Two responses to my recent confession that while I loved flying airplanes, I was basically frightened of helicopters. Airplanes are meant to stay up in the air; helicopters are meant to fall out of it. First is from a reader who is a helicopter pilot in Alaska; then, from a reader who flies neither helicopters nor airplanes but is a professor of physics.
From the pilot:
Perhaps you've heard the expression, "Helicopters don't fly, they beat the air into submission."
From the professor -- Steven Lepp, of the physics department at UNLV.
"I am sure you will hear from all kinds of helicopter pilots, who will probably know more then I do. But as a Physics Professor (though Atomic and Molecular Astrophysics rather then Fluids is my specialty), I can say I don't think there is much difference between a helicopter and a fixed wing airplane in terms of how much it "likes to fly".
"Maple seeds are a good example of "Helicopters love to fly". As a kid I could play with these things for hours,...
"An airplane (helicopter) that loses power can only keep flying by keeping its airspeed (rotor rotation rate) up. To do this requires trading altitude for speed (rotation rate). If you use the elevator (cyclic) to keep the wings (rotor) pitched upward, the wing (rotor) will eventually slow enough to stall and the airplane (helicopter) will fall. If you use the elevator (cyclic) to pitch the nose (rotor) down the wing (rotor) will gain speed and you'll keep flying.
"An airplane that lost its power is just a wing with some control surfaces attached and some weight pulling down. A helicopter is just three wings in rotation, with a weight and various controls. While an airplane may travel a long distance on its wing and a helicopter's wings will certainly travel far (the helicopter not so much) but this also means a gliding helicopter's forward speed can be quite slow, even zero and its wings are still flying and so can land in a much tighter spot....
"Boomerangs are another example of "Helicopters love to fly". A boomerang is really just a gliding helicopter. A well thrown boomerang will make a large circle and come back to you. It is initially thrown banked over a lot (like 80 degrees) and as it goes around the circle it will flatten out so when it comes back it is just hovering above the ground. I threw my favorite boomerang once 5 times without taking a single step, it just flew out 15 yards in a big sweeping turn, came in and hovered by my feet each time, if I hadn't caught it it would hover right down to a gentle landing on the ground. The long distance record for a boomerang is 238 meters (which is how far it reached before it turned about and came back), not bad for something that doesn't want to fly."
To which I respond: sounds good in principle! Makes me want to learn the boomerang. And if I were a helicopter pilot, I'd use this for reassurance -- just as, when flying airplanes, I am reassured by all the aerodynamic arguments in their favor. But when I see helicopter pilots practicing "autorotation" in training, which is essentially a managed/dampened high-speed plunge, I think: I'll stick with the planes. And I'm bolstered by this afterthought from the chopper pilot:
"I used to think [helicopters] were harder to fly, but not so sure anymore. Helicopters are harder to learn to fly, for sure, but once you've got it down, their supreme maneuverability make them easier. I say that after reflecting on beach and gravel-bar landings of fixed-wing I've seen over the years here in rural AK, in particular some landings on the AK Peninsula, where the pilot had to put a heavily loaded [Cessna] 180 (or 185? - a taildragger, anyway) down on an uneven beach at low tide with a stiff wind blowing crossways up and over grassy dunes that ran the length of the beach. That would be no problem whatsoever with a helicopter."
Just as I suspected! I truly was heroic to manage all those crosswind landings in an airplane. That finishes the subject for now.
UPDATE: Professor Lepp sends a breaking-news clip about a helicopter that just successfully / survivably "autorotated" its way to the ground. It's here.
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