AHC: Successful Supersonic Airliners

Oh. Yeah.
I know the soviets had quite a few designs for liquid-hydrogen powered bombers, of which precious little info exists.

Can't say the US ever seriously considered LH2 for the military :) Frankly it's note very good for 'operational' use due to its nature. Ammonia was more a 'suitable' military fuel if we had to make our own initially at least. (It was the 'default' propellant IIRC for production using a portable nuclear reactor) Methane production and use was studied IIRC, (and not just in the context that the "troops" produce it in quantity :) ) but you want as many 'low-tech' capabilities as you can get for storage and handling and LH2 has very few of those :)

Randy
 

Archibald

Banned
On trans-pacific airways the 2707-300 suffers from its limited range, 4000 miles at best. The main airway is obviously L.A - Tokyo. There is no other solution than to make a stopover. I thought Hawaii was the only option, but Anchorage is actually closer, and the entire trip far shorter !
Once again, the key is Mach 2.7. They did tried Concorde on trans-Pacific, but a 747 without a stopover did a job better (how surprising !).
At Mach 2.7 however it is a different matter, and the 2707 saves some time.

I can see a SST lifting off from Tokyo, fly to Anchorage, and then fly along the western coast, either to Seattle or to L.A or San Fransisco. The trick is to fly far enough from the coast so that the sonic boom is confined to the Pacific ocean.

This is a useful website to plot air ways. https://www.distancefromto.net/

Tokyo - Anchorage is 3500 miles (2 hours flight)
From Anchorage
- Seattle: 1460 miles (note: Tokyo - Seattle, direct, is 4800 miles: too long)
- San Fransisco: 2042 miles
- Los Angeles: 2334 miles (1h:30 mn)

Now through Hawaii / Honolulu

Tokyo - Honolulu: 3870 miles (let's say three hours including the stopover)
Honolulu - L.A: 2570 miles
Honolulu - Seattle: 2675 miles (1h:30 minutes)

Now how about Australia ? forget Anchorage :p and the distance from Hawaii is too long, 5000 miles. The trick is to replace Hawaii by French polynesia - Tahiti, with the capital Papaete.

Los Angeles - Tahiti is 4125 miles, at the aircraft extreme range.
Tahiti - Sidney is 3800 miles.
Tahiti to Auckland is only 2500 miles.

Concorde initial range was 3600 miles, but some tweaking here and there resulted in flights as far as Barbados, 4200 miles from London. I can see the 2707 evolving like this.

for the sake of comparison Mach 2.7 is 1800 miles an hour. Hence the 2707 can cover 3600 miles in only two hours.
Most of the distances above are more or less 3600 miles, two hours of flight time.

Which mean trans-Pacific flight times are cut to 5 hours (including the usual 1h stopover).

finally, with 250 passengers, the 2707 is not unlike an A330 or the earlier 747SP and A300.
 
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Archibald

Banned
The neat thing is, when carrying less passengers, the SST can fly farther. Concorde did that, it had 140 seats but best range was with 100 passengers. Of course that made Concorde economics even worse.

The SST can afford that better than Concorde. By starting from 250 passengers (I even see 280 !) cutting to 180 or 200 should help range a little, notably on LA - Hawaii.

This document is a 1969 Boeing brochure that describes the 2707-300, the definitive variant to be build (not the swing wing siliness that had zero payload)
http://www.emotionreports.com/downloads/pdfs/boeing.pdf

The first two prototypes were to fly in November 1972 but construction stopped in May 1971. Which mean that Boeing had started to cut metal, perhaps 15% of the entire thing.

What is mind-boggling with the 2707-300 is how it would have dwarfed both Concorde and even the XB-70 Valkyrie. There is not many ways around packing 250 passengers into a thin, supersonic-shaped fuselage: length, length, more length. Forget double-deck or wide fuselage.
At 298 ft the SST would have been the longest airliner or even aircraft ever build. Far longer than even the An-225 Mryia - by 20 ft !

800px-Giant_planes_comparison_-_Updated.svg.png
 
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Indeed, it is the trans-Pacific routing that I think would have driven a USA effort. This should give you a bigger aircraft carrying not just more passengers but more fuel to hit destinations between Japan and the US west coast. Concorde had the slightly less ambitious routes from London or Paris to NYC and potentially to intermediate stopovers in the middle east. Given the USA westward slant its SST should be bigger and faster and thus more competitive on trans-Atlantic routes. That is the basis I used to pencil out a joint US/German effort since Germany needs a little more legs to route from Berlin or Frankfurt, going at least as far sub-sonic as Air France out of Paris if not more so. That gave me excuse to effectively double the population of SSTs, approximately 7 each to BOAC, Air France, Luft Hansa, and Pan Am (a hint to how the ATL may be shades different). Stretch it and you could add some more to any of these or add more players such a surviving TWA or more ambitious Northwest or KLM or most likely Japan's flag carrier. Again this should be a premium service that skims the cream off, wide bodied jets still do the grunt work of lower tier business, tourist and freight. Depending on how you weave in a spike in oil prices then this might be a niche scenario for some decades just as Concorde survived in OTL. For me this was the next logical leap from the Airship versus Airliner/Ocean Liner paradigm and a potential bridge to hypersonic and/or SSTO designs. I let the fiction of the Orion III be my guide way out to can I dream it so. If you want SSTs then build the foundation for how they take better root and how they play their part, the concepts herein show it is not all pie in the sky despite some cold hard economics.

And for me I do like the trans-Polar or circular routes in the Pacific, I toy with a surviving Imperial Japan, a multi-lateral worlds with at minimum a three-way Cold War, and more complicated European relations so SSTs advance the political tensions nicely. And how about the environmental impact of multiple SST flights up and down the California coast? What is the impact of sonic booms over those costal habitats and offshore environs? Again the shiny technology can tease out some strange new butterflies in any ATL. Fun stuff to ponder even if one is not an aeronautical engineer or airline executive.
 

Wimble Toot

Banned
If the cost per mile travelled is significantly greater than the cost of flying a passenger in a 747 or 747SP, few airlines will be able to amortise the cost of operations over the life of the aircraft.

SSTs are prestige projects, requiring extensive state subsidy, like the US space program only even more pointless.
 
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