Why are you supposed to put the flaps down when landing a plane?

Question

When i put them down on flight simulator, they make the plane rise. How do they help in landing???

Answer 1

try pulling the throttle to about 1600 rpm's ( if flying a single engine)before deploying flaps and ensure you are in the white arch on the Airspeed indicator. ballooning will not be as pronounced.


Short and simple, flaps are designed to increase the efficiency of the airfoil at low speeds.

When used properly, flaps increase the lifting efficiency of the wing and decrease stall speed. This allows you to fly at a reduced speed while maintaining sufficient control and lift for sustained flight.
The ability to fly at slows speeds is particularly important during the approach and landing phases. For example, an approach with full flaps permits you to fly at a fairly steep decent angle WITHOUT GAINING AIRSPEED, which allows the airplane to touch down at a slower speed. In addition, you can land nearer the approach end of the runway, even when there are obstacles along the approach path.

Note to the know-it-all non pilots, you can, and I do often ,land without even deploying flaps . Hell, the PA-12 I have the luck to occasionally fly does not even have them. a slip to a landing works just as well IMHO

Answer 2

Flaps During Landing

Answer 3

By putting the flaps down the wings will produce more lift releative to the airspeed at which the aircraft is moving resulting in a lower approach an landing speed and also a steeper angle of descent, for example an aircraft that land at about 100 mph would need 150 mph landing speed without flaps.

Answer 4

Lowering flaps produces lift, wich is needed when most planes or jets land. They are flying so slow that without the extra lift provided by the flaps they wouldnt be able to controll the aircraft.

Answer 5

There are different types of flaps for a number of aircraft.Each type increases drag. Your initial question reguarding landings and the use of flaps can be sumed up by saying a good landing is touchdown at the proper speed and the proper attitude.Not to over explain it,but simply put,flaps produce an increase in drag while also increaseing lift for about the first 20 degrees deflection.So now with an increase in lift,your approach speed can be lowered.After 20degrees or more of deflection more drag than lift is produced.Part 2 of your question.An aircraft seeks it's airspeed once all four forces have equalled.Lift vs weight,thrust vs drag.It's trimmed out.When you applied flaps and increased your lift,the center of lift moved forward raiseing the nose until reaching it's new lower airspeed needed to produce the same amount of lift for your aircraft's weight.Left alone, a balance is restored at that new lowered speed.

Answer 6

The flaps increase surface area on the wings, which allows the plane to fly slower, while creating sufficient lift for it to fly.
You will see jet fighters will have thin swept back wings with little surface area, the speed of these air crafts will generate enough lift for it to fly, as for a small two seater plane, the wings are large, and straight, which generates more lift at lower speeds because of more surface area.

Answer 7

It is up to the pilot to decide if he needs flaps or not given the particular conditions under which he is landing or taking off. Flaps lower your stall speed by changing the curve of you wing. In a lot of cases the way they are rigged, they extend towards the back as they move down, this makes for increased wing area as well as increasing the curve of the wing. When you change your flap setting, you are in effect moving the centre of pressure on the wing and this will make your nose rise or fall. In my airplane, the nose drops, but I think it is more accurately to describe it as the nose stays where it is and the back of the airplane goes up, because it feels like that is what is happening. Conversely when you retract the flaps it feels like the airplane is hinged on the prop and the tail drops. I don't know if this answers your question, but it sure was fun trying to explain this.

pilot and 30 years as a military aircraft maintainer

Answer 8

On most aircraft flaps have multiple positions and multiple uses. These all involve some combination of lift and drag.

In fast low drag planes it can be exceedingly hard to slow down and decend without the application of approach flaps (usually 15 degrees). They are also useful in the process of stage cooling (sequential limited power reductions) in large piston engine management.

During the final approach phase additional flaps are added to both lower the stall speed and provide better control of the decent angle (match the VASI lights or the instrument glideslope). On short final full flaps are usually added to further reduce the stall speed and add drag to slow the plane in the roundout and shorten rollout.

Gusty winds usually suggest a higher speed touchdown and full flaps are not used.

On some planes the short field takeoff calls for approach flaps to get the plane in the air with shorter ground roll. Almost all jets use some flaps at takeoff.

On really low drag newer planes, like the Mooney, wing spoilers are used in addition to flaps. Spoilers "spoil" lift as well as adding drag. Almost all jets have spoilers which you can hear woosh as they are extended.

Turboprop and turbojet aircraft also have thrust reversers which are deployed in the rollout to shorten runway usage. These work by reversing the prop a bit in turboprops (beta range) and by deflecting the jet output thrust with paddles on jets.

The combination of all these devices is exceedingly important in helping to manage the landing (and maybe the takeoff) environment which are by far the most risky portions of any flight.

Answer 9

Flaps *reduce* your angle of attack for a given speed. They let you fly slower with the nose down. In addition to the speed reduction, this helps a lot with visibility.

Flaps increase lift AND drag. A little flap extension mostly provides lift, but a lot (full flaps) mostly provides drag. That drag lets you make a steeper approach (again, at slow speed, with the nose pointed down instead of up).

Also, the increased lift reduce stall speed. So you have a greater margin of safety at slow speed.

You don't *need* any flaps. Flying airplanes without flaps requires a technique called a slip, where you bank the airplane as if in a turn, but use rudder to stop that turn. The result is that the airplane flys almost sideways, and the side of the airplane produces the drag that flaps otherwise would. Slips also help with visibility, because even though you have the nose up to slow down, you're not looking out the front - you're looking out the side.

Answer 10

putting flaps down when landing decreases the airplane's stall speed (the speed at which the wings cannot generate lift any more) because it increases the surface area of the wing. This allows them to land at a slower speed and decrease the roll-out distance (the distance the plane travels after the wheels have touched the ground)