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Frequently Asked Questions


  ZETJET does not describe jet engines from the perspective of a pilot inside the aircraft, but from the viewpoint of the air traffic controllers on the ground. For a pilot, the air flies through the engine, for an air traffic controllers the jet engine flies through the air.

Changing the viewpoint gives new solutions for aircraft propulsion.

A different point of view provoked strong opposition at times of Galileo Galilei already, and it holds true until today:

Experts and media are discussing ZETJET very controversial.

1 Does ZETJET violate the conservation law of momentum?

No, ZETJET complies with the conservation law of momentum. However, propulsion theory of jet engines needs extensions in order to account for local pressure changes. That is a challenge
2 Does ZETJET violate the conservation law of energy?

No, ZETJET complies with the conservation law of energy, because it needs power to drive a propeller. Without a powered propeller, ZETJET does not work.
3 Does ZETJET violate the law of entropy?

No, ZETJET complies with the law of entropy, because a powered propeller generates the flow. In front of the propeller, a low-pressure area is active during all flight. Air from the side then flows in, and the temperature drops. The process is isentropic.
4 Is ZETJET a perpetual motion machine?

There are physicists who have said that, but this is fundamentally wrong.

ZETJET is no perpetual motion machine of the first kind, because it needs power for the propeller. ZETJET is no perpetual motion machine of the second kind, because the driving force is a mechanical propeller, which maintains a
low-pressure area. When the ambient air flows in, the temperature drops.

Heat engines produce pressure differences from different temperatures. ZETJET generates a temperature difference from different pressure. It is exactly the other way around.

Mechanically generated pressure differences do not violate the law of entropy.
5 What is the difference between gross thrust and net thrust?

Gross thrust is the total thrust of the jet engine. If installed inside a nacelle under the wing, the engine first must push itself and the nacelle through the air. This needs thrust, which is not available for transport of the payload. Only net thrust remains for the airplane. ZETJET maximizes net thrust, thus reducing fuel requirements for the same transport task.
6 Why is ZETJET getting better with increasing speed?

The behavior was previously unknown, and it is beyond the current propulsion theory of jet engines. Conventional engines generate thrust by inertial forces of the accelerated air only.  Inside ZETJET, the secondary flow provides some additional thrust component by means of aerodynamic lift forces at flow surfaces. Their power contribution increases with speed. This was not possible so far.
7 Why do you use a carousel?

A carousel is the ONLY possible test arrangement to compare model jet engines under laboratory conditions with real aerodynamic loads. In a wind tunnel, the wind energy comes from the blower of the wind tunnel and not from the jet engine. This results in a different flow field than with a start in static air

No airport in the world has a blower to blow air into launching aircraft. A stationary test rig cannot simulate the interaction between moving aircraft and engine.
8 How big is the measuring error of the carousel?

Otto Lilienthal already had used a carousel for his research. He had analyzed the flight of birds and established the science of aerodynamics. A carousel generates some "wind" in stationary air by the mechanical drive. However, when using a model engine, the jet flow of the engine compensates that "wind” due to conservation of angular momentum. Therefore, the measurement error is very small when comparing model engines in stationary flight.




Design 1
UAV with ZETJET integrated in the fuselage. Aerodynamic profiles generating additonal thrust exploiting the secondary airflow from the side.
(click on picture for video)
Design 2
UAV with ZETJET integrated in the fuselage receiving air from the back. No aerodynamic profiles to exploit secondary airflow.
(click on picture for video)
Design 3
UAV with twin ZETJET integrated in fuselage. Aerodynamic profiles generate additional thrust from secondary airflow coming from the top.
(click on picture for video)
Test rig: carousel
A carousel allows us to easily measure forces and power consumption.
(click on picture for video)


Website updated: April 2017