Report Card for Donald Trump

[SomeGuy]

(01-16-2017, 02:56 PM)David Horn Wrote:

(01-16-2017, 01:13 PM)SomeGuy Wrote:

Warren Dew Wrote:Supersonic flight is not inherently less fuel efficient on a per mile basis, just on a per hour basis.

Yes, it is.  Fuel use is largely a function drag, and drag is a function of speed.  In addition, the drag coefficient increases significantly after about Mach 0.8, pushing up fuel consumption dramatically.

It's not that it is impossible to fly past the sound barrier, I just question whether it is possible to do so cheaply.

But what would I know?

The only model that's even reasonably fuel efficient is the semi-ballistic model, that involves near-space flight during most of the trip.  Essentially shooting the vehicle into sub-orbit using a rail launcher, and more-or-less coasting in for a landing seems a bit extreme for all but the truly adventurous.  I don't see it, but it seems possible.

Which, you know, would look an awful lot like a ballistic missile launch on the radar.  I am sure you could work out institutional arrangements, but I'm not seeing it as a routine mode of transportation.  A lot still goes wrong with launches, and I can't imagine it being a pleasant trip.

Nor would it be particularly cheap.  But sure, it is presumably possible.