Vert. Landing: How do you deal with Harrier waving uncontrollably at sub 30 knots?

[kraze]

Trying to learn how to land Harrier vertically or at least make it hover with any kind of control.

 

 

The weight is sub 17000 lbs. The mission has no wind.

 

 

 

Getting it down to 200-300 feet while gradually swinging nozzles to 50 degrees until it reaches ~80 knots - and then setting nozzles angle to ~62 and flaps to 62 degrees when at 80 knots, after which I trim to keep witch's hat at horizon level, as well as FPM so my descent rate is no more than 100-150 feet per minute. It's worth noting that I only do very slight left-right adjustments with a stick to keep the aircraft flying in the correct direction, otherwise I control the pitch only with thrust and trim.

 

 

Then I gradually increase nozzles angle to ~70 degrees until my speed is sub 50 knots and then to ~85 degrees where the air speed drops below 30 knots...

 

 

...at which point my aircraft starts to wave from one side to the other uncontrollably with it becoming worse and worse as a speed reaches 10 knots at which point AV8B turns into a complete Yo-Yo and it ends with a crash landing unless I abort. Another note - I do not do any roll adjustments anymore when it's sub 50 knots, leaving it level.

 

 

When watching other people do it on YouTube - they don't have this kind of shake and stay in control. Again as I've said the mission has no wind.

 

 

What am I missing?

Edited July 1, 2020 by kraze

[Helles Belle]

https://www.mudspike.com/chucks-guides-dcs-av-8b-harrier-ii/

 

Do you have chucks guide?

[Chaders]

It sounds like you’re doing it right, have you got a track file and I’ll have a gander?

[proszekOMO]

IMHO it needs a little bit of practice;) Use rudder , very gentle input. I had the same problem at the beginning but after several landings you will gain muscle memory to do it properly

[Victor3]

Don't go past 82 degrees on your nozzles for one, 82 is the setting for vertical. You're inducing rearward velocity at 85.

[Mars Exulte]

Yep, 85 is too far for doing it by the book, and will have you drifting backwards. Also, depending on wind, etc, you need to be a bit flexible. Always try to face into the wind, and be ready to adjust nozzles and pitch, etc. Corrections.must be fast, and strong, but remember it flies like a helicopter in hover mode, so any action you take also needs to be canceled out.

 

You're probably drifting backwards a bit and over correcting. Just keep practicing, it's a bit clumsy at first, but it's actually pretty stable once you get the hang of it. I was barnstorming through hangars in hover profile. If I can do it, anybody can.

[gtsab]

Quick two-cents: I'm not a real Harrier pilot but I've worked around them for decades and watched thousands of landings up close. I've flown the real simulator several times and can vertical land the Harrier easy. I think I can say that the pendulum effect at low speeds that I also get into very easily flying DCS does not happen on a real jet. I don't know if its how the puffer jets (RCS) are modeled, but a real Harrier is much more stable and the pilot-induced waving is not a thing in real life. I've never seen a real just start waving side to side as it landed. It seems like DCS does not take into account the mass-inertia of the jet, I don't know. I'll talk to some Harrier pilots about it when I get a chance and let you know if I hear something different.

[Motomouse]

VKB Gunfighter with 20cm extension ;-)

[Supmua]

A few tips from me.

 

For the Harrier, the witch hat dictates your horizontal velocity and VVM dictates vertical velocity. When the nozzle angle is at 82 deg, if you want to slow down put the witch hat above horizon bar on HUD. If you want to go forward then witch hat below horizon.

 

For descend, VVM below horizon and observe the vertical velocity indicator on the right side of the HUD. Ascending is the opposite.

 

And it is important to keep these changes small as you are closer to the ground to avoid oscillations.

 

Use the rudder to turn/spin around when you are hovering.

 

During landing, if you are <10 ft above ground (always use Radar Altitude not Baro) you can just slap the throttle back to idle and brake, the plane will just plop down and shouldn’t crash—make sure the witch hat is below horizon before touchdown. When you are used to this then you can add more finesse to it.

Edited July 1, 2020 by Supmua

[kraze]

It sounds like you’re doing it right, have you got a track file and I’ll have a gander?

 

 

Sure, here's a quick mission I've setup just to show it, the track is attached.

Disregard the less than perfect approach - what I can't wrap my head around is why at sub 30 knots the aircraft completely loses stability (I don't touch the roll axis in any way) and I just have to land it instead of getting it to hover.

 

 

It's not a ground effect either, same happens at 200 feet above the sea

 

 

Don't go past 82 degrees on your nozzles for one, 82 is the setting for vertical. You're inducing rearward velocity at 85.

OK, thanks, but it's not that.

 

 

I can go full 99 degrees to slow an aircraft from 200 to something like 60 knots without losing any stability and then set it to straight 82 and it will be stable at that speed, but the moment it reaches 30 knots - I just completely lose control due to side to side waving and sometimes heavy pitch increase/decrease that is not trimmable.

