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Comment by jzwinck | Hacker News Reader

The article title refers to a "plane engine" not a "plane." There is a huge difference: the passenger plane airframes everyone knows and flies on are made by totally separate companies (Airbus, Boeing) from the engines (Rolls Royce, GE, Pratt & Whitney).

A great engine will get you nowhere without a great airframe, and when you start talking about supersonic passenger service, you have to add politicians as well. For example, the Concorde briefly flew between London and Singapore but was stopped partly due to complaints from the Malaysian government. And of course the Concorde is long since retired, despite no comparable replacement existing; this has nothing to do with its engines not being good enough.

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Also important to mention why Concordes got cancelled: even with cheap oil, there wasn't much demand for the plane. After a certain point, not much changes between a 4 hour flight and an 8 hour flight, especially if you have red-eye flights. Unless we figure out a way to have fast planes be cheaper to run than current models, then markets seem to show lack of interest in a Concorde-like

the Concorde used about triple the fuel per passenger of other aircraft of its era (like the 747). Even with relatively cheap oil, that added fairly substantial cost.

Additional factors that led to its demise:

- it was a very loud aircraft, and couldn't go supersonic over populated areas due to sonic booms. This led to significant limitations on viable routes.

- it didn't have the fuel capacity to make trans-pacific flights. This also led to limitations on viable routes.

- Concorde required specialized pilot training, specialized maintenance, and even a flight engineer (which more modern jets don't require).

- supersonic flight wears out airframes. I worked in a museum with Concorde G-BOAG, and could see several spots where the airframe had been patched in more substantial ways than our other similarly-aged or older airliners (Eisenhower's 707-based Air Force One and the prototype 727, 737, and 747's.) Airbus didn't want to keep maintaining the airframes given the condition they were already in.

The Concorde used about triple the fuel per passenger of other aircraft of its era.

As a rule of thumb, going supersonic triples fuel consumption. There's some research on improving that, and also reducing the sonic boom, but nothing flying yet. The aircraft geometries proposed are exotic. Angled flying wings, aircraft that transition from long/narrow to short/wide, and double inline wings have been considered.

http://www6.miami.edu/acfdlab/projects/AIAA2010-1013_slides_...

http://aero.stanford.edu/reports/vki_kroo_supersonics.pdf

Meanwhile, there's a startup proposing to build a supersonic bizjet.

http://www.aerionsupersonic.com

If you have to ask how much it costs, you can't afford it. It's only Mach 1.4 to Mach 1.6, though. The Concorde cruised just above Mach 2.

Triple is an odd figure. I know that air resistance at low speeds is typically modeled as a power between 1 and 2. How do we wind up with the factor of 3?

If you keep the geometry constant, air drag is normaly a power of 3 of the speed. But one exception of that rule is when you go supersonic.

The Kennedy administration funded a Mach-3 airliner that was supposed to be an answer to the European Concorde project.

http://en.wikipedia.org/wiki/Lockheed_L-2000

http://en.wikipedia.org/wiki/Boeing_2707

The Soviets also had a design that supposedly incorporated stolen Concorde blueprints.

http://en.wikipedia.org/wiki/Tupolev_Tu-144

> "The Soviets also had a design that supposedly incorporated stolen Concorde blueprints"

From what I understand, the Tu-144 didn't really incorporate anything of significance from Concorde -- the plans they had access to were more like sketches than fully fleshed out blueprints, and they only had usable details on a few minor components. The Tu-144 shares mostly superficial similarities with Concorde, with only a couple of similarities that might possibly have been the result of espionage.

> - supersonic flight wears out airframes.

Given conventional materials. The SR-71's skin is reported to get harder with all those heating cycles.

The reason that not much changes between a 4 hour flight and an 8 hour flight is that the journey adds about 2 hours on each end, making it a 8 hour vs. 12 hour journey. (1 hour to the airport and 1 hour at the airport).

Urban transit systems and airport security/boarding procedures will need to get a lot more efficient before supersonic flight will be commercially viable.

I would love to only have to spend one hour at the airport. From my experience, that's minimum for a domestic flight. International and you're talking 2+ hours.

(Unless we're talking about Europe; in that case 15 minutes should usually suffice^; at least last time I was there, a few years back. It was great.)

