World land speed record - Some questions..
Discussion
6,453 mph. http://uk.youtube.com/watch?v=L5bPu58fSc0
http://www.impactlab.com/2006/01/15/the-fastest-ro...
I presume these are NOT mentioned in LAND speed records due to being unmaned.
So, this raised some questions:
What would be the maximum speed that anyone could travel at on land without dying?
Supercars seem to be getting faster. What would happen if a car company produced a road legal 300 mph car? or 400? Would there be a limit?
http://www.impactlab.com/2006/01/15/the-fastest-ro...
I presume these are NOT mentioned in LAND speed records due to being unmaned.
So, this raised some questions:
What would be the maximum speed that anyone could travel at on land without dying?
Supercars seem to be getting faster. What would happen if a car company produced a road legal 300 mph car? or 400? Would there be a limit?
Edited by Morningside on Saturday 17th January 21:55
I'd imagine that it is less to do with ultimate speed than the acceleration to get there.
One article mentions that the human body can withstand only 8-9g. Presumably this is sustained acceleration, since much higher instantaneous levels can be reached in impacts that don't result in death.
One article mentions that the human body can withstand only 8-9g. Presumably this is sustained acceleration, since much higher instantaneous levels can be reached in impacts that don't result in death.
Speed is not the problem, manned space craft travel at 15000? MPH.
If you built a smooth enough track, and could produce enough power, and keep it on the ground, i guess you could go at the speed of light. You would have to accelrate slowly though.
That is my (i am not a scientist) wild stab at an answer.
If you built a smooth enough track, and could produce enough power, and keep it on the ground, i guess you could go at the speed of light. You would have to accelrate slowly though.
That is my (i am not a scientist) wild stab at an answer.
Morningside said:
I presume these are NOT mentioned in LAND speed records due to being unmaned.
The land speed record has to be done in 2 directions within a certain time, to eliminate the wind factor - an average is then taken as the official time.With cars they have to be 4 wheeled, and there are two records - one for driven wheels and one for thrust driven. There's also one for piston engines I think.
tlracing said:
I'd imagine that it is less to do with ultimate speed than the acceleration to get there.
One article mentions that the human body can withstand only 8-9g. Presumably this is sustained acceleration, since much higher instantaneous levels can be reached in impacts that don't result in death.
As above - the theoretical limitation is the acceleration forces that the pilot can withstand, coupled with the (relatively} short tracks that are available. On a good year, you can lay out a track about 11 miles long on the Bonneville Salt Flats. You've got to cover the same flying kilometre in opposite directions to comply with the rules for the LSR, whicgh means you get a little over 5 miles run-up.One article mentions that the human body can withstand only 8-9g. Presumably this is sustained acceleration, since much higher instantaneous levels can be reached in impacts that don't result in death.
In practice, we're a long way from reaching that theoretical acceleration limit, though. The More practical problem is the vicious circle of fuel consumption and fuel weight required to create the acceleration...
8-9g is indeed only the limit for sustained acceleration. I worked on a design for a rocket-engined WWSR boat some years ago, as part of the research for which I spoke at some length to the late Sammy Miller. Miller ran rocket engined dragsters at Santa Pod, and regularly hit peak accelerations of 14g over the quarter mile. The forces were enough to burst blood vessels in his eyes, though, so it was not unusual to see him with red eyes.
Slightly ironic, given the risks involved with his dragsters, that he was killed in an industrial accident in the Texas oilfields
BIANCO said:
As for road legal cars there are very few if any, roads that you could go over 250mph. So even if they did build a car that did 300mph there would never be anywhere to do it on the public highway anyway. So it would be pointless limiting it, but more importantly pointless building it in the first place.
Surely the same could be said for roads where it's capable of doing 200mph? Morningside said:
What would happen if a car company produced a road legal 300 mph car? or 400? Would there be a limit?
One of the key factors, imho, is the size of the vehicle concerned. Have you seen any land speed cars in the metal? They're f''''ing HUGE. Physically they bear no resemblance to cars and ought really be referred to as land speed trucks. A quick google on Thrust SSC shows a length of 54 feet and a weight of 10.5 tonnes.
The planet already rotates at 1600mph or so! Dunno what speed the earth goes round the sun etc.
