Page 20 - Volume 16 Number 2

zero-fuel weight li mitation, making it more reasonable to consider the 421 a six-seat airplane, even though it’s officially certificated for up to ten.
Getting Underway
Starting is typical of big Continentals, priming up fuel pressure then releasing the primer to crank. Beginning in 1981, a seventh primer nozzle at the top of the intake manifold allowed starting in idle- cutoff, as an alternate method. Once awakened, the distant engines are quiet and smooth; the tachs display propeller rpm, not actual engine revs, so when the runup is performed at 1,500 rpm, the engine is turning about 2250. Taxiing is routine with the bungee-softened nosegear steering, requiring only mild rudder pressure; the 17-foot-wide maingear calls for adhering to the centerline on narrow taxiways. However, the prop spinners are in line with the maingear, making it easy to track the gear when turning.
Pretakeoff checks are reasonably few; run-up, verify desired pressur- ization altitude and rate, place fuel pumps on “low”, and turn the air conditioner off just before departure. There are no cowl flaps, wing flaps are left up and the prop synchrophaser can be left on. As with all turbocharged engines, a pause after bringing power to 25 inches or so allows the turbos to stabilize, then power is fed in to 39.5 inches, verifying fuel flows. The 421C’s 750 horsepower makes for spritely acceleration unless heavily loaded. Vmc is 80 knots, but rotation is delayed to 95 knots, just below Vxse of 105; Vy and Vyse are both 111 knots. Liftoff takes about 2,000 feet of roll; Cessna’s accelerate/stop numbers are around 3,200 feet, but sticking to 4,000-foot runways is a better procedure.
Gear up with power back to top- of-the-green, 32.5 inches and 1900
rpm, produces a good cruise-climb at 125 knots, showing about 1,000 fpmonafuelflowof25gphper side. The rate drops to 800 fpm at the VFR limit of 17,500 feet, where the 421 does some of its best work. Leveling off there, leaving the power as is and leaning for cruise, produces around 220 KTAS, using 22 gph per engine. Pulling the props back to 1700 rpm, for about 65% power, quiets things down and gives 205-208 KTAS at 20 gph per side. To coast with a tailwind, reducing power to 31 inches and 1600 rpm drops TAS to just under 200 knots but cuts fuel flow to 17 gph per engine.
Chris Van Ginkel, 421C pilot with Sioux Center Aviation in Sioux Center, Iowa (KSOY), says he plans for 180 knots at 4,000 feet, increasing 2 knots per thousand feet of altitude. He sees 210 knots at FL210, burning 21 gph per engine at 65%, leaned 75-degrees rich.
18 • TWIN & TURBINE
FEBRUARY 2012