So building a bridge is a massive infrastructure undertaking. Can we do something more fun? Physics of cannon balls and gliding is well known, and we have the math right for control of gliding, and light propulsion engines.
The Catapult Plates for cars works by using your car's momentum as the initial energy, magnetically locking and clamping your car to the plate, and then using the rail-gun technology to accelerate it to the speed of say over 500 mph over a short distance, so that relatively small wings on the sides of the plate would be enough for your car to fly over a distance without road (such as a mountain range, a large crevice, or just about any two places of the city).
Your car would take a near-quadratic equation trajectory to reach the destination, every time feeling near-0G experiences in the midst of it.
The plate would have mini liquid fuel rocket engines to adjust the glide to precision-align with the plate capturing end, which would decelerate by recuperating the kinetic energy to the large high capacity condensers, to be used by another other ride towards the opposite direction.
To avoid the in-air collisions, the mini rocket engines would be used as well, allowing for a controlled in-air car flows between two points of a city.
Slash the road infrastructure development costs by large margins. And, can't see how this wouldn't work for capsules with individual humans too. Could be closest thing to teleportation, and a direct application of projectile control technology.-- Mindey, Nov 18 2019 Previous 'art' https://www.nfb.ca/...evil_at_your_heels/KenCarter, shades of early HB and RedGreen [Sgt Teacup, Nov 20 2019] Lift to drag ratio https://en.wikipedi.../Lift-to-drag_ratioLargely dictated by the aerodynamics of your vehicle. [Frankx, Nov 20 2019] What could possibly go wrong ...? [+]-- 8th of 7, Nov 18 2019 I'm picturing a brown-out, in which power to the rail gun is not shut off completely but is reduced enough for the glide-plate and payload to fall a bit short of the off-ramp.-- pertinax, Nov 19 2019 So are we.
<Sniggering/>
<Sets up GoPro to capture Epic Fail/>-- 8th of 7, Nov 19 2019 // What could possibly go wrong ...? //
Like, re-accelerate and jump again at the other end, like flat stones on water?-- Mindey, Nov 19 2019 A very small change to the specification would produce "Catapult Plates for Cats".
We will buy the entire IPO for that, cash down.-- 8th of 7, Nov 19 2019 //I'm picturing a brown-out// What's needed, shirley, is a system powered by gravity, since gravity rarely fails. You just need a spiral road climbing up to the top of a very tall ski-jump type slope. Drive to top; put car in neutral; wait. The car should leave the ski-jump with sufficient speed to arc gracefully across the river and land gently on a ramp on the other side.
Obviously, the ramp should be made of orange plastic. For fun, one or two loop-de-loops could be incorporated. Such a system has the advantage that it will be self-calibrating with respect to vehicle mass.-- MaxwellBuchanan, Nov 19 2019 // Such a system has the advantage that it will be self-calibrating with respect to vehicle mass. //
So, even trucks could pay in gravitational potential? Still, trucks would need a longer board and much more energy. Passenger vehicles, being small, lightweight and nimble, with slight variance in weight, and dimensions, seem much more practicable.-- Mindey, Nov 20 2019 //trucks would need a longer board// No, all vehicles can use the same board, assuming that they have a low (negligible) rolling resistance.
Thought experiment as follows: (1) Build 2 ramps side by side, suitable for cars (2) Send 2 cars simultaneously down the ramps; both cars make the jump (3) Repeat (2), but with a layer of glue between the two cars as they jump side-by-side; nothing significant has changed, so they'll jump together. (4) Replace the glue with a welded joint. Again, nothing important has changed, so the two cars jump side by side (5) If (4) works, then a truck weighting the same as 2 cars will also work.-- MaxwellBuchanan, Nov 20 2019 // shirley, is a system powered by gravity, since gravity rarely fails //
Terminal velocity upon gravity may be insufficient for gliding desired distances with small wings. Though, the wings on the plates may be made larger of course, small velocities may still be sufficient for jumping over small rivers, but not over larger, like River Thames. Or, for getting from one city district to another.
The example by [Sgt Teacup] of KenCarter stunt driver trying to make a mile, shows how small velocities with a too steep trajectory end up ending.
// How efficient are gliders? //
"A ratio of 30:1 means that in smooth air a glider can travel forward 30 meters while losing only 1 meter of altitude." (Wikipedia:Glider_(Sailplane))
As a toy experiment, I'd start with a brick on wheels that catches on a cardboard wing.-- Mindey, Nov 20 2019 //gliders// Gliders only achieve ratios of 30:1 by having very long wings and very very low drag (or rather, high L/D ratios)-- Frankx, Nov 20 2019 // having very long wings and very very low drag //
That's precisely why I think higher velocities are needed, beyond terminal velocity upon natural gravity, as in what [MB]'s imagined.-- Mindey, Nov 20 2019 // a brick on wheels that catches on a cardboard wing //
Boeing seem to have a lot of Prior Art in that area ...-- 8th of 7, Nov 21 2019 //terminal velocity//... only applies to things falling under gravity in an atmosphere. It's the velocity at which upward aerodynamic drag balances weight.
It's not usually applied as a concept to aircraft or ballistic trajectories.-- Frankx, Nov 22 2019 random, halfbakery