But acceleration is the key which is why the boneville salt flats arnt any use to drive wheel record seekers any more as they reduced the distance available for acceleration ( not human limited there but grip).
Humans dont like more than 3g or so for very long at all.
But acceleration is the key which is why the boneville salt flats arnt any use to drive wheel record seekers any more as they reduced the distance available for acceleration ( not human limited there but grip).
Humans dont like more than 3g or so for very long at all.
BIANCO said:
Well now I think of it isn’t 8-9G vertical max not horizontal. If you are sat down with vertical Gs the blood will flow away from the head, but if accelerating horizontal (forward) then the blood wouldn’t run away from the head. So theatrically higher Gs could be achieved.
It remanded me of John Stapp he took 46.2 Gs in a rocket sledge test. http://www.ejectionsite.com/stapp.htm
Nice link. The 46.2G's was instantaneous peak but he did 25 for 1.1 seconds which I think gives a nicer upper limit for sustained acceleration. Someone mentioned the longest salt flats track is 11 miles so let’s use that too, although it'd need surfacing somehow. Assume he goes from full tolerable acceleration to full deceleration instantaneously in the middle. Ignore aerodynamic effects.It remanded me of John Stapp he took 46.2 Gs in a rocket sledge test. http://www.ejectionsite.com/stapp.htm
I get ~7500km/h or about 4600 miles an hour. I'm not sure what you'd make the wheels out of...
Edited by hairykrishna on Sunday 18th January 00:22
LSRs are limited by geography and G loads.
In order to accelerate up to speed, go through the measured mile, slow down, allow a safety distance and still be able to turn around and do the same the other way you need at least 13 miles of absolutely flat track. There's Black rock and Bonneville. The later has been restricted by salt mining which has put big pits in the flats. This is one of the reasons that Thrust 2 ran at Black Rock. Other long flats may exist but haven't been properly checked out because they are in China and Iraq.
So we are running out of room to do the job.
In order to go faster we need more G loads. 8g is very close to what you can sustain while actually driving a car. Just because you can survive a higher G does not mean that you can do other things such as actually hold on to a steering wheel when your arms weigh more than you normally do.
So we are not able to go faster in the room we've got.
In order to accelerate up to speed, go through the measured mile, slow down, allow a safety distance and still be able to turn around and do the same the other way you need at least 13 miles of absolutely flat track. There's Black rock and Bonneville. The later has been restricted by salt mining which has put big pits in the flats. This is one of the reasons that Thrust 2 ran at Black Rock. Other long flats may exist but haven't been properly checked out because they are in China and Iraq.
So we are running out of room to do the job.
In order to go faster we need more G loads. 8g is very close to what you can sustain while actually driving a car. Just because you can survive a higher G does not mean that you can do other things such as actually hold on to a steering wheel when your arms weigh more than you normally do.
So we are not able to go faster in the room we've got.
Silent1 said:
Travelling at the speed of light is impossible due to E=MC(2) As your energy must equal your mass multiplied by the speed of light squared.
You cannot exceed the speed of light due to the fact as you exceed 0.9C (C is used in physics to reference the speed of light) your mass increases exponentially as you approach C, resulting in infinite mass at C.Basically you would need an infinite amount of energy to get there.
Note this is also relative.
Edited by annodomini2 on Sunday 18th January 13:21
RobDickinson said:
The planet already rotates at 1600mph or so! Dunno what speed the earth goes round the sun etc.
But acceleration is the key which is why the boneville salt flats arnt any use to drive wheel record seekers any more as they reduced the distance available for acceleration ( not human limited there but grip).
Humans dont like more than 3g or so for very long at all.
1. Earth rotational velocity is approximately 1000mph (It fluctuates)But acceleration is the key which is why the boneville salt flats arnt any use to drive wheel record seekers any more as they reduced the distance available for acceleration ( not human limited there but grip).
Humans dont like more than 3g or so for very long at all.
2. Earth Orbital Velocity around the sun approx. 67000mph
3. Velocity of the Sol system around the Milky way galactic centre approx 558,000mph
4. Supposed velocity of milky way relative to Andromeda Galaxy 1,000,000 Km/h
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