Aircraft Approach and Landing PDF
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Uploaded by MesmerizingPulsar
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Summary
This document discusses aircraft landing performance, including take-off and approach characteristics. It analyzes the factors that determine lift and drag during landing, and explains the concepts of powered descent and flare distance. Key concepts like angle of attack (AOA), parasitic drag, and induced drag calculations, along with the limitations of certain formulas, are also described.
Full Transcript
Landing Performance - During take-off and landing, the CL and CD are determined by 2 things: 1. The AOA 2. The configuration of the aircraft (flap, slats, spoiler and gear extension) - AOA is not considered from the start of the flow seperation up to and inclusing th...
Landing Performance - During take-off and landing, the CL and CD are determined by 2 things: 1. The AOA 2. The configuration of the aircraft (flap, slats, spoiler and gear extension) - AOA is not considered from the start of the flow seperation up to and inclusing the stall - The parasitic drag (CDO) is independent of the AOA - The parabolic characteristics equation is valid Approach Distance - Due to the landing configuration (flaps, slats and gear activated) an idle descent is not possible during a ILS approach, so we have to use thrust This is known as powered descent - Flaps configurations are only be used during landing and take-off, because of it’s increase in drag. - The flaps will be retracted as soon after the take-off to reduce noise for citizens and to save fuel consumption - When the plane is in landing configuration, the CD0 will increase, which means the parasitic drag will increase - The brown(CD0), green (CDi) and dark green (Total Drag), line shows the airplane in clean configuration - The pink line shows the parasitic drag (CD0) increasing when the plane is in the landing configuration - The induced drag (CDi) will increase because of its increasing CL and the Oswald factor decreases slightly because of its changing wind shape These 2 won’t change so much/significant so we can assume that the green line will not change - The dark green line is the clean configuration and will change to the blue line (D) which is the landing configuration - The minimum happens at the lowest speed Flare Distance - Sum of the forces parallel to the TAS are equal to zero because the TAS is constant Y = (D-T)/W - Sum of the force prependicular to the TAS ae equal to the centripetal force r= radius of the arc The formula is limited of use because: - The radius needs to be constant throughout the arc - While the flight angle Y decreases during the flare arc - So the lift has to increase during the flare arc and so does the AOA because the speed is kept constant
