Comment by K0balt | Hacker News Reader

Comment by K0balt | Hacker News Reader

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Umm, this is not true. Supersonic speeds allow higher altitudes, which allows for higher efficiencies. This of course only applies if the aircraft is designed to take advantage of this, but I’m sure this one will be.

The limiting speed of subsonic aircraft is Mach .96 approximately.

For the u2, at its cruise altitude, this means about 100mph of airspeed… barely above its stall speed.

But if you go supersonic, you can break through that barrier and make use of the fact that there is much less air resistance at those altitudes. Not only that, but by riding past your shockwave, you can pick up a bit of recovered energy.

In some corners of the envelope, supersonic actually uses less fuel for the trip than Mach 0.9ish travel - which is where we fly our jetliners.

Also, we nasa has been experimenting with aerodynamic shapes that all but eliminate the sonic boom effect.

It’s not all bad.

> I’m sure this one will be.

If they are planning to make it more efficient than subsonic trips, it would be the first thing you would see in the website, or at least the FAQ. Supersonic flight is very cool, but for me this is just like Bugatti announcing a faster car for the rich, or an airline showing its first class luxury cabin: not very interesting.

I agree that this particular aircraft / project has limited potential. What I am most excited about is the potential for advancement of the field that could lead to realizing the potential benefits in supersonic transport.

It’s like props vs jets. Jet aircraft were less efficient but faster… until the altitude benefits made them more efficient and faster. Flying at the edge of space is the next step in that speed/ efficiency curve, and that is necessarily supersonic.

I would be exited if there were doing that, something really revolutionary, being faster with less fuel, or at least, flying at the same speed with less fuel. Unfortunately, it's something for the rich masquerading as an improvement for the entire world.

Still happy for the engineers working on this, they are probably having a great time designing a new aircraft.

>nasa has been experimenting with aerodynamic shapes that all but eliminate the sonic boom effect.

Yes, they've been trying to do that since the 1960s. I haven't seen any signs that they've been what I would call successful.

The x59 would have a thing or two to say about that. The sound pulse at ground level with the aircraft at altitude is about the same as a dishwasher, below the level of street traffic.

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