Goal: thrust experiment.
No wings, no rotor, no propeller, no jet, no rocket...
(2004-12-03) This very first experiment did not create enough thrust to lift. It did create thrust (about 0,4 Kg), but less than its weight (about 1,2 Kg). The photo is turned 90 degrees... If it had more power or less weight, it would have lifted itself 100%
The next model should be more efficient; same weight, same power, more thrust.
How does it work?
How does it create lower air pressure on top of the disc?
The atmospheric pressure is the thrust here. The pressure on top has to be reduced some efficient way.
1) The turbine sucks the air away from the center top. This creates a low pressure area, as long as the turbine is turning. The pressure is lowest near the intake but reaches very far; as far as air goes. Pressure "information" travels with the speed of sound. When creating a pressure difference, the air at 340 meter distance will "know" and react on it, in only 1 second.
2) The "Coanda effect".
Air is accelerated by the turbine.
Be aware of one misconception; there is no such thing as "fast air"! Acceleration can be measured and how space inbetween two objects changes, but there is no known way (to me) to tell what the absolute speed of an object is.
So, there now is a great difference between the motion of the disc and the motion of the turbine-air. Also is there a great motion difference between the ambient-air (surrounding-air) and the turbine-air.
Air is mass, and mass does not "want" to change its motion, unless it is forced to do so. The turbine-air is in conflict (friction) with the ambient-air, causing both to accelerate to less of a difference in motion. In short; "air sucks" (Although I must say that I'm not sure if air can suck/pull... It can push for sure. adhesion might explain the pulling, viscosity (stickiness)). This pulling of air is causing low airpressure in the airstream and in the nearby ambient air. Inbetween the turbine airstream and the disc, the ambient air has more resistance, more "trouble" getting into the area of less pressure, because of the disc that is blocking the way. This causes the airpressure to drop even more. Now there is a pressure difference: a little less pressure above the airstream and a lot less pressure inbetween the airstream and the disc. This causes the ambient air above, to push the airstream down towards the disc, and also does the ambient air push the disc up towards the airstream.
As the distance between the airstream and the disc is reduced; the pressure drops even more, and this is why an airstream tents to "stick" to a solid surface.
Remember that an airstream and a solid surface are pushed together by the high pressure (about 1.033 kg/cm2) of the atmosphere (when lower air pressure is inbetween). A gasstream in space (a vacuum) does not "stick" to a surface. (correct me if I'm wrong)
3) Secondary air.
The airstream on top of the disc is in conflict with the disc and the ambient air. The disc has a solid surface which does not mix with the airstream, but the ambient air does. So, the primary airstream sucks in "secondary" ambient air, and thus; gaining weight and losing speed (speed relative to the disc). Above the airstream, the airpressure drops because the ambient air is dragged into the airstream.
4) Newton. Action = Reaction. Air has weight (Standard air weighs about 1,225 kg/m3). The action airstream is horizontal at first, but enlarged (by the weight of the secondary air) and then re-directed vertical downwards, thus the reaction force is vertical upwards.
5) Ground effect.
The airstream leaving downwards can create a pillow of high pressure air inbetween the disc and the ground, which is a very efficient way to fly, but only works up to a few meter, or less.
Note: I did an extra test without a surface under the disc. Thrust was about equal, so the ground effect has near to no effect on this craft. 2004-12-07
Thrust and drag
On top there is a lot of thrust going upwards, but further from the center the thrust force are going more and more sideways. Thrust going Left + Right together = Zero thrust.
And the drag; the drag forces are horizontal at first. But the further from the center the more they are pointing downwards!
So, it seems more efficient to not curve down all the way, but to stop at about 45 degrees.
And the shape of the curve can be improved for sure.
The suggested profile for GN003B
An airstream over a flat surface does not create thrust, or hardly any. But how about "vacuum cells"? An airstream can suck a tube/cell (closed at the bottom) to less pressure (not a real vacuum).
A solid surface can not become of lower pressure, not like a gas can. The vacuum tubes must be small and don't need to be deep, could be dip-shaped like on a golfball. The air friction would be low, because the air in the airholes can act like wheels, bearings, lubricant.
How about turning the whole top of the disc. Then there would be no friction between the airstream and the disc, not on top anyhow. The boundary layer could be used to accelerate the air. Then there would not be a need for a turbine on top, because the top surface is serving as a turbine already. (just like a Tesla turbine)
A turning top in combination with vacuum cells?
Air inside turning vacuum cells will only want to turn like the position of the turning top, because of gyroscopic forces.
When the airstream slowes down too much, it can easily become pure turbulent, which is not good. Friction between the airstream and the surface is also not good. The speed of the airstream right at the surface is about zero. Inbetween the solid surface and an airstream is a "boundary layer", in which a lot of collisions occur (friction). Friction = a los of energy, turning motion into heat and turbulance.
Nowadays, some aircraft use heat to expand & accelerate air. How about using a high electrostatic charge to expand & electro magnetic accelerate the air? And removing the electrostatic charge will result in an implosion, a low pressure area.
A solution for creating a large "Coanda Disc" airflow, without any moving parts, to keep it simple and light weight:
