CHAPTER I THE PROBLEM AND ITS BACKGROUND

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 LFnew/LForiginal = (Vnew/Voriginal)^2

 Flap extension causes a reduction in stall speed and the maximum glide distance.

 The Principle of Continuity states: "If the cross sectional area of a streamlined

flow of subsonic air is increased, the flow velocity will decrease".

 The Continuity equation is: "Cross-sectional area (A) x Velocity (V) = Constant".

 The illustration shows the relationships between CAS (C), TAS (T) and Mach

number (M) with changing Pressure Altitude. It can be seen that when in a climb

above the tropopause at a constant Mach number the TAS must remain constant.



 VS0 is the stall speed in the landing configuration

 VS1 is the stall speed in a specified configuration

 VS1g is the minimum speed at which the aeroplane can develop a lift force

(normal to the flight path) equal to its Weight

 The reference stall speed is VSR

 The Induced Drag coefficient formula is: CDi = (CL)2 / Aspect Ratio

 Tip vortices are weaker when the aircraft is close to the ground (within half a

wing span). The illustration shows that when an aeroplane is out of ground effect,

the induced downwash (angle) is increased and consequently the induced angle of

attack is increased.

 The angle of attack of an aerofoil section is defined as the angle between the

undisturbed airflow and the chord line.

 As flaps are deployed the wing camber increases and sometimes, in addition, the

wing area. So if a constant angle of attack is maintained, the Lift coefficient

would increase.

 The illustration shows a slat (a moveable part of the leading edge, which when

activated forms a slot at the wing leading edge). The slot thus formed, directs high

energy air onto the wing upper surface which increases the boundary layer kinetic

energy on the top of the wing and delays the stall to a higher angle of attack

It can be seen from the illustration that slats do not change the camber of the wing

because the Lift curve is merely extended

 Regarding subsonic airflow in a ventury:

1. the dynamic pressure in the undisturbed flow and in the throat are not equal

2. The total pressure in the undisturbed flow and in the throat are equal

3. Static pressure acts in all directions

 Stall speed (IAS) varies with weight.

 The Lift formula is: L = 1/2rho V2 CL S, where rho is the air density, V is the

True Airspeed (TAS), CL is the Lift coefficient and S is the wing area. Together,

1/2rho V2 = Dynamic Pressure (q). Although the question asks you to consider

the Lift formula, it is actually necessary to consider how the Airspeed Indicator

works. We know from the Dynamic Pressure formula (q = 1/2rho V2), if we

double the speed of the aircraft through the air (double the TAS), Dynamic

pressure (q) will be four times greater but because of the square root gearing

inside the ASI, the Indicated Airspeed will only double. If you now put four times

the Dynamic Pressure into the Lift formula, it is clear that the Lift will be four

times greater.

If you prefer the math’s explanation, IAS is proportional to the square root of

Dynamic Pressure (q). Transposed this becomes Dynamic Pressure (q) is

proportional to IAS squared.

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POF LFnew/LForiginal = (Vnew/Voriginal)^2 Flap extension causes a reduction in stall speed and the maximum glide distance. The Principle of Continuity states: "If the cross sectional area of a streamlined flow of subsonic air is increased, the flow velocity will decrease". The Continuity equation is: "Cross-sectional area (A) x Velocity (V) = Constant". The illustration shows the relationships between CAS (C), TAS (T) and Mach number (M) with changing Pressure Altitude. It can be seen that when in a climb above the tropopause at a constant Mach number the TAS must remain constant. VS0 is the stall speed in the landing configuration VS1 is the stall speed in a specified configuration VS1g is the minimum speed at which the aeroplane can develop a lift force (normal to the flight path) equal to its Weight The reference stall speed is VSR The Induced Drag coefficient formula is: CDi = (CL)2 / Aspect Ratio Tip vortices are weaker when the aircraft is close to the ground (within half a wing span). The illustration shows that when an aeroplane is out of ground effect, the induced downwash (angle) is increased and consequently the induced angle of attack is increased. The angle of attack of an aerofoil section is defined as the angle between the undisturbed airflow and the chord line. As flaps are deployed the wing camber increases and sometimes, in addition, the wing area. So if a constant angle of attack is maintained, the Lift coefficient would increase. ...
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