Vortex Ring State demonstration in RC helicopter.
03-11-2011 | 10:43 AM
#1
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From: Sydney, AUSTRALIA
Vortex Ring State demonstration in RC helicopter.
I just picked up a Blade MCPX two days ago...
It is highly prone to Vortex Ring State and is easily repeatable..
This video demonstrates...
[youtube]http://www.youtube.com/watch?v=0Kz_gOWaR7Y[/youtube]
It is highly prone to Vortex Ring State and is easily repeatable..
This video demonstrates...
[youtube]http://www.youtube.com/watch?v=0Kz_gOWaR7Y[/youtube]
03-12-2011 | 08:09 AM
#2
RE: Vortex Ring State demonstration in RC helicopter.
Copied from http://en.wikipedia.org/wiki/Vortex_ring
"Vortex ring state (VRS), also known as settling with power, is a hazardous condition encountered in helicopter flight.
It occurs when the helicopter has three things occurring: A high rate of descent, an airspeed lower than effective translational lift, and the helicopter is using a large portion of its available power.
A helicopter's main rotor typically directs airflow downwards to create lift, but with low horizontal airspeed, it induces a vortex ring.
A toroid-shaped path of airflow circumscribes the blade disc, as the airflow moves down through the disc, then outward, up, inward, and then down through the top again.
This re-circulation of flow can negate much of the lifting force and cause a catastrophic loss of altitude.
Specific to vortex ring state is that the helicopter, operating in its own downwash, is descending through descending air.
Applying more power (increasing collective pitch) serves to further accelerate the downwash through which the main-rotor is descending, exacerbating the condition.
In single rotor helicopters, a VRS can be corrected by moving the cyclic forward, which controls the pitch angle of the rotor blade, slightly pitching nose down, and establishing forward flight.
In tandem-rotor helicopters, recovery is accomplished through lateral cyclic or pedal input.
The aircraft will fly into "clean air", and will be able to regain lift."
"Vortex ring state (VRS), also known as settling with power, is a hazardous condition encountered in helicopter flight.
It occurs when the helicopter has three things occurring: A high rate of descent, an airspeed lower than effective translational lift, and the helicopter is using a large portion of its available power.
A helicopter's main rotor typically directs airflow downwards to create lift, but with low horizontal airspeed, it induces a vortex ring.
A toroid-shaped path of airflow circumscribes the blade disc, as the airflow moves down through the disc, then outward, up, inward, and then down through the top again.
This re-circulation of flow can negate much of the lifting force and cause a catastrophic loss of altitude.
Specific to vortex ring state is that the helicopter, operating in its own downwash, is descending through descending air.
Applying more power (increasing collective pitch) serves to further accelerate the downwash through which the main-rotor is descending, exacerbating the condition.
In single rotor helicopters, a VRS can be corrected by moving the cyclic forward, which controls the pitch angle of the rotor blade, slightly pitching nose down, and establishing forward flight.
In tandem-rotor helicopters, recovery is accomplished through lateral cyclic or pedal input.
The aircraft will fly into "clean air", and will be able to regain lift."
