Landing Hover, Then Crash

[LtMacGowan]

Every time I try and land the Mi-8 I approach the runway, I lower power and pull up to kill airspeed, and when i've got no airspeed, and im dropping at like 2.5m per second in a hover, the entire helicopter starts to shake and i just drop out of the sky, even if i increase power it doesn't help i just fall like a rock

 

is this "ring vortex" or whatever its called?

 

what am I doing wrong? and how should I land properly.

[Cibit]

Started this thread to help.

http://forums.eagle.ru/showthread.php?t=155017

Check out the video and try to suss out the procedure.

Remember even though your reducing power to slow down you have to raise collective too it a juggle but practice makes perfect:)

[gospadin]

General thoughts:

 

1. Don't change the collective too quickly, or you'll overcome the engine governors, which can cause your generators to fail. 1 degree of pitch change per second is close to the limit.

 

2. As you're slowing down, watch your airspeed very closely. As you approach 50km/h, you need to be already raising collective and applying right pedal, to configure the aircraft for a stable hover. Ideally you want to enter hover with a vertical velocity of 0.

 

3. If there's any wind, you need to adjust for it. Always land and takeoff into the wind. This will reduce the effective ground speed of your hover transition.

 

4. If you *do* trigger VRS (vortex ring state) immediately push the cyclic forward (assuming no obstacle there) to gain some airspeed and hopefully escape your own prop wash and VRS. You should have no problem recovering from VRS above 175m/500' AGL.

 

When I am landing, I try to maintain a nice stable but low descent rate, maybe 1m/s, such that my transition into hover won't trigger VRS. This makes landings relatively easy. Just like an airplane, you should be lining up your landing from pretty far away instead of "forcing it" at the last second.

[jimcarrel]

I know, I know, it's fun isn't it?

[LtMacGowan]

I tried again and ended up with the same results

I've included a track. Please can some one play it and tell me what I'm doing wrong. I mean i cant play the damned campaign and such if i am incapable of landing.

 

https://www.dropbox.com/s/rtcpb051fuimcda/rvs.trk?dl=0

[cichlidfan]

So let me get this straight.

 

The helicopter is supposed to be in flyable condition after I land it?!! Hmmmm.

 

I am going to have to give this new approach a lot of thought. :D

[gospadin]

I tried again and ended up with the same results

I've included a track. Please can some one play it and tell me what I'm doing wrong. I mean i cant play the damned campaign and such if i am incapable of landing.

 

https://www.dropbox.com/s/rtcpb051fuimcda/rvs.trk?dl=0

 

Okay, I watched the track.

 

The thing that's confusing for most people is that centered controls (your stick and rudder are centered as you apply collective at takeoff) are NOT how you want them at takeoff.

 

On the Mi-8, you want to slowly hover in place, so you'll need to begin with a bit of back and right cyclic.

 

Then, as you are slowly raising collective, continue to apply more and more right pedal to keep the nose of the helicopter pointing in the same direction.

 

Eventually, you'll be hovering in ground effect, a few feet off the ground, with your stick maybe 10% right and 15% back, and your pedals perhaps 25% to the right. (These numbers all change based on how heavily loaded your Mi-8 is)

 

Remember, make small adjustments.

 

 

Now, after you transition to forward flight, and there's enough wind pushing on the tail of the aircraft (above 100km/h or so), you can then reduce the pedal input as the helicoptor will mostly fly straight. You'll still likely need a bit of right cyclic input though to fly straight, since the engine and rotors are canted a few degrees. This input will change with your forward airspeed. 100km/h is about the point of lowest control input, as you go faster, you'll need more input to stay straight.

 

--gos

[Cibit]

I added another video see how your controls should be at various stages