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Smart blades: NASA tested its new actuators in a wind tunnel at Ames Research Center using full-scale helicopter blades (top). The actuator (bottom) contains piezoelectric materials, which change shape when subjected to an electrical field. The wires in the upper right of the image are piezoelectric stacks. When voltage is applied, they extend a small amount, creating a mechanical motion that moves a flap up and down. (The flap is the long, thin, yellow portion of the blade in the top image.)
NASA
NASA researchers are using smart materials to improve helicopter performance.
Helicopters can perform some incredible aerobatic feats, but they're also noisy, shaky, and expensive to run. NASA researchers are developing helicopter blades featuring a shape-shifting smart material that could lead to a smoother, quieter, more fuel-efficient ride.
The blades use piezoelectric actuators--mechanical devices incorporating a material that changes shape when subjected to an electrical field. This shape change deforms the rotor blade as it spins, improving a helicopter's aerodynamic performance.
Last year, NASA, in collaboration with aerospace company Boeing, the Defense Advanced Research Projects Agency (DARPA), and the U.S. Army, tested the first full-scale rotor blade to use the technology in a wind tunnel that simulates flight conditions. The system significantly reduced vibrations, saved energy, and allowed rotor movement to be more precisely controlled. In the future, the system could also reduce noise. It is now ready to be flight-tested, although a date for the first flight has not yet been set.
"Right now, we are trying to understand and appreciate everything that we have accomplished in the full-scale wind tunnel," says William Warmbrodt, the project leader from the Flight Vehicle Research and Technology Division at NASA's Ames Research Center, in California.
As a helicopter blade passes through the air, it leaves behind a wake, and as the blade behind it passes through that wake, it experiences a periodic vibration. "Having blade actuation allows you to put a periodic motion into the blade flaps with the right amplitude, phase, and frequency to cancel out that vibration," says Steven Hall, a professor of aeronautics and astronautics at MIT and a consultant on the NASA project.
"People have been talking about using smart materials in aircraft for a long time, but what [has] really been lacking is the right kind of actuator to make it practical," says Hall. Previous efforts, involving hydraulic actuators, proved too heavy and slow to be practical. "It is hard to do hydraulics in a rotating frame: you need enough force to deflect the flap because the air loads are very high, and you have to do it at the frequency required," Hall says.
A bit of info:
Flaps are not just used for take-offs and landings. Aircraft use flaps in conjunction with ailerons during flight as a way to dramatically increase roll rate. The aerobatic folks know this well!
Soarhead
Isn't this what the Europeans (Eurocopter) started testflying with in an actual BK117 helicopter back in 2005 ;-)
Link: www.eurocopter.com/publications/FO/scripts/newsFO_complet.php?lang=EN&news_id=330
Sorry no on the Turbine blades
Sorry they won't work on turbine blades, beside they deflect very minimally and produce minimal vibration, (they are short and stiff)
Commercialization
Innovation Management
It is about time they applied active control to the helicopter blades!
If this increase efficiency this may be a standard addition to every helicopter.
Brian Glassman
Commercialization
Innovation Management
The technology is still in its infancy and it can play a major role in building truely stealth Helicopters and not just the ones under an electronic cloak. In other words, the technology has more applications in Defense than in any other area.... so you can expect it to be available to public in about 2 dacades or so.
Moreover the technology is too expensive to be used in commercial noisy wind turbines.. at least for now.
For turbines in engines... the material has to withstand the thermal loads. At later stages the piezoelectric coatings may be used on the tips of the turbine blades so that manufacturing is made easy while the close tolerances in the engine maybe achieved dynamically through electronic control.
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ms
190 Comments
Turbine blades?
Could this same technology improve the efficiency of wind turbines?
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prechtl
1 Comment
Re: Turbine blades?
I believe so. Aeroelastically, (wind) turbine blades are closely related to helicopter blades. Thus, the same kind of performance benefits possible in helicopters can likely be realized in wind turbines. This technology, applied to (wind) turbine blades, offers the operational freedom to reduce hub bearing loads, improve turbine efficiency, or decrease noise as required based on wind conditions...
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