I'm just beginning the third rewrite of the Vehicles section of IHW:SC. When I began writing this game in the long gone and sorely missed days of Spring - I speak now of a temporal unit corresponding roughly to a three month period, beginning in March and concluding in May, as there is no Spring Season in New England; then again February is at least 90 days long here, so I may be somewhat off - everything was falling into place so quickly I had visions of finishing it before Summer - which is a season here.
Since then I have re-written vast swaths of it. I have dropped almost anything already in StarCluster 2, instead using generators to create the setting and people it. In doing so, I have done my best to slant those generators towards creating the StarCluster "feel". This is because there is no such thing as a generic SF setting. Every SF setting contains fundamental setting assumptions which define the setting in key ways. For example, in StarCluster the fact that Fleets can't jump through wormholes with any expectation of arriving at the same time gives huge advantages to defenses already in-place, which means it's hard for the "typical" space-empire to form, which means cultures are extremely different from world to world, which means it's had to get them to agree on anything, which means any supra-system organization which they would form would of necessity be as loose and un-limiting as possible, which means... See what I mean? This one thing defines a lot of other seemingly unrelated things.
Anyway, the vehicle section has been giving me fits, but I have finally decided on two things - I will adapt the notation system of IHW: Wild Blue, which means three dimensionality is important in gravity wells; and I will use the Cold Space Vehicle Design Guide method of creating vehicles. In the CSVDG, I supplied base or iconic vehicles, and the GM could take one and use the system to change a number of parameters about the vehicle in positive or negative steps, so long as the steps in the end totalled zero. Example: Take a hover tank. Increase the Speed by 4 steps. Increase the Armor by three steps. Now you have to find some way to balance those seven steps! You end up decreasing the Range by five steps, and mounting a smaller primary weapon, giving two steps. You have a balanced vehicle, ready to introduce into play.
Because I finished the vehicle section twice before and changed my mind, this is the third total re-write of the chapter. The first modified the starship rules. Then I changed the starship rules and the vehicle rules carried the same awkwardness I had escaped from in the first starship section. So I re-wrote it, this time basing the system on the StarCluster Vehicle Design Guide. This system is very detailed, and allows you to construct any vehicle from scratch. It led to tracking too many factors in combat - the SCVDG combat rules are designed to work with small groups in small numbers of vehicles. Mass combat would be impossible. I got involved in a mares nest of "increasing X means that Y is too low, so that needs to increase, which means Z is totally out of phase for the mass..." AAARGH!
SO this time I'm going in clean. The IHW:Wild Blue vehicle combat system is designed for mass combat, it focuses only on those aspects needed in play, and it will work with the CSVDG balanced vehicle design system. I think this is the final iteration! I'm happy with the results so far!