Plane physics

Game Mechanics
#1

I’m making a small game in which you will fly a plane. Currently I’m trying to make good physics, however I’m lacking knowledge about physics. Would be nice if someone could answer some of my questions.

For now I have one question.

Lets say that red rectangle is a wing, moving on horizontal axis (horizon) as shown by blue arrow, and is generating lift on vertical axis (green arrow). The result is that the plane is flying up.

In this example, the plane has stalled and is now falling to the ground. The wing is moving down on vertical axis, and is generating lift. Does this mean that the plane is now moving no horizontal (horizon) axis?

I’m kinda confused on this topic, because a lot of times in movies planes are falling down, and yet they are not moving on horizontal axis. (I mean its possible, but in movies planes fall directly downwards without any pilot interaction, I mean its movies maybe thats the reason :D)

#2

This might come in handy, it’s plane physics but explained simple. I don’t know whether you’re making a 2d or 3d game though so this is the best I can give you. :slight_smile:

#3

Its 2d.

#4

Well, I can’t help you much more in that case but I guess it’s about the same as in 3d. Just a bit simpler.

#5

A lot simpler. Its same as 3D but without a lot of extra stuff.

#6

No, by definition, the wing would not be generating any lift. Lift is defined as , “Upward-acting force on an aircraft wing or airfoil.” If the plane is still moving forward when it stalls and begins to fall, that is due to the momentum that the plane has from it’s previous movement. Now, assuming the wind speed is 0, you just have the force of the wind moving at the horizontal speed of the plane colliding with the top of the wing, slowing its horizontal speed. I hope that makes sense to you.

#7

Could you rephrase that? I didn’t quite catch you. Maybe you mixed up arrow colours? Blue line is the direction that the aircraft is moving, and the green arrow is the direction of the lift.

#8

I’m getting my private pilot license :wink:

If the plane is stalled and flying nose down to the ground, then essenentially no lift will be generated. The wing is curved on top and flat on the bottom so that when air rushes across the wing, it actually takes more time for air to travel across the top, thus creating a pressure difference between the top and bottom of the wing, which must be corrected (its how pressure works), which will then generate life. If the wing is vertical (nose down) then there may be tiny amounts of lift, but nothing serious.

Think about it this way. Essentially there are 4 forces acting upon an aircraft. Gravity, obviously in the downwards direction, thrust (generally thrust pushes the aircraft forward), friction (from the air, pushes back on the aircraft as it travels through the air) and lift (pushing up from under the aircraft). When lift and thrust are “greater” than gravity and friction, the aircraft is in flight. Hell, if thrust or lift is “greater” than the other 3, you will be flying for at least a little bit, that’s why we can throw things and they actually go somewhere. The issue comes when gravity and friction are greater than thrust and lift. That’s when the plane will fall out of the sky.

Your 2 arrows in your diagrams aren’t enough to accurately represent plane physics, and it will only help if you draw all 4 so you can figure out what’s really happening.

But to answer your question, yes, the plane will be moving a little horizontally while stalled. It has flat surfaces that air can hit against, so it will move the plane. Movies almost never accurately represent plane physics at all.

#9

@opiop65
That’s a much better way at explaining it that what I had. Thank you.

#10

Do you guyz mean that plane wings stop functioning when plane is diving nose down?

#11

Essentially yes. Because the wing cannot generate any lift. The thrust obviously will not help, it will only propel the plane to the ground faster. Thrust is only there to help the plane break the force friction, if you didn’t have thrust then you would not be able to fly very far. The same thing goes for lift. If you don’t have it, the plane isn’t going to go very far.

#12

Ok I will try to draw up a diagram with 4 forces, because either you are misunderstanding my question, or I’m completely green at physics (I would say the latter is more probable)

#13

In this picture, Blue arrow is gravity, Green arrow is lift, Yellow arrow is the direction the aircraft is heading (thrust), Gray arrow is opposite force of thrust (drag).

In this picture, the engine has stalled, so there is no more thrust force from the engine. The plane is falling with its nose completely vertically. The Gray arrow is drag, and the Green arrow is now the lift. Does this mean that the lift from wings making the aircraft move on horizontal axis?

#14

[s]Since the thrust of the engine is what generates your lift and how atmospheric pressure works I assume no, but I don’t have a physics degree and haven’t had a class in years.

edit: I found a picture!


[/s]

edit2: I don’t know how to embed :’(

edit3: read reply 16

#15

Isn’t gravity the engine of the aircraft in the second picture? From my logic, lift is a force that generates upward force, but no upward force in a sense of the ground and sky, but the upward force of where the planes roof is rotated.

#16

Yes I understand what you mean, but the way wings are built and the atmosphere works I don’t think it generates any lift, or very very tiny amounts, check out the picture I linked in my last post.

Edit: read reply 16

#17

Well, according to my father, I’m incorrect and as long as there is air moving both over and under the wing it will produce lift, “at an unfortunate attitude”.

Source: He used to be a airplane mechanic, has a degree in physics, and is an avid RC pilot.

but…he’s also a “know it all” and so I can never tell if he’s telling the truth. So do what you will with that info :stuck_out_tongue:

#18

From what I understand when plane is falling nose down, its the same as plane is flying horizontally, but thrust is removed, gravity acts as plane’s engine, and there is no gravity pulling the plane down (from planes perspective).

Will have to see if this gets me a nice feel in the game :smiley:

#19

@thedanisaur

Lift is generated from the wings, they are also stabilizers. But think about it, why would we have wings in the shape they are if it had no purpose? Your father is obviously correct, I was also saying exactly what he said. Lift is generated from the wings, thrust is generated from the engines. Drag comes from air friction and gravity pulls down on the plane. Those are the four biggest forces acting up an aircraft.

I mean, I did say I am getting my pilots license, I do know what I am talking about no offense to you :stuck_out_tongue:

#20

@opiop65 none taken, like I said it’s not may area of expertise ;D. Thanks for the clarification.