# Tag Info

0

Flaps provides extra lift at lower airspeeds but for the cost of huge drag. At some point the drag stops the plane acceleration and it cannot climb any faster. Note that the airlines want as fast transport from Gate A(XYZ) to Gate B(HKL). Airports want as short runways as possible. Government wants as small noise-loaded areas as possible. Short runway limits ...

1

Flaps give you more lift, but also more drag. The drag means that your horizontal speed is lower. The usual phases of flight where low speed is an advantage are: When taking off from a runway. You don't want to run out of runway and you want to end wheel drag as soon as possible. When trying to clear obstacles. You want as much time to gain altitude before ...

1

Most people fly in order to get somewhere, so cruise climb is used as it covers more ground while getting to altitude. Here is the DA40 airspeed table that would have been nice to include in your question. Depending on weight, cruise climb speed is 6-9kt higher than takeoff climb speed. If your objective was just to gain altitude, as for local observation, ...

16

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 it is we wish to optimize. It's worth examining two goal states: To climb to altitude as quickly and efficiently as possible. For instance: the winds aloft ...

30

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 even quicker than the lift. Increasing lift is good, but if it comes at the cost of more drag, it will require more thrust (therefore fuel) to maintain this ...

7

Because it would not be efficient. Flaps increase drag (and lift), so you would burn more fuel climbing to cruise altitude with flaps extended compared to if if you retract them.

1

If the net forces are zero, the movement will be steady, as per Newton's second law. If upwards vertical forces equals weight, we will have net zero vertical forces and a no vertical movement (hover). If the total upward forces are greater than weight we will have a vertical acceleration until drag brings velocity to a steady state. If all vertical forces = ...

1

Yes, always, unless aerodynamic drag does not exist. For winged aircraft, the above is impossible, therefor the answer is yes, always. It is important to realize excess thrust is required to climb. Excess thrust closes the weight/lift triangle but does not account for aerodynamic drag, which equals the amount of additional thrust required to maintain ...

5

This question is purely a definition issue, and the answer is 'yes' or 'no' based only on which definitions you use. In Newtonian physics, a lot of complex interactions are modelled as single, lumped vectors which we call "forces". These forces share nice properties with vectors: notably, that we can decompose vectors into multiple vectors, or sum ...

Top 50 recent answers are included