Falling

[koyan]

Okay, i consider myself mastering this Kamov very well at the moment. After a lot of practice i now can fly it, trim it, hover it and put it back on the ground or even a moving ship with no problems.

 

However there's one thing i don't understand. When i pull the nose up to slow down and lower the collective to maintain altitude. Then when i come to a stop (i think i also might go a little backward), sometimes the Shark starts falling from the sky. No mather what i do (change pitch, more/less collective) it keeps falling until it hits the ground.:helpsmilie:

[slug88]

http://en.wikipedia.org/wiki/Settling_with_power

 

You can find lots of info if you do a forum search for "Vortex Ring State". Generally, you can avoid this by descending at no greater than 5 m/s when at low speed.

[sobek]

Okay, i consider myself mastering this Kamov very well at the moment. After a lot of practice i now can fly it, trim it, hover it and put it back on the ground or even a moving ship with no problems.

 

However there's one thing i don't understand. When i pull the nose up to slow down and lower the collective to maintain altitude. Then when i come to a stop (i think i also might go a little backward), sometimes the Shark starts falling from the sky. No mather what i do (change pitch, more/less collective) it keeps falling until it hits the ground.:helpsmilie:

 

If this is accompanied by a slight shaking of the airframe, you sure got to know mr. vortex ring (aka the antichrist of helicopter flight), the unholy child of mr. descending too fast and ms. hover. Search the manual for vortex ring, i'm sure it explains things a lot better than i can. In the meantime, start pulling collective earlier and don't brake too violently.

[JDski]

I found you can get out of this situation by pushing forward hard on the stick and getting some forward momentum. It feels almost like recovering from a stall in a fixed wing.

[sobek]

What i also found to ease recover (but maybe that's just my imagination) is to floor the collective to reduce downwash and then increase it as quickly as the flight parameters allow. But as stated before, the most common way is to gain speed (the direction is not of importance, though) to transition out of the vortex.

[AlphaInfinity]

Agreed,

 

I normally try not to descend at more than 2 m/s when I am landing, especially when my forward speed is less than 10kph.

 

One other thing that isn't mentioned here is that you can use auto descent mode when the auto hover feature is engaged. This will drop you to the ground at 2 m/s and you can avoid that pesky Vortex Ring State issue.

[koyan]

Thanks guys for the help. After a search a wealth of information came up. The difference was that i didn't notice any airframe vibration, neither had a too high descend rate. Only after stopping i went backwards and most likely came in the still downward airflow, i figured. Anyway, i think i know now how to avoid this.

 

Thanks again:pilotfly:

[Draco]

Loosing altitude after a quick stop will lead to VRS. After you slow down, add collective as you level the ship. It's better to gain a few feet after the flare then settle into your down wash and crash. To recover I was taught to both lower the collective to break up the vortex and use cyclic to gain airspeed and move out of the down wash. The problem is you usually encounter it on approach close to the ground and may not have enough time/altitude to recover before impact.