^ Although I'd give it 45 to be safe.

I was talking about first class passengers who can go to the front of ticketing and security lines, since economy class passengers are not likely to be in the market for supersonic flights.

Even with priority check-in/boarding and TSA pre-check, it's still a good idea to show up at the airport ~2 hours before an international flight. You can probably cut it closer but, personally, the last thing I want before an international flight is to be stressed about cutting things close.

Correct, especially with the added time of getting to, from and through the airports.

Some materials about a short-lived Hindenburg airship (http://www.retronaut.com/2011/04/inside-the-hindenburg-in-co...) mention its travel time between Europe and North America to be 40+ hours. I wonder, if they were available today, would there be a demand for this type of travel? For me the choice between a seat in 8 hour flight or a comfortable cabin in 40 hour is often not in favour of speed.

You can get a very comfortable "nook" for an eight hour flight across the Atlantic by flying First where available. And frankly, for that sort of time window, recline-flat business is is perfectly fine. I can't imagine anyone other than a Zeppelin buff wanting to spend 2 days to make the same trip. There's a market. As with long distance train travel and (basically the one) ocean liner. But it's minimal.

A one-way Hindenburg ticket cost something like $450 in the 1930s, which is over $7000 now.

Checking now, round-trip FRA - JFK on Lufthansa, "First Flex", is $4,500.

If you have the time, freighter travel is a possibility. http://cargoshipvoyages.com/VoyageDetails/?SCID=54&VID=143&S... shows a Europe/US route at $2,300, for 2 weeks at sea.

Airship travel is left with a limited market. It's not fast. It's not cheap.

There have been murmurs of this possibly having a renaissance. [1]

I read an article in a magazine sometime back as well, talking about the possibility of luxury flights like London -> New York, but boarding in a nice piece of park land instead of an airport. The flight would be much longer, but there would be essentially no jet lag, much nicer quarters to sleep in, five star restaurant food, etc. It certainly seemed to me there is potentially a niche market there somewhere.

EDIT - all I can find is a DailyMail(!) article - http://www.dailymail.co.uk/home/moslive/article-1357747/Airs...

EDIT 2 - seems to be this company - http://www.hybridairship.net

1 - http://m.ibtimes.com/zeppelins-making-comeback-aeroscraft-ai...

> boarding in a nice piece of park land instead of an airport.

I don't see this happening in the current climate of hysteria.

I really hope so. I'm someone who is scared of flying, but would happily go on board an airship for some reason.

I agree with this, and most of the reservations expressed, but just to note: he said Europe to Australia in 4 hours. That's... more like 22 hours now, right? That would be a very significant improvement.

I would pay $1000 more per ticket to do Australia to Europe in 4 hours.

For businesses that cost would be a no-brainer: landing and being able to actually function, would be amazing.

Well $1,000/trip is a super low premium to chase.

50 years of commercial airline operations have been hard for niche aircrafts. I'm not bullish on the hopes of a LEO commercial plane in our lifespan. It's a tough equation:

- a LEO plane won't be developed without presales that warrant safe funding (ie. from flagship airlines)

- incumbents are all about kerosene and do not want to add a significantly different tech to their already complex operations.

- new comers will not get access to enough capital to secure the development of a disruptive engine technology

Airlines make cash by moving a diversified mix of people and cargo. I just don't see anyone moving to the (super volatile) premium-only market with a supersonic high fixed cost jet.

You can currently pay $5000 more per return ticket (if you shop around) to do it business class. Full lie-flat bed, decent service, leg room, seatback power. You arrive feeling reasonably fresh (modulo the jet lag) and you can work en-route. That's the competition, and it'll be upgraded to compete if a hypersonic option ever comes on the market within an order of magnitude of its price -- think in terms of the first class cabins and bathrooms with showers that Emirates already put on their A380s, then upgrade it to a compact en suite hotel room with in-flight internet.

This. The maximum possible time saving looks even less significant when considering that since the physics and maintenance requirements for transporting people in turbofan-engined aluminium tubes at 1000km/h at 30,000ft is pretty well understood after half a century, the A380 will have better dispatch reliability and be substantially less likely to send your VIPs to a fiery death.

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