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# "Wall of death" spinning tunnel

 (+9) [vote for, against]

One of the problems of cities is lack of real estate to build additional roads.

However, engineers at BorgCo, after a large lunch and a pleasant afternoon in a pub, have developed an almost foolproof solution.

Existing roads carry traffic only on their single planar upper surface.

However, if the space occupied by a conventional roadway was used to accomodate a cylinder, the interior of the cylinder would have an area of pi x the width of the cylinder; over three times bigger.

Therefore, for space-constrained limited access urban thruways, the road is replaced with a sucession of sturdy frames supporting long cylindrical sections, which are spun such that the centripetal force at the top of the cycle is about 0.8g, giving about 1.8g at the bottom.

This allows the entire inner surface of the cylinder to be used for traffic.

Occupants will experience nothing more than a" gravity" field that that averages out at 1.4g, not a problem when seated.

To the occupants of the tunnel, there is no sensation of rotation as the entire environment is rotating.

 — 8th of 7, Aug 19 2012

O'Neill cylinder http://en.wikipedia.../O%27neil_cylinders
[CraigD, Aug 19 2012]

Round Up amusement park ride http://en.wikipedia...Round_Up_%28ride%29
[CraigD, Aug 19 2012]

This? [tatterdemalion, Aug 20 2012]

 Nicely halfbaked idea, [8th of 7] – kinda an O'Neill cylinder on Earth – but you’ve dropped a term in your calculations. If the cylinder’s centripetal acceleration is 1.8 g, the “feels like gravity” acceleration at its top is 0.8 g (1.8 - 1), but at the bottom not 1.8, but 2.8 g (1.8 + 1).

As a thrill ride, the sight of vehicles (or pedestrians) above, below, and all sides would be worth it to me, but I’m pretty sure the ralph factor would be about the same as on a Round Up amusement park ride, and more than the commuting public would be willing to tolerate.
 — CraigD, Aug 19 2012

 "I don't understand it, officer. I just made a quick lane change and suddenly I was upside-down on top of this caravan."

(Which prompts the comment that the tunnel need not rotate; simply have helical lanes and a recommended minimum speed. Congestion would be self-clearing.)
 — MaxwellBuchanan, Aug 19 2012

 Damned minus signs … yes, correct, but even so the average g is still only 1.8, quite tolerable by a healthy victim, sorry user.

Neglecting coriolis force, the chunder coefficient should be within limits, as on the fairground rides the patrons have external fixed references - in the tube, everything moves together.
 — 8th of 7, Aug 19 2012

Can't picture it, can you elaborate a bit on the orientation of the cylinder to the roadway it replaces? And a bit about how it interfaces with non-cylindrical parts of the world, that is to say, how does one become "on" the cylinder from a state of previously being "not on" it? Or not.
 — tatterdemalion, Aug 19 2012

Bicycles work better in high velocity. Meaning they can accelerate with gravity and follow a curved path.
 — rcarty, Aug 19 2012

Unless the vehicles are all wedge shaped, this is going to have a very sharp height limit.
 — MechE, Aug 19 2012

 Getting on is simple. You drive at high speed onto a very wide moving sidewalk that is going the same direction you are going. Restart you car since it stalled when the wheels came to a sudden stop. Start driving forward at the designated speed, then make a left turn when instructed and floor the accelerator.

The "moving sidewalk" you are on is going at the same speed as the surface of the rotating cylinder, so if you get the timing right, you enter the tube just as you go off the edge of the moving sidewalk and don't have any laterall acceleration, you just feel the force of gravity increase (plus some sudden rotational acceleration). If you get to the edge of the sidewalk too early, you drive off the edge before the tunnel, but because of your sideway momentum you slamm into the outside of the tunnel which is suitably reinfoced. If you are late, you miss the entrance and spin out in the gravel deceleration area. If you are just a tiny bit late, the front of the car gets into the tube and the front gets lifted, but the back doesn't so the car goes spinning and tumbling through the air.
 — scad mientist, Aug 20 2012

