Why is it So hard to land the MI 8

Zuhkov

 

Probaly true, but I think whats is making this last year so frustrating is that, I have yet to see thru numerous videos or been told a kinda guide of what to do when( I know the helos its not a step by step thing). I get the vibration, watching the VSI, looking out ahead and such. Like for example most I have scoured the forums and seen " Keep a steady descent at 2-3ms don't go over 5, down collective and eas back the nose, then come to a hover over your spot and set here down" almost everything I have read and video I have seen. this happens. But none explain the how.(As to what you are or need to be doing) I have done all that above but either vrs or spin left right before or after the shakes. It never goes into a Hover.

 

and kind of same picking up into a hover. I followed chucks guides, watched videos, matched the controls and trimmed and as soon as I slowly pick up like everything says. I spin out or I get up and I am cockeyed. never flat and level. So once again something is missing there. And I know practice practice and more but after over 100hrs it should have clicked.

Do you fly other helicopters beside the Hip?

It seems like you might struggle with general rotary aerodynamics not related to the Mi-8 itself.

In general I would say undershooting a bit is not that bad, just slow it down without loosing your landing spot out of sight and then sneak in the last bit in hover taxi.

For the setup of controls, i guess you can make anything work if you try hard enough.

I am using a Logitech G940 and my configs look like this on Mi-8 (and Huey):

DZ 0

X 100

Y 100

Curve 0

The only chopper where I am using curves is the Gazelle.

The best thing would be to meet on e.g. Aerobatics Online Server and do some circuits together.

As a last note, even after lots of hours I manage to screw up occasionally and VRS it in to the ground... :music_whistling::doh:

Seems that in DCS Vortex ring state or settling with power is modelled to be quite unforgiving of steep approaches at low airspeeds. There's some great advice throughout this thread of how to minimise the risk, particularly during approach to land where it is most dangerous.

IRL in can be quite difficult to demonstrate VRS on anything but a flat calm day, I've flown quite a few different helicopters and all have their own vices, but VRS is predictable, it always involves low to nil airspeed, a moderate to high rate of descent, and crucially a high power demand (ie pulling up on the collective). It's no surprise that these conditions occur in a rushed approach to the hover, particularly if you're not landing into wind.

My first 2 years of flying were in the role of front seat air observer/gunner. We were trained to fly the aircraft to a safe landing in the case of pilot incapacitation. This always involved recovering the aircraft from an unusual attitude (wings level, bar to bar on the artificial horizon), securing the pilot off the controls with harness lock, and carrying out a sight picture approach in a safe location.

A sight picture approach is very similar to landing a light fixed wing. pick a large flat landing field, free from obstructions with a shallow approach into wind. Pick a spot one third distance into the landing area. Start the approach from 500 feet and 1 mile at 60 knots. Keep the landing spot in the same place on the windscreen as you approach (sight picture approach).

As you start the approach lower the collective gently a small amount and maintain the picture with a little aft cyclic pressure, you should be at around 50kts at 400 feet above the ground, 40knots at 300 feet, 30 knots at 200 feet etc.

At first resist the urge to come to a hover, no one is marking you for prettiness here, once you're at less than around 30 knots the airspeed indicator becomes unreliable so maintain your focus on that sight picture, keep looking at and ahead of the chosen landing spot, use peripheral vision to judge speed, as you arrive at the landing site you keep looking ahead past the landing spot, keep the aircraft straight with pedals, gently pull collective smoothly to arrest the rate of descent but not stop it and don't attempt to come to the hover by pulling back on the cyclic.

As the rotor loses translational lift the aircraft will vibrate and become a little unstable in roll, at this point you may actually have to push the cyclic forward a little to keep moving ahead at a jogging pace. You may also feel the ground effect build up so you may need to lower the collective gently to push through it, as you make contact with the ground you should be looking well ahead, keeping it straight with pedals and cyclic, and then gently lowering the collective to stick the aircraft to the ground and slow to a full stop, do not dump the collective as this may result in digging in. even touching down at 20 kts will only see a run on of 50 yards or so.

Once you've done 20 or 30 of these move on to take off to the low hover and then land again, we had hover squares marked on the airfield that measured 40 yards by 40 yards. The object of the hour long lesson was to first keep it in the square after take of and then land it in the square from the hover, by the end of the lesson you should be quite happy to take off to the hover from the centre and land in the centre.

Main point of all this is don't rush the approach and landing, keep your brain ahead of the aircraft so you're never catching up with it.

@Backdraft.

