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Syllabus Dot Point
fundamental flight mechanics
– relationship between lift, thrust,
– weight and drag
– lift to drag ratio
– effect of angle of attack
Compile a list of each part of a plane. Write a brief description of its function.
An aircraft in flight is acted upon by four forces:
Gravity or weight—the force that pulls the aircraft toward the earth. Weight is the force of gravity acting downward upon everything that goes into the aircraft, such as the aircraft itself, crew, fuel, and cargo.
Lift—the force that pushes the aircraft upward. Lift acts vertically and counteracts the effects of weight.
Thrust—the force that moves the aircraft forward. Thrust is the forward force produced by the powerplant that overcomes the force of drag.
Drag—the force that exerts a braking action to hold the aircraft back. Drag is a backward deterrent force and is caused by the disruption of the airflow by the wings, fuselage, and protruding objects.
These four forces are in perfect balance only when the aircraft is in straight-and-level unaccelerated flight.
Winglets
Watch the youtube clip on winglets and answer the following questions in your workbook.
What is the difference between induced drag and parasitic drag?
Outline how winglets improve efficiency of an aircraft.
Wingtip vortecies
Lift to Drag ratio
Lift to Drag ratio
In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under given flight conditions. The L/D ratio for any given body will vary according to these flight conditions.
Angle of attack and aerodynamics can be applied to F1 racing cars and also high performance sailing boats.
Angle of Attack
Angle of Attack
As a wing moves through the air, the wing is inclined to the flight direction at some angle. The angle between the chord line and the flight direction is called the angle of attack and has a large effect on the lift generated by a wing. When an airplane takes off, the pilot applies as much thrust as possible to make the airplane roll along the runway. But just before lifting off, the pilot "rotates" the aircraft. The nose of the airplane rises, increasing the angle of attack and producing the increased lift needed for takeoff
What happens if the angle of attach is to great?
A 3250 kg aircraft is flying in level flight at constant speed. Draw a free-body diagram showing weight, thrust, lift and drag. Calculate the thrust on the plane if the lift to drag ratio of the aircraft is 12 : 1.
Free Body Diagram
Lift to drag ratio L = 12 where L = W therefore L = 32500N
D 1
32500 = 12
D
Therefore D = 32500
12
D = 2708 N
Therefore thrust = 2708N
View the two google slides.
Complete the mechanics questions given in your workbook. You will find completing the questions graphically will be easier than doing mathematically.
Online HSC_3.13_Fundamental Flight Mechanics.pptxOnline HSC_3.13_Fundamental Flight Mechanics_2.pptxCopy of Answer 13.1.pdfCopy of Answer 13.2.pdfCopy of Answer 13.4.pdfCopy of Answer 13.5.pdfCopy of Answer 13.6.pdfCopy of Answer 13.7.pdfPage updated
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