What part turns a plane
04-28-2005, 06:01 PM
#29
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RE: What part turns a plane
This thread is getting a bit old, but this reply may just help someone so it's worth the trouble.
It is too easy to get bogged down in the details of a problem. Strip off the details and look to the underlying physics. Details such as rudders and wings etc. are merely devices to achieve the proper conditions for turning flight. They do not actually turn the aeroplane.
TURNING motion is ACCELERATED motion. To turn it is necessary to accelerate towards the centre of rotation, ie. the point about which the turning motion is centred. Acceleration of a body requires a force (Newtons law), therefore to TURN requires that a FORCE be exerted on the body towards the centre of rotation of the turn, ie. at right angles to the direction of motion. In plain english, if you want to turn then you need a push in the direction of the turn.
How this turning force is generated is COMPLETELY IRRELEVANT to the business of turning.
Here are some ways to generate the turning force;
1. Use a tether (string tied to a pole like control line, rotor blade holder).
2. Gravity (used by cannon shells).
3. Friction between road surface and tyres.
4. Force of car seat on human body.
5. Wing lift vector angled towards centre of turn (balanced turn).
6. Sideways force on fuselage (yawed flight).
7. Wind gusts.
8. Boundary layer asymmetry on a golf ball (or baseball or cricket ball or NOTAR tail boom).
Note that in the case of an aeroplane there are TWO primary forces acting in a turn;
1. The aerodynamic force resulting from aircraft motion and attitude.
2. Gravity.
How the aircraft turns is a result of the action of BOTH of these forces.
It is too easy to get bogged down in the details of a problem. Strip off the details and look to the underlying physics. Details such as rudders and wings etc. are merely devices to achieve the proper conditions for turning flight. They do not actually turn the aeroplane.
TURNING motion is ACCELERATED motion. To turn it is necessary to accelerate towards the centre of rotation, ie. the point about which the turning motion is centred. Acceleration of a body requires a force (Newtons law), therefore to TURN requires that a FORCE be exerted on the body towards the centre of rotation of the turn, ie. at right angles to the direction of motion. In plain english, if you want to turn then you need a push in the direction of the turn.
How this turning force is generated is COMPLETELY IRRELEVANT to the business of turning.
Here are some ways to generate the turning force;
1. Use a tether (string tied to a pole like control line, rotor blade holder).
2. Gravity (used by cannon shells).
3. Friction between road surface and tyres.
4. Force of car seat on human body.
5. Wing lift vector angled towards centre of turn (balanced turn).
6. Sideways force on fuselage (yawed flight).
7. Wind gusts.
8. Boundary layer asymmetry on a golf ball (or baseball or cricket ball or NOTAR tail boom).
Note that in the case of an aeroplane there are TWO primary forces acting in a turn;
1. The aerodynamic force resulting from aircraft motion and attitude.
2. Gravity.
How the aircraft turns is a result of the action of BOTH of these forces.
05-02-2005, 09:38 PM
#32
RE: What part turns a plane
I have a number of models which will execute a 180 turn with only a yaw input .
The airfoil is simple flat plate, no dihedral.
Yaw, simply allows the huge, balanced side area to establish the turn
the models do NOT bank, do not stall, do not become uncontrollable .
They simply, quickly reverse direction.
If it is light enough with enough power - it all works perfectly.
So what turns it?
The fuselage.
The airfoil is simple flat plate, no dihedral.
Yaw, simply allows the huge, balanced side area to establish the turn
the models do NOT bank, do not stall, do not become uncontrollable .
They simply, quickly reverse direction.
If it is light enough with enough power - it all works perfectly.
So what turns it?
The fuselage.
05-02-2005, 09:45 PM
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RE: What part turns a plane
In those aircraft yes.... but typically it's not the fuse that turns an airplane... I don't think the question was, how many ways can you turn an airplane was it?
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05-03-2005, 12:58 AM
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RE: What part turns a plane
Read my post. A force at 90 deg to the direction of motion is what turns an object.
How you get that force is another subject altogether.
If you yaw an aeroplane the fuselage makes like a wing and a force is developed on the fuselage at 90 deg to the direction of motion therefore the aeroplane will turn. It will not be a balanced turn, but it sure will be a turn.
Up elevator will result in a force on the wings 90 deg to the direction of motion and a vertical turn (loop).
90 deg angle of bank and up elevator will result in a horizontal turn - loop laid on its side (pylon turn, knucklehead turn).
A bit less than 90 deg bank leaves some of the force remaining to overcome gravity and support the weight of the aeroplane, and now the turn is balanced.
How you get that force is another subject altogether.
If you yaw an aeroplane the fuselage makes like a wing and a force is developed on the fuselage at 90 deg to the direction of motion therefore the aeroplane will turn. It will not be a balanced turn, but it sure will be a turn.
Up elevator will result in a force on the wings 90 deg to the direction of motion and a vertical turn (loop).
90 deg angle of bank and up elevator will result in a horizontal turn - loop laid on its side (pylon turn, knucklehead turn).
A bit less than 90 deg bank leaves some of the force remaining to overcome gravity and support the weight of the aeroplane, and now the turn is balanced.
05-03-2005, 06:21 AM
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RE: What part turns a plane
Wow, a page and a half of thread to answer a dumb and vague question. I guess we all have too much time on our hands.
Problem with the question #1: The thread title says what part turns a plane. The first post says more vaguely,"What turns a plane." So if we're answering the thread title, gravity, thumbs, air, all those type of answers are disqualified, IMO.
Problem #2: Depends on what the definition of "turns" is.
Problem #3: There are a multitude of correct answers (a lot of the answers depend on what axis of flight we're talking about, hence my original post "Which axis.")
Problem #4: No one part works alone. If you answer with the first obvious answer, for the sake of argument, "the rudder," how can that be right when you need something to move the rudder, and eventually a pilot to step on the pedals, etc.
I could go on ... but what's the point?
Problem with the question #1: The thread title says what part turns a plane. The first post says more vaguely,"What turns a plane." So if we're answering the thread title, gravity, thumbs, air, all those type of answers are disqualified, IMO.
Problem #2: Depends on what the definition of "turns" is.
Problem #3: There are a multitude of correct answers (a lot of the answers depend on what axis of flight we're talking about, hence my original post "Which axis.")
Problem #4: No one part works alone. If you answer with the first obvious answer, for the sake of argument, "the rudder," how can that be right when you need something to move the rudder, and eventually a pilot to step on the pedals, etc.
I could go on ... but what's the point?
06-26-2005, 02:07 PM
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RE: What part turns a plane
I'm sure it is turned by the air pushing on the rudder, which is pushed by the pushrod that is pushed by the servo as a result of the thumb/forefinger pushing on the joystick…
