Loss of tail rotor authority

[press]

I've setup a mission of free flying to get used to the machine. During two landing attempts I noticed the tail rotor just loses authority. With my right pedal fully pressed the helicopter continued to rotate to th e left (counterclockwise). Yaw channel was also engaged. I've attached a track file for analysis.

 

Mi-24 tail rotor.trk

[ARM505]

I haven't watched the track file. But I've had what you describe happen. Here's a quick test: first, enable your controls indicator. Then, when it happens again, take your feet off the pedals. Note the position of the pedal indicator on the control indicator. You will almost certainly see that it is not centered, even though your physical pedals are centered, and you are unable to get full pedal authority because of this, almost as if the virtual pedals have taken a trim bias to the neutral position as well, even though you don't have this option selected under the 'special' menu. This seems to 'stack up' over time. To fix this: double tap your trim button (this centers all trim, so watch out), observe that the virtual pedals return to center, continue from there. It occurs only if the rudder yaw channel is engaged for some reason.

 

I cannot comment if this is accurate to the real aircraft, but the other helicopters don't behave like this (notably the Hip).

[kengou]

Loss of tail rotor authority isn't modeled in other DCS helicopters although it should be. I believe the Hind is the first aircraft to model it.

[S. Low]

Without looking at the track, it most likely is because you have the yaw channel on and the pedal gets stuck to the left. 
 

To land you should really disengage yaw ap, and reset trim.

 

I can’t say one way or another if all of this is functioning correctly. I think there’s a known ap bug related to trim. 

Try your method again, with yaw ap on. When you “lose tail  authority” lift your feet off of physical pedals and see if virtual pedals are to the left and not moving much or at all. That’s the yaw ap and pedal dampening is believe.

 

Turn off yaw, reset trim. 

[ARM505]

Another thing I just noticed. If you let Petrovich fly, then move back to the pilot seat, he will trim the pedals away from neutral (normally to the left obviously). You'll once again need to reset the trim to get the pedals back to neutral to allow your full range of motion. And yes, as has been mentioned, LTE is not simulated.

[foxit]

The static droop of the anti-torque system (T/Rotor) is excessive and does not match the Hind behavior in real flight. I have the impression to fly a Ka-50 which uses the differential torque (T is a function of P and Nr)  from both main rotors to produce a yaw, where the droop is justified, or flying an upset caw with its tail flapping from side to side.  Also, a light hard landing can set the aircraft on fire; these aircrafts are built like a brick shit-house and are not sensitive to small impacts. However, this aircraft is challenging to fly, thank you DCS.

Edited June 30, 2021 by foxit

[S. Low]

Damage model is WIP. Be glad we have damage at all. 

[randomTOTEN]

I tried watching your track but on my replay you struck the main rotors on takeoff and never left the ground.

 

EDIT: 3rd replay and you get off the ground, slide backwards, strike the tailrotor while traveling backwards, flip over and crash.

 

I'm gonna guess this was a really wobbly takeoff when you tried it? It looks like it.

Edited June 30, 2021 by randomTOTEN

[JetCat]

A similar problem occured in my Syria border patrol mission. The helicopter behaved very strange and not as usual in other missions or trainings - it was not able to gain altitude, was just hoovering 20 feet above the ground as if incapable of leaving ground effect, and rotating counter-clockwise the whole time no matter how much pedal I gave.

It did that two or three times until I checked where the tail rotor pitch limit system in the cockpit is positioned because I thought this is the problem (I read that in hot areas the air is less dense and the tail rotor needs a sharper angle of attack to be effective enough - this handbook is absolute fantastic! So much background info about the history of the heli, technical details, physics and cockpit stuff....) but the SPUU-52 tail rotor limiter was not the problem - it was switched to off all the time.

Even if I cannot really read this manual moving map and hope in secret that the Hind will get an avionics update some day (a more modern cockpit to choose from with some kind of MFD screen for map navigation while the rest of that AWESOME cockpit should stay the same), and even if it cannot leave ground effect in the Syria mission but only have a Hind that is helplessly turning in endless circles ten feet above ground without gaining altitude - still one of the best helicopters ever made for any simulator because in all other locations and missions it works flawless so far.

[admiki]

What was the air temperature? It looks you were overweight for conditions you were in.

[CrazyGman]

On 11/5/2021 at 5:59 PM, JetCat said:

A similar problem occured in my Syria border patrol mission. The helicopter behaved very strange and not as usual in other missions or trainings - it was not able to gain altitude, was just hoovering 20 feet above the ground as if incapable of leaving ground effect, and rotating counter-clockwise the whole time no matter how much pedal I gave.

It did that two or three times until I checked where the tail rotor pitch limit system in the cockpit is positioned because I thought this is the problem (I read that in hot areas the air is less dense and the tail rotor needs a sharper angle of attack to be effective enough - this handbook is absolute fantastic! So much background info about the history of the heli, technical details, physics and cockpit stuff....) but the SPUU-52 tail rotor limiter was not the problem - it was switched to off all the time.

Even if I cannot really read this manual moving map and hope in secret that the Hind will get an avionics update some day (a more modern cockpit to choose from with some kind of MFD screen for map navigation while the rest of that AWESOME cockpit should stay the same), and even if it cannot leave ground effect in the Syria mission but only have a Hind that is helplessly turning in endless circles ten feet above ground without gaining altitude - still one of the best helicopters ever made for any simulator because in all other locations and missions it works flawless so far.

You're a bit too heavy, and your pulling too much collective too quickly. When you want to yaw right and maintain altitude you actually lower collective to gain more authority. Yawning right, actually will cause you to assend slightly as the helicopter supplies torque to the rear rotar, but also to the main rotars. When in hot and heavy conditions you need to very gently and gradually raise collective to the point where you will just hover but still have rudder authority. Then pitch the aircraft forward till you have about 50 kph forward air speed then she will be fine. Alternatively you can do a rolling takeoff. 

In case you pull too much collective and get into the spin you describe, don't fight the spin, but control it so s that the aircraft is vectoring in one direction by pushing the cyclic in the direction of your movement vector in relation to the spin, once you get enough airspeed in one direction it will sort itself out.

Edited November 9, 2021 by CrazyGman