Flying taxi engines produce weird sound, but scientists have found a fix
Engineers want to use next-generation BLI engines in electric flying vehicles, but a noise issue still needs to be fixed.
Ever wonder why some machines just sound so horrible, not just loud, but truly irritating to the ear? You may not believe it, but future electric aircraft engines, especially those being developed for air taxis and eco-friendly planes, might suffer from this exact problem.
A new study from researchers at the University of Bristol and the University of Salford reveals the hidden physics behind the unpleasant sound of a new type of engine called a boundary layer ingesting (BLI) engine.
These engines promise better fuel efficiency and lower emissions, making them vital for green aviation. However, there’s been one major issue; they make a strange, buzzing noise that people find particularly annoying, even more than traditional engines. Thanks to the new study, now we know exactly why, and more importantly, how to design quieter versions.
Until now, engineers designing next-generation electric aircraft engines could measure how loud these engines were, but they couldn’t explain why the noise felt unpleasant to human ears. To solve this dilemma, the study authors focused on BLI engines.
These engines are built to swallow the slow, messy layer of air that clings to the aircraft’s body during flight. This design helps improve efficiency and reduce drag. However, the downside is that it pulls in turbulent air, which ends up making noise.
The researchers wanted to find out exactly how this disturbed airflow leads to sound, and more importantly, why that sound feels so annoying to people. They set up a high-tech wind tunnel experiment to mimic real flying conditions.