Gas Extension to Archimedes October 26th 2018
Tights	The old Archimedes law about liquids, goes to gases with small changes.

When object moves in gas, it follows Archimedes law about liquids. The object takes it's volume from the gas. The difference is that, gas shrinks and liquid escapes, when object comes.

The shrinking gas creates a pressure system around the intruder. When you go outdoors, and stop. The pressure system spreads into surroundings. When you move, you create new pressure systems around yourself all the time. When you are in closed space, the pressure system cannot spread, it remains.

It does not matter much, whether object moves or it is blown. It is easier to keep your momentary place, when you stand in the typhoon winds. Walk in hurricane winds is more difficult : Standing object has usually some stable parts in the surrounding pressure system.

In gas captured volume creates pressure systems to all available directions.

It is well known, that air resistance factor comes from turbulences around object. The resistance remains relatively stable, until some major part in the front starts to create bigger turbulences. Turbulences creates buffers to front of the moving object. Moving object itself creates only pressure systems to the front.

With aerodynamic front, you can slow down the creation of pressure. With tilted top and bottom you redirect part from the pressure to the top or bottom of the object. You cannot redirect pressure away from the object. Moving object must always handle the pressure, which comes from the frontal side projection.

By default gas atoms do not change their relative positions, when object comes. The grid stretches and shrinks as whole. The atoms start to move, and the grid gets broke, when you have too much speed and area. Quite obvious that badly broken grid creates the turbulences to the air / gas.

In order to get air in and out from combustion engine's cylinder, you must break the atom grid with speed. You cannot do such with pressure only. Propel for example moves atoms with it's wings.

It is known that you can move atoms and objects with flow, without turbulence. Turbulence could come from the broken movement system. When so turbulence is born, when long threads, with what atoms moves, gets broke : Atoms do not keep the marching order, they search new locations from where-ever they can.

In planes the captured volume creates red pressure system  to above. Green to below.
Green pressure system creates the force, which keeps the plane in the air.
The big red arrow denotes planes weight, and gravitational force. Car shares the system.

From the above can say, that objects ... like cars and planes ... would need measured cw curves for various speeds. Speed increases the amount of turbulunces. There obviously are some key points, when for example windshield starts to create turbulences.

When you test cars and planes in wind tunnel, you should find a speed, when shape loses it's aerodynamics. Air becomes a turbulent mess. You could inform the constructional speeds for the shapes and bodies. ( Idea / proof comes from pressurized gas and oil tubes. Electric wire has similar kind of electric power limit. )

You can never measure cw factor with 3D model. Air resistance factor must be tested in wind tunnel or nature. Pressure system around moving object is too complicated for computer program. A small change in mirror's mounting leads to total change in the remaining pressure system and so on. In cars, side mirrors are well known to be one of the biggest disturbers of the flow. Mirrors downgrades the overall ( announced ) cw coefficient factor.

Boat with big top speed needs also aerodynamics. All boats need hydrodynamics for the bottom. Hydrodynamics is compilation from aerodynamics and on-ground friction system.

In the picture above you see diagram from bird's over-under pressure system. Flying bird keeps top pressure steady, head and body are straight lined. Bird can create a small vacuum to the top with it's head. After bird has made a hole into air, with it's peak, it uses neck and belly for boosting the lower pressure and increasing the lift. Lower body tilt keeps the pressure under body. Feathers' small threads obviously prevents air from escaping from under the body and wings. Lower-body tilt and feathers allows birds to fly slowly.

Although birds flying system is widely researched, no has measured how "poor" bird's air resistance factor is. You could have done it with killed and filled flying bird.
Long necked bird, like swan,  goes to modified needle shape when it flies. All birds uses belly-body for maintaining the pressure under body. 

Birds are the finest flying things on earth.

Things you find from our nature are hardly ever without some meaning. It is always a big step from mankind and manmade things. Certainty that you are almost 100% sure to find a reason for everything eases science making quite a lot. You do not get lost as easily as you do with manmade things.