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decending,

Pro Member Trainee
aviation_capting_mathew Trainee

Hi Guy's the other day i brought the boeing 737-800 addon for fs04 it has wing views out the window views everything realy good, anyways, this will prob sound realy silly but when i drop the flaps it dont decend i set ils/ifr and all that, and then i drop my flaps and i dont decend ive tryed using air brakes and still deosnt how can i get it to decend :S

10 Responses

Guest

Dropping flaps doesn't make a aircraft descent; it does change the angle of attack (raises the nose) as you have changed the shape of the wing. Maybe you are flying with auto pilot engaged? Altitude hold? You need to slow down, nose the aircraft over, then at a certain airspeed, start lowering flaps in stages. Flaps are there to allow for lift at slower airspeeds. Others may want to spend more typing time answering this, but it's a flying lesson. rob

Guest

Anonymous wrote:

Dropping flaps doesn't make a aircraft descent; it does change the angle of attack (raises the nose)

I thought flaps lowered the nose, all else being equal. ❓ You are effectively increasing the angle of attack of the wing, so you don't need to keep the nose so high.

Ed

don wood Guest

The previous post did a good job of answering this. Descent is controlled by a combination of attitude (the relative angle of the nose to the horizon) and power. To descend without building airspeed, you nose over and reduce power to the approprate value. If you do not know what that value is from experience and training, you just have to experiment with it until you find the right combination.

Flaps and speed brakes are tools used to allow a proper low-nose attitude without excess airspeed for the power value selected. Many aircraft can be landed without the use of flaps or speed brakes. They just help in making a smoother approach, and, on some aircraft, are necessary to avoid shcok-cooling the engine by requiring too low a power setting.

Pro Member First Officer
rob (Habu) First Officer

No, No, No ! Flaps have one purpose only...to create more lift at lower airspeeds. They do this by changing the shape of the wing to increase airspeed over the top of the wing (lowering pressure), and decreasing airspeed over the bottom of the wing (increasing pressure), which equals more lift. And Flaps down definitely has the tendency to RAISE the nose, not lower it. The proper way to descent is to first reduce power to slow the aircraft, then nose it over, using a combination of power and speed brakes to control the descent speed. Aircraft stall speeds change with the weight of the aircraft and also the flap setting. Yes, you can land without flaps, but a much higher landing speed is required to make up for the less lift associated with no flaps. You can try this in Flight Sim...Try a flap-less landing. Also approach the runway and fully lower flaps...which way does the nose go?? Happy flying... and crashing on that flap-less landing in a 747 !! rob

Pro Member First Officer
PH First Officer

Habu, disagree in part, unfortunately on my way out the door! Will explain later.

Don Wood Guest

Habu: We are both correct. You are talking about the aerodynamic forces and how they are effected by use of flaps and speed brakes. I am talking about the practical aspect of piloting.

There is a published ideal airspeed for appraoches for any given aircraft type at any given weight. That airspeed (in most airplanes) can be achieved with or without the use of flaps. The practical effect of using flaps at that airspeed is a lower nose angle, thereby creating greater forward visibility. You are correct that that use of flaps alone will raise the nose (and lower airspeed) at any given power setting. That is why God invented trim.

No aircraft control surface is intended to be used in isolation. Correct pilotage requires all the necessary controls be used in harmony to achieve the intended purpose.

I'll pass your challenge back to you. Fly a standard approach at the published airspeed without the use of flaps in your aircraft of choice. Then fly it with recommended flap settings and maintain published approach speed with the use power and trim. Notice that you use a bit more power and the improved forward visibility in that approach.

Guest

I don't think gross weight has any impact on the stall speed of an aircraft. An aircraft will always stall as the wings pass the critical angle of attack, regardless of weight.

Pro Member Chief Captain
Alex (Fire_Emblem_Master) Chief Captain

I was going to ask, if all flaps do is create lift, why does airspeed go down? In my experience, flaps create lift, and drag. Because while a fast wing is a small wing, it doesn't generate lift enough to get you off the ground within the runway limit usually.

Also, doesn't gross weight affect stall speeds because the heavier, the more nose up it takes to maintain straight flight, and weight increases the speed needed to stay level, which increases the nose up amount???

That makes sense to me, what I just said at least 😀

Guest

Right-on, Chief Captain ! rob

Pro Member First Officer
rob (Habu) First Officer

oops, twas I, right-oning you ! rob

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