Excellent. This idea is quite clearly the safest and easiest way of making best use of our road capacity.
 — hippo, Aug 20 2012

bun for bouncing cars
 — Voice, Aug 20 2012

//an almost foolproof solution.//

[marked-for-tagline]
 — DrBob, Aug 20 2012

 // how does one become "on" the cylinder from a state of previously being "not on" it //

You've seen The Italian Job, haven't you? Well, just like that.
 — 8th of 7, Aug 20 2012

 Completely insane. [+]

 I'd like to see a race track that spins around the stadium pinning the cars to the vertical surface making them go much faster relative to the audience. They'd also be easier to view since they'd all be racing on a vertical wall. It would be like watching the cars from overhead on a conventional racetrack.

But back to your idea, could you have a non-spinning version of this where the cars just have 3 spiral lanes where they all supply their own centripetal force? They might get a bit dizzy but other than that it should work.
 — doctorremulac3, Aug 20 2012

One problem with this is that it wont really solve traffic congestion because the tunnel can only be entered and exited flat on the ground. So enhanced traffic flow in the tunnel will result in back ups particularly when exiting.
 — rcarty, Aug 20 2012

I saw a real "wall of death" at a travelling fair recently - they had two motorbikes riding round inside a 5 metre high vertical wall, with the riders riding sidesaddle with no hands. They would zoom up the top of the wall (where the spectators were, leaning over) and then change direction at the last second. Terrifying stuff.
 — hippo, Aug 20 2012

 //could you have a non-spinning version of this where the cars just have 3 spiral lanes//

May I refer the good Doctor to the annotation of my esteemed colleague, [MaxwellBuchanan] toward the northern pole of this page?
 — MaxwellBuchanan, Aug 20 2012

 //May I refer the good Doctor to the annotation of my esteemed colleague, [MaxwellBuchanan] toward the northern pole of this page?//

Oopsie doodle, missed it. Credit (or blame) for that idea goes to you.
 — doctorremulac3, Aug 20 2012

 // add some more horizontal levels within the square tunnel. //

Two words: "Cypress Structure".
 — 8th of 7, Aug 20 2012

 //Two words: "Cypress Structure"// Perhaps I’m not cut of the same bold stuff as a well-liquored BorgCo engineer, but I’d be reluctant to bring up earthquakes and our proposed giant wall of death spinning tunnels in the same conversation.

 Some example numbers seem in order: Let’s use a US standard 10 3.7 m wide lane roadway, with a 2 slightly less wide median strips, for a total circumference of 44 m, radius 7 m; Rather than 1.8 g cent accel, use 1.22 (12 m/s/s); This gives rim/roadbed speed of 9.17 m/s (20.5 MPH), period of rotation 4.8 s.

 Not too bad numbers for the necessary entering/exiting machinery. Moving sidewalks could manage it, as could a well-steered pedal bike or automobile, or a run and jump. Moving too fast (0.89 m/s (2 MPH)) anti-spinward could drop you from the topside, so as [MaxwellBuchanan] notes, lane changes need be made with care.

I’m thinking a burner (or similarly culturally inclined folk) project of record-setting scale could actually prototype this as a sort of black market amusement ride. Harness everybody into chairs for the entering/exiting, and this could be a commercial park ride.
 — CraigD, Aug 21 2012

 On a test scale, it could be demonstrated as follows:

 Build a 7m x 30m tube.

 Place a car in the tube, facing circumferentially.

 The tube starts to rotate, increasing to the "ooperating" speed. At the same time, the car accelerates in the opposite direction, remaining at the lowest point of the tube, matching velocity.

 When the tube reaches operating speed, the driver gets a signal, which is their cue to turn sharply along the axis of the tube, and at the same time braking sharply.

The vehicle should come to rest facing along the primary axis, and "stuck" tto the inner wall.
 — 8th of 7, Aug 21 2012

Yes, but where does the driver come to rest?
 — MaxwellBuchanan, Aug 21 2012

Their first stop will be a mortuary van …
 — 8th of 7, Aug 21 2012

 //Perhaps I’m not cut of the same bold stuff as a well-liquored BorgCo engineer//

Perhaps?
 — AusCan531, Aug 22 2012

 [annotate]

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