domingo, 19 de dezembro de 2010

'Swirl tubes' make quiet, efficient jet planes

Image: United States Patent and Trademark Office)

04:02 10 November 2010
Michael Reilly, technology editor

For anyone with even a hint of trepidation about flying, landing is almost always the worst. The ground, once so far away now looms, scary and real. Then there's the noise of the plane, a racket that sets us all on edge as we dangle in the sky, waiting for touchdown.
It's more than just the roar of the engines - flaps, spoilers, even the undercarriage of the plane itself rip up the air, raising a mighty ruckus. They're necessary because a plane needs lots of drag to be able to slow down enough to land without stalling. Fortunately for our frayed nerves, a group of researchers from the Massachusetts Institute of Technology aim to quiet the din by way of their new invention: "swirl tubes" that could be fitted to wingtips.
According to a recently published patent application, a group of inventors led by Zoltan Spakovsky of MIT have been testing their design in wind tunnels on campus and at NASA. They found that swirl tubes were able to generate large amounts of drag without creating much more noise than is found in the average home.
Each tube contains an array of fixed vanes that could be open to let air pass through during flight, then tilted to swirl it into a vortex during landing. Even better, the vanes could be tilted in a slightly different direction while the plane is cruising to siphon power off of natural vortices corkscrewing off the end of the wings, improving fuel efficiency. Another design calls for vanes to be affixed at the back of each engine to create a vortex in the exhaust (below).

Resumo;( Tubos de turbulência)
Estudos mostram que a colocação de tubos nas pontas das asas conforme desenho é um método eficiente de gerar arrasto nas operações de pouso sem provocar trepidação e ruido na aeronave, nos tubos são colocadas alétas reguláveis em função do arrasto necessário, em vôo podem ser ajustadas para cancelar vórtices que normalmente são gerados pelas pontas das asas reduzindo o consumo de combustível O mesmo estudo afirma que se instaladas nas saídas dos motores podem aumentar a eficiência dos mesmos.

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