Superman, step aside

Flight Journal, Feb 2000 by Davisson, Budd

Faster than a speeding bullet! Able to leap tall .... You know the rest of the Superman thing. But do any of us stop to think what "faster than a speeding bullet" actually means? To the normal way of thinking, a bullet is pretty darned fast. Or is it? And is Superman the only imaginary figure capable of traveling those speeds?

First, we have to define "speeding bullet." Let's say we're talking about the 1911 .45 Colt that a bazillion ex-GIs know because for threequarters of a century-- WW I to Vietnam-it was the standard U.S. military sidearm (until recently replaced by a European pip-squeak). This 250-grain (approximately) lump rumbles through the air at about 1,200 feet per second (fps), depending on the load. The speed of sound varies with temperature, but within normal aeronautical ranges, it goes from about 950fps at minus 80 deg F to 1,150fps at plus 80 degrees F. In other words, on a really good day, a .45 bullet motors along at roughly Mach 1.

Now, let's go to the other end of the spectrum: the standard military rifle bullet-the .3006 that took us through three wars and is still the standard by which all other small-arms ammo is measured-pushes a 168 grain (depending on the version and load) at around 2,900fps. Now, that's really whistling! At a normal, high-altitude temperature, that's roughly Mach 2.9.

So, our definition of a "speeding bullet" ranges from a little Over Mach I to almost Mach 3. This means that Concorde flight attendants are in the aisle and serving coffee while traveling faster than a speeding bullet. And they don't even wear red capes! An SR-71 Blackbird crew could go blasting past a .45 slug while still in a low-speed climb; in fact, they wouldn't want to fly that slowly because it would burn too much gas.

Once the Blackbird guys were cruising at their normal operating altitudes, they could run up behind a .30-06 slug, slow down, look it over and then easily accelerate away from it. How's that for fast? The single most impressive fact about that kind of performance, however, is that they could cruise that fast for hours on end. It wasn't a shortterm, pedal-to-the-metal effort.

And then there were the first fighters, such as the Nieuport 11. At an optimistic 85mph, it did about 125fps, or .11 Mach. A bolt from a crossbow could have caught it, and a Nieuport pilot would have to huff and puff to catch a '67 VW "bug." But all things are relative. They are relative to what else exists at the time.

In WW I, the Nieuport represented the state of the art, but it was driven rapidly into obsolescence by the artificial stimuli that war brings to technology. Also, in its day, "faster than a speeding bullet" was a definitive phrase. There was no argument. That was fast.

I don't mean to denigrate Superman. He, too, is an icon of American creativity and imagination. But, sooner or later, everything needs to be updated. Maybe the statement should be modified to "faster than a speeding Blackbird." Then it would really mean something.