Fast Jets

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Mike Tomasky wants to know why jet planes haven’t gotten any faster:

But here’s my question. Ever since the development of the noble Boeing 707, which started flying in 1958, transatlantic travel has taken what it takes today: seven or eight hours. Doesn’t it seem weird that they’ve never been able to improve this at a price regular people can afford? We had the SSTs, but a seat on one ran $10,000 a pop and they’ve now been discontinued anyway. […] We have ovens that cook food faster than they did in 1958. We have computers that compute a million times faster. In 50 years’ time, the advance in innovation and speed in any number of areas has been breathtaking. Trains are faster (usually, where governments have invested in it, which excludes my beloved nation). So how is it that jet travel reached its technological end point in 1958? I’ve always wondered about this and would appreciate explanations.

My understanding is that this mostly has to do with fuel consumption. The underlying technology of “making planes go fast” has advanced quite a bit and was applied to the Concorde and a variety of military applications. The way a jet works, if you want to generate more power you need to use (and carry) more fuel and that costs money for reasons that have nothing to do with the R&D or production costs of the plane. Existing passenger jets typically operate at somewhat slower speeds than their engines are capable of achieving precisely for fuel economy reasons. Modern jet engines are very efficient at converting fuel into power already; the technological improvement needed would be some way to make the fuel itself cheaper. It’s also worth noting that passenger jets are already quite fast. To go substantially faster, you’d be traveling supersonically and that would restrict the number of routes your plane could actually fly on due to sonic boom issues. That, in turn, would make it hard to amortize the R&D costs in a way that made the planes a reasonable deal on a per-unit basis.

All this adds up to a situation in which the thing airlines are looking for from Boeing and Airbus are ways to make planes more efficient in the sense of moving more passengers per unit of fuel.

It is interesting, however, that based on the rapid pace of advance in aerospace technology in the roughly sixty years between the Wright Brothers getting their patent and 1969’s double-wammy of the Concorde and the Moon Landing you would have thought the ensuing 40 years might be full of further exciting innovations. Instead we decided that neither supersonic passenger travel nor landing people on the Moon was a particularly economical use of fuel.