 

 

I just don't understand what makes it go wild at low speeds for me, it's not something I introduce because I literally don't touch the roll axis whatsoever. I don't see none of that in literally any tutorial video - and f.e. Spudknocker rolls it hard right away at 4:56 here and it still remains stable:

track4.trk

Edited July 1, 2020 by kraze

[Cornelius]

Quick two-cents: I'm not a real Harrier pilot but I've worked around them for decades and watched thousands of landings up close. I've flown the real simulator several times and can vertical land the Harrier easy. I think I can say that the pendulum effect at low speeds that I also get into very easily flying DCS does not happen on a real jet. I don't know if its how the puffer jets (RCS) are modeled, but a real Harrier is much more stable and the pilot-induced waving is not a thing in real life. I've never seen a real just start waving side to side as it landed. It seems like DCS does not take into account the mass-inertia of the jet, I don't know. I'll talk to some Harrier pilots about it when I get a chance and let you know if I hear something different.

 

Very interesting :thumbup:

[FoxTwo]

Watching/taking control of your track, you're trimmed WAY nose up which is contributing to your instability. Watch your AoA. Control your altitude with your throttle and your speed with your pitch. Your AoA should be in the white range (8-10) and you're at 12-15. Add in a dash of pilot-induced oscillation and you've got your instability.

[Blackeye]

In your track I get a 8 knot tail wind which isn't helping.

 

 

While the Harrier in DCS might be a little more unstable I think it's mainly down to practice, anticipation and muscle memory.

 

 

As training exercise you could set up a mission with unlimited fuel and a light enough loadout for a hover (not super light though) and try hovering around the airfield for some time following the taxiways, etc.

 

That way you can train keeping a controlled hover for a longer time and not just 30 seconds of each mission.

 

 

 

Take it slow and use only minimal input to initiate maneuvers so you don't upset the aircraft.

Edited July 2, 2020 by Blackeye

[kraze]

Should it be a tailwind or the front wind?

 

 

Perhaps I'm approaching it way too much as F/A18C carrier landings - e.g. set trim and glide onto the deck using the help of a tailwind - which is now obvious that it is not the way to treat a Harrier.

 

 

I actually managed to land on (a moving) Tarawa (with a tail wind) from the 6th attempt today, it was terrible compared to how it should've been done, but I've landed in a correct rear area, didn't break anything and managed even to hover for a bit.

 

 

But what I was doing differently is constantly using a stick for both pitch and roll to counteract any pendulum effect, as well as moving nozzles back and forth to help with the direction of movement - which made the aircraft way more controllable - even if too much work

Edited July 2, 2020 by kraze

[Ramsay]

Should it be a tailwind or the front wind?

It should be a headwind for both Hornet and Harrier.

 

A strong headwind allows a higher airspeed and lower ground speed at touchdown.

 

One thing to note is that IRL, wind direction is usually referenced as to where the wind to coming from i.e. a north wind is FROM the north, while in DCS's ME and weather brief - wind direction is where it is blowing TO i.e. a 5 m/s ( ~10 knot) ground wind @ 270° in DCS is TOWARDS 270°

[FoxTwo]

But what I was doing differently is constantly using a stick for both pitch and roll to counteract any pendulum effect, as well as moving nozzles back and forth to help with the direction of movement - which made the aircraft way more controllable - even if too much work

 

Once you've transitioned to a stable hover you shouldn't touch the nozzles.

 

82 degrees. Set it there. Don't touch it.

 

Throttle up to gain altitude, throttle down to decrease. Stick forward to go forward, stick back to go backward.

 

Just like a helicopter.

[Blackeye]

Should it be a tailwind or the front wind?

 

Pretty much always headwind in aviation when touching the ground is involved:

 

Carriers turn into the wind and speed up as necessary to maintain 20+ knots headwind over the deck.

For runways you usually choose the one with the largest headwind component, unless the wind speed is really low and there's a good reason to pick another.

 

This reduces the speed over ground and thus the energy the brakes (or wires) have to dissipate and reduces the landing distance - also it gives you more time during approach.

 

Turning into the wind is mandatory for vertical landings in the Harrier AFAIK to avoid instabilities due to the weather vane effect and to prevent debris and hot air from being blown forward and ingested by the engine.

Edited July 2, 2020 by Blackeye

[kraze]

Tried with casually landing into the wind on Tarawa - and immediately noticed the difference. Two good landings out of two tries. It was considerably easier, to a point where I was rolling and using rudder to keep the nose straight to do a sideways landing from hover - and easily dealing with a pendulum effect.

 

 

Landing into the wind made it that much better than I only now realized I didn't even monitor thrust

Edited July 4, 2020 by kraze

[Steinsch]

Quick two-cents: I'm not a real Harrier pilot but I've worked around them for decades and watched thousands of landings up close. I've flown the real simulator several times and can vertical land the Harrier easy. I think I can say that the pendulum effect at low speeds that I also get into very easily flying DCS does not happen on a real jet. I don't know if its how the puffer jets (RCS) are modeled, but a real Harrier is much more stable and the pilot-induced waving is not a thing in real life. I've never seen a real just start waving side to side as it landed. It seems like DCS does not take into account the mass-inertia of the jet, I don't know. I'll talk to some Harrier pilots about it when I get a chance and let you know if I hear something different.

 

 

Exactly what I was wondering about. Great to hear from someone with real world experience about this.

[Ladan]

Hey everyone, just joined yesterday. I am also working on landing the AV-8B Harrier. Took me a couple days to figure it out. Yesterday, I tried 4 times, and on the 4th try I did it. I think 82 degrees is ideal. Just need to play with the throttle and direction, as well as the angle of the nose. I went a little high, so ended up coming down tail first haha, but it was pretty good. I was really happy with it. I will keep working on it.