Raisbeck Engineering is introducing new performance mods for Beechcraft King Air 90s and celebrating the arrival on the market of its aft fuselage locker for the Learjet 60. Company founder James Raisbeck told AIN that his firm is now studying Cessna Citations for possible modification opportunities.
Beechcraft will make the new Raisbeck-Hartzell swept-blade “turbofan” aluminum propeller and Raisbeck dual aft-body strakes standard on new production C90GTx turboprops beginning in the fourth quarter of this year. Raisbeck introduced these modifications to the retrofit market for all C90 and E90 King Airs last year.
The four-bladed propeller has a 30-degree sweep and is six inches longer–at 96 inches–than the previous prop. It shortens the C90GTx’s takeoff roll by 600 feet to 1,984 feet and landing roll by 10 percent over a 50-foot obstacle to 2,160 feet (1,580 feet with props in reverse). The new props also allow an rpm reduction for cruise power settings to 1,750 rpm, reducing cabin noise by 1.6 dBA to 74.6 dBA, a level found in most new luxury automobiles. Beechcraft has added other improvements to the new C90GTx including a new high-speed nose gear tire and updates to the Collins Pro Line 21 flight displays.
The Raisbeck upgrade, packaged as the C90GTRx Epic Performance Package, is available as a retrofit to the installed fleet of approximately 150 King Air C90GTx aircraft through all Raisbeck independent and Hawker Beechcraft service centers worldwide. The 2014 price for the retrofit Epic Package is $99,864 plus installation.
The improved performance generated by the King Air C90GTx Epic modification came from a combination of the new turbofan propeller working in concert with the dual aft-body strakes and it takes advantage of the low-speed contribution of the factory-installed winglets on that specific model. The strakes allow for reduced minimum control speed (Vmca) and increased directional stability in all phases of flight. They also reduce the airplane’s aft-body aerodynamic drag, slightly increasing cruise speeds. These strakes were initially certified on the King Air C90 in 1986. Winglets and an increased gross weight make up the balance of the new C90GTx factory offering.
James Raisbeck said the Epic package for new C90GTxs on the Beechcraft production line “completes the penetration of many of our products on all three King Air models in production. The 350 has our strakes and wing lockers and the 250 has our Ram Air Recovery system.”
Raisbeck also recently completed a five-year, $10 million effort to design and certify a new aft fuselage locker for the Bombardier Learjet 60. As part of that effort, Raisbeck completely digitized its engineering department. That $295,000 kit initially will be sold directly to customers instead of through Raisbeck’s dealer network. The price does not include installation, which Raisbeck estimates at 600 to 700 manhours. The dual compartment, 12-foot-long locker weighs 276 pounds and virtually doubles the Lear 60’s luggage capacity, adding 28 cu ft of baggage space with a capacity of 210 pounds. The locker is fully lined and is fitted with fire-detection sensors.
According to Raisbeck, the lockers make the Learjet 60 marginally more aerodynamically efficient due to their shape and aft CG shift, with flight-testing showing an overall improvement of 3 percent. Drag reduction due to the locker’s shape accounts for 1 percent of this while the empty weight addition of the locker contributes an additional 2 percent due to the aft CG shift, which reduces horizontal tail trim drag.
Raisbeck has traditionally offered modifications for King Airs and Learjets but is now exploring the market for Citations as well. The company’s study of Cessna products is being led by Keith Anderson, Raisbeck’s vice president of engineering.
