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Helicopter Lands top Mount Everest
FlyByPC writes "The Eurcopter team has succeeded in landing a helicopter on Everest and returning safely to base, setting another ultimate aviation milestone -- for highest-altitude takeoff and landing. Interesting pictures of Lukla airfield, as well -- essentially a runway carved out of a mountainside."
From the pictures it looks like the top of Everest isn't flat enough to actually touch down and turn off your engines. Instead, they lowered until one of the landing gear ("feet"? not sure what you call those things on a helicopter) sunk into the snow, but kept the engines running the whole time to keep them balanced. The video makes it appear that they just hovered that way, partially airborne, partially touching the surface, until the 2 minute time requirement was achieved. Then they powered back to full engines and took off again.
Not that I fault them.... :) This is probably the best you can do given the area.
essentially a runway carved out of a mountainside
That was describing the base camp...
They didn't build a runway atop Everest!
Short version: Yes, helicopters use runways.
Long version: Most people assume helicopters just jump off the ground and are suddenly flying. The reality is a good deal more complex than that. (Which is a true statement about almost everything to do with helicopters.)
1. When a helicopter first lifts off the ground it is inside its 'ground effect envelope', where part of its lift is coming from pushing air against the ground. Once it is above a certain height (varies by aircraft -- anywhere from 10 feet to 80 feet), the ground effect falls away and it is now fully airborne.
2. Pure hovering (outside of the ground effect) takes an amazing amount of energy. It also has the danger, if maintained in one place on a still day, of creating a torroid of moving air: first pushed down by the blades, then sucked up and over the top to be pushed down again. This means the copter now has to push harder and faster to make up for the fact that the air it is pushing against is already moving down at some speed.
3. Most fly time in a helictopter is spent moving forward in the air. The disc created by the spinning blade generates lift as it moves forward through the air. In fact, helicopters are called 'rotary-wing aricraft'.
4. During takeoff, a heavily loaded helicopter -- or one operating at high alititude -- will want to stay inside its ground effect envelope while building up forward speed. Once it's going fast enough to generate lift forward motion, then they can start to gain altitude and move out of the ground effect.
One page with more info: http://www.helicopterpage.com/
Peter
284th AVN Co, ATC, 8th Army
I flew into Lukla once, so I can assure you it's used all the time for plane arrivals and departures. There were a few planes pushed off the end of the runway, for the times when a plane couldn't stop fast enough and crashed. It's probably too hard to retrieve the plane or fix it, since there's no driveable roads to Lukla and not much in the way of airplane facilities. The airstrip gets shut quite often due to clouds, since if you can't see the runway you can't land.
The fatality rate from attempts is even less since more people attempt it each year than actually summit. Look something up before you spout off stats that sound good.