[captainmuon]

Can anybody tell how such a plane will sound like over land? Growing up in Europe in the 90s, we regularly saw fighter jets doing maneuver and we called the noise they make a sonic boom: a loud, scratching and thundering noise that seems to come from the wrong direction. But I've also heard that planes almost never flew supersonic over civilian areas and an actual sonic boom sounds like a double clap, and is much more terrible. So is the noise I remember a sonic boom or not?

I think I could live with the kind of booms we heard as kids, as they were not worse than "regular" airport noise and the double- or triple-glassed windows common here block them out mostly. Especially since a civilian plane will have >30 years of technological advantage and will take noise into consideration, which military designs likely don't.

[Reventlov]

There is not really a sonic "boom": the sound you hear is shaped as a cone (behind the plane) so it's continuous and emitted as soon as the plane is supersonic. You only hear it one time because you're static, hence the "boom" (everyone on the path of the plane will hear it at different times). A supersonic plane is very loud, and if you're static it sounds like some explosion ( https://www.thelocal.fr/20200930/loud-bang-heard-in-paris-wa... for a "recent" example).

Usually military plane avoid going supersonic close to cities.

Extract from wikipedia:

  A sonic boom does not occur only at the moment an object crosses the speed of sound; and neither is it heard in all directions emanating from the supersonic object. Rather the boom is a continuous effect that occurs while the object is travelling at supersonic speeds. But it affects only observers that are positioned at a point that intersects a region in the shape of a geometrical cone behind the object. As the object moves, this conical region also moves behind it and when the cone passes over the observer, they will briefly experience the boom.

[fanf2]

Another example was January this year when a couple of RAF Typhoons intercepted an unresponsive civilian plane, and their sonic boom was heard over large parts of southeast England https://www.bbc.co.uk/news/uk-england-essex-55645967

[mrfusion]

I think you were just hearing the engines, brother. The boom is two loud claps like you say and you might be worried about your Windows.

[chiph]

Former USAFE member here. You weren't hearing a sonic boom, just the normal engine noise. If I recall correctly, we would do supersonic training off the coast of Spain. Flying supersonic over populated areas would do things like break windows in people's houses and that's not good.

The engine noise you heard was loud because military aircraft are normally exempt from sound level limits (when non-supersonic). And the engines for the F-16, Tornado, etc. were designed in the 1970s. Even for modern military engines, performance comes first. So they are still going to be loud.

The chart in this PDF shows that for the F-16, the allowed exposure time could be as short as 21 seconds with the older "muff + plugs" hearing protection. They're just LOUD (and I have the tinnitus to prove it)

https://www.faa.gov/about/office_org/headquarters_offices/av...

[LargoLasskhyfv]

Lol, dude, you would have loved flying in Germany in the 80ies. Nosuch nonsense having to care about broken windows.

Officially, maybe. In practice it was very, very different, and loud.

[chiph]

I was there in the mid-80's. We had a 100m tall microwave tower on base. The Luftwaffe pilots from Flugplatz Pferdsfeld would fly loops around it in their F-4 Phantoms during joint exercises. The US pilots had been told they would receive Article-15's if they tried that stunt.

An interesting story about property damage however, was during the REFORGER exercises. What I heard was that every convoy would have a Captain or Major in a Jeep at the end of it, and he would have a checkbook to pay for any damages to homes, vehicles, gardens, etc. caused by the tanks.

[LargoLasskhyfv]

Strange. I lived and was born there. Though I can tell you my experience was very different from yours. Maybe it differed by region? Mine was mainly Bonn (Bad Godesberg) and surroundings, and later Burscheid, which seemed to be some sort of path where they did their low flying(though slower there, not near sonic). Nonetheless I feel there were times where almost no day went by without several sonic booms. Especially in Bonn from say 1980 to 1986. And those were F-15, F-16, F-18, rarely F-14, besides the stuff the German Airforce flew. Maybe Belgium, Netherlands? Oh, some Mirages and Gripen also! (But even more rare than the F-14) I could tell them apart because someone gifted me a set of cards for aircraft recognition ;->

[BrianOnHN]

Fighter jets are loud as hell, without the sonic boom.

I've heard a lot of fighter jets. But I also don't believe I've heard an actual sonic boom.