Aircraft design pioneer Ed Swearingen is as convinced today as he was 30 years ago that business aircraft manufacturers are selling their customers short by delivering products that still don’t get close to airliners in terms of efficiency. Why? Essentially, because they are still designing business jets as if they were powered by turboprop engines, the veteran told an April 11 press briefing in London.
When the SJ30 was just a twinkle in Swearingen’s eye, he used to gaze out of airport windows at the new-generation jetliners and wonder why they had a performance edge on business aircraft. Eventually, this inspired him to take a design leap toward smaller, more efficient wings and specially conceived airfoils, as opposed to “cookbook” airfoils, he said.
“If you shape the aircraft for higher speed you are getting a discount on the engine’s performance,” he argued. “This is what has allowed the SJ30 to give people the range and speed they really want at an affordable price.” He added that most business jets have about three pounds of weight for every pound of thrust, compared with the typical 4:1 ratio of airliners.
“You need to use all available technology, including an uncompromised high-speed wing, airfoil and swept wing to get more airflow to the engine,” Swearingen concluded. He remains an advisor to the Sino-Swearingen board but is no longer a company officer.
Swearingen offered an example of what the difference in performance can mean in practice. He told the press of a recent trip where he and a group of colleagues were to travel from Martinsburg, West Virginia, to San Antonio. There wasn’t room for them all in the SJ30-2 prototype and so they chartered a Bombardier Learjet 35 to carry some of the passengers.
The SJ30-2 took off with almost a full fuel load of 4,800 pounds. The Lear 35 departed with 6,800 pounds. For much of the flight the two aircraft faced high 175-knot headwinds which forced the Learjet to refuel, while the SJ30 made it to Texas nonstop, and with enough reserves to have continued into New Mexico.