweaking, in the near future.

We will also look into the limiters: normally, there is the 8° setting (cyclic gain), which—if I understand correctly—can be used to limit the maximum cyclic output on a flybarred heli, and which is radius'd by the cyclic limiter ring. Then, there are the collective min/max settings, which are also hard limits, on a flybarred heli.

Kind regards

Eddi

Born to fly ...
forced to work.

Oh cool, that sounds great!

Yes, I can use the 8 degrees setup to limit the servo with gain turned to 0 but unfortunately only as a general setting not for different banks.
The collective curves and cyclic ring work as foreseen also with gain at zero.

I will stay tuned and also looking forward to the EVOmax ;-)

Best regards
Christian

We will allow the Agility to work with gain=0, so you can used a banked Throw. Its on the Next Update of NEO/EVO.
EVOmax is on the way, its just a matter of time.

so long ... Uli
http://www.vstabi.de

Tiptop!
You guys are superb, unfortunately I only have two thumbs to point up :-)