Ummm... maybe let's make sure the most obvious things are not causing issues. Game flight model or simulation? Controllers set up accordingly (i.e. "simulation" controls while flying the chopper in smulation mode)? "Control helper" in special options turned off? Also, I personally wouldn't tinker with rudder trimmer on if you don't understand how it works in DCS (hint: the same way as cyclic stick trimmer in "center position" mode).

Thanks Oldahpilot, that post was chock-a-block with useful info! Always interesting to hear how the pros do it :thumbup:

Go to options and click the flight helper box... it helped me get a feel for the mi-8 and now fly with out the pilot helper on

The biggest factors for why it "feels" more difficult in DCS imho are below:

1. Cyclic works very different irl from what the majority has for sims and this makes big difference

2. Collective - IRL the collective is much longer lever which gives it much more precision from our throttles.

3. Last but not least for sure, bud feel. IRL you can "sense" the rate of descent/climb/speed and general attitude and therefore react to it much faster and intuitively then in sim, especially 2d monitor. VR helps a lot for helos, still no bud feel tho.

Most of the time we simmers trigger VRS because we lower the collective too much, as we don't have precise enough hardware control. At the same time we don't have our eyes on vvi 100% of the time as we have to cross check everywhere with our single pair of eyes. While in real live your but feel is sensing non stop, so you will feel the descent rate while your eyes are focused outside and intuitively check the vvi and adjust collective if needed.

We can get used to do it well enough in the sim with enough practice of course but it is just a little more challenging I believe.

I am no pilot irl, but I have many hours in CAR/Motorcycle racing sim games and IRL and it suffers from absolutely the same issues because of the lack of real hardware and feel of the motion and environment.

The biggest factors for why it "feels" more difficult in DCS imho are below:

 

1. Cyclic works very different irl from what the majority has for sims and this makes big difference

 

2. Collective - IRL the collective is much longer lever which gives it much more precision from our throttles.

 

3. Last but not least for sure, bud feel. IRL you can "sense" the rate of descent/climb/speed and general attitude and therefore react to it much faster and intuitively then in sim, especially 2d monitor. VR helps a lot for helos, still no bud feel tho.

Those are certainly limitations of a desktop sim, but I doubt they're likely to be the biggest issue here. I'd bet Backdraft's approach are simply too steep.

Most of the time we simmers trigger VRS because we lower the collective too much, as we don't have precise enough hardware control. At the same time we don't have our eyes on vvi 100% of the time as we have to cross check everywhere with our single pair of eyes. While in real live your but feel is sensing non stop, so you will feel the descent rate while your eyes are focused outside and intuitively check the vvi and adjust collective if needed.

We can get used to do it well enough in the sim with enough practice of course but it is just a little more challenging I believe.

You don't get into VRS from lowering the collective; in fact quite the opposite. 3 things are required to enter VRS:

1. Low forward airspeed
   
2. Descending
   
3. Power (collective) applied
   

This is why steep approaches are so risky, because by their very nature you're likely to be checking off points 1 and 2 from the list. Add power to arrest your descent at the end, and you're straight into VRS.

No need to check VVI either. If you maintain a constant (shallow) angle of approach, you won't be able to enter VRS because you can't be flying slowly and descending quickly at the same time. Once you're comfortable with sight picture, you can start monitoring airspeed to ensure a nice gradual deceleration to the landing point.

Those are certainly limitations of a desktop sim, but I doubt they're likely to be the biggest issue here. I'd bet Backdraft's approach are simply too steep.

 

 

 

You don't get into VRS from lowering the collective; in fact quite the opposite. 3 things are required to enter VRS:

 

1. Low forward airspeed
   
2. Descending
   
3. Power (collective) applied
   

 

This is why steep approaches are so risky, because by their very nature you're likely to be checking off points 1 and 2 from the list. Add power to arrest your descent at the end, and you're straight into VRS.

 

No need to check VVI either. If you maintain a constant (shallow) angle of approach, you won't be able to enter VRS because you can't be flying slowly and descending quickly at the same time. Once you're comfortable with sight picture, you can start monitoring airspeed to ensure a nice gradual deceleration to the landing point.

By lowering the collective I meant during the approach and while the decent rate is still under control, trying to compensate the steep approach by slowing down fast, pitching up and dropping the collective to avoid climbing, then transitinal lift is lost and you enter VRS before you know it. At least this is my observation in the sim from watching other players.

I have no issues with landing any of the hellos personally.

The biggest factors for why it "feels" more difficult in DCS imho are below:

 

1. Cyclic works very different irl from what the majority has for sims and this makes big difference

 

2. Collective - IRL the collective is much longer lever which gives it much more precision from our throttles.

 

3. Last but not least for sure, bud feel. IRL you can "sense" the rate of descent/climb/speed and general attitude and therefore react to it much faster and intuitively then in sim, especially 2d monitor. VR helps a lot for helos, still no bud feel tho.

