I did the pressure in pounds and inches. 
"For a 100 ton train, this would result in an acceleration of a = F/m = 180e3 N / 100e3 kg = 1.8 g."
Without working it out I'd say 19T on 100T train would give only 1/5 g acceleration.
You are right, the result of my calculation was 1.8 m/s^2, which is only 0.18 g. Still 3 times higher than the ICE 3.
Good. Thanks. Let's do some numbers:
3 inches diameter:
pi*((2,54*3)^2)= 182,5 cm2 @ 100bar => 182500 kgf (what you said)
No you square the radius not the diameter.
The volume of air required would indeed be high. 100 bar is 100 times the weight of air in the same volume of atmosphere. It would require 100 cubic metres for every cubic metre. Quite some volume. I wonder what the local impact would be of pulling so much air out of the atmosphere at such a rate.
Let's say our train weight is 5500 tons, and we want it to go @ 200 km/h:
f= m*a => a= 19/5500 = 0,003454545455 m/s2
200km/h= 200e3/3600= 55,55 m/s
55,55/0,003454545455= 16080s => 16080/3600= 4.46 h
It takes 4.46 hours to get to speed.
Your calculation is wrong. If you push the train with 19 tons, this is a force of 180 kN. Acceleration would be 180e3 N / 5.5e6 kg = 0.033 m/s^2. So it would need about half an hour. Still a lot, but I think a freight train might not be a good application for it, because the motor weight etc. are only a small fraction compared to the freight weight.
I wouldn't want to live near the air valves or pumping station.
FrankBuss my train is 55 times heavier than yours LOL.
How much does a passenger train weigh fully loaded?
How much does a passenger train weigh fully loaded?
See my previous posting: E.g. the ICE 3 has a capacity of 441 passengers and weighs 409 tons empty. Now it depends on how obese your passengers are
How much does a passenger train weigh fully loaded?
See my previous posting: E.g. the ICE 3 has a capacity of 441 passengers and weighs 409 tons empty. Now it depends on how obese your passengers are
Hahaha. I found this:
https://www.trainorders.com/discussion/read.php?4,1824865 it seems about 600 tons fully loaded, between 57 and 85 tons per car. That's 6x times more than yours, 1/9th mine. They also say the weight of the passengers can be disregarded.
Right, but my assumption was that it can be built lighter than conventional trains, because of the additional support of the attached piston and no motors. It could be definitely lighter than the ICE, which weighs only 409 tons.
A local train, something like the "S-Bahn" for short distances, might be a good application for it, because of the high acceleration. E.g. this one:
https://de.wikipedia.org/wiki/DB-Baureihe_420Capacity is 458 passengers (standing and seats added) and empty weight is 129 tons, very close to my estimation, maximum speed 120 km/h. And for the air system you wouldn't need the motors.
Now tell me how it is impossible to build a tube which is 1000km long which has an internal pressure near 0 (approx. -1bar relative to atmospheric pressure).
Pipelines of significant length usually need relief in form of bends, just because the changes in ambient temp (and pressure) will elongate the whole structure. Now it is simple to pump media through such bends, but not people.
Now tell me how it is impossible to build a tube which is 1000km long which has an internal pressure near 0 (approx. -1bar relative to atmospheric pressure).
Pipelines of significant length usually need relief in form of bends, just because the changes in ambient temp (and pressure) will elongate the whole structure. Now it is simple to pump media through such bends, but not people.
Bends are not the only solution. Another option is to use pieces which can stretch/shrink. These kind of solutions are already used on conventional railroads.
Capacity is 458 passengers (standing and seats added) and empty weight is 129 tons, very close to my estimation, maximum speed 120 km/h. And for the air system you wouldn't need the motors.
You wouldn't need the motors... in the train. But you still need them outside the train to compress the air, right?
For comparison, a normal-ish 2 litres ICE engine at 4000 rpm sucks air in at a rate of 2*4000/60/2= 66 litres per second, in 1/2 hour that's 30*60*66= 118800 litres= 119 m3= 1,25*119= 149kg of air => To pump out 31225 tons of air,
you'd have to put 31225/0,149= 209536 engines in parallel. Unless I goofed up again...
I first read about this concept back in the 70s or early 80s as I recall. I suppose if it were a workable idea, it would be a reality by now, or maybe it could have worked, but the development got caught up in red tape. I'm not convinced either way at this point.
At any rate, I recall the system being described as a solution to long-distance, express travel in an evacuated tunnel and a maglev train suspended on superconducting magnets. The first part of the trip would expend the energy accelerating the train to outlandish speeds, and then nearly all the energy would be regenerated by decelerating the train at its destination. Theoretically the top speed would only be limited by the straightness of the "track" and the length of time available to accelerate/decelerate. They discussed a transcontinental train that could be faster than an SST, and much more economical to run. The initial construction cost of course would be preposterous.
Let's say our train weight is 5500 tons, and we want it to go @ 200 km/h:
No point even doing any calculations for 200Kmh.
