41–47 of 47 posts
I admit, I was a little disappointed to find no mention of Skylon, even if it's at an earlier stage of development than some of these other contenders. The SABRE engine appears to be coming along well, with one of the largest challenges - cooling the incoming air extremely rapidly - seemingly overcome. http://www.reactionengines.co.uk/sabre_howworks.html
"This thoroughbred airliner could fly from London to Sydney in 17 hours, three minutes and 45 seconds; compared to around 22 hours on a Boeing 747." This sounds wrong - the concorde's cruising speed was more than double that of a 747. Unless they're taking the refueling time into account (Concorde would need more refueling stops)
Concorde had to stop for ground refuelling something like 4 times on the London-Sydney trip. Each time it took about an hour and a half to come down from cruising altitude and land, slurp up a hundred tons of jet fuel, and take off again. Short legs.
Last time I flew trans-Atlantic -- last month -- in-flight wifi with mid-ocean coverage was available for $30. And we've got Facebook, SpaceX, et al promising us all clusters of satellites delivering broadband everywhere on the planet within 5-10 years. As the energy cost of high speed travel goes up with the square of the velocity, it'd be a whole lot cheaper to stick to subsonic travel in business class -- lie-flat…
I flew first class on a Virgin American domestic leg lately, and the legroom was absurd-- I couldn't even reach the seat in front of my with my legs outstretched. I don't need that much room, and in fact it makes it difficult to reach my underseat bag. (although it means I can escape to the aisle without disturbing my seatmate).
If a narrowbody jet went from a 3+3 coach config to a 2+2 that's 50% more cost per passenger. Throw in a couple more inches of legroom. Call it 100% more cost to be generous. How are there not plenty of folks like myself who would be happy to pay it, but can't even fathom the idea of paying 5x as much for today's business class?
Yes, I realize today's first and business class fares subsidize coach to some extent, but .. I just don't understand how a premium service can't catch on in this day and age. Talk about customer loyalty.
If the engine has no moving parts, how do you get a ramjet off the ground?
The biggest challenge will the same thing that killed Concorde: finding customers to pay super prices for super speed.
Sonic booms are a not-insignificant problem as well. We've been pouring money and research into it for decades and we have barely made a dent in it. The only known shape which produces no sonic boom (Busemann's Biplane) also produces no lift. There is a known shape called the Sears-Haack body which produces very little turbulence - basically it's like a very long pointed football. The best we have been able to do is…
(I'm a computer programmer, not an aero engineer, so probably both these solutions are naive)
Earlier quoted context omitted.
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.
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 wr…
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 :)