Java-Gaming.org    
Featured games (81)
games approved by the League of Dukes
Games in Showcase (498)
Games in Android Showcase (117)
games submitted by our members
Games in WIP (564)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
 
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  Plane physics  (Read 1728 times)
0 Members and 1 Guest are viewing this topic.
Offline trollwarrior1
« Posted 2014-08-09 13:12:32 »

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 Cheesy)
Offline mag

Junior Member


Medals: 9
Exp: 2 years



« Reply #1 - Posted 2014-08-09 14:52:54 »

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. Smiley
Offline trollwarrior1
« Reply #2 - Posted 2014-08-09 15:21:51 »

Its 2d.
Games published by our own members! Check 'em out!
Legends of Yore - The Casual Retro Roguelike
Offline mag

Junior Member


Medals: 9
Exp: 2 years



« Reply #3 - Posted 2014-08-09 15:36:49 »

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.
Offline trollwarrior1
« Reply #4 - Posted 2014-08-09 15:38:59 »

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.

A lot simpler. Its same as 3D but without a lot of extra stuff.
Offline cubemaster21
« Reply #5 - Posted 2014-08-11 12:34:48 »

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.

Check out my game, Viking Supermarket Smash
http://www.java-gaming.org/topics/iconified/28984/view.html
Offline trollwarrior1
« Reply #6 - Posted 2014-08-11 13:03:38 »

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.
Offline opiop65

JGO Kernel


Medals: 154
Projects: 7
Exp: 3 years


JumpButton Studios


« Reply #7 - Posted 2014-08-11 13:30:06 »

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.

Offline cubemaster21
« Reply #8 - Posted 2014-08-11 13:59:46 »

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

Check out my game, Viking Supermarket Smash
http://www.java-gaming.org/topics/iconified/28984/view.html
Offline trollwarrior1
« Reply #9 - Posted 2014-08-11 14:04:50 »

Do you guyz mean that plane wings stop functioning when plane is diving nose down?
Games published by our own members! Check 'em out!
Legends of Yore - The Casual Retro Roguelike
Offline opiop65

JGO Kernel


Medals: 154
Projects: 7
Exp: 3 years


JumpButton Studios


« Reply #10 - Posted 2014-08-11 14:35:00 »

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.

Offline trollwarrior1
« Reply #11 - Posted 2014-08-11 15:40:37 »

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)
Offline trollwarrior1
« Reply #12 - Posted 2014-08-11 17:26:40 »

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?
Offline thedanisaur

Senior Member


Medals: 10
Exp: 1 year



« Reply #13 - Posted 2014-08-11 17:48:41 »

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!


http://science.howstuffworks.com/transport/flight/modern/airplanes3.htm


edit2: I don't know how to embed  Cry

edit3: read reply 16

Every village needs an idiot Cool
Offline trollwarrior1
« Reply #14 - Posted 2014-08-11 17:52:04 »

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.
Offline thedanisaur

Senior Member


Medals: 10
Exp: 1 year



« Reply #15 - Posted 2014-08-11 17:53:29 »

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

Every village needs an idiot Cool
Offline thedanisaur

Senior Member


Medals: 10
Exp: 1 year



« Reply #16 - Posted 2014-08-11 18:06:02 »

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  Tongue

Every village needs an idiot Cool
Offline trollwarrior1
« Reply #17 - Posted 2014-08-11 18:12:10 »

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 Cheesy
Offline opiop65

JGO Kernel


Medals: 154
Projects: 7
Exp: 3 years


JumpButton Studios


« Reply #18 - Posted 2014-08-11 19:04:44 »

@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 Tongue

Offline thedanisaur

Senior Member


Medals: 10
Exp: 1 year



« Reply #19 - Posted 2014-08-11 19:14:31 »

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

Every village needs an idiot Cool
Offline trollwarrior1
« Reply #20 - Posted 2014-08-13 17:28:53 »

Does anybody know good equations for the following things?

- Lift amount for an angle of attack specified
- Drag amount for an angle of attack specified

I need to basically get some kind of values that would describe how air craft behaves as angle of attack changes.
Offline thedanisaur

Senior Member


Medals: 10
Exp: 1 year



« Reply #21 - Posted 2014-08-13 19:03:01 »

This might help:

http://www.av8n.com/how/htm/4forces.html

Just know that thrust plays an important roll in those equations as well, as it's easier for a plane to climb/fall than maintain altitude.

Every village needs an idiot Cool
Offline pjt33
« Reply #22 - Posted 2014-08-14 09:07:53 »

Does anybody know good equations for the following things?

- Lift amount for an angle of attack specified
- Drag amount for an angle of attack specified
Those will vary by aircraft. You need to decide whether you're trying to simulate a Cessna, a 747, an F-14, a Lancaster, ... and then try to find data specific to that plane. Bear in mind that airspeed also makes a big difference: especially the switch from laminar to turbulent flow which guarantees a stall.
Pages: [1]
  ignore  |  Print  
 
 

 

Add your game by posting it in the WIP section,
or publish it in Showcase.

The first screenshot will be displayed as a thumbnail.

Grunnt (20 views)
2014-09-23 14:38:19

radar3301 (14 views)
2014-09-21 23:33:17

BurntPizza (31 views)
2014-09-21 02:42:18

BurntPizza (22 views)
2014-09-21 01:30:30

moogie (20 views)
2014-09-21 00:26:15

UprightPath (29 views)
2014-09-20 20:14:06

BurntPizza (33 views)
2014-09-19 03:14:18

Dwinin (48 views)
2014-09-12 09:08:26

Norakomi (75 views)
2014-09-10 13:57:51

TehJavaDev (107 views)
2014-09-10 06:39:09
List of Learning Resources
by Longor1996
2014-08-16 10:40:00

List of Learning Resources
by SilverTiger
2014-08-05 19:33:27

Resources for WIP games
by CogWheelz
2014-08-01 16:20:17

Resources for WIP games
by CogWheelz
2014-08-01 16:19:50

List of Learning Resources
by SilverTiger
2014-07-31 16:29:50

List of Learning Resources
by SilverTiger
2014-07-31 16:26:06

List of Learning Resources
by SilverTiger
2014-07-31 11:54:12

HotSpot Options
by dleskov
2014-07-08 01:59:08
java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!