US Army Seeking Quieter Helicopter and Drone Technology
The US military is looking towards the development of drone stealth technology. In its press release, the administrative division announced the USA military’s priority to seek advanced drone technology prospects. The aircraft design will hold noise reduction and can penetrate hostile areas hassle-free.

News and it’s Potential

The USA has decided to make new drones that have very little noise or zero noise. U.S. Army Combat Capabilities Development Command has collaborated with Uber and the University of Texas to investigate electric vertical takeoff and landing aircraft’s acoustic properties. These vehicles use electric propulsion systems for flights. Due to the stealth technology, the aircraft does not come on the radar. Hence, drones and aircraft are getting successful by building military camouflage. The mere noise somewhere lets the hostile actors become aware of any activity that is not suitable and compatible with them. Hence, there is a need for new designs in the drones to utilize more robust structures with better defense surveillance.

Why is there a need?

The eVTOL (electric Vehicles Take-off and Landing) vehicles have traditional rotors. Two significant types of noise are generated due to these vehicles. One is the thickness noise, and the other is the loading noise. The thickness noise comes from the air’s displacement by the rotor blades, whereas the loading noise forms during lift and drag forces acting on the air that flows around the rotary wings. The sum of these two noises is the tonal noise. The researchers observed turbulence noise (or broadband noise) more than the tonal noise in defense aircraft. The researcher’s team monitored the orthodox model of noise existing in the aircraft and measured helicopter noise simulations’ modeling capabilities for eVTOL rotors.

How was the test done?

The researchers designed a test stand. On this stand, they kept two rotors on it. Nine microphones were surrounding the test stand in a circular array to measure the noise above the rotor and below the rotor. For the simulations, the team developed a Rotorcraft Comprehensive Analysis System (RCAS). Coupled with a separate program called PSU-WOPWOP, RCAS analyzed a routine noise prediction code-named after an onomatopoeia for the sound that helicopter blades make. Some of the critical observations came out from the test were:

Co-axial, co-rotating rotors, or stacked rotors, may provide better performance and lower noise than a conventional and traditional rotor.

One of the reasons behind stack rotors performing well is the blades’ arrangement in multiple planes, unlike conventional rotors with blades in a single plane.

Conclusion

Drone and helicopter technology can witness new upgrades with modern designs. Though the models are a part of current research, the US army is working on these designs to convert them soon into reality. The Army research team published its paper, “Experimental and Computational Investigation of Stacked Rotor Acoustics in Hover,” during the Vertical Flight Society’s 76th Annual Forum Proceedings.

Everleig is a Blog expert and has been working in the technology industry since 2003. As a technical expert, Everleig has written technical blogs, manuals, white papers, and reviews for many websites such as thoughtg.com

Source: US Army Seeking Quieter Helicopter and Drone Technology
['Grace Taylor']
['Drone', 'Technology', 'Helicopter']