Jan Peter Apel
How flies a plane?
For each object that can fly, the basic principle of flying
applies: air mass push down to get the recoil force as lift force.
Subsequently, it is shown how that makes an airplane. (In the next
chapter follows, as it makes the bumblebee.)
Only with overview natural processes can understand properly. So must
assume the right view, the correct coordinate system. The coordinate
system of a natural phenomenon may not be selected at will or
expediency, it must be found!
An airplane can fly only if it moves against the air. Whether the air
is stationary or moving as a counter, back or side wind above the
ground. If an aircraft is too slow against the air, it falls down. So,
the air is the natural and only correct coordinate system for flying.
The air does not do anything! If an air jet takes something with
upwardly, then is this not a fly, but a fall in the air jet, in which
the rate of fall down just less than the air jet velocity by upward. A
glider does not fall in a rising thermal air area, but flies in it. For
this fly it needs the indispensable energy for a horizontally fly to
generate lift. It takes this energy from its height by downhill force.
Its flight path is always slightly inclined relative downward to the
air. Increases the thermal air faster upwards as it flies in it down so
it gains altitude.
How generate a plane lift force? In each case energy is
necessary. Air mass must accelerate downward, it mast pushed down. The
energy previously required is then included in the down wash. The down
wash forms with the surrounding air vortices, that sinks! They are
called wake turbulence.
For aircrafts with fixed wings is the specific principle to push air
down the operating principle of an inclined plane. The leading edge of
the wings are always higher than the trailing edge, so that by moving
the wings horizontal the surfaces of the wings will be lowered. This is normally as well as in inverted flight!
effect of the wings working as inclined plates can be seen in the
following animation. Shown are representative of
every other air particles two, as they are accelerated by simplest
wings surfaces, caused by its horizontal forward movement and the
mechanical action of the inclined plane down. Profils of teh thickness
of the wings have signifikations for the technologie and
economics, but not for flying ability per se.
The motions of the air
particles are their movements relative to the surrounding air, thus not
the relative, which can be observed from the aircraft or in the wind
tunnel. Only these changing movements of air mass are effective for
An aircraft wing moving air above and below the wing down. The lower
volume of air is pushed down directly from the underside of the wing,
the upper air is therefore torn down from above, because the horizontal
movement of the inclined plane creates a vacuum on the falling surface
to the rear of the wing, which is filled immediately by inflowing air
from above. The air down push give birth naturally a positive pressure
below the wing, the down tearing of air from the top creates a negative
pressure above the wing. The terms "push" and "tearing" are necessary
because this is done in only milliseconds! This time is the one that a
wing with its forward speed has to pass through each point in the air.
Air particles perceive their acceleration down by an aircraft wing like
red marked part of swing movement which performs the upper air
particles, is an absolute movement of the air to the rear, against the
coordinate system of flying, the air, which increases the wind on the
wing upper surface (about 10%). This movement results from the fact
that the wing of the lower side pressed air downward, that a little bit
air swells slightly in front of the wing upwards and flows above the
wing to the rear. In this only 10% effective true flow inside the only
running wind creates indeed a Bernoulli's negative pressure, which added to
the negative pressure previously formed from the drawing down of the
upper air. In the rear wing area results by the addition but a
reduction of the negative pressure generated by the inclined plane. The
reason: the air from the bottom side slows down again until the
trailing edge as in a diffuser. This goes so far, that on the trailing
edge the total negative pressure is zero. All Bernoulli's pressure
changes add up around an airfoil to zero, so that it does
produced no lift! In supersonic flight can no more air swell up before
the wing. The loss of the Bernoulli's vacuum does not lead to a
decrease of lift force, which proves that it previously produced too no
increase in lift force. The Bernoulli's pressure influence are only a
consequence of the lift force originating by the mechanical principle
of an inclined plate. One consequence of a causation, however, can not
have influences to its generating process!
following animation shows, as in reality the downwash flows downward. The lines at the individual points are
wind vanes, showing with there directions the directions of
the air flow and with there lenghts the velocities of the air at these
points. The area of downward movement air extends in both distance
above and beneath to a distance equal to the wingspan of an airplane.
For flying also applies to aircraft: the aircraft moves to the air and
not vice versa! That passenger of an airplane see the air "flow", is an
illusion by relative view: they are moving, not the air!
So the explanation of "Why does an airplane fly?" is finished: by
pressing air down. That's the whole secret!
That the explanation of flying of an airplane is as easy, although the
teachings complexity are not to exceed, is not an accident, but a MUST!
The Nobel Prize winner Paul Dirac presented already noticed: "A
physical theory is either short, or false" and Johann Wolfgang von
Goethe: "Everything is simpler than one may think, also entangled, as
can be understood." In nature it is always so, that the phenomena
(symptoms) of their apearances are confusing, although the underlying
causes are quite simple. Therefore, it is so difficult to understand
the nature. Whereby add to that is, that we see often relatively, so
wrong, how it is especially by flying. Why do we do that? Because we
like it, to be the coordinate system. One and a half millennia we spent
that the sun circle around us, although we go on earth carousel. Now we
spend more than 100 years in the belief, that the air flows backward
along our aircraft and not we move with it forward.
Flying is a purely mechanical process, in which by means of energy
input air is accelerated downwards. So does not apply the laws of
aerodynamics, but the aerokinetics. The essence of the aerodynamic by
Bernoulli consists precisely in the fact that no energy may be used.
But without transver from energy to the air, no object can fly! A glider
takes the required energy from its height to which it was previously
raised by use of energy, a powered aircraft has its own engine. In both
cases, the energy is require to move the aircraft
horizontally through the air. Therefor must overcome the resistance for
the displacement of air and the "resistance component", which arise by the function of the wing as an inclined plane.
Out of this correct physics of flying arised the comprehensible formula
for lift force.
For flying there are next to the Bernoulli theory two other popular
explanations. All three are
wrong, which is also evaluated by NASA to see at
www.grc.nasa.gov/WWW/K-12/airplane/wrong1.html and following.