Because there are a wide variety of Lycoming engines in operation, the paragraphs below may be helpful in understanding the different modes of operation required when operating each type at takeoff and climb power settings. The Pilots Operating Handbook for the aircraft in which the engines are installed should be the final authority as to how the engine should be operated.
DIRECT DRIVE ENGINES
Most normally aspirated engines are rated at full power for takeoff and climb indefinitely, provided engine temperatures and pressures are within the green arc area of the engine instruments. Extra fuel, sensible airspeed, and cowl flaps, if available, are all helpful in keeping cylinder head temperatures within desired limits during takeoff or climb.
Climb requirements may vary; as an example, on a warm day with the airplane close to gross weight, and a direct drive engine with a fixed pitch prop, the pilot will need full throttle all the way to cruise altitude. The same airplane on a cold day and lightly loaded may not require full power for climb. After full throttle at takeoff, the pilot may want to reduce power 100 or 200 RPM and still not see performance suffer.
Those direct drive normally aspirated engines with a prop governor are also rated indefinitely at full power, and the manuals all recommend full power for takeoff, but specify a small reduction in power, generally to 85% power climb. Study the specific airplane Pilot’s Operating Handbook for detailed power settings.
GEARED, TURBOCHARGED AND SUPERCHARGED ENGINES
Turning to the more complex powerplants such as the geared, turbocharged and supercharged models, the manuals are quite specific in their description of takeoff and climb techniques. Our geared and supercharged powerplants have a limit of five minutes at takeoff power. However, it is advisable to throttle power to the recommended climb power as stipulated in the manual as soon as takeoff obstructions have been cleared and proper airspeed attained.
The turbocharged Lycomings (including the TIGO-541-E series) do not have a five-minute limit at takeoff power. However, the manual clearly stipulates a reduction to a proper climb power when clear of obstacles, and when climb speed has been established, and cylinder head, oil and turbine inlet temperatures are within limits. Due to the more complete engine instrumentation in the airplane, the manuals allow some leaning at climb, but with the engine instruments indicating within specified limits listed in the airplane manual.
The more complex powerplants (geared, supercharged, and turbocharged) demand smooth, careful operation of the throttle at all times, particularly at high power, but especially when engines and oil are not up to normal operating temperatures such as for the initial takeoff. Overboost or erratic engine operation will result from abrupt movements of the throttle. All supercharged and turbocharged engines must use full rich mixture for all takeoffs regardless of field elevation.