On Vox: Not a day: In which scramjets are debunked

[theorb]

On another site (we don't like to advertise), I came across a http://www.popsci.com/popsci/aviationspace/a3bfe2e6fb5c6110vgnvcm1000004eecbccdrcrd.html , in which scramjets are discussed.  It's been making the rounds again, so you've quite likely seen it elsewhere.  I thought I'd do a little looking into their claims, and here's what I came up with

Comments

[herveus]

When you computed the acceleration for the SCRAMjet, what did you use as the initial velocity? SCRAMjets won't work until you are already going something like Mach 5 or so.

That minor nit aside, I do accept your overall thesis.

[theorb]

I assumed uniform acceleration from a standing start all the way to the halfway point, then uniform deceleration all the way to a standstill at the destination. While that's highly unlikely, in no small part because of that nit, it's the best case scenerio for making sure you aren't going to kill your passengers from acceleration ripping apart their insides.