We've all heard the story of Rudolph, the reindeer that saved Christmas because of his bright red nose. But while a nose that shines like a beacon through the fog may be the stuff of fantasy, Rudolph is far from the only reindeer with a red nose.
Of course, the story was rooted in myth. But there’s actually more truth to it than most of us realize. A fraction of reindeer—the species of deer scientifically known as Rangifer tarandus, native to Arctic regions in Alaska, Canada, Greenland, Russia and Scandinavia—actually do have noses colored with a distinctive red hue.
Now, just in time for Christmas, a group of researchers from the Netherlands and Norway have systematically looked into the reason for this unusual coloration for the first time. Their study, published yesterday in the online medical journal BMJ, indicates that the color is due to an extremely dense array of blood vessels, packed into the nose in order to supply blood and regulate body temperature in extreme environments.
How did they determine this? The study involved infrared imaging, comparing reindeer and human noses, and putting reindeer on a treadmill! Who says science isn't fun? Read all about the study at Surprising Science. Link
(Image credit: Ince et. al.)
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It appears to be geared with the main rotor, but is likely pitched such that it doesn't provide any thrust to the left or right during flight. When the pilot wants to turn, he pitches the tail rotor blades to provide thrust.
If the tail rotor failed, the helicopter would be just fine, although it would have no ability to turn on its emergency descent.
actually it would start to spin uncontrollably with out the tail rotor, just because there is no powered axle between the main rotor and the main body of the helicopter doesn't mean that the friction from the rotor and where it is connected to the body isn't enough to cause it to start spinning. We don't live in a world with frictionless bearings. Also the fuel delivery system to the rockets probably add's a lot more friction to the main rotors axle.
It might not happen as quickly and violently as a normal heli would if it lost it's rotor, but if he were high enough, by the time he got the heli to the ground he could be spinning like a tea cup.
I like the noise of that thing- While most chopperbuilders work frantically on reducing or even cancelling the noise of their rotorblades as best as they can to make their choppers more useable in crowded areas, these guys come up with a system that wakes up the whole valley when they start up their machine. :-D
http://www.youtube.com/watch?v=8jhpUJLhQfs
http://en.wikipedia.org/wiki/Nederlandse_Helikopter_Industrie_(NHI)
And an American prototype:
http://en.wikipedia.org/wiki/YH-32_Hornet
All designs failed...
The difference with friction as a force is two fold. First, obviously, is that it would be in the direction of the rotors, not the opposite direction. Second, we're talking an incredibly small amount of the output of the engine being transferred via friction (easily as low as .01%). Third, it takes much more energy to spin the heavier body of the helicopter than the rotors.
So it would take very, very little to cancel it out.