Climb Flashcards
An aircraft’s climb capabilities come from …
excess thrust
For a steady climb to be maintained the thrust and the two retarding effects of … and … must be equal
This can be written as a formula T = …
And can be transposed to read …
This formula gives climb gradient as a number, to convert to percentage just multiply the answer by …
aerodynamic drag
the weight element (weight apparant drag)
D + W (sin theta)
Sin theta (climb gradient) = T – D/W
100
Vx for a jet aircraft is …
Vmd
Vx for a prop aircraft is …
1.1 Vs
what are the affect of flaps on climb gradient?
increasing flap setting increases drag and the increased lift has no benefit on climb gradient so climb gradient reduces when using flaps
what effect does mass have on Vx?
an increase in mass increases induced drag due to more lift but the profile drag remains unchanged. As the total drag increases (see graphs on flap settings) Vs and Vmd increase. This means than an increase in mass increases Vx for both jet and prop aircraft
what effect does lowering flaps have on Vx?
when flap setting is increased the wings ability to produce more lift increases but the actual amount of lift used does not change (as it only balances the weight), the profile drag does however increase and therefore Vmd decreases (see flap setting graphs again). This means that as flap setting is increased Vx decreases
what effect does increased altitude and temp have on both climb gradient and the value of Vx?
the drag for a given EAS stays the same with variations in temp and pressure but the thrust does not. Because thrust reduces at high temps and low pressures, either of these will produce a decrease in climb gradient
thrust reduces with increasing temp or reducing pressure but the EAS at which the greatest excess thrust is found remains substantially the same. This means that the EAS of Vx is unchanged with altitude
V2 for two and three-engine turboprops, and jets without provisions for obtaining a significant reduction in the one-engine inop power-on stall speed is the higher of …
(4 speeds)
- 13 Vsr
- 10 Vmc
Vr plus the speed increment attained before reaching a height of 35 ft above the take-off surface
A speed that provides adequate manoeuvring capability
V2 for turboprops with more than three engines and jets with provisions for obtaining a significant reduction in the one-engine inop power-on stall speed is the higher of …
(4 speeds)
- 08 Vsr
- 10 Vmc
Vr plus the speed increment attained before reaching a height of 35 ft above the take-off surface
A speed that provides adequate manoeuvring capability
Remember that V2 is only used as the initial target speed in the climb for jets if an engine has been lost on the take-off run
In the all engines case a jet is usually accelerated to … after rotation because it gives a better angle of climb, a more manageable pitch attitude and, if and engine fails, the climb gradient will be better than calculated for the situation where an engine fails at Vef
V2 +10kt (V4)
After engine failure at Vef and the take-off continues, V2 must be achieved by …ft and maintained to …ft above the take-off surface
35
400
What is the minimum climb gradient (climb/WAT limit) for
two-engine aircraft?
three-engine aircraft?
four-engine aircraft?
- 4%
- 7%
- 0%
the net take-off flight path is the gross take-off flight path reduced by the regulatory requirement of …
… for a twin
… for three engines
… for four engines
- 8%
- 9%
- 0%
Turns in take-off path are permitted but avoided whenever possible
No turns allowed below …ft or …, whichever is greater
Bank angle limited to … degrees below … ft and … degrees thereafter
50ft
half a wingspan
15
400
25
The NTFP is divided into four segments
Segment 1 starts at the … above reference zero at V2 and ends when …
Segment 2 is flown at V2 to … gross (It can be higher provided Segment 3 is completed within the time limitation for maximum take-off thrust-see note below.)
Segment 3 is flown …, … and … on schedule to VFTO, the final take-off speed
Segment 4. At this point MCT is set and segment 4 is from 400ft, (min ha) to …ft where the aircraft is said to be en-route
screen height, 35ft
the gear retraction is complete
400ft (the minimum acceleration altitude)
level, accelerating and retracting flap
1500
best rate of climb depends on …
excess power
rate of climb formula from power =
(power available - power required) / weight
Vy for a jet is quite … and the speed can vary widely from the optimum and not affect rate of climb much
Vy for a prop is quite … and speeds above the optimum do not affect rate of climb much but speeds below Vy lead to very low climb rates
high
low
what is the effect of altitude and temp on rate of climb?
as aircraft climbs thrust reduces and therefore power available reduces. Drag remains constant for a fixed EAS but drag times TAS (power required) increases as the TAS increases. As the power available decreases so does the rate of climb with an increase of height and also decreases with an increase in temp
what is the effect of mass on rate of climb?
because the rate of climb is the difference in power available and power required over weight, an increase in weight will decrease rate of climb
what happens to the value of Vy with increasing mass?
Increasing mass increases induced drag due to increased lift and therefore has the effect of lifting the left-hand side of the power required curve
This leads to an increase of Vy as mass increases
How does wind affect rate of climb?
it doesn’t!
What happens to Vy with an increase of altitude?
As altitude increases thrust reduces. This and the changing relationship between IAS and TAS move the power available line down and the power required line up and to the right to increase the TAS for best rate of climb as altitude increases
For a given TAS the IAS reduces with an increase in altitude. The reduction in IAS is faster than the increase of TAS with increasing altitude so the overall result is that the indicated speed Vy decreases as height increases because Vy is an IAS
lowering flaps or gear has what effect on Vy?
Increased flap and the use of gear increase the profile drag which has the effect of lifting the right-hand side of the power required curve. Increasing flap reduces Vy
with increasing altitude or temp
rate of climb …
Vy is …
reduces
lower
with increasing mass
rate of climb …
Vy is …
reduces
higher
increasing flap angle
rate of climb …
Vy is …
lower
lower
increasing altitude or temp
climb gradient …
Vx is …
reduces
the same
increasing mass
climb gradient …
Vx is …
reduces
higher
increasing flap angle
climb gradient …
Vx is …
reduces
lower
If you continue climbing you may reach a height where there is no excess thrust and therefore no excess power available
… will have reduced to … which is Vx and you will be at …
Vy
Vmd
your absolute ceiling
when are Vx and Vy the same?
Vx is always a lower value than Vy except at the absolute ceiling where Vx equals Vy
when climbing at a constant Mach no, what happens to alpha?
in the constant Mach phase of the climb the IAS will reduce and the angle of attack increases
