Following landmark aeroacoustics research, the University of Bristol’s world-leading team will use their state-of-the-art wind-tunnel facilities to test Aeroberm’s patented fractal panel vertiport geometry — with an open invitation for eVTOL manufacturers to help optimise it for their aircraft.
As the Advanced Air Mobility industry races toward commercial launch, a new collaboration between the University of Bristol, Swinburne University of Technology and Aeroberm™ aims to tackle what many in the industry now consider the single biggest threat to public acceptance of a vertiport ecosystem: noise.
The University of Bristol’s Aeroacoustics Research Group has published a series of studies establishing that the solid ground surface beneath a rotor or propeller plays a significant role in noise generation. Research has shown that when an aircraft operates close to the ground — as every air taxi must during take-off and landing — a phenomenon called “ground effect” measurably amplifies noise.
“From our studies to date on various generic surfaces we believe that replacing a solid ground surface with the elevated Aeroberm™ pad with a perforated fractal design will likely substantially reduce that noise penalty,” said Dr. Esmaeel Masoudi, lecturer in aeroacoustics at University of Bristol.
“While results will differ between aircraft configurations, based on the tests carried out in our wind tunnel facilities, we anticipate that the noise reduction could be up to 13 decibels for the first tonal component and up to 7 decibels in overall sound pressure level. At some observer angles, the elevated Aeroberm landing pad may effectively eliminate the additional noise associated with propeller–ground interaction, reducing the measured noise to the isolated propeller (baseline) level,” said Dr Masoudi
An Open Invitation to Air Taxi Manufacturers
Every aircraft has its own distinct downwash, outwash, and noise signature — shaped by rotor count, disc loading, weight, and flight profile. Aeroberm and the University of Bristol are inviting eVTOL manufacturers to participate directly in the testing program, helping optimise the Aeroberm panel geometry for their own aircraft — and shape a landing surface standard tailored to their specific acoustic and aerodynamic characteristics.
“It is a myth that electric air taxis will be silent. While they will blend into the background noise of a city when flying at altitude, there is no escaping the aero physics at a vertiport. A lot of air needs to be moved to achieve vertical flight and while the electric motor noise will be minimal, there will still be significant noise that could render some great vertiport sites unfeasible if not ameliorated,” said Clem Newton-Brown, CEO and founder of Aeroberm (a Skyportz company).
Noise concerns are anticipated to be among the most common reasons vertiport proposals will stall at the planning stage. Unlike aircraft certification or battery technology, noise is experienced directly by the public. A vertiport that meaningfully cuts noise doesn’t just tick a regulatory box — it builds the social licence the AAM industry needs to fly where people actually want to go.
BACKGROUND ADDENDUM
Why noise is the industry’s hardest problem
Industry leaders have increasingly recognised that the Advanced Air Mobility sector will succeed or fail based on ground infrastructure, not just aircraft technology. A vertiport that meaningfully reduces noise does more than tick a regulatory box — it helps build the social licence the entire industry needs to operate in the places people actually want to fly to and from. Quieter vertiports mean fewer objections, faster approvals, and a foundation the wider AAM ecosystem can be built on with public support rather than public resistance.
The physics: what “ground effect noise” actually is
The University of Bristol’s Aeroacoustics Research Group has published a series of studies establishing that the solid ground surface beneath a rotor or propeller plays an important role in noise generation. When an aircraft operates close to the ground — as every air taxi must during take-off and landing — a phenomenon called ground effect measurably amplifies noise. Prior published Bristol research (Hanson et al., Journal of Sound and Vibration, 2023) found rotors can be up to 4 dB louder operating in ground effect near a solid surface than in free flight. This new wind-tunnel testing program will build directly on that published foundation, applying it specifically to Aeroberm’s fractal panel geometry rather than generic surfaces.
How the fractal panel works
Aeroberm’s fractal geometry was originally engineered to solve the downwash and outwash safety problem that limits how close a vertiport can be built to people and property. The design uses self-similar, logarithmically-spaced vanes in a wavy, non-sinusoidal pattern to disrupt and redirect rotor outwash at the ground plane (a Magnus-effect-based redirection mechanism), rather than allowing air to strike a flat, solid surface and reflect toward the aircraft and bystanders. CFD modelling conducted by Swinburne University of Technology (Professor Justin Leontini and Andrew Che) found the fractal panel achieves roughly 90% faster viscous energy dissipation than flat tarmac.
This same physical mechanism — breaking up airflow at the surface rather than letting it strike and reflect off a solid ground plane — is what the Bristol wind-tunnel program will now quantify acoustically. The aerodynamic dissipation properties that solve the outwash safety problem are now being tested for their acoustic dissipation properties as well.
What the collaboration will actually test
The University of Bristol’s wind-tunnel facilities will test Aeroberm’s fractal panel under controlled propeller/rotor conditions to measure the noise penalty associated with ground effect, comparing it against flat and generic perforated ground surfaces. Early indicative opinion shared by Dr. Esmaeel Masoudi point to noise reductions of up to 13 dB for the first tonal component and up to 7 dB in overall sound pressure level, with some observer angles showing the additional ground-interaction noise penalty effectively eliminated — returning to isolated-propeller baseline levels. These are described as anticipated results based on testing to date; results will differ by aircraft configuration, rotor count, disc loading, weight, and flight profile, which is the basis for the open invitation to manufacturers.
