So.
First, my basic assumption about Speed drives is that the term is flat-out wrong. That is, the craft carrying the drive never moves at all relative to the hunk of space-time it happens to be occupying. Its apparent speed is determined by how much it can cause that chunk to displace in any given femptosecond.
(Incidentally - local spacetime around planets and other orbiting objects moves with them rather than being static, which is why orbital velocities don't become an issue - the 'surfboard' starts moving with the local space when the drive goes off, but the craft itself still hasn't moved)
(most) Acceleration drives slope local spacetime - generate gravity fields, pretty much - to change real velocity, instead, but use what's recognizably the same mechanisms.
Second, apparent speed is limited by the proximity of the dominant object of the immediate area; this is an on/off condition, not a graduated one. Wazzat mean? It means that ships go slower when they're close to other things. Somewhere inside Mercury's orbit there's another Limit, where the Sun's influence locks a ship down to 'atmospheric speeds'. The Cochrane Limit is where the galactic core becomes 'dominant'.
Third, other ships may be dominant. If two craft in fenspace approach each other closely enough, they'll both be slammed down to 'atmospheric speeds' until they can get farther away again. Drive field interaction means that this effect is sort of sticky and occupies a larger space than you'd expect from the mass of the ships alone. This lets you have dogfights. ^_^
Ja, -n
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"Puripuri puripuri... Bang!"
First, my basic assumption about Speed drives is that the term is flat-out wrong. That is, the craft carrying the drive never moves at all relative to the hunk of space-time it happens to be occupying. Its apparent speed is determined by how much it can cause that chunk to displace in any given femptosecond.
(Incidentally - local spacetime around planets and other orbiting objects moves with them rather than being static, which is why orbital velocities don't become an issue - the 'surfboard' starts moving with the local space when the drive goes off, but the craft itself still hasn't moved)
(most) Acceleration drives slope local spacetime - generate gravity fields, pretty much - to change real velocity, instead, but use what's recognizably the same mechanisms.
Second, apparent speed is limited by the proximity of the dominant object of the immediate area; this is an on/off condition, not a graduated one. Wazzat mean? It means that ships go slower when they're close to other things. Somewhere inside Mercury's orbit there's another Limit, where the Sun's influence locks a ship down to 'atmospheric speeds'. The Cochrane Limit is where the galactic core becomes 'dominant'.
Third, other ships may be dominant. If two craft in fenspace approach each other closely enough, they'll both be slammed down to 'atmospheric speeds' until they can get farther away again. Drive field interaction means that this effect is sort of sticky and occupies a larger space than you'd expect from the mass of the ships alone. This lets you have dogfights. ^_^
Ja, -n
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"Puripuri puripuri... Bang!"