Physics Question

OK sort of see where you are coming from, but wouldnt the lift vector direction "pull" the nose round into a turn?
No, because the Tail is 'ignored' for the purpose of this debate.

The Nose of an aircraft does nothing in flight (with regards to direction of flight). It is all done by the tail.
 
Where would the yaw come from? Or do you mean rolling ala "Do a barrell roll!!!11"? :p
Think of what happened to that plane that crashed just after 9/11 in New York when the tail fin fell off, the plane kept travelling in a straight line but was in a flat spin going round and round.
 
Ok my view... Path 1 because:
mavity and the upwards verticle component of the lift cancel (No change in altitude)
The horizontal component of the lift provides an acceleration (to the right in this diagram)
The plane can not twist, as all forces act through the centre of mass (mavity always does, and the lift would have to to counter mavity), so there is nothing to change the direction which the plane faces, and therefore, the horizontal component is always in the same direction.

This would give a parabolic curve (mine isn't an exact diagram, but shows the point) because if we call forward the y axis and sideways the x axis:
y is proportional to t
x is proportional to t squared so t is proportional to root x
Therefore, y is proportional to root x giving the parabolic curve

The plane starts of moving forward yeah, bottom to top in your picture? Your parabolic solution reduces this velocity, how? What you describe is a straight 'diagonal' accelerating trajectory.
 
No, because the Tail is 'ignored' for the purpose of this debate.

The Nose of an aircraft does nothing in flight (with regards to direction of flight). It is all done by the tail.

Didnt realise we were ignoring the tail, my bad.

Seems very complicated rules for this debate, might as well just said it was a frisbee :s
 
Not enough information. In reality for the aircraft to maintain level flight it must have a slight nose up attitude. This would mean that the bank would pull the nose around and the aircraft would fly in a circle. If there is no nose up attitude then it would follow a path with an increasing speed to the right while maintaining the same forward speed. Kind of like a logarythmic curve on it's side.
 
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Ok my view... Path 1 because:
mavity and the upwards verticle component of the lift cancel (No change in altitude)
The horizontal component of the lift provides an acceleration (to the right in this diagram)
The plane can not twist, as all forces act through the centre of mass (mavity always does, and the lift would have to to counter mavity), so there is nothing to change the direction which the plane faces, and therefore, the horizontal component is always in the same direction.

This would give a parabolic curve (mine isn't an exact diagram, but shows the point) because if we call forward the y axis and sideways the x axis:
y is proportional to t
x is proportional to t squared so t is proportional to root x
Therefore, y is proportional to root x giving the parabolic curve


But we are producing less lift when banked and so we would lose altitude
 
So it looks like there is a degree of tilt to the aircraft which would cause it to move in a diagonal trajectory, and the rudder is also at a degree of tilt which would cause a rotational motion.

I'd say the resultant vector of motion would be toward the center of a circle from a three dimensional view. I'd guess the path will eventually become a large circle at a degree of tilt.

A parabolic curve is straight at one instance of time and also curved at another instance of time. If the trajectory of the aircraft remains constant, I would say it is impossible for a path to curve in one instance and then straighten in another.

However, it does depend on the angle that you view your path in the three dimentional plane and the portion of the path you choose to view also. I think it's possible for both paths to be true.

If it's not a trick question about the perception of the second and third dimensions, then I'd say path 2.
 
Didnt realise we were ignoring the tail, my bad.

Seems very complicated rules for this debate, might as well just said it was a frisbee :s

The only 2 rules are:
1: the only forces included are mavity and lift from the wings
2: The aeroplane stays the same altitude

Everything else is a consequence of this
 
Not enough information. In reality for the aircraft to maintain level flight it must have a slight nose up attitude. This would mean that the bank would pull the nose around and the aircraft would fly in a circle. If there is no nose up attitude then it would follow path 1 (assuming that there is no thrust).

No it wouldn't... It's perfectly possible to produce a plane which could be straight or even tilting very very slightly down and maintain level flight... The lift from the wing is caused by lower air pressure above than below caused by the shape of the wing... Not by tilting it up to get a reaction force from pushing the air down
 
Ok basically this is a terribly over simplified problem.

