Vortex Ring State...

[jcomm]

It had been a year since I last played with the UH-1H... so I rushed comparing how easily I could get it into and out of VRS using the wrong techniques...

 

It surprised me that I need more than 3000fpm descending to get VRS ? Is it really that permissive IRL too ?

 

 

[Ramsay]

Last time I entered VRS in the DCS Huey I had a descent rate of approx. ~850 fpm in a stop turn while using an aggressive amount of collective, easing off on the collective and bank allowed me to recover safely.

 

Requirements for VRS are

 

• speed below ETL

• descent rate more than 300 fpm (R22, exact value depends on rotor diameter, aircraft weight and air density)

• 20-100% power/torque applied

 

Note: The lighter the helicopter and larger the rotor, the easier it is to enter VRS.

 

IIRC the consensus on a helicopter forum was that realistic values for entering VRS IRL was 40-60% TQ and 0.65 of the downwash.

RL pilots are trained to use lower values when flying to add a safety margin that allows for instrument lag, pilot response, etc.

 

 

 

Edited Tuesday at 10:55 AM by Ramsay

[Lurker]

On 1/13/2021 at 3:44 PM, jcomm said:

It had been a year since I last played with the UH-1H... so I rushed comparing how easily I could get it into and out of VRS using the wrong techniques...

 

It surprised me that I need more than 3000fpm descending to get VRS ? Is it really that permissive IRL too ?

 

 

 

Did you have any ETL? (Translational Lift) The Huey is quite forgiving with VRS if you have at least some translational speed. It only get's dangerous below 30-40kph.