Hydraulic failures

Mikoyan89 · December 21, 2011

Hi,

I've noticed that after losing hydraulic pressure,both in the main and in the common system,i can fly perfectly just using the hydraulic accumulators . It happened in the rookie terrorists mission,where i took some ground fire,and it happened even if i select the dual hydraulic failure in the mission editor.

Now i ask,is it normal that i can have hydraulic pressure from the accumulators and fly around for 20 min???For me, if i have a dual hyd failure i should have an handful of seconds to bring the chopper to the ground,thanks to the accumulators...they shouldn't have capacity for long time....

New TrackHYD_FAIL.trk

26-J39 · December 22, 2011

I not 100% certain but I would think the cyclic & collective are "hydraulic assisted" .. Meaning there is still direct linkage to the controls.

Similar to "power steering" in a car (no such thing really it's power assisted) where you still have the mechanical rack & pinion but is hydraulically assisted.

Devrim · December 22, 2011

As I know, as long as rotor spins, somehow you can control the heli. Of course it's very hard.

I think spinning rotor maintains amount of hydaulic pressure...

Mikoyan89 · December 22, 2011

I not 100% certain but I would think the cyclic & collective are "hydraulic assisted" .. Meaning there is still direct linkage to the controls.
Similar to "power steering" in a car (no such thing really it's power assisted) where you still have the mechanical rack & pinion but is hydraulically assisted.

Yes i think you're right,but for what i know it should be almost impossible to control the helicopter only with mechanical links,because of the aerodynamical forces acting on the rotors. Instead i was able to perform abrupt maneuvers,and gain high speeds,the only limitation was that the pedals could not move over half of their range. I think that if there are two independent hydraulic systems,it's because with no pressure the helicopter isn't flyable.

In addition i cannot understand why the accumulators still have pressure.

@Devrim Of course,it's because the hydraulic pumps are attached on the rotors' gearbox,if the rotors spin, so the pumps do the same.

But if i have zero pressure,i assume there's a leakage in the hydraulic fluid, so I shouldn't have the possibility of controlling the helicopter anymore.

Obviously all of what i said above,all my doubts, can be wrong,it's only my opinion ;)

Kite · December 22, 2011

hi mik. how are you? check this out..

manual page 4-3 . Cyclic is mechanical connected to rotor plate and hydraulic assisted.

"

The sketch in figure 4-3 shows the main rotor, cyclic and collectives, anti-torque pedals, and anti-torque rotor. Basically, the cyclic control is a mechanical linkage used to change the pitch of the main rotor blades. Pitch change is accomplished at a specific point in the plane of rotation to tilt the main rotor disc. Most current military helicopters now have hydraulic assistance in addition to the mechanical linkages. The collective changes the pitch of all the main rotor blades equally and simultaneously. The anti-torque pedals are used to adjust the pitch in the anti-torque rotor blades to compensate for main rotor torque. "

in the page of manuale can see also a drawing .

This should be the reason why also without hyd pressure you are able to fly.

Ciao

AlphaOneSix · December 22, 2011

The game has no way of knowing how strong you are, so it just assumes you have super-human strength and can move the controls without the hydraulic assistance. ;)

Kite · December 22, 2011

..or maybe "levers" can make you have superman strenght

AlphaOneSix · December 22, 2011

There aren't any levers built in that make it any easier to move the controls without hydraulics. If there were, you wouldn't need hydraulics.

Mikoyan89 · December 22, 2011

The game has no way of knowing how strong you are, so it just assumes you have super-human strength and can move the controls without the hydraulic assistance. ;)

thx,i was waiting for a reply from you :D...but still i don't understand why the hydraulic accumulators don't discharge :huh: ......anyway,i don't remember if there was this behaviour in BS1,in any case you can now fly happy even without hydraulics.it's a little strange but i don't complain,it's a minor lack in a wonderful flight sim :thumbup:

@Kite Grazie :D ,but that's a figure of another type of helicopters,it seems a "Bell" rotor.Anyway,see you soon on the virtual skies :pilotfly:

zoomie36 · December 22, 2011

Dual Hydraulic Failure

It would be impossible to control, this is why we have the magical device called "EJECTION".

AlphaOneSix · December 22, 2011

Well "impossible" is a strong word. It's definitely possible, although it is very unlikely that safe flight and landing could be accomplished.

In the Mi-8 flight manual, the emergency procedure for a dual hydraulics failure is "prepare crew for bailout".

Jona33 · December 22, 2011

Reassuring.

zoomie36 · December 22, 2011

Dual Hydraulics

The words read like this: "control is not possible with a dual hydraulic failure"....pretty well sums it up.....

Well "impossible" is a strong word. It's definitely possible, although it is very unlikely that safe flight and landing could be accomplished.

In the Mi-8 flight manual, the emergency procedure for a dual hydraulics failure is "prepare crew for bailout".

AlphaOneSix · December 22, 2011

Fair enough, I think the happy medium would be to say that controlled flight won't be possible (at least not anything approaching "safe") although it might be possible to physically move the controls, although it would be extremely difficult to move them, and you wouldn't be able to move them in a fast enough or coordinated manner that could be called "controlled flight".

But again, the only reason controlled flight is not possible is because the pilot is not strong enough. This is clearly not yet modeled in the game. That is, if your joystick moves, so do the flight controls. You can see this prior to starting the aircraft, moving the controls around moves the rotors.

It would probably be best to alter the game so that in the event of a dual hydraulic failure, your controls basically just jam in the position they were in when the failure occurred.

But if there is still pressure showing in the accumulators, then there is no reason for the controls to not work. I will give this a test and see what happens.

AlphaOneSix · December 22, 2011

I just did a test where both hydraulic systems failed. When they failed, the accumulators dropped to zero. If you're looking at the pressure gauges, the left-most gauge is the pressure in the main system (including its accumulator), followed by the common system, then the brake system accumulator, and finally, the brakes themselves. In the English cockpit, the pressure gauge labeled "ACC" is the accumulator for the wheel brakes, and is separate from the main and common accumulators.

Mikoyan89 · December 23, 2011

I just did a test where both hydraulic systems failed. When they failed, the accumulators dropped to zero. If you're looking at the pressure gauges, the left-most gauge is the pressure in the main system (including its accumulator), followed by the common system, then the brake system accumulator, and finally, the brakes themselves. In the English cockpit, the pressure gauge labeled "ACC" is the accumulator for the wheel brakes, and is separate from the main and common accumulators.

Ok,this clears my doubts.The manual says "Accumulators pressure" for that pressure gauge,it doesn't says that it's the brake accumulator gauge :doh:.Thanks for the test and for the explanation,i appreciated :thumbup:

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