Regarding Loss of Hydraulics

Hi all,

Question for devs, why is that when you lose hydraulic power in the cyclic control it starts to wander like crazy?

As far as my real experience tells me, you will not receive this type of movement in real life, although without hydraulics the movement force will be factored a lot in the Huey.

The only time I was flying without hydraulics was in the AS350 and I can assure you it is really stiff!!! You only have a brief accumulator force to bring the aircraft to safe speed, 80 KIAS or below, after that it will be brute force.

But, I've never experience this kind of behavior in real life.

What was the reason to implement that wandering cyclic?

Kind regards.

I wonder the same. I got my hydraulics shot out the other day while landing and after landing I watched the cyclic float slowly around.

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I've never lost my hydraulics, but I have turned them off purposely and flown without that and force trim....and it seemed to fly better on approaches??

Another time I did lost all of my trans fluid and the thing still made it 30nm to home.....always thought that was weird too.

...

What was the reason to implement that wandering cyclic?

I guess it's by design as an effort to simulate the un-simulateble (or whatever it can be called).

When you IRL get close to the ground and reduce speed it's very easy to get problems with the controls without hydraulics, struggling with them to keep your balance.

(the reason for running landings in rather high speed if possible)

Not really possible to simulate that kind of feeling in consumer controls.

Just me guessing.

Ooooooh....nice Holton. Thanks!

I have heard pilots talk about struggling with the controls... Much like losing power steering on your car. While at low speeds you may struggle to turn the wheel in a 1 dementional plane try doing in 3.

To horse a 7,500 pound helicopter around without hydro would take the work of two strong individuals. I think that is what is being simulated.

Yes you struggle to control the helicopter if you are in hover for example or at greater than 80 KIAS speed. You have to be precise with brute force in hover, and just have brute force >80 KIAS.

Usually in real life, you make a running landing, with some forward speed, ~10 KIAS, in order to maintain it manageable. Although I have hover the AS350 without a problem with hydraulics cut out for the purpose of training. The mess starts when you try to compensate every movement.

Ok, so it is clear that without hydraulics you have a rough time at the controls, but you can control the helicopter.

Now, in this simulation, you cannot control the helicopter. As a real world pilot, for me in this simulation, I would rather have a lag on the controls vs out of control! I my humble opinion it would be better simulated the lag, because in real life, its a bit about lag because you don't have the force to instantly manage the cyclic/rotor disk.

But again, you have always control on the helicopter.

I read someone saying that you are "simulate the un-simulateble", well, if you have FFB joystick it can be simulated if devs what to get a more deep level, for those who do not have FFB joystick, a simple lag in joystick vs in game cyclic would simulate best what it is lacking of hydraulics in real life.

Meaning, as long as you are in 80~20 KIAS of range, you have control over the flight. When you pass the 80 KIAS mark, you will struggle a lot to maintain force on the cyclic, and you will end up not having resistance enough. Another problem is hovering because you have lag in your cyclic (you simply don't have the force to react quickly enough to changes) and that could be simulated with lag in controls.

Please, for the devs, remove the cyclic wandering because it is not realistic at all and there is other manners of simulating it.

Thank you.

PS: For those with curiosity, in the AS365 N1, if I lose both hydraulic systems, I cannot control the helicopter, you lose all the control and it is impossible to move the cyclic or collective. Thank engineers for dual hyd system! :)

I think the power steering thing is a bad analogy. Once you get a vehicle with no power steering moving it drives perfectly fine.

It's a lazy way of implementing a stiff cyclic simulation. It's all just a huge amount of lag from your joystick. Annoying.

Yes you struggle to control the helicopter if you are in hover for example or at greater than 80 KIAS speed. You have to be precise with brute force in hover, and just have brute force >80 KIAS.

 

Usually in real life, you make a running landing, with some forward speed, ~10 KIAS, in order to maintain it manageable. Although I have hover the AS350 without a problem with hydraulics cut out for the purpose of training. The mess starts when you try to compensate every movement.

 

Ok, so it is clear that without hydraulics you have a rough time at the controls, but you can control the helicopter.

 

Now, in this simulation, you cannot control the helicopter. As a real world pilot, for me in this simulation, I would rather have a lag on the controls vs out of control! I my humble opinion it would be better simulated the lag, because in real life, its a bit about lag because you don't have the force to instantly manage the cyclic/rotor disk.

 

But again, you have always control on the helicopter.

 

I read someone saying that you are "simulate the un-simulateble", well, if you have FFB joystick it can be simulated if devs what to get a more deep level, for those who do not have FFB joystick, a simple lag in joystick vs in game cyclic would simulate best what it is lacking of hydraulics in real life.

 

Meaning, as long as you are in 80~20 KIAS of range, you have control over the flight. When you pass the 80 KIAS mark, you will struggle a lot to maintain force on the cyclic, and you will end up not having resistance enough. Another problem is hovering because you have lag in your cyclic (you simply don't have the force to react quickly enough to changes) and that could be simulated with lag in controls.

 

Please, for the devs, remove the cyclic wandering because it is not realistic at all and there is other manners of simulating it.

 

Thank you.

 

PS: For those with curiosity, in the AS365 N1, if I lose both hydraulic systems, I cannot control the helicopter, you lose all the control and it is impossible to move the cyclic or collective. Thank engineers for dual hyd system! :)

I like this approach.

