On landing roll. Uncontrollable roll to side, that cannot be arrested

[DmitriKozlowsky]

On  landing roll. Uncontrollable roll to side, that cannot be arrested by throttle down, cyclic deflection, pedals in opposite direction. Simply happens, the Hind rolls until blades strike ground. Flight is fine, touchdown seems OK, while rolling and slowing down using brakes, and cyclic back a bit, aircraft rolls, and once it starts there is no stopping it. Since I am rolling, I dont think that ground resonance is an issue, but I don't know.

[Blackeye]

What speed are you landing at? Should be around 50-80 kph AFAIK. Make sure the brakes are disengaged (brake light off).

Once touched down slowly bring back the collective a bit and compensate the torque changes with the pedals.

Keep a good bit of collective in and pull slightly back cyclic to slow down - don't apply back cyclic with no collective as the the blades may strike the tail (IRL).

Then center the cyclic and apply brakes for a full stop and lower the collective.

 

If you're still having problems a track might help to find out what the problem is (Press the save track button on the mission exit screen)

 

 

Edited June 29, 2021 by Blackeye

[Rongor]

It's mainly a matter of practice.

Maybe adjust your controls curves to at least 20. Then practice taxiing from a cold start. Commence with very slow speeds. Practice to find the neutral stick position on ground, it will be slightly to the right and backwards, trim it there. Experiment with the AP channels. Personally, for taxiing on wheels, I use the roll and pitch channels only. Practice anticipating roll moments. Practice taxiing with very slow speeds at first. Make use of the wheel brake. Also brake by pulling the stick back gently. If you taxi through turns by applying pedals, expect the helicopter wanting to roll into the opposite direction. Practice to counter this roll moment by moving the stick in the direction you want to turn. Concentrate and practice this by driving around all the taxiways on your airfield. When you start feeling progress, do all that again, only this time you concentrate to taxi exactly on the yellow centerlines.

 

1. Keep it slow, until you feel progress.

2. Keep in mind you can control all taxi speeds with your stick alone: accelerating and slowing down.

3. If you give right pedals to taxi into a right turn, move stick slightly to the right, to counteract the roll-over tendency to the opposite direction. The amount of stick movement depends on your speed. You'll have to find your personal feeling how much stick movement is necessary for each situation.

4. Don't try to learn this while landing with speed. You don't want to learn how to revover from uncontrollable rolling (you can try that later), you want to learn how to not get into a state of uncontrollable roll moments. Start slow.

5. Keep practicing.

 

In your training, as a thumb rule, if you need to apply wheel brake, you were too fast already. Try to do it with stick only.

Edited June 29, 2021 by Rongor

[Rongor]

16 hours ago, Blackeye said:

don't apply back cyclic with no collective as the the blades may strike the tail (IRL).

where did you get this from? You can slow down to a stop by pulling the stick slightly backwards just fine. It's actually much smoother than applying the wheel brakes...

[Blackeye]

27 minutes ago, Rongor said:

where did you get this from? You can slow down to a stop by pulling the stick slightly backwards just fine. It's actually much smoother than applying the wheel brakes...

 

You can but you need to have some collective pulled otherwise the main rotor blades might drop too low with aft stick possibly striking the tail boom.

And once you've slowed down brakes should be used to come to a full stop with a neutral cyclic - I suspect to avoid issues with tipping over backwards as rearward taxiing is prohibited as well - although with failed brakes cyclic braking to full stop is allowed but only with a minimum of 3 degrees of collective pitch.

 

Source is "that" Mi-35 flight manual p 2-63:

WARNINGS: 1. CONTROL STICK DEFLECTION TOWARDS ONESELF BEYOND THE NEUTRAL POSITION AT THE  MINIMUM COLLECTIVE PITCH VALUE DURING RUNNING IS PROHIBITED TO PREVENT MAIN ROTOR BLADES STRIKING AGAINST TAIL BOOM

 

Also p 2-7

To stop the helicopter during taxiing: set the control stick to a position close to neutral one; reduce the collective's pitch down to the minimum and apply wheel brakes. In case of failure of the wheel brakes, it is allowed to brake the helicopter by deflecting the control stick towards oneself by a value not greater than 50 mm from the neutral position, with the collective pitch value not less than 3 degrees by the rotor pitch indicator RPI

 

I think that would apply to the Mi-24P as well - not sure if this is modeled in DCS though.

Edited June 29, 2021 by Blackeye

[VampireNZ]

Just remember to keep 'flying' the aircraft after touchdown, just because you have touched the ground doesn't mean you just relax and let it do whatever it wants to.

[Rongor]

8 hours ago, Blackeye said:

 

You can but you need to have some collective pulled otherwise the main rotor blades might drop too low with aft stick possibly striking the tail boom.

And once you've slowed down brakes should be used to come to a full stop with a neutral cyclic - I suspect to avoid issues with tipping over backwards as rearward taxiing is prohibited as well - although with failed brakes cyclic braking to full stop is allowed but only with a minimum of 3 degrees of collective pitch.

 

Source is "that" Mi-35 flight manual p 2-63:

WARNINGS: 1. CONTROL STICK DEFLECTION TOWARDS ONESELF BEYOND THE NEUTRAL POSITION AT THE  MINIMUM COLLECTIVE PITCH VALUE DURING RUNNING IS PROHIBITED TO PREVENT MAIN ROTOR BLADES STRIKING AGAINST TAIL BOOM

 

Also p 2-7

To stop the helicopter during taxiing: set the control stick to a position close to neutral one; reduce the collective's pitch down to the minimum and apply wheel brakes. In case of failure of the wheel brakes, it is allowed to brake the helicopter by deflecting the control stick towards oneself by a value not greater than 50 mm from the neutral position, with the collective pitch value not less than 3 degrees by the rotor pitch indicator RPI

 

I think that would apply to the Mi-24P as well - not sure if this is modeled in DCS though.

 

I don't think so either, yet thank you for posting this.

Tried to reproduce this yesterday by violently yanking the stick to its back detent, so far I couldn't achieve tailstrikes.

[Blackeye]

39 minutes ago, Rongor said:

Tried to reproduce this yesterday by violently yanking the stick to its back detent, so far I couldn't achieve tailstrikes.

 

Yeah, didn't expect them to implement this since it's probably quite a bit of work only to have people complain how the Hind blows up on the ground, hence the "(IRL)" addendum.

 

[Eldur]

There's probably a safety margin as well. I guess the rotor won't directly strike the tail boom as soon as you pull back a little with low collective. But having the actual possibility in DCS would just be realistic, maybe consider adding it as a special option.

[Rogue Trooper]

On a rolling landing ensure as you slow down you replicate the hover trim (or hold) to distribute weight across the wheels.

Do not drop your collective, ease it down, those thick short blades store so much energy it can be a whole new world of pain if not managed correctly! 

As the others said, pull back on the cyclic to slow down.... bleed the energy out of the airframe. Do not brake until slower.

Edited June 30, 2021 by Rogue Trooper