Re: (Off Topic) Basic Aerodynamics

On Oct 1, 3:53 pm, "matan...@xxxxxxxxx" <matan...@xxxxxxxxx> wrote:
Since Michael Thames exhibits such deep knowledge of the science of
aerodynamics, perhaps he would be kind enough to explain this:

There are four forces impinging on an aircraft in flight.

To know these forces exhibits a knowledge of the science of
aeronautics not aerodynamics. Aeronautics looks at aerodynamics in
their own less than accurate way. This is why pilots do not know the
simple difference between the two aerodynamic forces.




1. Gravity which pulls it down
2.Liftwhich lifts it up.
3.dragwhich resists its movement through the air
4. thrust which pushes it on through the air.

Lift and drag are infinite in direction and either one can cause or
oppose the motion of an object in any direction or help support the
weight of the aircraft. The only time thrust is an aerodynamic force
is when it happens to be lift or drag. Thrust is the motion of an
object as a result of an onboard power source. Thrust can not only
move an aircraft through the air but can hold it in moving air and
everything that moves an aircraft through the air (say gravity) is not
thrust.




Now, ifliftis greater than gravity, the airplane goes up, if it is
less than gravity, it goes down.

Similarly, ifdragis great than thrust, the airplane slows down. If
thrust is greater thandrag, the airplane accelerates.

Which follows that in the case of an airplane in straight and level
flight at a constant speed, all four forces must be equal. If that is
the case, what makes the airplane move at all?

This question is based on the false primus that something has to make
the airplane move. The aircraft only has to have force to accelerate.
Once it’s moving it will move forever (without force) unless acted
upon by an outside force. Some aircraft at top speed (as much as
250mph) generate no aerodynamic force. This aircraft uses drag
exclusively as a means of horizontal acceleration. The faster it goes
the less drag it generates. This aircraft was the first to fly, its
called a balloon.






MO.

.

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