Alternative Energy

We use helicopters for medical emergencies, search operations, traffic reporting or protecting celebrity privacy from paparazzi. They are loud, give us bumps (not birthday bumps) and are considered not very efficient and comfortable for daily travel. But NASA wants to give them a makeover. They are researching into shape of rotor blades and material used for constructing those blades. This may ease the load on domestic airports and aircrafts. They may carry (in near twenty years) at least hundred passengers to their destination without loud noise and bumps. We may prefer helicopters for shorter destinations.

William Warmbrodt, who is the chief of the Aeromechanics Branch at NASA’s Ames Research Center in California, states, “Today’s limitations preclude us from having such an airplane. So NASA is reaching beyond today’s technology for the future.” NASA and the Defense Advanced Research Projects Agency, also known as DARPA, the U.S. Army, and The Boeing Company have utilized the past ten years experimenting with smart material actuated rotor, or SMART, technology. Warmbrodt again assures us of the further advantages of the SMART rotor technology. He says, “SMART rotor technology holds the promise of substantially improving the performance of the rotor and allowing it to fly much farther using the same amount of fuel, while also enabling much quieter operations.”

The researchers concentrated on rotor blades which are made up of piezoelectric materials that flex when subjected to electrical fields. They work differently from the way human muscles work when stimulated by a current of electricity sent from the brain. Helicopter rotors depend on passive designs. The blade shape is very crucial to optimize the efficiency of the system. If we compare them with airplane’s wings we can detect the difference such as flaps, slats and even the ability to change its shape in flight. NASA researchers and others are attempting to integrate the same uniqueness and capability in a helicopter blade.

The SMART Rotor technology can diminish noise significantly. They have successfully experimented with the only full-scale SMART Rotor ever constructed in the United States. This SMART rotor was run through a series of wind tunnel tests between February and April 2008 in the National Full-Scale Aerodynamics Complex at Ames. The SMART Rotor partners also witnessed the whole exercise with the U.S. Air Force, which operates the tunnel. They simulated the typical conditions that rotors can experience in high-speed forward flight. The trailing end flap was tested in the 40- by 80-foot tunnel in 155-knot wind. The rotor also was put to the cruise speed conditions of 124 knots. This situation pointed out which of three trailing edge flap patterns produced the least vibration and noise.

Results were not disappointing. A SMART Rotor can reduce by half the amount of noise it puts out within the controlled environment of the wind tunnel. The actual litmus test of the SMART rotor noise reduction capability will only be passed when this technology is actually used on a real helicopter during a commercial flight in the open, under the natural environment.

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