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Adjacent to SpaceX headquarters, 25 teams gathered for another Hyperloop Pod Competition. This time the winner would be judged by how quickly they could go down the 1.25 kilometer (about .77 miles) track. On the final day of competition, three teams advanced to the finals and had the chance to push their pod to the limit.
With a speed of just over 200 miles per-hour, the Warr (pronounced Varr) team from the Technical University of Munich handily beat the two other finalists with its small, but quick pod. Weighing just 80 kg (176 pounds) and powered by a 50kw motor, the vehicle was essentially a small electric car built specifically for winning the competition.
[...] At the end of the competition, SpaceX CEO Elon Musk mused that there's no reason why future pods in the competition couldn't hit 500 to 600 miles per-hour on the 1.25 kilometer track. Of course that means that there will be another Hyperloop Pod Competition sometime next year and who knows, maybe we'll see pods hitting the speeds that'll make the mode of transportation truly rival air travel.
Source: https://www.engadget.com/2017/08/27/hyperloop-pod-competition-winner-hits-200-mph/
(Score: 2) by anotherblackhat on Tuesday August 29 2017, @12:05AM (6 children)
Suppose you accelerate for half the distance, and decelerate for the other half.
If I've done the math correctly, to reach 220m/s (500 mph) in the middle of a 1,250m track, you'd need to accelerate at 38.7 m/sec2
4 G's won't kill (most) people, but it is the point at which you start graying out.
(Score: 0) by Anonymous Coward on Tuesday August 29 2017, @12:10AM (1 child)
You should find a hobby, the math you just did to prove they need a bigger track was perhaps the most useless exercise I've yet seen.
(Score: 1, Insightful) by Anonymous Coward on Tuesday August 29 2017, @12:27AM
> You should find a hobby,
Making "back of the envelope" rough calculations is one of the very best hobbies ever. If you can't do this for yourself, you are at the mercy of whatever numbers you hear or read, with no way to sanity check them.
Since there are no people in these half-sized pods, 4+ g's won't hurt anybody. I hope they go for it at the next event.
The official SpaceX site hasn't been updated yet (competition was just a few days ago), but fyi it is at http://www.spacex.com/hyperloop [spacex.com]
(Score: 2) by FatPhil on Tuesday August 29 2017, @02:03AM (2 children)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2, Informative) by Anonymous Coward on Tuesday August 29 2017, @03:04AM (1 child)
> braking's always quicker than accellerating,
normal friction braking's usually quicker than accelerating,
Ftfy. In recent 0-100-0 mph tests by MotorTrend of an awd Tesla car, the accel and decel were about the same below about 50 mph, where the performance is limited by tire traction. Above 50 mph the motor power limit came into effect, so braking from high speed down to ~50 mph was "quicker" than the corresponding interval of accel.
Any commercial pod worth the trouble will include regenerative braking. In this case the motor power (and motor heating) limits the power for accel and for decel in roughly equal amounts. With proper scheduling a (conceptual) hyperloop system would use the power generated by decel on one pod to accel another nearby pod. Some electric train (subway/metro) systems may do this already?? (not sure) Friction brakes would be reserved for emergency backup--turning valuable electricity into heat is to be avoided when possible.
For these student-made "test pods" with internal power it could be a little different. If a hard accel heats up the traction battery, then the battery may not be able to accept charge so quickly on the decel, so it won't be perfectly symmetric... With this competition that is based on top speed over limited distance, friction brakes may make sense. However, normal friction brakes in vacuum are limited by the heat capacity of the pads and rotors (or friction rail) -- they won't air cool like typical vehicle brakes. Sizing of the parts in the brake system must take this into account or there will be some melted parts inside the SpaceX tube.
(Score: 2) by Open4D on Tuesday August 29 2017, @02:17PM
Given that Musk is involved, they would use batteries, and not have to worry about that aspect of scheduling. And for above-ground hyperloops, the plan was to have solar panels on top, so you'd want batteries anyway.
(Score: 2) by Open4D on Tuesday August 29 2017, @02:12PM
Sounds about right. But I believe Musk was just suggesting they could do high speed tests even on their short test track. (Without humans)
In a real life system, the acceleration and deceleration would be slow enough to be comfortable for humans, and yet still only a small part of the journey time.
There's a graph of this at the top of page 43 of the original PDF [spacex.com] It seems that for the LA->SF journey, they looked at the geography and planned for 3 separate cruising speeds, with 3 phases of acceleration and 3 phases of deceleration. The slopes of the lines are nearly vertical, but I think they are accurate, and represent perfectly comfortable 'g forces'.