116
votes
Accepted
Why did my flight climb so sharply on takeoff?
Your flight took off during a storm. During a storm, the wind speed close to the surface of the earth is much lower than the wind speed a bit higher up. This variation of wind speed over a short ...
- 78.1k
71
votes
Accepted
Does lift equal weight in a climb?
It depends on exactly how you define "lift" and "weight". You might say intuitively that lift is all the forces acting on the aircraft in the upward direction, like this:
In this case, lift must ...
- 1,043
32
votes
Why aren't takeoff flaps used all the way up to cruise altitude?
The image below from this answer shows characteristics of airfoils with flaps.
As you rightfully concluded, lift ($C_{L_{max}}$) goes up with the deployment of flaps, but the drag also goes up and ...
- 6,321
23
votes
Does lift equal weight in a climb?
In an aircraft that is climbing at a constant vertical velocity, the total of the upward-directed vertical forces is the same as the total of the downward-directed vertical forces.
Were it not so, ...
- 10.7k
21
votes
Accepted
What could cause an irregular climbing pattern on takeoff?
The brief period of leveling off is not unique to the flight on that day. Looking at track logs for previous days, it always levels off at around 7,000 feet for some period.
As Terry commented, this ...
- 70.8k
21
votes
Accepted
How long did the SR-71 take to get to cruising altitude?
According to the performance data in the manual it takes 19.9 minutes to get to 70,600 feet.
Refueling time will depend on how much fuel is needed for the mission as well as how long it takes to ...
- 99.2k
20
votes
Accepted
Is excess lift or excess power needed for a climb?
As the answers to your original question already explained, you do need extra lift to accelerate upwards. Once the wing is set into a vertical motion, however, lift again exactly equals weight to keep ...
- 226k
19
votes
Why aren't takeoff flaps used all the way up to cruise altitude?
This is a good question, and I don't feel the other answers get at the essential part which is:
Is it optimal to climb with the flaps deployed?
As with any optimal question, the answer relies on what ...
- 4,399
16
votes
Accepted
Under what conditions can the maximum angle of climb be achieved for jet and propeller aircraft?
What you say is true only for turbojets and aircraft with fixed-pitch propellers. Generally, all optimum points for variable-pitch propeller driven aircraft are at lower speeds than those of jet ...
- 226k
16
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Does lift equal weight in a climb?
Short answer: No.
Long answer: When the flight path is not horizontal, lift will not be vertical but perpendicular to the direction of motion (in still air). Thrust will also have a vertical ...
- 226k
15
votes
Why is it not a good idea to climb higher than a level at which you would have a cruise weight-climb speed less than 500 ft/min?
Because ATC expects you to climb with at least 500 fpm when crossing to the next level. Otherwise you will block intermediate levels for an extended period of time.
If you are climbing 2000ft to the ...
- 78.1k
14
votes
Accepted
What is the difference between rate of climb and climb gradient?
The climb gradient is the percentage of the rise over run (100% if you are climbing at 45 degrees) that your aircraft is climbing at while the rate of climb is the speed at which you are climbing ...
- 11.8k
14
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Why did my flight climb so sharply on takeoff?
Sometimes a departing airplane will receive or be offered an accelerated climb profile from ATC which gets it up and out of the published approach and departure patterns quickly. If the pilot elects ...
- 19.6k
13
votes
A plane is flying at constant velocity in equilibrium, then pitches up. What happens?
A step increase in elevator (which is then held) will first upset the pitching moment equilibrium of the aircraft -- the pitching moment will be non-zero. It will pitch nose up, increasing angle of ...
- 3,547
12
votes
What could cause an irregular climbing pattern on takeoff?
Looks like an intermediate altitude assignment from atc. A look at the standard instrument departure plates (SID's) for Stansted shows that the final altitude on some of the procedures is 6000 ft. ...
- 28.2k
12
votes
What is the relation between aircraft descent rate and speed?
If the pilot commands a certain glide path angle, any change in airspeed will also change vertical speed, because both are connected by the glide path angle $\gamma$.
Note that the vertical speed is ...
- 226k
12
votes
Accepted
Why do flaps retract?
Flaps retract in order to reduce wing area. This has several advantages when flying fast:
The higher wing loading (weight per lift-producing area) reduces gust loads. When hit by a vertical gust, the ...
- 226k
11
votes
How do you calculate the ground distance in a climb?
One key point that has not been explicitly mentioned so far, though it's apparent from the example given in another answer, is that for light piston-engine airplanes, the angle of climb is so shallow ...
- 20.3k
10
votes
Is excess lift or excess power needed for a climb?
When you say,
No power invested by the propeller goes into potential energy of the wing; the climb of the wing is done purely by lift.
you're missing where the energy of the wing comes from. Lift ...
- 12.6k
10
votes
Under what conditions can the maximum angle of climb be achieved for jet and propeller aircraft?
The maximum angle of climb for all aircraft is achieved when the specific excess thrust available is maximum.
$sin \ \gamma_{max} \ = \frac{(T-D)_{max}}{W}$
However, the thrust varies differently ...
- 99.6k
10
votes
What is the difference between rate of climb and climb gradient?
A climb gradient is a geometry problem -- the relationship of two points in 3-dimensional space... to get from one to the other you gain X' in Y NM, so you have X/Y feet per nautical mile as a climb ...
- 47.6k
10
votes
Accepted
How should I read these climb and descent profile notations?
For the climb profile, the first two values are indicated airspeed -- below 10,000 and above 10,000 feet MSL, and the final value is a Mach fraction. So 250/280/78 would be a climb of 250 knots below ...
- 47.6k
9
votes
Does a headwind affect the climb gradient?
The gradient of climb is the ratio of the increase of altitude to horizontal distance through the air, not over the ground.
The definition used by the UK CAA in CAP 698 is:
Climb Gradient
...
- 52.3k
8
votes
What is the optimal way to climb fastest between two points on a Cessna 172N?
Aircraft drag scales with the power of speed. This by itself should make clear that deviating from the point of optimum performance will always incur higher losses which cannot be made up for later.
...
- 226k
8
votes
What is the optimal way to climb fastest between two points on a Cessna 172N?
Ron nailed it. (See comment on OP.)
It depends on what you’re trying to achieve.
Climbing “fast” in terms of maximum vertical speed = Vy (best rate)
If the noise sensitive zone is immediately ...
- 6,008
8
votes
Accepted
How to perform climbs and descents?
To enter the climb, it's power, attitude, trim. That is, start by setting climb power, as you already know. Remember to compensate for adverse yaw with the rudder. Immediately raise the nose to the ...
- 12.6k
8
votes
Does lift equal weight in a climb?
If we define lift as the component of the total aerodynamic forces on the aircraft that is perpendicular to its direction of motion, then lift will be slightly smaller in a stable climb.
It is ...
8
votes
Is thrust larger than weight in a vertical climb?
Yes, thrust force vector must have a force equal to (but opposite) the combined gravitational force and aerodynamic drag force (from velocity) to climb at constant speed.
In horizontal flight, thrust ...
- 18.2k
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