Rudster816
They designed the Concorde for the sole purpose of supersonic air travel. Anything besides that would have been a huge letdown. Nobody has wants to do it because of $$$, not because it's insanely difficult. Unlike military aircraft (*cough* F35 *cough*) civilian aircraft have to be economical enough to be able to at least cut even. Despite nearly 30 years of service they were only ever able to sell 20 Concordes, and it lost a huge amount of money.
Actually is was a political race, Europe's moonshot against the US and USSR, they haven't been better since the Comet. It was assumed that supersonic travel would flourish while air freight would go to jumbo jets. No one counted on the influence of the environmental lobby on supersonic travel which reduced the 76 orders for Concorde down to just 16 for the flag carriers, banning overland flight due to the sonic boom around the world, and killed the US supersonic project. No one counted on passengers flocking to jumbo jets for cheaper fares and lower fuel consumption, I think, due to in part to the aftermath of the
oil embargo. Politics created and then tried to kill Concorde.
But it beat the odds by surviving the politics of the 60's and 70's all the way to 2003. Operating costs weren't that much, there was a major premium, a la multi-socket Xeons. Concorde may have charged 10 times more for a 2-way trip at the time, but NASA/Boeing could have done it for just 25% more; but pushing the economic argument is a bit difficult. Can't beat physics, going faster always costs more, but I believe in design challenges, not showstoppers.
Purely technically speaking, variations of the jets of the day (Boeing 707, DC-8 and Convair 990) had the same fuel economy as Concorde and the same range. That was their original marketing thinking, and it could have worked if Boeing didn't create the 747 with their high BPR engines. That opened up a whole new market where Lockheed joined and Convair was bought by General Dynamics and the rest is history.
Rudster816
I've come to understand that in order for an engine to break the sound barrier it has to be specifically designed to do so.
For fully custom designs not based on off-shelf engines, yes, but not necessarily.
Back in the day, early civilian jet engines were all low-BPR like the Pratt & Whitney JT8D on Boeing 727. But the same engine was used to power a
Saab 37 Viggen supersonic fighter jet as well as an upcoming
supersonic business jet by Aerion Corp that is set to debut in a few years. The difference is the choice of inlet and exhaust systems, they aren't just ducts; although BPR still plays a critical role in maximum Mach numbers. For instance, Concorde's engines only produced 12% of the power at Mach 2, the rest came from the inlet and exhaust systems (
scroll midway).
Breaking the speed of sound isn't just about the engine. Back in the 50's Convair made a interceptor for the UASF called
F-102 Delta Dagger, but for some reason it couldn't pass the speed of sound even though it was designed for Mach 2. It turned out that the progression of area cross section of an aircraft from front to back determines whether a plane actually goes supersonic, if not by brute-force rocket-style thrust (which wastes fuel for any application). Discovered by a NASA engineer, Robert T Jones, his "Area Rule" allowed Convair to
redesigned the jet with a bottleneck in the middle fuselage so the cross section due to the wing and engine blended more; there after it could go supersonic, and renamed F-106 Delta Dart. From then on, all supersonics were designed with Area Rule in mind.
Look at the F-22, where the canopy tapers off, the engine body grows; and the vertical fins happen to be placed where the wing's cross section tapers off, etc. Subsonics don't need Area Rule, but some take it into account for the spared-no-expense drag reduction technique like on the Learjet 60, see the
subtle fuselage pinch just above the wing near the engines? Not so subtle is Aerion Corp's SSBJ attempt which uses a
rather extreme version of Area Rule on the top view.
Rudster816More engines may not increase to speed of the aircraft very much, but it will allow larger and larger aircraft to achieve a similar speed.
Yes, this is how all first-generation aircraft were made practical, from the four engines applied on a Comet, to Concorde, to 747 and then to A380. But, having two engines on civilian jets is more safe as they go through more certification.
Rudster816
In a military vs civilian aircraft comparison, you also have to consider that military R&D results in many of the innovations that are applied to civilian aircraft. This is true of a lot of technology. I don't think it's proper to say that a former apprentice is more impressive than the master craftsman he learned his trade from. 
Winglets were not invented by the world's military.
The last time the military influenced civicial aircraft design was pre-Korean war era, back when many military transports and bombers were converted to civilian use; from then on, circa oil embargo, they split off. Boeing already has had a hard time introducing C-17 as a commercial freighter, all while Boeing's 747-800 stretch is getting more attention for the company.
Overall, I'd say military R&D may have influenced civil innovations is more true of modern day airliner usages, but Concorde was being developed at the same time these military projects were still secret, so sharing and learning was limited. The primary contribution to soaring costs is having to do the ground work yourself. But that doesn't mean if there was equally distributed cooperation, then Concorde would have been cheaper.
Designed as a civilian aircraft, many military supersonics didn't use fully-pressurized cabins where everyday folks can be seated without any training in altitude effects-- there were many challenges to water down that the military industry more or less took for granted.
We can say making an airframe out of carbon-fiber reinforced plastics came from the F-15 first before showing up on Boeing 787; but the same technique wasn't employed, Boeing had to make their own.
post edited by lehpron - 2012/09/10 13:30:37