UH-1H Landing question

[drz400dude]

I can go in circles and then bring it to an upright hover when I'm a few feet off the ground, but I was trying to come straight in and bring it to a hover about 30-40 ft, and set it straight down (for say, setting it down in a tree clearing or something). I can get it to the hover position, and I'll start SLOWLY lowering the collective. But at somewhere around 20-30 ft (just high enough to explode on impact!) it loses lift completely and I smash into the ground. What am I doing wrong?

[Mt5_Roie]

Your hitting the vortex ring. Basically you are flying in your own downwash. So you have you keep a little speed either forward or to the side. Also make sure you don't raise the collective when this happens since it'll make it worst.

[Konrad Friedrich]

One of the nasty things that you have to deal with flying helicopters.

Apart from the other one million nasty things. :P

 

I can't remember who said it - but it's true: (Think it's from a movie)

I don't trust aircrafts which wings are moving faster than the rest of the damn thing. :joystick::D:P

Edited June 24, 2013 by Konrad Friedrich

[drz400dude]

Your hitting the vortex ring. Basically you are flying in your own downwash. So you have you keep a little speed either forward or to the side. Also make sure you don't raise the collective when this happens since it'll make it worst.

 

Yup, found this out the hard way:doh:

 

So there is no way to counteract this other than lateral movement?

[ARM505]

I can't comment on the real thing, and therefore logically not on how realistically this phenomenon is implemented in the DCS UH1, but let's just say once it starts happening, it's murderously fast in DCS.

 

I remember they toned the KA50's VRS down a bit after a patch or two when it was released. Might happen here too (think it may have received a mild toning down already actually)

[IonicRipper]

You can raise the collective as soon as you feel the very first signs of entering VRS. If you're fast enough, you can get away with it.

 

If not the only way is to pitch forward (or any direction for that matter) to exit the unstable air as soon as possible.

 

You can also land vertically but you have to keep your vertical velocity above -500 ft/min if I remember correctly.

[Yurgon]

You need to keep an eye firmly on the climb/descent gauge, as soon as you see the descent accelerating increase the collective. Its best if you can anticipate this.

 

Second that.

 

I'd like to throw in ETL - Effective Translational Lift. As you take off and accelerate, that's when the rotor blades start to work in "clean" air and become a lot more efficient. This effect happens around 20 to 30 kts and coincides with the shaking of the cabin.

 

As you slow down to come to a hover, the effect is reversed, the blades lose efficiency when the chopper goes below ca. 30 kts. I assume that this effect is part of the problem. As MadTommy said, you should try to anticipate it and adjust the collective accordingly. This does take a lot of practice, so don't worry if you don't get it right the first couple of times.

 

I've had this kind of crash a lot until I specifically picked a training mission that contains lots and lots and lots of combat landings: Sample: huey troop pickup/dropoff via radio command.

 

One more thing, just to make sure the effect is known: Hover In Ground Effect (IGE) vs. Hover Out of Ground Effect (OGE). IGE means (simplified) that the rotor downwash acts as some sort of cushion so that less blade pitch/less power is required to remain in hover. IGE occurs up to half the rotor diameter, so that's up to around 24ft.

 

If you come to a hover above that altitude, more collective is needed and thus the sudden drop in blade efficiency when going through ETL might be even more pronounced than it would be IGE.

 

But what I'm really trying to say here: Practice, practice, practice. :)

[jay43]

She's a bit unforgiving sometimes.

 

Try this to come into a hoover say at around 500ft try to approach your intended set down spot at 60knts slow and steady and lower collective as she starts to descend pull back on pitch 10 degrees nose up you may need to drop the collective more she will climb a little but ignore that don't try to correct that.

You are climbing because of forward momentum = lift, suddenly the nose will begin to lower on its own as you get close to hovering at 40 knts start to pull up on the collective gradual not sudden and steadily to stabilise your decent to between 0 - 500ft around the 250 mark is good if you can hit 0 first time than all is good hold it stabilise and then slowly lower the collective and maintain 250ft decent rate.

Word of caution though this landing approach is ok for landing at an airfield or farp if you are not in hurry or not being shot at not the best approach or landing style for fast and quick deployment or collection of troops YOU ARE A SITTING DUCK IN A HOVER LANDING as I discovered my pilot got killed then my co-pilot and then I was there as the gunner for the ride into the ground what the heck throw open the door if i'm going in i'm take some with me well I tried.

[drz400dude]

Thanks for the tips and info. :thumbup:

[spud3030]

I actually had to put negative expo ie made it more

sensitve around the lower end of its' travel, on my collective.

I found that when landing I couldn't or wouldn't move

the collective enough to stop the plummet.

I still land messy, but now I live !(mostly)

Great simulation btw

seeyas spud

[Erk104]

When in a high descent from near 0 air speed keep your rate of descent at about 300 feet/min it's painfully slow but it helps you avoid the Vortex Ring State.