Land Speed Record Broken: 0-6,400 in Six Seconds

linuxwrangler writes "Researchers at Holloman AFB have broken their own two decades old land speed record for rail vehicles. The rocket powered sled covered the 3 mile track in roughly 6 seconds. Preliminary numbers put the sled's speed at mach 8.6 or about 6,400 mph - it covered the last 1.8 miles in just 1.3 seconds. The previous record of 6,122 mph was set on Oct. 5, 1982. Other accounts are at the Alamogordo Daily News, the Denver Post, and CNN."

Comments

Yikes! Is there an EDITOR in the house?!?

[Sabu mark]

The Alamogordo Daily News article has some of the worst writing I've ever seen. Get this guy an editor, quick! Not only is the science explained incorrectly, but paragraph after paragraph is filled with laughably awful sentence structure.

Here are just four paragraphs, with my commentary on them. The entire article is this bad.

Obviously, the world record was broken and the Test Track now owns the fastest thing ever attached to Earth. Jolliffe even suspects that once data is evaluated, the speed could exceed Mach 8.6.

It's usually unprofessional to use "obviously" in news articles.
Somehow I think the speed isn't going to exceed zero anymore. What the writer means is that they'll FIND that the speed DID exceed Mach 8.6, not that the speed WILL exceed Mach 8.6.
You probably should insert "the" before "data," buddy, because you're probably not referring to the data I evaluated this morning, which as far as I know didn't affect the missile's speed.

The spline system succeeded. Previously, double-sided tape held the plastic to the track. For this test, seven tankers pumped helium into the 11,000-foot tube. Because helium is 1/7th air's density, when the sled shot through the tube for the last two miles of the three-mile run, the sled's momentum increased by a "tremendous amount of speed," Kurtz said. As the sled entered through a diaphragm, the tube immediately disintegrated; but because of the speed the vacuum created helped the sled to continue unimpeded.

Jesus - the sled's momentum increased by an amount of speed? I bet its energy also increased in power and its current went up by fifteen volts.
I think the guy means TANK, not "tanker." A tanker is a vehicle containing tanks. A tank is a vessel containing the actual helium.
What's with the last clause, the one after the inappropriate semicolon? Because of the speed the vacuum created helped? What? There's too many verbs. It took me a long time to parse this sentence. My best guess is "Because of the speed, the vacuum WHICH WAS created helped the sled...."

The Hypersonic Upgrade began in 1997. The program converted the monorail sled (which held all previous speed records) to a double, narrow-gauge track with the rails 26 inches apart. (Supersonic speed transitions to hypersonic at Mach 5.) The monorail generated "high vibrations," Jolliffe said. The dual track reduces vibration by a factor of four (from 80 Gs to 18 Gs), helping in the push to faster speeds.

They converted a sled to a track?
Somehow I doubt the monorail sled held ALL previous land speed records. For instance, the speed records that were set before it was invented. Those were probably held by something else.
"Supersonic speed transitions to hypersonic at Mach 5" - what an opaque way of explaining it. I would say "The term 'hypersonic' refers to speeds of Mach 5 and above; speeds below Mach 5 but above Mach 2 are called 'supersonic.'"
And why the hell is that sentence in that location, in between two sentences that discuss rail construction? It should have been immediately after the sentence in which "hypersonic" appeared.
Was it really necessary to quote the words "high vibrations" directly?

According to Kurtz, the sled's first three stages were designed to traverse 1.4 miles in 4.65 seconds, and the final two stages 1.8 miles in 1.3 seconds. At a pre-specified point along the three-mile route, bolts on the missile front were explosively detached -- allowing the simulated warhead to lift about 20 degrees -- and a fraction of a moment later the back bolts were detonated. The track then dipped, and centrifugal force carried the missile upward into the target.

As George Carlin would say, "pre-specified" should mean it hasn't been specified yet. Even if it doesn't, the "pre-" is still redundant.
"A fraction of a moment" is bad. Just use a "moment" or "split second" - you don't have to be accurate to within a fraction of your made-up time interval.
It would appear from this paragraph that 1.4 plus 1.8 equals three.
And, of course, centrifugal force has ABSOLUTELY NOTHING to do with the motion of the missile. Centrifugal force isn't even real.