resolved Apache cannot recover from VRS with Vuichard Recovery

[zenatsu]

While I am not the best pilot in the world, I've noticed that when performing a Vuichard Recovery the apache still sinks in VRS and is unable to recover.

To recap, the Vuichard Recovery is a maneuver that when you enter into a VRS state, you pitch to the right 10-20 degrees, increase collective, add left pedal, until you are upwind of the vortex and recover (for CW rotor systems, cyclic and pedal inputs are opposite). When executed properly this will allow you to recover with minimal loss in altitude.

However what I am seeing in the apache is that the sink rate is still increasing despite:

1. Increasing airspeed to above ETL within the side-slip
2. Side slipping dozens of feet out of the VRS "location"

Additionally, I have noticed that in order to get into the VRS state, the conditions have changed (unknown at which point they did). It used to be Below ETL and -500FPM. Now it's below ETL and -1000FPM. This is also causing the "traditional method" (nose down and gain speed) to require much higher airspeeds before a recovery is possible.

I had a friend of mine test the same recovery in several other aircraft, namely the Huey, Kiowa, Gazelle, and each aircraft was able to perform the maneuver and recover as expected. I have provided a track file with one of my better attempts.

VRS_RECOVERY.trk

[petsild]

Hi,

Interesting topic, most often George got me into the vertex, that has been fixed in several updates.
I fly so low that I can't afford a VRS, I've been using the HF8 for a year now, so I'm in control.
Nevertheless, I would like to improve myself, I hope that real pilots will recommend the best way.

[JetCat]

A sideways recovery, interesting! I always try to put the Apache into a nose-dive. Thanks for mentioning that new trick to get out of VRS.

 

[Lord Vader]

Hi @zenatsu

The DCS: AH-64D flight model is still a work in progress, undergoing improvements that will be shared in the future.

Thank you all for your patience.

[bradmick]

On 7/1/2024 at 11:33 AM, zenatsu said:

While I am not the best pilot in the world, I've noticed that when performing a Vuichard Recovery the apache still sinks in VRS and is unable to recover.

To recap, the Vuichard Recovery is a maneuver that when you enter into a VRS state, you pitch to the right 10-20 degrees, increase collective, add left pedal, until you are upwind of the vortex and recover (for CW rotor systems, cyclic and pedal inputs are opposite). When executed properly this will allow you to recover with minimal loss in altitude.

However what I am seeing in the apache is that the sink rate is still increasing despite:

1. Increasing airspeed to above ETL within the side-slip
2. Side slipping dozens of feet out of the VRS "location"

Additionally, I have noticed that in order to get into the VRS state, the conditions have changed (unknown at which point they did). It used to be Below ETL and -500FPM. Now it's below ETL and -1000FPM. This is also causing the "traditional method" (nose down and gain speed) to require much higher airspeeds before a recovery is possible.

I had a friend of mine test the same recovery in several other aircraft, namely the Huey, Kiowa, Gazelle, and each aircraft was able to perform the maneuver and recover as expected. I have provided a track file with one of my better attempts.

VRS_RECOVERY.trk 1.6 MB · 1 download

1000fpm is definitely better since the expected range for VRS in the Apache is roughly between 760 to 4100fpm. Airspeed gets a vote in that range. At the end of the day, it’s super hard to get into VRS. The dcs VRS mechanic is…what it is. The problem is it’s super binary in dcs. The other fun thing is you have to force the helicopter to stay in the bad column of air, because the tail rotor will naturally pull you in the direction of tail rotor thrust as the main rotor stalls…because the tail rotor is actually becoming more efficient. It’s why the Vuichard technique makes sense, the aircraft is already naturally going to want to go in the tail rotor thrust direction.