An article I read at work yesterday...
"Merrill, a wiry 73-year-old, tells me that, compared to current propeller-driven light airplanes (which he dismisses as “archaic crap”), the airplane on his wall will fly twice as fast, get better fuel mileage, and be 30 times quieter."
"The results of optimizing a turbofan engine for low and slow are breathtaking—on paper, at least. According to Merrill’s numbers, his theoretical 490-pound-thrust turbofan would, at 10,000 feet, push along his theoretical two-seat Cloudster airplane at 270 mph while burning 12 gallons of fuel per hour. That’s 22 miles per gallon—about the same fuel efficiency that Cessna claims for its two-seat, propeller-driven 152, which flies not even half as fast. Climb to 23,000 feet, and the Cloudster will do 220 mph while burning seven gallons per hour. That’s 31 miles per gallon. So much for the notion that jets at low altitude suck too much fuel, Merrill says."
It was here that Merrill first launched his quixotic quest to create a small turbofan for private airplanes—and where he first felt the sting of rejection and betrayal. In 1966, Foster and Merrill started work on a small general aviation jet engine. Their design for a 1,300-pound-thrust turbofan with a bypass ratio of 3:1 was a radical departure from the general aviation jet engines of the day—noisy, fuel-hungry turbojets with around 3,000 pounds of thrust. When Foster and Merrill first pitched their idea for a quiet, fuel-efficient turbofan to Cessna, the company was interested. But Cessna president Dwayne Wallace kept asking for more power, Merrill says, and the proposed Teledyne engine eventually grew to 2,100 pounds.
But then, according to Richard A. Leyes’ book, The History of North American Small Gas Turbine Aircraft Engines, “Wallace...called Bill Gwinn, president of United Aircraft Corp., explaining that Cessna wanted to build a small jet, and that they wanted a Pratt & Whitney engine on it. Gwinn then called Pratt & Whitney Canada president Thor Stevenson, and the next day P&WC engineers were designing their first fanjet engine.”
“Wallace wanted a screaming eagle logo on the nacelle,” Merrill says bitterly, referring to the Pratt & Whitney logo. “So he passed on the specs of our engine to Pratt & Whitney.” Whatever the case, in 1969 Pratt & Whitney delivered to Cessna the first JT15D, a 2,200-pound-thrust turbofan with a bypass ratio of about 3:1. Cessna used it to power its new Citation 500, which quickly became the world’s best-selling business jet. The JT15D is still in production today.
http://www.airspacemag.com/issues/2008/ ... rbines.php