5 ms·

I wonder what will be different financially this time around, to make SST profitable. Customers are as price conscious as always and the first class crowd is li

I wonder what will be different financially this time around, to make SST profitable. Customers are as price conscious as always and the first class crowd is limited, especially so for a higher priced option.

bryananderson 9y ago
More fuel-efficient engines. Lighter structural materials (carbon composites instead of metal). More advanced aerodynamics (less drag, thus less fuel is needed). And while not directly related to cost, aerodynamic advances have also led to the possibility of nearly eliminating the sonic boom, thus allowing flight over populated areas.
- thedrbrian 9y ago
  Going to struggle on the engine front as the major manufacturers have shifted to high-bypass turbofans rather than turbo jets in the civilian world.
  - kristianp 9y ago
    Boom is planning on using "off-the-shelf" medium-bypass turbofans, with proprietary intake and exhaust: https://boomsupersonic.com/airliner https://boomsupersonic.com/airliner
- mshook 9y ago
  Actually the fuel efficiency of Concorde in "max cruise" auto pilot mode (aka max speed) is way better than people think: it didn't fly with reheat on (that's what is called supercruising in military planes). Reheat (aka afterburners) was applied from Mach 0.95 to 1.7 and for taking off. The hourly flow rate in supersonic is roughly the same than in subsonic (cruising speed was around Mach 0.9), something like 20 metric tons per hour. So the faster you went supersonic, the better as your fuel efficiency would increase. There's even an entry about that in wikipedia: https://en.wikipedia.org/wiki/Thrust_specific_fuel_consumption#Significance_of_SFC https://en.wikipedia.org/wiki/Thrust_specific_fuel_consumpti... For example, Concorde cruised at Mach 2.05 with its engines giving an SFC of 1.195 lb/(lbf·h) (see below); this is equivalent to an SFC of 0.51 lb/(lbf·h) for an aircraft flying at Mach 0.85, which would be better than even modern engines; the Olympus 593 was the world's most efficient jet engine.[2][3] However, Concorde ultimately has a heavier airframe and, due to being supersonic, is less aerodynamically efficient, i.e., the lift to drag ratio is far lower. In general the total fuel burn of a complete aircraft is of far more importance to the customer. And on the Olympus page: https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593 https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593 The overall thermal efficiency of the engine in supersonic cruising flight (supercruise) was about 43%, which at the time was the highest figure recorded for any normal thermodynamic machine.[3]
mhneu 9y ago
Engineering is a problem too. Skin heating and reliability are big problems for supersonic speeds. You might get a prototype done, but building a stable fleet will be hard. The first accident will be crippling.
cyberferret 9y ago
Concorde was very advanced for its time, but it still had things like vacuum tube technology in the avionics bays etc. that would have been supremely expensive to upgrade/replace/repair. Also construction material etc. were good, but have advanced incredibly in the past few decades. Engine technology too. But there are still physical limitations around size of a supersonic capable airframe and the like, which limits the design of new aircraft and will still keep the price per seat quite high. However, by far, the biggest limitation that I can foresee is that the aircraft will have to fly non standard routes in order to avoid creating sonic booms over densely populated areas.
- chillydawg 9y ago
  London - New York alone is probably enough to make it worthwhile.
  - notahacker 9y ago
    New York to London is nowhere near enough to make an aircraft development programme worthwhile, especially not one requiring substantial technological novelty. Demand for high speed business class flights on that route is - based on the last supersonic operator - in the region of one flight per day. The A380 programme has over 200 aircraft delivered and over 100 more ordered and is not expected to break even.
masklinn 9y ago
BA's Concordes were actually profitable once they started making customers pay the price those customers expected to pay: prospective passengers expected prices to be way higher than what they were originally set at, leading to both chronic under-capacity flights and less income. Increasing prices to match expectations made BA profitable. The other issues were mostly politics/NIMBY. IIRC the estimated operating costs were about twice a 747 in seat/nmi in the early 70s.

bryananderson 9y ago

More fuel-efficient engines. Lighter structural materials (carbon composites instead of metal). More advanced aerodynamics (less drag, thus less fuel is needed). And while not directly related to cost, aerodynamic advances have also led to the possibility of nearly eliminating the sonic boom, thus allowing flight over populated areas.

thedrbrian 9y ago
Going to struggle on the engine front as the major manufacturers have shifted to high-bypass turbofans rather than turbo jets in the civilian world.
- kristianp 9y ago
  Boom is planning on using "off-the-shelf" medium-bypass turbofans, with proprietary intake and exhaust: https://boomsupersonic.com/airliner https://boomsupersonic.com/airliner
mshook 9y ago
Actually the fuel efficiency of Concorde in "max cruise" auto pilot mode (aka max speed) is way better than people think: it didn't fly with reheat on (that's what is called supercruising in military planes). Reheat (aka afterburners) was applied from Mach 0.95 to 1.7 and for taking off. The hourly flow rate in supersonic is roughly the same than in subsonic (cruising speed was around Mach 0.9), something like 20 metric tons per hour. So the faster you went supersonic, the better as your fuel efficiency would increase. There's even an entry about that in wikipedia: https://en.wikipedia.org/wiki/Thrust_specific_fuel_consumption#Significance_of_SFC https://en.wikipedia.org/wiki/Thrust_specific_fuel_consumpti... For example, Concorde cruised at Mach 2.05 with its engines giving an SFC of 1.195 lb/(lbf·h) (see below); this is equivalent to an SFC of 0.51 lb/(lbf·h) for an aircraft flying at Mach 0.85, which would be better than even modern engines; the Olympus 593 was the world's most efficient jet engine.[2][3] However, Concorde ultimately has a heavier airframe and, due to being supersonic, is less aerodynamically efficient, i.e., the lift to drag ratio is far lower. In general the total fuel burn of a complete aircraft is of far more importance to the customer. And on the Olympus page: https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593 https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593 The overall thermal efficiency of the engine in supersonic cruising flight (supercruise) was about 43%, which at the time was the highest figure recorded for any normal thermodynamic machine.[3]

mhneu 9y ago

Engineering is a problem too. Skin heating and reliability are big problems for supersonic speeds. You might get a prototype done, but building a stable fleet will be hard. The first accident will be crippling.

cyberferret 9y ago

Concorde was very advanced for its time, but it still had things like vacuum tube technology in the avionics bays etc. that would have been supremely expensive to upgrade/replace/repair. Also construction material etc. were good, but have advanced incredibly in the past few decades. Engine technology too. But there are still physical limitations around size of a supersonic capable airframe and the like, which limits the design of new aircraft and will still keep the price per seat quite high. However, by far, the biggest limitation that I can foresee is that the aircraft will have to fly non standard routes in order to avoid creating sonic booms over densely populated areas.

chillydawg 9y ago
London - New York alone is probably enough to make it worthwhile.
- notahacker 9y ago
  New York to London is nowhere near enough to make an aircraft development programme worthwhile, especially not one requiring substantial technological novelty. Demand for high speed business class flights on that route is - based on the last supersonic operator - in the region of one flight per day. The A380 programme has over 200 aircraft delivered and over 100 more ordered and is not expected to break even.

masklinn 9y ago

BA's Concordes were actually profitable once they started making customers pay the price those customers expected to pay: prospective passengers expected prices to be way higher than what they were originally set at, leading to both chronic under-capacity flights and less income. Increasing prices to match expectations made BA profitable. The other issues were mostly politics/NIMBY. IIRC the estimated operating costs were about twice a 747 in seat/nmi in the early 70s.