 

Most of the time we simmers trigger VRS because we lower the collective too much, as we don't have precise enough hardware control. At the same time we don't have our eyes on vvi 100% of the time as we have to cross check everywhere with our single pair of eyes. While in real live your but feel is sensing non stop, so you will feel the descent rate while your eyes are focused outside and intuitively check the vvi and adjust collective if needed.

We can get used to do it well enough in the sim with enough practice of course but it is just a little more challenging I believe.

 

 

I am no pilot irl, but I have many hours in CAR/Motorcycle racing sim games and IRL and it suffers from absolutely the same issues because of the lack of real hardware and feel of the motion and environment.

Mostly agree with you. I had about 150hours IRL in Mi-8 behind controls when I firstly install the DCS and immediately got to the VRS. The model is very unforgiving. Looks like when you get under the certain speed probably 40km/h the 4m/s of descend, you immediately got to the VRS. I personally see my instructor ending hover check with higher speed (roughly 5-8m/s) of descend without even closing to VRS.

That must have been uncomfortable.

8 m/s descent is nearly 30 km/h (28.8 km/h, 18 mph) & equivalent to stepping off a 3.28m drop.

That's a pretty good smack into the ground your instructor was giving the aircraft...

(roughly 5-8m/s)

Can't hit the ground at that speed. Too high for the humans and the machine too.

Well unless you just drop the collective to the floor when you're really, really low, but then you won't have the time to hit those numbers before you're on the ground already.

Mostly agree with you. I had about 150hours IRL in Mi-8 behind controls when I firstly install the DCS and immediately got to the VRS. The model is very unforgiving. Looks like when you get under the certain speed probably 40km/h the 4m/s of descend, you immediately got to the VRS. I personally see my instructor ending hover check with higher speed (roughly 5-8m/s) of descend without even closing to VRS.

And promptly popped the tyres and landing gear and generally had a bad day at the office, you may get away with maybe 0.5 mtr/sec but that is still a hard landing. IMPO.

If you mean under 40kph and 4mtr/sec you are loosing any benefit of translational Lift and so need more collective to reduce sink rate and if you do not have enough power you will continue to sink.

Keep the VSI rate in check :helpsmilie:

That must have been uncomfortable.

8 m/s descent is nearly 30 km/h (28.8 km/h, 18 mph) & equivalent to stepping off a 3.28m drop.

That's a pretty good smack into the ground your instructor was giving the aircraft...

But we didn’t hit the ground. We ended in stable 5m hover, then continue with normal take off. I cannot see the precise value on right seat because VSI is useless in hover due main rotor flow.

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And promptly popped the tyres and landing gear and generally had a bad day at the office, you may get away with maybe 0.5 mtr/sec but that is still a hard landing. IMPO.

 

 

 

If you mean under 40kph and 4mtr/sec you are loosing any benefit of translational Lift and so need more collective to reduce sink rate and if you do not have enough power you will continue to sink.

 

 

 

Keep the VSI rate in check :helpsmilie:

None of that. It was pretty nice flight. Thanks for explanation cpt. Obvious...

All I want to say is that RL Mi-8 is not so willing to fall into VRS as the DCS model.

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None of that. It was pretty nice flight. Thanks for explanation cpt. Obvious...

All I want to say is that RL Mi-8 is not so willing to fall into VRS as the DCS model.

 

 

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And I have found that to be the case with DCS Mi-8 as well.

My question, what are you using for controls?

And I have found that to be the case with DCS Mi-8 as well.

 

 

 

My question, what are you using for controls?

Hotas Warhog. I know about the differences between travels and even when I take them into account it feels too prone to VRS.

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if you do not have enough power you will continue to sink.

The DCS Mi-8 has huge power reserves...

But yeah if you want to come in the last hundred meters vertical you will have to take at least 20 seconds to do so VRS free!

SWP below HOGE altitude can only happen if you pull in power so fast that rotor RPM drops because Governor is a bit slow.

The DCS Mi-8 has huge power reserves...

 

But yeah if you want to come in the last hundred meters vertical you will have to take at least 20 seconds to do so VRS free!

 

SWP below HOGE altitude can only happen if you pull in power so fast that rotor RPM drops because Governor is a bit slow.

Don't know really. Maybe, but if your near MTOW there isn't a lot of power reserve and really need to keep VS rate in check. Way too easy to draw down rotor RPM and fall if you let sink rate get away.

