Tuesday, March 27, 2012
Transitioning from a piston to a turbine
In a turbine aircraft, there's no vibration, shock cooling or mixture control to worry about. Turbine engines are smooth, powerful and easy to operate.
Engine and Systems
Forget about vibration, shock cooling, and fiddling with mixtures—turbine engines are smooth, powerful and easy to operate. Starting most turbines basically involves engaging a starter motor, spinning up the turbines and introducing fuel. Starting a turbofan equipped with fully automatic digital engine control (FADEC) is virtually a single-button operation. Unlike starting a piston, you never even think about starting with a weak battery. It takes a lot of juice to get things safely up to speed, and monitoring temperatures, particularly during the start, is a big part of operating any turbine. Once running, a single lever controls power—although, you'll have to get used to the relatively slow "spool-up" time needed to go from idle to full power, which can range from two to eight seconds, depending on the engine. On the other hand, pulling the power to idle happens rapidly and is harmless.
Making the transition into a turbine isn't easy, cheap or quick, but it's possible. Jumping into the left seat opens up an amazing world of performance and capability.Turbine power will quickly transport you into the flight levels, and once you fly with pressurization, it's hard to ever go back. Cabin pressure is provided by a small amount of air siphoned from the engine through a "bleed valve." This air is cooled and fed into the pressure vessel at a continuous rate. Pressure-relief valves, usually located at the rear bulkhead, regulate cabin pressure by controlling the cabin-leak rate. Normally, two valves provide redundant operation with a safety valve to prevent overpressurization. Operation is simple, and many light jets like the Mustang are totally automatic, requiring only the field elevation to be input.
Cessna Citation Mustang
Multi-Engine Turbine Considerations
In the multi-engine turbine world, checklists cover every procedure, and all landing and takeoff speeds are computed for every flight, taking into account aircraft weight, temperatures and field elevation. There are three critical speeds for takeoff; V1, Vr, and V2. V1 is called decision speed. Experience any kind of failure before V1, and you stop on the runway. Lose an engine going faster than V1 and you keep going. Accelerate to rotation speed (Vr), rotate, establish a climb, lift the gear, accelerate to the best single engine climb speed of V2, and at a predetermined safety altitude, accelerate to a "single-engine enroute" speed and raise the flaps.
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Labels: Features, Flight Training, Flying Skills, Learn To Fly, Learning Center, Piston Engines, Turbine Twins, Turbine Singles, Engines