-
Asked by cheese2000 to Kate, Mark U, Tess, Yue on 15 May 2012.
-
Tess Newman answered on 15 May 2012:
Ooh… this is going to test how much of my engineering degree I can remember!
It is mainly to do with the shape of the wings – this shape is called an ‘aerofoil’. The engines are mainly there to create a flow of air over the wings and to keep the plane moving forward. It’s actually easier for a plane to take off than to keep to a certain height!
The shape of the wing causes the air moving over the top of the wing to move faster than the air beneath. This creates an upwards force, called ‘lift’, as the faster air puts less pressure on the wing than the slower air. This is basically how an aeroplane works. You can alter how much lift you get by changing the shape of the wing – you may notice this happening when you fly, as different flaps move up and down.
You can kind of see how this works if you stick your hand out to your side when you are on your bike. If you rotate your wrist you will feel the forces in it, either wanting to push your hand up, or down.
I know all this and I still hate flying….
-
Comments
sam1234 commented on :
If you have a piston engiend aircraft with a single prop at the front, then as you encreas the power of the engine but stay at a fairly low speed (say angling the aircraft up at a 20 degree pitch) the controls become very responcive. this is a phnomonon known as in the aviation world as “prop wash”. But this only haperns over the rudder and elevator. the rudder is the surface on the back of the tail plane, the elevator is the wing at the rear of the aircraft. it dose not work on the aielrons (the flap that makes the aircraft bank) as they are out of the prop wash.
nor dose it work on jet aircraft as the jet egsast is angled away from the control surphaces as the engins are so powerful they would damage the control surphace.
jbiddles commented on :
It is commonly attributed to the Bernoulli effect, but this is a myth. The main factor in aeroplane flight is “angle of attack”. If you hold your hand out of a car window when the car is gong quite fast at an angle like this: / only a little flatter, your hand will be pushed up. Aeroplane wings are angled like this. The other factor is the Coanda effect: aeroplane wings are curved at the top and air tends to cling to surfaces a litte. The curve forces the air downwards, and Newton’s laws of motion show that for each action is an equal and opposite reaction. Thus, air being forced down pushes the aeroplane up. Angle of attack is the main one, however.
sam1234 commented on :
It’s not a myth
i do flying lessons and i notice this effect
it is like in a stall tern if you idel your throttle and yaw to the left then there will be very little effect.
if you have the throttal at 100% and the prop control at 100% then the rudder will be more responcive. this is because the prop wash gose over the elevator and rudder which means that that there is more air flowing over the rear control serfices.
jbiddles commented on :
For the Bernoulli effect (curved surface makes air on top of the wing move faster than that below, causing a lower pressure pushing down on the wing than up) to make a plane fly, the wings would have to be shaped like whales or the plane would have to go ridiculously fast. The effect does contribute a little, but nowhere near as much as angle of attack or the Coanda effect (in order of significance). Otherwise, how can stunt planes fly upside down and the right way up?