1. We have no resistance what so ever, which implies no lift (contradiction!)
2. We have no Thrust, yet no change in altitude which implies thrust (contradiction!)
3. The aircraft is simply banked, no turning, just banked. :s


Assuming all of this, we can say a couple of things.

If the Plane is banked then the components of the 'lift' are partly perpendicular to the motion of travel. This causes a couple around the North-South axis of the plane, I.e. barrel roll.

IF there was some air resistance, then this rolling motion would indeed push the plane to the right. But there isn't, so it will simply carry on the in straight line.

Now if The banking of the plane is due to the way a plane normally turns, then the motion will be circular ( constant force perpendicular to the motion of travel, and no change in the magnitude of the velocity)

If the angle of the banking is kept constant, then the motion will be similar to that of path 1.
 
The plane starts of moving forward yeah, bottom to top in your picture? Your parabolic solution reduces this velocity, how? What you describe is a straight 'diagonal' accelerating trajectory.

It doesn't increase in velocity forwards. The acceleration means that the velocity is increasing horizontally, so for example, if the velocity is 1 m/s and the acceleration is 1 m/s squared

at t=0, y=0, x=0
t=1, y=1, x=0.5 (average horizontal velocity is 0.5 m/s)
t=2, y=2, x=2 (average horizontal velocity is 1.5 m/s)
t=3, y=3, x=4.5 (average horizontal velocity is 2.5 m/s)

So you can see that this would produce a curved flight path

edit: The average horizontal velocity is for that second only of course :p
 
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It doesn't increase in velocity forwards. The acceleration means that the velocity is increasing horizontally, so for example, if the velocity is 1 m/s and the acceleration is 1 m/s squared

at t=0, y=0, x=0
t=1, y=1, x=0.5 (average horizontal velocity is 0.5 m/s)
t=2, y=2, x=2 (average horizontal velocity is 1.5 m/s)
t=3, y=3, x=4.5 (average horizontal velocity is 2.5 m/s)

So you can see that this would produce a curved flight path

Ah yeah, okay. The way your planes are drawn on the picture suggests it's slowing down in the y direction.
 
No it wouldn't... It's perfectly possible to produce a plane which could be straight or even tilting very very slightly down and maintain level flight... The lift from the wing is caused by lower air pressure above than below caused by the shape of the wing... Not by tilting it up to get a reaction force from pushing the air down

But its the Angle of Attack that changes the amount of lift produced.

So we now need to know the exact aerofoil section please ;)
 
I have a flight dynamics exam on Wednesday, I'll save you all from Bairstow, Lanchester and Pradeep equations.

I'm staying out of this.

BTW, if you had just said a particle, it would have made the problem far easier to digest.
 
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The Nose of an aircraft does nothing in flight (with regards to direction of flight). It is all done by the tail.

No that is totally wrong.
look at flying wings such as the B-2 boomer. It just has flaperons which turn opposite directions to bank the craft then the flaperons work like elevators also to push the nose up and turn it or at least rotate it around the centre of mavity.

But for the question the plane will not follow path 1

If it has:- 1: a symmetrical wing section 2: No dihedral 3:Totaly flat trim, then it will just continue dead ahead at the angle.

If any of the above is not true the it will continue in a circle until another input is put in apart from the dihedral, which if there is any it will return to a straight flight, pull out of the turn and the flight path will look like path 2 but the nose will follow the path.
 
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No that is totally wrong.
look at flying wings such as the B-2 boomer. It just has flaperons which turn opposite directions to bank the craft then the flaperons work like elevators also to push the nose up and turn it or at least rotate it around the centre of mavity.

But for the question the plane will not follow path 1

If it has:- 1: a symmetrical wing section 2: No dihedral 3:Totaly flat trim, then it will just continue dead ahead at the angle.

If any of the above is not true the it will continue in a circle until another input is put in apart from the dihedral, which if there is any it will return to a straight flight, pull out of the turn and the flight path will look like path 2.

But isnt there 'less' vertical lift and 'more' horizontal lift? i.e. the lift vector has changed.

Wouldnt this induce an altitude loss, and movement/turn in the direction of the horizontal lift element?
 
No, not if you assume its a symmetrical wing, and just to edit post this is why stunt planes have a symmetrical or close to symmetrical wing. You can get a perfect barrel roll without cork-screwing.
 
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