CLIMB

Question 1

What is Vx?

Answer 1

Best angle of clmib speed giving us the best altitude gain per unit ground distance covered

Question 2

What increases the AOC?

Answer 2

Excess thrust

Question 3

What is the best speed to get best AOC?

Answer 3

Vmd, since it gives most excess drag

Question 4

Why is speed for best AOC lower on a propeller aircraft?

Answer 4

Thrust available decreases with speed because the propellers AOA decreases with forward airspeed
Vx is slower than Vmd due to this

Question 5

How are the following factors affecting Vx?

1. Weight
2. Configuration
3. Density altitude
4. Wind

Answer 5

1. Weight:
   Drag curve moves up and right cause induced drag increases. Excess thrust decreases and AOC decreases
   Speed for best AOC increases
2. Config:
   Drag curve moves up and left cause parasite drag increases. Excess thrust decreases and AOC decreases
   Speed for best AOC decreases
3. Density alt:
   Reduces thrust available so excess thrust decreases and AOC decreases
   Vx stays the same as a CAS but increases as a TAS
4. Wind:
   - Air gradients: Start and end points are in the air so they both move and has no effect on AOC.
   Used by CAA to lay down min performance limits
   - Ground gradients: Headwind increases the gradient and Tailwinds decreases the gradient since start point is fixed on the ground.

Question 6

What is Vy?

Answer 6

Best rate of climb speed giving the best height gain per unit time (VSI)
ROC = AOC + velocity on that gradient (AOC+TAS)

Question 7

What increases ROC?

Answer 7

Excess power increases ROC

Question 8

How do we draw the “Power Required Curve”?

Answer 8

Power required = Drag x TAS
Curve is derived for each speed by multiplying the drag at that speed by the TAS
Vmp (0,76 x Vmd) is lower than Vmd
Vy is 1,32 Vmd

Question 9

Define power?

Answer 9

Power is the rate at which fuel must be supplied to allow the engine to make the required thrust. Thrust opposes drag and makes forward motion possible.
Power is needed whenever an aircraft is moving forward even if there is no thrust

Question 10

How is the ROC formula derived from the AOC formula?

Answer 10

AOC = T - D/ W
ROC = TV - DV /W --- T x TAS - D x TAS / W ---            Power avail - Power req / W

Question 11

How are the following factors affect Vy?

1. Weight
2. Configuration
3. Altitude

Answer 11

1. Weight:
   Induced drag increases which leads to Total drag curve moves up and right
   Pwr req curve is based on the drag curve so therefore it goes up-right which reduces excess power which leads to ROC decreases and Vy increases
2. Config:
   Parasite drag increases which leads to Total drag curve moves up and left.
   Pwr req curve moves up-left which leads to excess power decreases which leads to ROC decreases and Vy decreases
3. Altitude:
   Pwr req curve = Drag x TAS. Total drag curve as a CAS doesn’t move with altitude but moves right if drawn against TAS
   For the same CAS the TAS increases with altitude or reduced altitude or density.
   Power available decreases with alt, so for a CAS the Vy decreases with alt if Pwr req curve stays the same
   As a TAS, Vy increases slightly as both Pwr avail and Pwr req curves moves. Pwr avail moves down and Pwr req moves up-right

Question 12

Draw the 4 step picture of the relationship with Vy as an IAS vs TAS

Answer 12

IAS = TAS @ MSL
TAS increases 2% per 1’000 ft
Vy as a TAS increases 1% per 1’000 ft

Question 13

Define:

1. Absolute ceiling

2. Service ceiling

Answer 13

1. Absolute ceiling = ROC is zero

2. Service ceiling = 500 ft/min (Jet) and 100 ft/min (Piston)

Question 14

Minimum trip fuel is achived by climbing the aircraft at what speed?

Answer 14

Vy (get to the most efficient operating environment
quickly, and when there, go for cruise climb as
the aircraft weight reduces in a LRC)