Page 15 - Volume 18 Number 3

usable for crossfeeding, should it be necessary. Boost pumps are switched on for takeoff and landing.Taking Off, 1950’s StyleThe original Twin Bonanza handbooks recommend using 20-degrees of flap for short takeoffs, often required to minimize wear-and-tear on turf runways. However, this assumed the risk of lifting off before the Vmc of 89 mph. Vxse is 100 mph, and all-engines Vy is 123 mph.Opening the throttles on the supercharged engines requires care to avoid exceeding manifold-pressure limitations and resultant detonation; while 48 inches m.p. is the takeoff redline, it’s wiser to use 46 inches or less to be kind to the cylinders. After one minute, normal rated power is limited to 45 inches at 3,200 rpm, where climb rate is 1,300-1,500 fpm, and a typical cruise-climb airspeed is 150-175 mph, producing 500- 700 fpm at a comfortable deck angle.All the GSO-480’s power management is in the hand of the pilot; these are not turbocharged, wastegate-controlled powerplants, so a change in altitude and rpm requires throttle adjustment. However, other than switching the boost pumps off and on, and keeping fuel flowing, there’s little else required; the mixtures are left in full rich until shutdown, because leaning is automatic unless the altitude compensation goes haywire.The big Twin Bonanza trims up and flies as if on rails, a great traveling machine. Cruise rpm is normally maintained in a range near 3,000, with manifold pressure at 30 inches or less. The supercharged airplanes do their best work up high, of course, and can deliver 200 mph or more, despite the airplane’s size. Fuel burn will run at least 20 gph per engine at high cruise, although it’s possible to get down to 18 gph at low settings.Easing throttles back in increments when descending, avoiding low power settings that let the propellers drive the engines, is the secret to prolonging the engines’ life. Planning ahead, leveling off for the pattern, and slowing to 150 mph to extend the gear and initial flaps, brings the airplane down to 120 mph with power left in a comfortable range. Flying the pattern at 100 and easing down to 95 on short final produces a predictable, full-flap arrival.As the progenitor of the King Air, the Twin Bonanza shares many of the King’s admirable flying characteristics and predictable manners. It did its job well, and it provided Beech Aircraft with a pathway to future success through its twelve years of production.And please don’•t call the Twin Bonanza a T-Bone. As the King Air’s honorable ancestor, it deserves more respect than that. T&TMARCH 2014TWIN & TURBINE • 13