The Sino Swearingen SJ30-2 flies in the face of conventional business jet wisdom in almost every respect. While the rest of the industry is firmly convinced that passengers demand the greatest possible amount of cabin space and simply won't endure a cramped cabin for very long, the SJ30 delivers coast-to-coast range at a cruise speed of 440 knots in an airplane with the smallest cabin in the category.
The belief that some people want to go as far and as fast as possible for the money, no matter how small the cabin, stretches back 20 years to when Ed Swearingen announced development of what he then called the Swearingen Fanjet. The airplane would take advantage of a brand new compact engine from Williams and would have 1,800-nm range cruising at Mach .72. The initial price in 1986 was set at $1.6 million, which was below the leading turboprop twins available at the time.
Swearingen has spent a lifetime in business aviation and is most famous for creating the Merlin and Metro turboprops. He also collaborated on the design of the Lockheed JetStar II, the Piper Twin Comanche, and was a protégé of Bill Lear, first at his avionics company and then at Lear Jet. Ed has even developed serious and complete designs for a supersonic business jet. Throughout his life, speed and range have been at the top of his list of airplane design priorities.
Ed then, and still, believes that business jet designers squander speed by using wings that are too big and cabins that are too large. A small, highly swept wing reduces drag. To reduce stall speed, and thus landing and takeoff speeds, Ed installs nearly full span leading edge slats and very large flaps, just like Boeing and the other big boys do. And as for comfort in a small cabin, in his view just put in good seats because people don't want to stand up and walk around, anyway. They just want to go fast and far.
The 20-year odyssey from the Fanjet to the certified SJ30-2 had many fits and starts. For a time Ed teamed with Gulfstream and the airplane was called the Gulfjet. Later, he partnered with the Jaffe Group and the name was changed from the SA30 to the SJ30. Along the way a proof-of-concept airplane was built and flew in 1991. The airplane had significant anhedral-negative dihedral-that brought the wingtips alarmingly close to the runway. The SJ30 also had fuel stored between the engines which, when certification rules changed, was no longer permissible because if one of the jet engines burst the shrapnel could easily pierce the fuel tanks.
The solution was a fuselage stretch that got the fuel ahead of the engine rotor burst zone, and a wing span increase to carry the extra weight. The new airplane was named the SJ30-2, and in 1996 a consortium of Taiwanese investors bankrolled the company and it was named Sino Swearingen. Full type certification was achieved last fall, including for flight in icing, but the first airplane had not yet been delivered by late summer of this year. The price is just over $6 million, and the company has several hundred orders.
The SJ30-2 wing has only 190 square feet of area, only a little more than a typical piston single. But the airplane can weigh up to 13,950 pounds for takeoff so each square foot of wing is called upon to lift 73 pounds. As a comparison, the Cessna CJ3, the current leader in light jet sales, has a wing loading of 47 pounds per square foot. The small wing, along with 32 degrees of sweep, reduces cruise drag in the SJ30-2, but the tradeoff is higher stall speed, small fuel capacity and no place to put the landing gear when retracted.
The SJ30-2 has nearly full span leading edge slats that extend to increase the camber of the wing at low speeds. The slats, combined with large slotted flaps, reduce stalling speed enough so that typical landing Vref approach speeds are between 100 and 105 knots. However, the slats and large flaps add weight and complexity to the airplane, and reduce internal volume for fuel storage in the already small wing. Only 1,820 pounds of total fuel capacity fits in the wings.