2 ms·

I never understood why this was an issue for crossing oceans from coastal airports. Is it a huge hassle to slow to 600kt as they get close to land? Also, at wh

by imglorp 11y ago

I never understood why this was an issue for crossing oceans from coastal airports. Is it a huge hassle to slow to 600kt as they get close to land? Also, at what altitudes does a boom become irrelevant? This thing will be very high so cross-continental might not be an issue either.

paulmd 11y ago
Most popular air corridors aren't over oceans. There's a reason that the only route the Concorde regularly ran was from JFK to London or Paris. Anything in South-East Asia is pretty close to land. The great-circle distance means that the shortest path runs over Canada or Greenland for many routes, and so on. And in the abstract it's more desirable to be over land because you have a place to ditch if something goes wrong. Typical pattern traffic is much slower than 600kt. It's a hazard to have aircraft at 600kt zooming around 747s approaching at 200kt and so on. You can come up with protocols to minimize the risks (eg running patterns at different flight levels and on different runways) but there's only so far you can take it, and there's still an increase in risk, particularly in emergency situations. When trans-sonic aircraft are operating at low speeds they're operating inefficiently. The longer and slower you're running them, the higher the fuel burn. That translates into higher operating cost and longer flight times. In an ideal world you would want them supersonic as soon as they can possibly get to cruising speed. You need to be pretty high before supersonic booms stop being a problem. The Concorde could do up to 60k altitude and was still a nuisance. So maybe 75k or 100k feet? Even that might not be enough - booms can travel as far as 100 miles and the difference in air density isn't significant enough to fully dampen this. You might be able to get away with flying lower with an aircraft that was designed to reduce booming.
- trhway 11y ago
  >You need to be pretty high before supersonic booms stop being a problem. what is the problem with sonic boom? i grew up on navy base in pretty militarized region and we had fighters frequently producing the booms (USSR, first half of 198x). It was fun, at least for us - for children :)

by imglorp 11y ago

paulmd 11y ago

Most popular air corridors aren't over oceans. There's a reason that the only route the Concorde regularly ran was from JFK to London or Paris. Anything in South-East Asia is pretty close to land. The great-circle distance means that the shortest path runs over Canada or Greenland for many routes, and so on. And in the abstract it's more desirable to be over land because you have a place to ditch if something goes wrong. Typical pattern traffic is much slower than 600kt. It's a hazard to have aircraft at 600kt zooming around 747s approaching at 200kt and so on. You can come up with protocols to minimize the risks (eg running patterns at different flight levels and on different runways) but there's only so far you can take it, and there's still an increase in risk, particularly in emergency situations. When trans-sonic aircraft are operating at low speeds they're operating inefficiently. The longer and slower you're running them, the higher the fuel burn. That translates into higher operating cost and longer flight times. In an ideal world you would want them supersonic as soon as they can possibly get to cruising speed. You need to be pretty high before supersonic booms stop being a problem. The Concorde could do up to 60k altitude and was still a nuisance. So maybe 75k or 100k feet? Even that might not be enough - booms can travel as far as 100 miles and the difference in air density isn't significant enough to fully dampen this. You might be able to get away with flying lower with an aircraft that was designed to reduce booming.

trhway 11y ago
>You need to be pretty high before supersonic booms stop being a problem. what is the problem with sonic boom? i grew up on navy base in pretty militarized region and we had fighters frequently producing the booms (USSR, first half of 198x). It was fun, at least for us - for children :)