ramjet

A ramjet is basically a tube open at both ends and moving very quickly so that air enters one end and leaves out the other.

Isn't that pretty much what a Ramjet is doing?

As such, the theoretical upper-bound speed limit relative to the interstellar medium of a Bussard ramjet is also ~0.12c.

For convenience, ramjet.linear, ramjet.easeIn, ramjet.easeOut and ramjet.easeInOut are included, but for best results I'd recommend combining it with an external easing library like eases.

If you crunch the numbers, it turns out the bad news is a Bussard ramjet won't work as an engine.

For turbojet engines altitudes of about 40 km appear to be possible, whereas for ramjet engines 55 km may be achievable.

The classic example of a system which does something like this is the Bussard ramjet.

Then at high speed, the J-58 transitions from a turbojet to a functional ramjet.

But that could make a pinch in spacetime that isn't completely symmetrical at the neck, so you end up with a sort of spacetime ramjet.

A Bussard ramjet will never work, even assuming we get the scoop part figured out.

At war, with no oil imports coming in, and in desperate need of operable aircraft, the investment of processing coal into even granules to burn in a ramjet might.

This in turn means that interstellar hydrogen, essentially at rest with respect to the ramjet-equipped spaceship ploughing through the medium, has to be accelerated pretty much from the rest frame to the velocity of the ship as part of the collection process.

This was due to the "turbojet-assisted ramjet" design of the Pratt and Whitney J-58.

There was a sci fi book where a ship's Bussard Ramjet got stuck in the "on" position and they kept accelerating until time dilation allowed them to survive a great crunch and another Big Bang.

(Although in practice your maximum speed is largely dictated by "melting the engine is considered shortsighted".) The theoretical upper-bound exhaust velocity of a Bussard ramjet is something like ~0.12c, assuming you start with 4 hydrogen and end with 1 helium.

That depends, however, on the assumption that the initial kinetic energy of the incoming hydrogen is completely wasted- that the ramjet does not have "regenerative braking", so to speak, that can recover some of the pre-existing kinetic energy.

Solar Sail, Laser Sail, Electric Sail, Magnetic Sail, Mini-magnetospheric plasma sail, MagBeam, Plasma Magnet Sail, Photon Drive, Bussard Ramjet, Ram-Augmented Interstellar Rocket.