Originally Posted by Capn Rex Havoc
Virtually There -
But there are forces that act on an inertial mass in relation to its position in reference to the earth (and other gravitational fields), so that when an aircraft changes direction in a constant air mass, the two inertial masses (air mass and aircraft) initially diverge in terms of reference. The
There is not such thing as an INERTIAL MASS.
There is just MASS. Good ole Newton came up the relationship - F (Force) = M (mass) x A (acceleration).
(Einstein refined it for relativistic speeds to include a correction factor based on the speed of light)
You can chuck the Inertial term out the window, its bulls.t
Lift is the Force that keeps the wings aloft, and the same thing that generates the turn.
Lift (Force) is generated by the air moving over the wings. FULL STOP. In a steady state air mass, the aircraft wings do not know if that airmass is doing 0 knots or 200 kts relative to the ground.
You can do 360 deg orbits all day, clockwise and anti clockwise in a steady state jet stream and you will never see one iota of IAS difference when turning.
Its not that hard.
I'm not sure how to even answer that. If you don't understand the difference between a non-inertial (accelerating) mass and an inertial (moving or stationary, depending on frame of reference) mass, then it is likely me who will be
in trying to explain.
But here's the tip (if you don't know how to use Google - that's a good start): lift opposes gravity - gravity is a (relatively weak) force that acts on all mass and varies with the formula
Fg = M1M2m/R2
Where gravitational force is the sum of Mass 1 multiplied by Mass 2 multiplied by the gravitational constant (m = 6.67 x 10 to the minus-eleventh) divided by distance squared.
Note the "distance squared" part - any time Mass 1 and 2 diverge, the gravitational forces between them change exponentially.
Secondly, kinetic energy is relative to where it is being measured. That is to say, it is relative to the frame of reference.
If the frame of reference is Planet Earth - which is circling the sun at 30km/s, in a solar system travelling at 230km/s, in a galaxy moving at 5833km/s in a universe that may or may not be moving (we think it spins, hence why it is flat) - and you are flying along in your little 172 at 110kt (51m/s), what is your kinetic energy?
EK = 1/2m V2
How do you measure the velocity in the above equation without a frame of reference?
BTW, if you'd actually read my posts, you'd realise that I completely agree with everyone else that there is absolutely no discernible difference in airspeed (induced drag aside) when turning in any direction in a constant airmass . . . but that doesn't mean there is
no difference.
My argument with FlexibleResponse is that inertial frames of reference have no real bearing on air speed turning upwind, downwind or cross wind - the velocity change is so miniscule as to be insignificant