“From a charter and passenger carrier standpoint, the wing lockers are awesome,” he says. “They can carry snowboards, hunting gear, golf clubs and skis up to 220 cm [7.2 feet] — things that are difficult to place inside the cabin.”
Wing lockers are available for all King Airs. They are mounted aft of the engine and certified to carry up to 300 pounds per side. They add a total of 16 cubic feet of stowage space, with no performance penalty.
While carrying capacity is important for charter operators, passenger comfort ranks high as well. Kenneth Stave, senior pilot and training captain at West Coast Charters, says one customer refuses to fly any King Air that does not have Raisbeck’s dual aft body strakes because of the differences in the noise level and vibration inside the cabin.
Raisbeck claims the strakes accomplish this by organizing wing root vortices, eliminating separation and reducing drag. The addition of dual aft body strakes also eliminates yaw-damper-inoperative restrictions for the King Air 200 and F90, and increases the altitude restriction for the King Air 350 series from 5,000 feet to 19,000 feet.
The dual aft body strakes are not the only components designed by Raisbeck to reduce noise. The four-blade, quiet turbofan propellers, co-designed with Hartzell, reduce the noise enough to meet even the most stringent noise requirements in Europe. These propellers are included with the Epic Platinum package, but not the Epic Gold on the West Coast Edition I flew. However, with Hawker Beechcraft’s four-blade propellers, the performance is the same — only the noise level is different, Raisbeck says.
A welcome feature on the ramp on the 30 degree C day when I flew the King Air was the air conditioning. One reason the system worked so well is the enhanced-performance leading edges. The more aerodynamic leading-edge shape makes the intercooler inside the wing more efficient, decreases stall speed and increases cruise speed.
Cruise and climb performance are also improved with the ram air recovery system. Small, flaplike pieces are installed at the rear end of the air intake of the PT6A engines, and several seals contain the airflow in one small area. Raisbeck claims this simple system results in an 8 percent increase in available horsepower under certain conditions, 8 to 11 percent block fuel savings and 20 degrees cooler engine ITT (interstage turbine temperature). Also, the ice vanes can be deployed at any time, including taxi and takeoff up to ISA +27 degrees C.
The last performance enhancement designed by Raisbeck is the high-flotation gear doors. These doors fully enclose high-flotation landing gear (a funny-sounding name for a gear that accommodates larger tires), which would normally protrude and create a lot of drag. By eliminating this drag, the high-flotation gear doors increase speed by 8 to 12 knots.