Autorotation

[sorcer3r]

 

 

Already one of my not so perfect first day autorotations gives me the impression, that we have here a very good flight model in dcs:

 

 

 

 

(real)

 

:thumbup:

[Mt5_Roie]

Nice....I survived my first auto rotation too...its the second and third that were the killers.

[sorcer3r]

the first one (huey muscle memory ;) ) killed me...

[tkid]

what is auto rotation?

[Thrud]

[ame]

[/ame]

[Mt5_Roie]

It's when your engine fails. In a plane you glide her down, in a helicopter you auto-rotate. Essentially you use the blades as a lifting body and try to minimize the impact on the ground. If you want to try it in the Gazelle, just pull the fuel lever back when your up in the air...and try to land safely.

 

what is auto rotation?

[Flamin_Squirrel]

I can do a safe auto rotation pretty much every time now (no damage). I'm yet to succeed in making it a soft landing however!

[Yurgon]

Can you guys share some tips regarding autorotation?

 

I can do it in the Huey and Ka-50 just fine, but in the Gazelle I always crash into the ground.

 

The manual doesn't seem to cover this topic, so what speed do you aim for and at which alt do you start applying collective?

 

Also, when I cut the fuel lever, rotor RPM goes down quite a bit even when I drop the collective to bottom right away. Is there a procedure to keep RPM at 100% right from the beginning?

[Deezle]

Yeah I'm having no luck either, I cannot keep the rotor RPM up like you need to. As I understand it, the transmission power turbine in the Gazelle is physically locked to the engine turbine once up and running, so it doesn't seem like the transmission can rotate freely from the engine if the engine dies, therefore the dying engine takes the rotor RPMs down with it (not sure if it works like that IRL or if the transmission is supposed to decouple from the engine in an emergency).

 

 

 

Typically helicopter transmissions are powered by a turbine in the exhaust of the engine that is not physically coupled to the engine, sort of like how a turbocharger is powered, for those that might not know.

Edited May 4, 2016 by Deezle

[gospadin]

Yeah I'm having no luck either, I cannot keep the rotor RPM up like you need to. As I understand it, the transmission power turbine in the Gazelle is physically locked to the engine turbine once up and running, so it doesn't seem like the transmission can rotate freely from the engine if the engine dies, therefore the dying engine takes the rotor RPMs down with it (not sure if it works like that IRL or if the transmission is supposed to decouple from the engine in an emergency).

 

 

 

Typically helicopter transmissions are powered by a turbine in the exhaust of the engine that is not physically coupled to the engine, sort of like how a turbocharger is powered, for those that might not know.

 

If that's the case, there must be some kind of rotor clutch we can disengage, though shouldn't it auto-disengage below 29,000 RPM?

[Jansgi]

I believe it uses a sprag clutch which allows the rotor to spin faster than the engine in an engine failure event. Even if the clutch is engaged the rotor can spin freely regardless of the clutch and engine rpm.

Edited May 4, 2016 by Jansgi

[Deezle]

I believe it uses a sprag clutch which allows the rotor to spin faster than the engine in an engine failure event. Even if the clutch is engaged the rotor can spin freely regardless of the clutch and engine rpm.

Makes sense, the in-game version does not appear to behave like this currently.

[Jansgi]

Makes sense, the in-game version does not appear to behave like this currently.

 

Well if you lose your engine the rotor rpm will drop for sure because the engine is not driving the rotor anymore and drag against the blades. I tested and was able to keep up the rotor rpm but then again I knew when my engine was gonna "fail" so I was able to react quickly to it. Key is reacting quickly and lowering your collective.

[MAVE94]

Also, when I cut the fuel lever, rotor RPM goes down quite a bit even when I drop the collective to bottom right away. Is there a procedure to keep RPM at 100% right from the beginning?

 

 

When engine failure occurs in flight, the rotor RPM will decrease rapidly in the beginning. The best thing to do to increase the RPM is to flare. So, collective down, counteract with left rudder, flare the helicopter to get RPM. When that is done, you push forward to increase speed. After that you can level out in a good attitude and pick you spot for landing. :)

[Kelevra9987]

When engine failure occurs in flight, the rotor RPM will decrease rapidly in the beginning. The best thing to do to increase the RPM is to flare. So, collective down, counteract with left rudder, flare the helicopter to get RPM. When that is done, you push forward to increase speed. After that you can level out in a good attitude and pick you spot for landing. :)

 

Thank you for that. Will try it later.

