NASA Explores Ways To Quiet Passage To Supersonic Flight

Remember the sonic booms of the 1960s? I do.

Windows shook and sometimes broke. Children were absolutely terrified at the massive claps of thunder that rocked the neighborhood. The sound was like a wall, knocking people and Grandma's favorite glass figurines on their collective butts. It was dizzying. And boy, was Grandma mad.

Now, NASA is working on ways to quiet the sonic storm. Over the very same desert where Chuck Yeager first broke the sound barrier in 1947, the space agency is investigating ways to make supersonic flight kinder and gentler.

But the question is how? Last week, NASA proved a long-held theory that says, changing the shape of the aircraft changes the shape and impact of its passage through the sound barrier.

Even though the sound barrier was broken more than five decades ago, no aircraft has gone quietly into that cold fast place. But by flattening the nose and changing the characteristics of the skin, NASA changed the sound of a Navy F-5E breaking into supersonic flight. Instead of the sharp crack of God's own firecracker, NASA engineers produced a duller boom, something just a bit less earth-shaking.

So What Good Is It?

There are a couple of applications that are immediately enticing. For instance, softening the sonic boom can improve a warplane's stealthiness.

Then there's the possibility that blunting the sonic boom of a passing aircraft could lead to a resurgence in supersonic passenger flight. That's a niche currently unserved. Boeing, of course, dropped plans for its Sonic Cruiser. Next month, the Concorde, the world's only supersonic passenger aircraft, will go the way of the dodo after being retired by both Air France and British Airways.

How They Did It

NASA engineers put a specially shaped "glove" on the nose of the F-5E, then applied a composite compound to the jet's belly. They compared the sonic boom created by the modified aircraft with that of another. "We were all blown away by the clarity of what we measured," said Peter Coen, of NASA's Langley Research Center in Hampton (VA). Cost of the test? A mere $7 million.

FMI: www.nasa.gov