HYPERDRIVE      MILITARY
CLASS   SIZE       SIZE
  1      10t         6t
  2      25t        12t
  3      45t        24t
  4      80t       (36t)
  5     150t        ---
  6     250t        ---
  7     400t        ---
  8      ??t        ---

300(CLASS2)
----------- = RANGE
 SHIP MASS

Ex: Wyvern Explorer, Mass 183t, Class 3 Hyperdrive;

300(32)   300*9   2700
------- = ----- = ---- = ~14.75 (lightyears)
  183      183     183


Class 4 Military drive is different though, its actually a "Class 20" drive.

Ex: Thargoid War Ship, Mass 182t, Class 4 Military Drive;

300(202)   300*400   120000
-------- = ------- = ------ = ~659.34 (lightyears)
   182       182       182

If you're planning on reaching the outer limits to explore,
your best choice would probably be a Class 3 or Class 4 hyperdrive.
Those two drives tops the list on range/weight ratio.

Suitable ships to fit those drives are few;
Harrier (134/109t), Asp Explorer (150/120t) and Wyvern (183/148t).

Not much goodies can be packed onto those ships once a Class 4 drive
has been fitted (especially on the Harrier).

Some estimated ranges (one way);

Class 4 Hyperdrive +
Harrier                1,450 LY
Asp Explorer           1,250 LY
Wyvern                 1,050 LY

You should be able to squeeze in about 40 jumps in a full year
of travelling (and scooping fuel). The border to the unexplored
systems is about 1,100 lightyears out, so you probably wouldnt
be planning any return trip...

With the Quest or Thargoid ship, exploring is easy. The problem with
these ships arent the life-time of the hyperdrive, its the fuel.

After completing the Thargoid quests, the Thargoid transport at
Polaris [0,76] will still be there and can be used to service your
equipment and to load up on military fuel (!!!).