22.20.10
Explain the factors affecting climb performance (power applied, airspeed, flap and/or undercarriage extension, weight, altitude, temperature, manoeuvring, and wind - in relation to net flight path).

Power applied;  Reducing power reduces climb performance. This is because the excess power required is reduced. Both climb rate and angle of climb will be reduced

Airspeed;  Flying at any speed other than best rate speed will reduce climb performance.

Flap and/or undercarriage extension;  Extending flap, particularly full flap will decrease climb performance, because for almost all aircraft the L/D ratio is reduced and the power required to maintain any speed is increased

The angle of climb will be reduced with any flap extended, because there is an overall poorer L/D ratio. Some aircraft flight manuals recommend flap for takeoff. This is to minimise the time the aircraft spends on the ground

If an aircraft with retractable undercarriage is left with the undercarriage extended the drag is increased and climb performance will be reduced

Weight;  Increasing aircraft weight will reduce climb performance. The power required to maintain any airspeed in level flight increases with weight. Therefore there is less excess power available for climb

Altitude;  The decrease in air density as altitude increases decreases performance in both the engine and aerodynamically

Temperature; If the air temperature is higher than standard climb performance will be reduced

Manoeuvring; Any manoeuvring while the aircraft is in the climb will absorb some or maybe all of the excess power available reducing climb performance

Wind; A headwind or tailwind will affect the climb angle over the ground but not the rate of climb

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22.20.8
Define absolute ceiling and service ceiling.

Service ceiling is the altitude at which the aircraft can still maintain a climb at 100 feet per minute. 

Absolute ceiling is the altitude at which the aircraft is no longer capable of climb.

                                        

22.20.6
State what the Vx and Vy speeds are and differentiate between these speeds and the normal climb speed.

Vx is also known as Maximum angle of climb. It is the airspeed where the aircraft will climb at it’s steepest possible angle. This speed is used where obstacle clearance is an issue.

Vy is also known as Maximum rate of climb. This airspeed is used to gain the most altitude in the least amount of time.

The normal climb speed also known as cruise climb is used when climbing long distances for cross countries etc. It has a lower climb rate than Vy but it has a lower nose attitude which aids cooling and gives better visibility.

                               

22.20.4
Given typical power required and power available curves, explain:
(a) how a curve of excess power available (EP) can be derived;
(b) where the speeds for maximum rate of climb, and maximum angle of climb occur on the EP curve.

(a) A Power required/ Power available curve is derived by flight testing the aircraft and measuring the results.

(b) The speed for maximum rate of climb is the point on the Power available/ Power required graph where there is the greatest distance between the two curves.

The speed for maximum angle of climb is a line drawn from the origin of the graph tangentially to the Power required curve. Where the two touch is maximum angle

                

22.20.2
Identify the forces acting in a steady climb.

By understanding these forces you can understand the climb and get the best performance out of the aeroplane

Weight acts towards the centre of Earth,  Due to the angle of the flight path the weight now acts towards the rear of the aircraft. This is similar to a car rolling backwards down a hill. A portion of weight acts opposite to lift as seen on the diagram. This is less than the total weight of the aircraft. 

Drag is still acting on the aircraft. It is similar in size to straight and level flight. Thrust must be  equal to

 drag, and must be increased to overcome the rearward component of weight so the aircraft can climb. In a steady climb the forces are in equilibrium. 

                        

                                                       L<W

                                                 T=D + RCW

Given typical power available and power required curves, explain:
(a) the maximum and minimum speeds for level flight;
(b) the effects of increased weight and altitude.

                    

(a) The minimum speed is basically the stall speed of the aircraft. The maximum speed is the point where the power required and power available curves meet.

(b) Weight affects the aircraft because every weight increase requires a higher angle of attack to maintain level flight. This has the effect of moving the power required curve up as increased power is required to maintain level flight at all speeds

Altitude also has an effect, If the aircraft is flown at a constant IAS as altitude is gained, TAS is going to have to increase. Because Power = Drag X TAS this means for a constant IAS any increase in altitude will require an increase in power

Also the power available will be decreasing as altitude increases. Eventually the lines on the graph will come together and maximum performance will have been reached 

22.18.8
For unaccelerated level flight:
(a) state the power required formula (Power = Drag x TAS);
(b) explain the difference between the drag curve and the power required curve;
(c) distinguish between the minimum drag speed and the minimum power speed.

(a) Power required = drag X TAS

(b) The drag curve which also represents thrust required, is the total drag of the aircraft based on the airspeed of the aircraft. As parasite drag is low at low airspeed and induced drag is high, there is a point on the curve where drag is at the minimum. The power required curve is the total power needed to maintain level flight at that TAS

(c) Minimum drag speed is the point on the graph where drag is the lowest. This is the maximum range speed. The minimum power speed is the lowest power required on the graph. This is the maximum endurance speed.

22.18.6
Explain the power and attitude relationships at various airspeeds in straight and level flight.

Attitude + Attitude = Performance

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22.18.4
For a conventional aeroplane configuration, describe:
(a) the lift/weight and thrust/drag couples;
(b) pitching moments and the tailplane stabilising moment;
(c) pitching moments caused by power changes, undercarriage and flap extension.

(a) The lift and weight are coupled through the aeroplane with a moment arm, this arm will cause the aircraft to pitch down generally.
The thrust drag couple also acts through the aircraft via a moment arm. This couple will cause the nose to pitch up.

(b) The tailplane provides a down force which balances the lift weight couple meaning the aircraft can maintain straight and level flight.

(c) Changing power will cause the aircraft to pitch. Increasing power will cause a nose-up pitching moment and reducing power will cause a nose-down pitching moment. 

Lowering the undercarriage will cause a nose-down pitching moment, as will lowering the flaps on a low wing aircraft. Lowering the flaps on a high wing aircraft will cause a nose up pitching moment.

                                   

22.18.2
Explain the four forces acting and the conditions required for steady straight and level flight.

There are four forces acting on the aircraft in level flight. This is useful to us as it will help us understand what is happening when we fly the aircraft.

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