Since now I ownly flared prior to touchdown and raised the Collective. Didn't work out that well :music_whistling:

 

+1

[MAVE94]

Thank you for that. Will try it later.

Since now I ownly flared prior to touchdown and raised the Collective. Didn't work out that well :music_whistling:

 

+1

 

Try this:

 

When about 100ft AGL, flare the helicopter without raising the collective, that will decrease the speed and the rate of descent. When you have about 30-20 knots airspeed, level out and slowly raise the collective until you touch the ground. When sliding forward on the ground, keep the collective up until it has stopped.

 

Autorotations is hard to get the hand of and it is varying with different helicopters. But when you get the hang of it, you can practically do anything to get to your landingspot, you can go sideways, backwards, 360 turn etc. Just keep the rotor RPM in range and your landingspot in sight. :)

[Deezle]

Well if you lose your engine the rotor rpm will drop for sure because the engine is not driving the rotor anymore and drag against the blades. I tested and was able to keep up the rotor rpm but then again I knew when my engine was gonna "fail" so I was able to react quickly to it. Key is reacting quickly and lowering your collective.

I know how to autorotate.

 

The Gazelle behaves oddly. Upon further testing, the rotor RPM isn't locked to the dead engine. If your descent is fairly vertical you can keep your rotor RPM up, forward movement dramatically slows the rotor RPM. It doesn't behave anything like the Huey.

[Olmba]

Nice!

 

Far better than my regular landing attempts..:helpsmilie::megalol:

[kobac]

The clutch is centrifugal and there is a autorotation bearing (similar to old bicycles) which separates engine from the transmission in the event of failure of the engine.

[exil]

Try 180° Auto's...your RPM is dying like nothing. It doesn't matter if left or right turns. Depending on the direction your rotorsystem is turning RPM needs either to drop or to raise. But it drops in both turning directions to the point the gaz becomes uncontrolable. Certainly not realistic.

[Yurgon]

When engine failure occurs in flight, the rotor RPM will decrease rapidly in the beginning. The best thing to do to increase the RPM is to flare. So, collective down, counteract with left rudder, flare the helicopter to get RPM. When that is done, you push forward to increase speed. After that you can level out in a good attitude and pick you spot for landing. :)

 

Awesome, that was absolutely spot-on! Managed 5 autorotations in a row now. Okay, I blacked out twice and I'm sure the skids are a little bent. But since I crashed into a road sign a little later on, I guess the bent skids don't really matter. ;)

 

Anyway, great advice, thanks! :thumbup:

[MAVE94]

Awesome, that was absolutely spot-on! Managed 5 autorotations in a row now. Okay, I blacked out twice and I'm sure the skids are a little bent. But since I crashed into a road sign a little later on, I guess the bent skids don't really matter. ;)

 

Anyway, great advice, thanks! :thumbup:

 

 

Well you know what they say, any landing you can walk away from is a good one ;)

[j0nx]

I tried it by rolling the fuel lever and the bird just dropped out of the sky at 150kph and slammed into the ground even with full collective flare near the ground. I would expect some continual forward motion since the rotors are basically wings but it drops quickly out of the sky and the collective was unresponsive. I'm sure it was due to something like rotor RPM etc but this helo just does not react like any other helo I've flown in any sim. It reacts more like one of those unrealistic addons from FSX that just drop like a stone to the ground when collective is dropped. What speed do you have to maintain to maintain rotor RPM for an auto in this bird? I would think that 125-150kph would be about right but maybe not? I just can't help but feel that something is just not right with this FM.

[Ramsay]

What speed do you have to maintain to maintain rotor RPM for an auto in this bird? I would think that 125-150kph would be about right but maybe not?

120-140 km/h for autorotations in the SA-341G but a loaded SA-342M is a very different beast.

[j0nx]

I had already edited the loadout to remove everything and add 35% fuel so I'm pretty sure I was within the airspeed and angle that I needed to do this maneuver. The ship just dropped like a rock and carried no lift at all when the fuel and collective were dumped. It reminded me exactly of what those cheap FSX helo addons do when the collective is dumped which is totally unrealistic. I'll keep trying and see what happens.