SST's and HST's

[DaMachinator]

Since supersonic commercial aircraft are clearly possible (see: Concorde) what would be the obstacles to the construction and operation of a new one?

Obstacles I see:

• Noise pollution
• Dubious economy of operation
• Low public interest
• Lack of obvious use in which they would significantly outperform existing subsonic aircraft 

 

Additionally, how impractical are theoretical hypersonic large aircraft that "skip" across the thicker layer of the atmosphere?

 

Edited July 21, 2016 by DaMachinator

[magnemoe]

Just posted this in the other forum, even if you avoid the noise issues who you can with modern aerodynamic, first its an premium service so you need enough well paying customers for the route, note that time is money so you will get people paying to do an day trip across the Atlantic but who would not pay for an first class ticket. however, this limit the routes and if you need to swap plane you could just as well fly first class direct, 
It might work well for Dubai airlines and Emirates with their ultra long flights and one hub, 20 hours flights is too much. 4 hours an 2 hour break and 3 hours makes more sense. 
The other option is premium charter and private jets, this two is combined most private jets are company owned and most is rented out then not used by company, this is why its so many private jets 

[PB666]

Here we go again?

[kerbiloid]

SST, HST... Skype kill'em all.

[wumpus]

Since the technological issues were "solved" in the 1970s, any remaining issues are presumably economic.

One fairly insurmountable issue is fuel usage.  Consider the lack of SST for most military jets "just to get there" (as oppose to using speed to defeat or evade enemy action).  Getting there "first with the most" is typically critical for military adventures, but as far as I know, the F22 is the only plane designed for long-term speed "to get to the action first" (it seems unlikely that the blackbird was expected to get to sites before anyone could cover them up, although it is possible).  Since military budgets generally don't have the "chicken and the egg" issues of starting up a technology, I'd assume that the economic issues can't simply be solved with throwing technology at them.

So the economic issues come down to "is the extra speed really worth it".  My guess is that a significant chunk of jet passengers are fairly high paid employees flying on their employers' dime, it all comes down to roughly the ratio of the cost to paid (as salary) to the employee in fight vs. the cost paid to fly said employee.  Right now these numbers justify jet flight (of course, management might unionize if you shipped them via greyhound) but not SST.  People who can afford SST flight seem more likely to splurge on larger areas during flight and simply overlap the "downtime" via electronic work/recreation.

My guess is that SST will happen when the (time saved)*(hourly cost of expensive flown employees) is less than added cost to fly SST.  That may not happen for awhile.  You also need to somehow allow for "overlapping" the downtime of sitting in what are effectively steerage-class seating (for above-first-class prices), VR headsets might help, but might not be popular while seating that squished together.

Also note that while sonic booms pretty much killed the idea of domestic SST, TSA pretty much stuck a stake through its heart.  Even before 9/11 (and before the OKC bombing), train was often the preferred means of traveling between NYC and DC (an obvious important "mostly overwater option" flight) and one of AMTRAK's only profitable routes: just getting to the airport adds a ton of overhead that makes any benefit from SST disappear fast.

[DaMachinator]

50 minutes ago, wumpus said:

Since the technological issues were "solved" in the 1970s, any remaining issues are presumably economic.

One fairly insurmountable issue is fuel usage.  Consider the lack of SST for most military jets "just to get there" (as oppose to using speed to defeat or evade enemy action).  Getting there "first with the most" is typically critical for military adventures, but as far as I know, the F22 is the only plane designed for long-term speed "to get to the action first" (it seems unlikely that the blackbird was expected to get to sites before anyone could cover them up, although it is possible).  Since military budgets generally don't have the "chicken and the egg" issues of starting up a technology, I'd assume that the economic issues can't simply be solved with throwing technology at them.

So the economic issues come down to "is the extra speed really worth it".  My guess is that a significant chunk of jet passengers are fairly high paid employees flying on their employers' dime, it all comes down to roughly the ratio of the cost to paid (as salary) to the employee in fight vs. the cost paid to fly said employee.  Right now these numbers justify jet flight (of course, management might unionize if you shipped them via greyhound) but not SST.  People who can afford SST flight seem more likely to splurge on larger areas during flight and simply overlap the "downtime" via electronic work/recreation.

My guess is that SST will happen when the (time saved)*(hourly cost of expensive flown employees) is less than added cost to fly SST.  That may not happen for awhile.  You also need to somehow allow for "overlapping" the downtime of sitting in what are effectively steerage-class seating (for above-first-class prices), VR headsets might help, but might not be popular while seating that squished together.

Also note that while sonic booms pretty much killed the idea of domestic SST, TSA pretty much stuck a stake through its heart.  Even before 9/11 (and before the OKC bombing), train was often the preferred means of traveling between NYC and DC (an obvious important "mostly overwater option" flight) and one of AMTRAK's only profitable routes: just getting to the airport adds a ton of overhead that makes any benefit from SST disappear fast.

Some of these issues might be solved by technological developments in engine technology - if pulse detonation engines or scramjets ever become practical, for instance. However, this discussion concerns the here and now.

As far as that goes:

The TSA is ineffective. Crazy people still get on planes, and there's no TSA for general aviation. Nobody's going to keep you from buying a used cargo jet if you have the money. 

If we're targeting this group of wealthier people who can afford SST flight, why not make the plane roomier? Say 2 or 3 seats an aisle instead of 4, and put the seats farther apart. Headroom will still be a bit of an issue, but the Concorde passengers didn't seem to care. The Concorde actually made British Airways money, as unbelievable as that is.

 

OT: Interestingly, one of AMTRAK's other profitable routes is Virginia? to Central Florida. Rich peoples love their beaches and expensive condos and (comparatively) warm winters.

[wumpus]

3 hours ago, DaMachinator said:

Some of these issues might be solved by technological developments in engine technology - if pulse detonation engines or scramjets ever become practical, for instance. However, this discussion concerns the here and now.

Airports already have NIMBY/noise issues.  And my understanding of pulse detonation is that it is likely to always be too loud for public use.  Wouldn't it also work if you provided the oxidizer as well (Vexhaust should be higher)?  I find the lack of rocket companies attempting to use this tech making me suspect it isn't going anywhere.

SCRAMJETS don't work below ~mach 4.5, and presumably pull past mach 10? (ok, the record so far is 9.4).  That isn't air travel, that is suborbital ballistic travel.  For seriously long (trans-oceanic) travel, it should make sense merely avoiding drag for the parts in space.  But so far that type of speed is only available (for consumer values of available) from Virgin Galactic and Blue Origin (and they only get you halfway there).  The price tags so far can't justify the speed.  No idea if you could get the price down with regular flights (that mach 9.4 craft was single use).