World War II Hyperdrive minimum jump distances

[Tom Kalbfus]

I'm developing the hyperdrive for my World War II Galaxy setting, but it could also be used in other settings of your choosing. Since I don't want ships just to make hyperdrive jumps from just anywhere, they hyperdrive, just like the standard jump drive, needs to be above a minimum distance from the nearest gravitational body in order to be activated. Since the High Guard book doesn't mention such a jump distance in this optional drive, I'll include it here. These distances are proportional to size digits which are proportional to the cube root of the gravitational mass, this lines up with planet diameters for terrestrial worlds, but not so much for gas giants, so I've listed some examples in the third column to give you a quick idea. The Hyperdrive is rated in the number of parsecs a ship can travel in an hour. I've decided that these ships will use Reaction Drives instead of standard reactionless maneuver drives, as I figure World War II analog spaceships should have range limitations, as these were worries in the actual World War II. So each ship has a limited number of g-turns based on its Reaction Drive fuel supply.

 

[Tom Kalbfus]

Here is the table for the minimum distances before the hyperdrive can be activated:

This assumes the ship starts on the planet's surface and then accelerates at the indicated number of Gs until that minimum distance is reached. This is the travel time without slowing down. That means the ship is at its maximum velocity upon reaching the minimum distance after traveling for the indicated amount of time listed on the table. To the left of the table are standard world size codes and planet examples that are of those world sizes. These world codes are based on World mass rather than physical size. For instance Venus is a size 7 planet on this table, however because of its lower density, if we go by planetary diameter, it falls under size 8. The gas giants are much less dense than rocky planets, so this table is based on the planet's mass not its diameter. These size codes are proportional to the cube root of each planet's mass. Planet diameter is just a rule of thumb for rocky planets, and it doesn't hold for objects that are significantly more or less dense than the Earth. For example a black hole with the mass of the Sun would have the same minimum distance as the Sun for making a hyperspace jump. So this assumption is going to influence my starship design. I am currently thinking of either having a space fold drive or a hyperdrive. The space fold eliminates the safety of hyperspace, it creates a fold in space, and teleports the starship to a new location. The fold in space persists for a time, so other starships and spaceships can follow it through if they are quick.