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

Re:Metric Conversion

[kahei]

Actually, some of us use real units not because we are from the US, but because they are more comfortable and intuitive, having evolved through use rather than being arbitrarily dictated by pompous French people.

Re:Metric Conversion

[b_pretender]

If you're going to make it INTERnational friendly, you have to go ALL THE WAY. Refer to european articles and get the time right.

Specifically, change the last sentence from:

The previous record of 9851 km/h was set on Oct. 5, 1982. Other accounts are at the Alamogordo Daily News, the Denver Post, and CNN.

to...

The previous record of 9851 km/h was set on 5 Oct 1982. Other accounts are at the London Daily News, the Paris Examinoir, and EuroDisney Reporter.

The numbers don't add up!

[Muad'Dave]

Correct me if I'm wrong, but how can you get 6400 MPH from their numbers? They must be claiming an instantaneous velocity as opposed to an average over any of the segments they mention.

From the article:

1. The sled covered the "roughly 3 mile course" in 6 seconds. That's 3 / 6 * 3600 = 1800 mi/hr.
2. It covered the first 1.4 mi in 4.65 s. That's 1.4 / 4.65 * 3600 = 1084 mi/hr.
3. It covered the last 1.8 mi in 1.3 s. That's 1.8 / 1.3 * 3600 = 4985 mi/hr.

If you _add_ the speeds, you get 6069 mi/hr, but that's certainly not legit.

The average speed over the whole 3.2 mile course was (1.4 + 1.8) / (4.65 + 1.3) * 3600 = 1936 mi/hr, which is close to the speed referred to in bullet point 1. Hardly impressive, and hardly 6400 mi/hr! My guess it they meant that the sled hit 6400 mi/hr when the rocket cut in at 4.65 s, but quickly slowed since the average speed after 4.65 s was only 4985 mi/hr.

Re:Metric Conversion

[black mariah]

Probably because, if I dare to be so presumptious, the majority of people here are American. The site's run by Americans. It's like accusing the Register of being too biased towards stories from England.

And yes, everyone should be able to easily convert miles and kilometers to a certain degree. It's not like the labyrinth that is Fahrenheit/Celcius calculations, at least.