$2 million study looks at hyperloop – 700 mph transit

I should add to my # 59 that the effect of the decreased pressure on the speed of sound would be small. The carriages could likely travel at or near 700 mph, while remaining subsonic. Depends on how much pressure is reduced.

A bigger challenge would be keeping the forward pressure reduced. The carriage would act like a huge piston.

I should add to my # 59 that the effect of the decreased pressure on the speed of sound would be small. The carriages could likely travel at or near 700 mph, while remaining subsonic. Depends on how much pressure is reduced.

A bigger challenge would be keeping the forward pressure reduced. The carriage would act like a huge piston.

Compressional wave such as sound can only exist in a compressible fluid air being one of them. In a hard vacuum sound waves are not possible. The whole point of the vaccum tube is to remove the air drag and sonic waves due to a hard vacuum which the hyperloop fast version would be a hard vacuum under .5psi. For maglev technology the theoretical speed limits are the speed of the traveling magnetic wave through the induction coils which without super conductor materials is around 5000mph the 700mph speed is arbitrary in a vacuum the speed dictates the minimum curvature of the turns due to G forces at anything above 500mph the radius of a turn needs to be miles in diameter to keep the G forces down to the point where banking the maglev is unnecessary. Put another way there is no speed of sound in space not sound at all, and in a sealed tube you can pump out all the air to a hard vacuum condition where air molecules are measured in atoms per cubic meter if you have enough pump capacity in a sealed tube with airlocks on each end the pump capacity over time is unlimited therefore a hard vacuum is not only possible it is necessary. With an analytical vacuum in the tubes the piston effect is eliminated as well as aerodynamic heating one could go thousands of miles per hour in a vacuum with zero drag and zero heating just like space above the atmosphere. As for acceleration it’s rate over time and distance not an issue with maglev and long tracks. Look at it this way if you had a spaceship that could accelerate at one G for days in less than a year you would be at lightspeed and never experienced more acceleration than standing up assuming the acceleration vector was through the floor. It sounds crazy but thats how acceleration over time and distance works. Aircraft do something similar everyday going from zero to 200mph in 10000 feet of runway and then 200 to 500+ mph over miles of climbing to cruise altitude reverse at the landing. Maglev would accelerate at less than one G for a few minutes and be at hundreds if not thousands of mph reverse at the other end. As long as the track is straight and long enough shocking speeds are possible, add in superconducting magnets and orbital speeds are possible that’s 7 miles per second btw.

“According to the turnpike’s research, a hyperloop combines a magnetic levitation train and a low pressure transit tube ... “

From it’s inception, the hyperloop concept involved only a partial vacuum — hot a hard vacuum. The notion of a hard-vacuum, mag-lev tube has been around for several decades. I remember reading about in the mid 1950’s. The hyperloop was different — using a partial vacuum, to get around the difficulties of creating, and maintaining a hard vacuum. The piston-effect remains one of the biggest challenges — but, probably not an insurmountable one.