Once again, the
entire point of Hyperloop is that it can go faster than any other land based form of mass transit. Current operational passenger record is 430km/h for MagLev, and there are more than 30 high speed trains that go over 300km/h
https://en.wikipedia.org/wiki/List_of_high-speed_trains
Capacity is 458 passengers (standing and seats added) and empty weight is 129 tons, very close to my estimation, maximum speed 120 km/h. And for the air system you wouldn't need the motors.
You wouldn't need the motors... in the train. But you still need them outside the train to compress the air, right?
For comparison, a normal-ish 2 litres ICE engine at 4000 rpm sucks air in at a rate of 2*4000/60/2= 66 litres per second, in 1/2 hour that's 30*60*66= 118800 litres= 119 m3= 1,25*119= 149kg of air => To pump out 31225 tons of air, you'd have to put 31225/0,149= 209536 engines in parallel. Unless I goofed up again...
You'd use high volume compressors with turbines for such an application. The efficiency wouldn't be that great though due to friction losses. Compressed air is an inefficient way of transporting energy. It wouldn't surprise me if the friction losses from compressing the air are on par with just putting the engine inside the train.
I think it's fairly clear that the efficiencies of such a system and the impossibility of implementing it make it no match for what we already have.
She went on about air pollution and yet I saw no demonstration or calculations as to how this fares against current technology and it's emissions. Again what was that "mentor" doing?
basically her video is mostly a rant about air pollution, exhortation of public transport and "I made this thing". May 13 is a bit young to run these schemes. If 3M are serious they should be talking to older teenagers but then this was just a publicity stunt for 3M anyway.
If 3M are serious they should be talking to older teenagers but then this was just a publicity stunt for 3M anyway.
Everything about 3M is fine here. Why don't you have a little search first before you say something:
https://www.youngscientistlab.com/challengeAlso look at the other
finalists - you will find more as you say "stupid ideas". Seems you guys have no clue what kid's science fair/competition/event actually is
Your pages cannot be loaded. No sorry, why let any kid fantasise about the impractical. How do kids learn? No i am not saying that this one project is bent but clearly this whole 3M science thing is a load of bollocks and is simply about PR and a way to weed their way into schools. Guess what. all companies like to "target" schools. Indoctrinate the future engineer in your products and your future sales are assured. You don't think ANY company really gives a fuck about the kids when they create these bogus programs that are just a really sad excuse for indoctrinating the young with their products to assure future sales?
If 3M are serious they should be talking to older teenagers but then this was just a publicity stunt for 3M anyway.
Everything about 3M is fine here. Why don't you have a little search first before you say something: https://www.youngscientistlab.com/challenge
Also look at the other finalists - you will find more as you say "stupid ideas". Seems you guys have no clue what kid's science fair/competition/event actually is
I'm breathing better already!
----------
Caroline Crouchley, who got second place, created a sustainable train that she told CBS News correspondent Nikki Battiste is safer and more efficient than Elon Musk's Hyperloop.
"Four million children develop asthma every year due to air pollution from cars and trucks, and there are 11,000 new cases every day," she said. "So I want to prevent all this from happening."
"You want to make the air we breathe safer?" Battiste asked.
"Yeah … I designed, developed a new train idea that can use renewable energy sources instead of fossil fuels, so it would help the environment," Crouchley said.
----------
(from
https://www.cbsnews.com/news/3m-young-scientist-challenge-14-year-old-wins-competition-with-nano-particle-liquid-bandage/)
Yep, I have still not heard the 13 year old say hyperloop......... So in order to use renewable energy (electricity) we have to have a new train system that won't work. Not just run the existing electric trans with renewable electricity....
An eco free chamber is an "adult project" erm, no, it called a test lab..... these reporter are just making shit up
You don't think ANY company really gives a fuck about the kids when they create these bogus programs that are just a really sad excuse for indoctrinating the young with their products to assure future sales?
No. You think 3M wants to increase sticky note sales?
In case of P&G I would agree to you. Here I believe that this is as they say - encourage kids
to pursue academic careers in the sciences.
Yep, I have still not heard the 13 year old say hyperloop.........
Hyperloop was introduced as clickbait - by news agencies and Dave
Let's say our train weight is 5500 tons, and we want it to go @ 200 km/h:
No point even doing any calculations for 200Kmh.
Once again, the entire point of Hyperloop is that it can go faster than any other land based form of mass transit. Current operational passenger record is 430km/h for MagLev, and there are more than 30 high speed trains that go over 300km/h
https://en.wikipedia.org/wiki/List_of_high-speed_trains
You're right :-) let's see that: n times the speed requires n
2 times the energy (mv
2/2), ergo:
400 km/h => 0.45*2*2 hours to get to speed (1.8h).
600 km/h => 0.45*3*3 hours to get to speed (4.05h).
800 km/h => 0.45*4*4 hours to get to speed (7.2h).
1000 km/h => 0.45*5*5 hours to get to speed (11.25h).
And 1/nth the mass, 1/nth the time. FrankBuss says ~ 500 tons is a right-ish weight, in that case it would be 1/11th these times. But let's not forget there are also
tens of thousands of tons of air that have to travel with the piston in a narrow pipe at the same speed of the train, that means I'd guess huge energy losses (that other trains don't have) and that we're not accounting for.