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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."
For the non-US people in the world:
"Researchers at Holloman AFB have broken their own two decades old land speed record for rail vehicles. The rocket powered sled covered the 4.8 km track in roughly 6 seconds. Preliminary numbers put the sled's speed at mach 8.6 or about 10300 km/h - it covered the last 2.9 km in just 1.3 seconds. 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."
Maybe we should make a rule that say you always have to supply metric and imperial units... It would make my job so much easier...
That is an urban legend. This story started it. Or rather, the events portrayed in the story led to the urban legend; the story was written long after the urban legend started flourishing.
This post is free (as in cheese in a mousetrap).
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Like the article said, it's a record for railed vehicles. RTFA, THEN post.
'Standards' in computing only impress those who are impressed by things like 'standards'.
To give you a clue how high that is, Dave Purley survived a crash where he pulled 179 G's. He suffered 29 fractures, six dislocations, and six heart stoppages. It was the result of a near-instantaneous stop while hitting a wall at 108MPH (about 160kph, I think). IIRC, the Guinness book puts the time he sustained that g-force at a couple of thousandths of a second.
.10 second area. The max sustained g-force is about 7. If you've ever seen a dragster accelerate up close, you can extrapolate the violence yourself. :D
As another perspective, Top Fuel drivers in the NHRA cover a quarter of a mile in roughly 4.4 seconds, from a standing start, reaching speeds of over 320MPH. The 0-100 times are generally in the
'Standards' in computing only impress those who are impressed by things like 'standards'.
Here's the deal: Regardless of whether the "vehicle" makes contact with the ground via wheels or a rail, it more or less is flying while in contact with the ground. Anyone who remembers "blue lightning" will recall that it was/is a missle painted blue with a driver's seat and wheels. If you want a record for the fastest gasoline-powered car, that's a whole separate arena. These people are trying to get something that 1) goes the fastest while 2) remaining in contact with the ground in some way. The reason this craft could go so fast is precisely because the rail system reduces the friction from the ground to a significant degree.
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Hmm, on his/her humanities course of study he/she says, "It is a lot of work, but the upshot is
improved grammer and spelling skills that are lacking in the technical."
OK, nice idea but it loses credibility when his/her post includes gems like this, "...humilaite them whenever possible." Or, "...astrology, the most rediculious of the sciences!" Or, "Whilst you want to trun collage into a trade school with yore narrow minded views that collage..." Or finally, "I'm going on to so a PhD in socialolgy..."
Come back when your improved spelling and grammar skills help you spell your major correctly and we'll talk. Until then, back to class, troll!
You are quibbling about power transfer methods. Simply put though, air resistance becomes much greater than your friction level contact between drive wheel and surface. Once you loose traction and spin at 400+ mph, you do serious damage to the friction material on your wheel, which won't be anything like you know as a pneumatic tire/wheel setup. The last land speed vehicles have had aluminum wheels with no rubber, it wouldn't stay attached at the speeds reached anyway. Then the matter of trying to get traction with smooth aluminum wheels shows the reason that wheel drive isn't very practical over 450mph or so.
Kindness is the language which the deaf can hear and the blind can see. - Mark Twain
In Canada month/day/year is also common (largely because we share so much technical literature with the US). The reasoning often given is that most people say "October 5th, 2003", and not "The fifth of October, 2003", so the numerical ordering follows the verbal ordering.
Having said that, they both stink because of the existence of the other. The simple fact that I have to wonder what "02/03/05" refers to because of the competing standards renders them all flawed. The only standard that anyone should use is the ISO 8601, which is as you mention yyyy-mm-dd (it's hardly a "Japanese" system - It's been used and advocated as a "metric" sort of date for many decades).
The numbers do add up. Here's the math:
Note - I am not writing out all the digits, but I kept them when doing the math to avoid rounding error.
Given:
x = x0 + v0*t + 1/2*a*t^2
v = v0 + a*t
Started from rest
1st segment: 1.4 miles in 4.65 seconds
2nd segment: 1.8 miles in 1.30 seconds
Assumption:
Constant acceleration during each segment, although different acceleration for the segements.
Solution:
First segment acceleration:
x = x0 + v0*t + 1/2*a*t^2
x = 1.4 miles; x0 = 0 (starting from here); v0 = 0 (starting from rest); t = 4.65 sec
1.4 = 1/2*a*4.65^2
solving: a = 1.4/10.81125 ~= 0.129 miles/sec^2
Final speed at end of first segment:
v = v0 + a*t
v0 = 0 (starting from rest); t = 4.65 sec; a ~= 0.129 miles/sec^2
v ~= 0.129*4.65
solving: v ~= 0.602 miles/sec or 2167 mph
Second segment acceleration:
x = x0 + v0*t + 1/2*a*t^2
x = 1.8 miles; x0 = 0 (starting from here, or we could add 1.4 to this and x); v0 = 0.602 miles/sec; t = 1.3 sec
1.8 = 0.602*t + 1/2*a*1.3^2
solving: a = 1.0172/0.845 ~= 1.204 miles/sec^2
Final speed at end of second segment:
v = v0 + a*t
v0 = 0.602 miles/sec; t = 1.3 sec
a ~= 1.204 miles/sec^2
solving: v ~= 2.17 miles/sec, or 7800 mph
Thus assuming constant acceleration, we actually achieve a velocity greater than 6400 mph. With decreasing acceleration (a real-world condition), 6400 mph is a believable result.
Are there even human beings "driving" it?
I think it's safe to say "no"
if there were humans driving it at the start then there wouldn't have been at the end. apart from the fact that the sled stopped yb hitting an immobile object, the humans would have been but a red paint job at the back of the cabin by then anyways
Not this time, anyway. Although over at the International Space Hall of Fame, only about 15 miles from where the above test occured, is the rocket sled ("Sonic Wind 1") that John Stapp rode in 1954 at the same testing grounds when he earned the title "Fastest Man Alive". Granted that was only 632 mph, but he did sustain a deceleration of around 40 Gs that reportly forced his eyes partially out of their sockets.
The forces on this particular test would have easily killed a human, so it's safe to assume that this one was riderless.
[I'm a former Space Hall tour guide, just sharing some trivia..]
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Some quick calculations here (all calculations assume the acceleration was constant).
6400 mph = 33,792,000 ft/hr = 9386.66 ft/sec.
9386.66 ft/sec divided by 6 seconds gives 1564.44 ft/sec/sec.
1G = 32 ft/sec/sec.
The acceleration felt by any passenger would have been 49G. No human could come close to surviving this.
If the "UK has been experimenting with trains using this technology", then I think such trains are unsafe. Maybe they are working on trains based upon rocket technology, or even working on trains based upon ideas from a similair experiment, but saying that they are working on "trains using this technology" makes no sense at all.
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