Quieter engines, quieter skies.

Noise Prevention at Source (NPaS) for ducted fan and open rotor guide vanes

Noise pollution from aircraft is all around us, and with the number of Regional and Urban Air Mobility vehicles expected to increase in the coming years, the negative impact on our environment, especially in cities, is set to get worse. The need for quieter engines is vital.

Much of the noise is caused by the interaction between the Fan and Outlet Guide Vanes (or Stators) which sit at the front of the engine bypass air ducts or directly behind an open fan. As the air hits the leading edge of the vanes, it fluctuates between high and low pressure, causing the air to vibrate and create noise.

Oscar Patented Noise Prevention at Source (NPaS) Technology

Objective – Noise Reduction

The interaction between the fan and the Outlet Guide Vane (OGV) is the dominant source of broadband noise in turbofan engines, but this can be reduced.

Our patented technology, NPaS, provides the solution. By placing porous material between the high and low-pressure sides of the vanes, we can reduce the fluctuations and associated noise by as much as 7dB in the frequency range to which the human ear is most susceptible. Engines fitted with NPaS will offer manufacturers a real competitive advantage.

An initial study locating porosity at the leading edge reduced turbulence aerofoil interaction noise, particularly in frequency range 1-5kHz, by up to 7dB.

Further work has demonstrated that locating the porosity away from the leading edge reduces the negative impact on aerodynamic performance while maintaining noise reduction. It is likely that effective noise reduction could be achieved by treating only 10% of the vane area.

Learn more about NPaS

“Oscar’s patented technology is at the leading edge of academic and industrial research into the mechanisms by which noise is generated from the interaction of high-speed air flows and OGVs/Stators.”

Prof. Philip Joseph, Professor of Engineering Acoustics at the University of Southampton


Oscar Propulsion is seeking collaboration with the next generation of sustainable aviation propulsion technology and is willing to license its patented noise reduction technology and know-how.


Together we can create clean and quiet propulsion systems.
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