The Minicraft rules sprang from the wacky results of the High Guard minimum sizes and the desire to build “vehicles” with High Guard. Calculate the performance, power output and duration of a TL 15 - 10 dTon craft (fighter size) with a minimum sized (1 dTon each) PP, MD and fuel. The MD would be 10 percent and yield about 3.67G performance, except that 3G performance would require only 3% of the ship for PP (0.3 dTons = 0.3 EP). The smallest PP is 1 dTon (1 EP at TL 15, 0.5 EP at TL 13, 0.33 EP at TL 9, and 0.25 EP at TL 7). At TL 15, the craft is dramatically over powered for its drive. One dTon of fuel, per book 5, will provide 1 EP for 4 weeks, so the 10 dTon small craft can operate at 3G using 0.3 EP with a duration of 13.3 weeks between refills. Who needs over 3 months duration on a personal transport? The HG minimums result in bizarrely unbalanced components.
Enter Striker.
I must admit that I was only semi-familiar with Striker. I liked the fact that it allowed the creation of vehicles and small craft, but found the rules much too complex and often incompatible with B2 and B5. What I wanted was a B5 compatible system that was as simple as B2 – plus a “logical” justification. From Striker, I learned 2 new things about ship components: (1) they can be built smaller than 1 dTon with a lower limit of 1 cubic meter, and (2) power plants became less efficient as they got smaller.
My solution.
I chose to combine all three components (MD, PP, Fuel) into a single unit and to set the minimum size of this unit at 1 cubic meter. This allowed the smallest possible craft before the minimum unit size became an issue again. Striker would allow a PP of 1 cubic meter, a MD of zero volume and an infinitely tiny fuel tank. This agrees with my proposed minimum size, but is otherwise completely different from B2 and B5. Hence the logic behind a combined unit.
Efficiency of Scale.
The other big concept from Striker was that smaller components suffered a cost in efficiency. The B5 MD percentage table indicates only 2 percent of the craft is required for 1G, but each additional G requires an additional 3 percent of the ship. (1G=2%, 2G=2+3=5%, 3G=2+3+3=8%, etc.) I saw an opportunity to simplify the B5 MD formula to a constant 3% per G, which would allow the number of engines to equal the performance in Gees and would provide a reduction in efficiency to keep the B5 designed small craft a little better than the Minicraft (important to reducing unintended abuse).
“Yes it is smaller than B5 allows, but it is also a less efficient. That is why the Imperial Shipyards do not build them this way.”
Fuel consumption.
Book 5 (High Guard) lists fuel consumption at 1 dTon of fuel will produce 1 EP for 4 weeks. Book 2 lists fuel consumption at 10 dTon of fuel will produce 1 EP for 4 weeks. Striker says that I can provide as much or as little fuel as I want to get whatever duration seems appropriate to the craft. I do not need 4 weeks duration for a craft whose size is between that of school bus and a VW beetle. Who would want to spend 4 weeks driving in a car with no stops? I chose to stick with the fuel = 1% from HG simply because I like High Guard, but I also remembered the lesson from Striker about decreasing fuel efficiency. I chose to scale the fuel volume and duration from a practical lower limit for personal transport up towards the B2 values as they got larger. It has been too long to remember for sure, but I think the progression yields a 4 week duration when the PP and fuel reach the B5 minimums.
All of this is just to explain my reasoning behind the choices that I made. Your solution is slightly more complex but appears to match HG more closely. Two other solutions are
(1) use Striker for vehicles
(2) use High Guard as is except to remove the minimum tonnage.
