ENGINE PERFORMANCE The performance data for takeoff and landing an aircraft can be obtained from the aircraft's flight manual or pilot's operating handbook. The actual performance of an aircraft is affected by many variables which must be taken into account.

ENGINES There are four types of engines in use on modern airplanes: 1. Reciprocating Engine – most efficient cruising speed < 250 MPH 2. Turboprop – works best in 250 to 450 MPH 3. Turbofan – most efficient above 450 MPH 4. Turbojet – most efficient above 450 MPH The Landing Climb Limit Weight is also known as a go-around scenario. Calculate all three and use the lower number.

ENGINES Manifold pressure (MAP) is a measurement of the power output of a reciprocating engine, pressure at the engine’s air inlet. In normal-aspirated (unsupercharged) engines MAP will drop as the aircraft climbs to altitude. Must be careful to observe published limits on MAP and RPM; high RPM and low MAP can produce severe wear, fatigue and damage Most piston-powered airplanes flown by air carriers are turbocharged. Exhaust gas from the engine is used as a power source for a compressor that in turns raises the MAP at any given altitude. The term Critical Altitude is used to describe the effect of turbocharging on the aircraft’s performance; highest altitude at which a desired MAP can be maintained.

ENGINES Turboprops, turbofans and turbojets are types of gas turbine engines. Turbine engines are classified by the type of compressors they use: Centrifugal flow, axial flow, centrifugal-axial flow Consists of Inlet Section, Compressor Section, Combustion Section, Turbine Section and Exhaust Air enters inlet at ambient temperature/pressure Compressor increases temperature/pressure due to heat compression Bleed air is tapped off for accessories Diffuser connects Compressor and Combustion Sections – slows air stream and increases pressure Combustion Section mixes air and fuel and is ignited Combustion increases volume and exits through turbine section Temperature rises rapidly as it passes from front to rear of combustion sect and reaches is highest point at the turbine inlet – could reach 4,000 degree F Turbine drives the compressor

ENGINES Jeppesen computes V1 for its customers based on the worst performing jet aircraft is use – the B747-100 with the smaller engines. They guarantee that if your pilots reject at or after V1, that they will clear all obstacles on departure as their aircraft will out perform a B747-100.

ENGINES Combination of slow airspeed and high engine RPM causes Compressor Stall Occurs when the angle of attack of the engine’s compressor blades becomes excessive and they stall If transient - will hear an intermittent “bang” as backfires and flow reversals in the compressor takes place If it develops to steady state – hear a loud roar and experience severe engine vibrations If it occurs, reduce fuel flow, reduce aircraft angle of attack and increase airspeed Jeppesen computes V1 for its customers based on the worst performing jet aircraft is use – the B747-100 with the smaller engines. They guarantee that if your pilots reject at or after V1, that they will clear all obstacles on departure as their aircraft will out perform a B747-100.

ENGINES Turboprop is a turbine engine that drives a conventional propeller. Can develop much more power per pound than can a piston engine More fuel efficient than the turbojet engine Limited to slower speeds and lower altitudes 25,000 feet to the tropopause The term Equivalent Shaft Horsepower (ESHP) is used to describe the total engine output. Term combines its output in shaft horsepower (used to drive the propeller) and the jet thrust it develops Jeppesen computes V1 for its customers based on the worst performing jet aircraft is use – the B747-100 with the smaller engines. They guarantee that if your pilots reject at or after V1, that they will clear all obstacles on departure as their aircraft will out perform a B747-100.

ENGINES As density altitude is increased, engine performance will decrease. Air becomes less dense, there is not as much oxygen available for combustion and potential thrust output is decreased. Density altitude is increased by increasing pressure altitude or by increasing ambient air temperature. Relative humidity will also affect engine performance Reciprocating engines in particular experience a significant loss of BHP (Brake Horsepower. Turbine engines are not affected as much by high humidity and will experience very little loss of thrust. Jeppesen computes V1 for its customers based on the worst performing jet aircraft is use – the B747-100 with the smaller engines. They guarantee that if your pilots reject at or after V1, that they will clear all obstacles on departure as their aircraft will out perform a B747-100.

ENGINES Jeppesen computes V1 for its customers based on the worst performing jet aircraft is use – the B747-100 with the smaller engines. They guarantee that if your pilots reject at or after V1, that they will clear all obstacles on departure as their aircraft will out perform a B747-100.