For me I like to keep VS below 3 usually 2mtr/sec so maybe 30 to 40 secs seems to work for me for long drops.

Hotas Warhog. I know about the differences between travels and even when I take them into account it feels too prone to VRS.

 

 

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Maybe I'll just say there is no substitute for even close approximations of real controls. ;)

<edit>

I might add here, this is where sometimes the use of "curves" might make a limited control work better in DCS.

Maybe I'll just say there is no substitute for even close approximations of real controls. ;)

I fly with Mi-171 in RL. I know pretty accurate how different are the controls in RL and how bad is joystick.

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HI All

And thanks everyone for helping, Sorry delay been at work a bit. and also I didn't mean for anyone to argue. Over my ?. so I got some help Online thank you so much Crom!! but I have 2 things I am conceptually needing I think. as the what to do and when.

1st is I probably am a little steep. But how do I keep a constant path down. I've watched all the videos I could find and see my landing space. and look ahead and glance down at instruments then back out. But still Falling short(mostly crashing) or long. but I'm staying under 5ms till the shakes.

2nd is when I'm descending and lowering collective an glued to the vsi, I get the shakes and pull up collective. I spin left or pop up. Rarely do I just mosey on down like I see or level to get into the hover.

so what am I missing or need to do. And this I just runway by the way trying land on the Numbers or 1000ft marks. No way I could do field yet or Oil Rigs as I found out 1st try after 2hours of learning.

To keep a nice constant decent, find a reference point on the canopy or frame in line with your landing spot and keep it there. It won't move up/down if your approach is steady.

Ignore the VSI. A steady approach angle and air speed control is what you need. A gradual reduction in air speed as you come in to land will help with the shaking (the faster you decelerate the more violent, so avoid that).

Once you've got the hang of that, start thinking about landing accuracy.

If I may, I'll add don't worry about oil platforms, stick to runways or just plain ole open fields for starters.

Setup a lightly loaded Mi8 say 30% fuel hot so it's already started.

That video I linked is not instructional but it should illustrate what I am saying below all inputs are measured and anticipated in other words I am correcting for where I want to be some seconds ahead.

You shouldn't be robotic with the controls or at least that is how you describe your inputs. As you loose speed and get less lift from translational lift you need to anticipate 2 basic things you will need to increase collective don't wait till VSI indicates your sinking and it should be a gradual increase to maintain your desired sink rate.

At the same time because you are increasing rotor load you need to anticipate anti-torque correction. Again gradually and just enough to maintain the aircraft in the correct attitude.

All this and cyclic input to correct roll and pitch, because all inputs interact to an extent.

And all at the same time. Try not to think I have done this now I need to do that, more I am doing this so I also need to do that. :D

Normally on approach there are land land marks that are picked for when turn into final and when to start to slow down to descent speed then normally a constant descent speed and sink rate about 3mtr/sec (~500ft /min).

Set up for some straight practice runs approach from say 300mtrs get a feel for how far out you need to be to hit the piano keys on the runway. That should give you about 1 min 40 + and try at about 150 klm/h IAS.

Another exercise same loadout from hover climb vertical to about 20 mtrs then control vertical descent at about 2mtr or less /sec you should settle at about 2 to 3 mtrs or so IGE.

For me, the key to avoiding VRS in the Mi-8 has been to drop to the deck first (so ground effect kicks in), before slowing down below 50km/h and attempting a hover (also, reset trim and use rudder and cyclic to keep the chopper stable).

The Mi-8's descent is much easier to control if you have ground effect... since most of the authority is shifted back to the collective (same as when taking off), without funny business.

The huey is more forgiving in this regard, you can get used to hovering at an altitude with it, which is bad if you're planning to switch back to the Mi-8...

So don't get used to hovering at an altitude (regardless of the helicopter), kiss the ground first, slow down later.

To keep a nice constant decent, find a reference point on the canopy or frame in line with your landing spot and keep it there. It won't move up/down if your approach is steady.

 

Ignore the VSI. A steady approach angle and air speed control is what you need. A gradual reduction in air speed as you come in to land will help with the shaking (the faster you decelerate the more violent, so avoid that).

 

Once you've got the hang of that, start thinking about landing accuracy.

I wouldn't ignore the VSI completely if you're below transition speed, but yes, in general I think this is the best idea. Don't think of stopping & landing, just landing & stopping simultaneously. If you're going to overshoot don't do anything drastic, just orbit & slow down that way. Technically kicking the tail out to get the fuselage side on should also help a little ( just like sideslipping in a FW ) but I've not noticed any appreciable difference in deceleration in the Mi8 doing that.