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I have only flown a jetranger without hydraulics, but the systems are very similar only smaller. I now fly the 412 which is literally uncontrollable without hydraulics (there are 2 systems, and failure of one requires immediate landing lest the other fail).

In the jetranger, the main issue was interaction between the cyclic and collective. Meaning, when you move the collective, you feel the cyclic get pushed to the side and have to physically muscle it to maintain attitude and control The opposite also applied. Therefore, the procedure was to get low and very gradually slow down to a run on landing just above TL, keeping the skids straight (the pedals are not hydraulic in the jetranger). The idea is to avoid large control inputs.

Although you can't simulate the interaction without FFB, I think they are trying to simulate the interaction between the controls. So, the key is to avoid large inputs. Slowing through TL requires a large collective input, which has a very adverse effect on cyclic stability. Try the procedure above, small inputs for a slow deceleration in ground effect, run on just above TL.

I have only flown a jetranger without hydraulics, but the systems are very similar only smaller. I now fly the 412 which is literally uncontrollable without hydraulics (there are 2 systems, and failure of one requires immediate landing lest the other fail).

 

In the jetranger, the main issue was interaction between the cyclic and collective. Meaning, when you move the collective, you feel the cyclic get pushed to the side and have to physically muscle it to maintain attitude and control The opposite also applied. Therefore, the procedure was to get low and very gradually slow down to a run on landing just above TL, keeping the skids straight (the pedals are not hydraulic in the jetranger). The idea is to avoid large control inputs.

 

Although you can't simulate the interaction without FFB, I think they are trying to simulate the interaction between the controls. So, the key is to avoid large inputs. Slowing through TL requires a large collective input, which has a very adverse effect on cyclic stability. Try the procedure above, small inputs for a slow deceleration in ground effect, run on just above TL.

I know, I am a real pilot too. :) I have those effects in the 350 also when training. The 412 it's like the 365, if you lose one hydraulic you have to land as soon as possible.

But even so they are trying to simulate the interaction, for me the way it is now it's not the best way to be simulated. In the sim you can easily simulate the interaction between the cyclic and the collective, plus the pedals if they are hydraulic assisted (which I guess they are not in the Huey's case).

The wobbling of the cyclic is just random, had it gets my nerves. :P Because if you try to apply what you learn in real life, it does not matter, because you will end up with its random effect, you have to apply huge amount of cyclic just to deal with the randomness of the wobbling. I guess there is a bit of lag, but the wandering cyclic its just too much. It's like you have a broken linkage in the rotor mast, that would be a good simulation if it was the case.

IRL you have thought time to control the helicopter but you have control, like you said, small inputs and not trying to correct each and every move. So I guess if they add lag to cyclic and collective, plus the interaction between those, it would be by far a more realistic approach to what a loss of hydraulic system would be.

I know, I am a real pilot too. :) I have those effects in the 350 also when training. The 412 it's like the 365, if you lose one hydraulic you have to land as soon as possible.

 

But even so they are trying to simulate the interaction, for me the way it is now it's not the best way to be simulated. In the sim you can easily simulate the interaction between the cyclic and the collective, plus the pedals if they are hydraulic assisted (which I guess they are not in the Huey's case).

 

The wobbling of the cyclic is just random, had it gets my nerves. :P Because if you try to apply what you learn in real life, it does not matter, because you will end up with its random effect, you have to apply huge amount of cyclic just to deal with the randomness of the wobbling. I guess there is a bit of lag, but the wandering cyclic its just too much. It's like you have a broken linkage in the rotor mast, that would be a good simulation if it was the case.

 

IRL you have thought time to control the helicopter but you have control, like you said, small inputs and not trying to correct each and every move. So I guess if they add lag to cyclic and collective, plus the interaction between those, it would be by far a more realistic approach to what a loss of hydraulic system would be.

Yeah, agreed. It's almost like flying the 412 autopilots off (never flown a 350, so I can't compare to that). Lots of lag and overly sloppy.

Thank you very much for your perseverance!:thumbup: You are absolutely right! We have even deeper studied the "SERVO HARDOVER" failure and there is no "wobbling of the cyclic" (as we thought earlier). In general, we will remodel the course of such a failure.

A "conventional" hydraulic system failure (one of two Huraulic Failure in our model), we have already done - since the release of the DCS: UH-1H (modeled as a delay cyclic control reaction), I think you have already tried it))

Good News! Thanx guys.

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Absolutely amazing guys! Thank you for listening people that can offer something valuable (experience) to your already great simulation.

Kind regards and continue the great work.

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You are absolutely right! ... we will remodel the course of such a failure.

Apologies if I misinterpreted, but was there a potential plan (back in 2017) to revisit and enhance the simulation of hydraulic failure?

(Some very articulate and comprehensive comments were made by customers to suggest a better simulation is possible than the current 'random cyclic wandering' model)

Is there anything the team can now share with us regarding whether such work made it on to a todo list and has or will receive some attention?

Many thanks.

Thanks for bumping this. I just watched a video with a pilot who stated he had to do simulated hydraulic failure training in his huey, and it's quite difficult to fly because it takes both the pilot and co pilot wrestling the cyclic to get it to move enough for a turn. So imo a simple solution would be to drop pitch and roll saturation 70% to simulate hydraulic failure. But there's probably better ways.

The current sim hydraulic failure is wrong.