[jjj123]

I’m really surprised by the noise levels. They say 65db flyover and 70db landing which is quieter than just about every (personal) drone [1].

I wonder how they’re getting those numbers. Like at what distance are they measuring from?

I find it hard to believe they’re able to make a flying vehicle quieter than a drone 1/100th of its size.

Edited for clarity

[1]: https://www.airbornedrones.co/drone-noise-levels/

[hef19898]

I would have to look up the details, but there are EASA certification standards covering noise level measurement. Looking at the pictures, I think they achieve low noise levels by having e-motors and mid sized props (multiple). That avoids engine noise, reduces individual prop noise and having something between rotors and turbines should be quieter than a conventional helicopter on the one side and something like jet on the other hand.

[LargoLasskhyfv]

The medevac helos where I live are some (meanwhile old?) Eurocopter 135/145.

[1] https://en.wikipedia.org/wiki/Eurocopter_EC135

They are really surprisingly not loud. Not silent either, but not annoyingly, or disturbingly loud. Not comparable to the much, much older Bell UH-1 which we called 'Teppichklopfer' (carpet banger?). So it seems they know something about making helos less noisy.

I say this from the experience of having seen them come down maybe 200 times in the last 15 years? Sometimes just practicing it seems, with inner city, suburban, or park and field background noise floor.