> The faster the plane goes, the more fuel it consumes due to the drag increase by the square of the speed.
... at the same altitude.
... at the same altitude.
Looking it up, the Concorde flew at 60,000 ft, compared to normal planes at 30,000 ft.
And atmospheric pressure at 60k ft is less than a quarter of what it is at 30k.
Is it possible to fly twice the speed of a regular aircraft but without using that much more fuel, by flying higher? Or does the plane have to burn even more fuel to get up to that altitude and maintain lift in a thinner atmosphere?
If you go higher, the speed of sound decreases so you have to go slower to avoid going above the critical Mach number for your aircraft. Normal airliners have to stay quite a bit below Mach 1 to avoid any part of the airflow going supersonic, since that would create big issues like shock waves making the aircraft uncontrollable.
But due to the air being really thin, you also have to go faster. Otherwise your wings will not generate enough lift to keep flying.
At some point you cannot go faster and you cannot go slower, that effect is called Coffin Corner and limits how high a subsonic airliner could fly: https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)
"In the days when the supersonic transport was in active service, and cruising at between 60 and 68,000 feet, the estimated radiation received by the crew was 50-130 mSv/yr. thus, obviously, as newer generations of aircraft cruise ever higher, by the time we reach altitudes above 60,000 feet, it is entirely possible that, especially with crews flying trans-Atlantic or transpolar routes, the acceptable maximum safe dose of radiation per year will be exceeded. In addition, these numbers do not take into account the possibility of pregnancy in female crewmembers. "
See Van Allen Belts.
If I edit my photos on the flight home, am I more likely to corrupt my files with bit flips?
It turns out that higher cruising altitude isn’t nearly as useful as atmospheric pressure might suggest. Aircraft end up optimized for their cruising altitude, but there’s a lot of tradeoffs when targeting a higher altitude.
As long as nothing ever seems to be mysteriously off course and heading for Moscow it sounds like a great idea. Is it easy to distinguish a ballistic missile full of passengers from the more bad kind?
But I was more curious about the fuel efficiency...
You do need more energy to go that high and fast, but it take a bit of analysis to figure out if it's problematic. Most likely it would be driven by the mission profile as to whether or not the trade-off is worth making.
The turbofan engines of today mitigate this inefficiency by, in essence, strapping a big prop in front of the turbine, except we call it a fan.
Props employ lift like a wing. Fans are screws.
It's really a spectrum where most props & fans actually posess at least a little of both properties, and there are some in the middle that had to simply be called propfans.