@Robert_Brandt@isaackuo@n1xnx@cstross@sudnadja@nyrath@hendric@KarlSchroeder@FredKiesche I literally have the math above for an example case. So yes, if you want any kind of velocity, they actually do weight an appreciable amount, so no, x+1 is not always better. Everything in space combat comes with a cost in mass, in expenses of manufacture. And some combinations don’t pay.
I remember calculating similar things back when I was trying to adapt the "intercept countdown" concept into an interesting board wargame. I was hoping to have an interesting mix of different propulsion systems and EM launch assist vs pure rocket missiles ...
Spoilers - chemical rocket propulsion beat everything else. Almost entirely across the board.
And it really bummed me out, because I came up with a freaking genius method of propellant tracking for variable Isp drives (solar thermal, nuclear thermal, solar electric, or nuclear electric). It was a stroke of brilliance ... players could elegantly choose any degree of tradeoff between thrust and specific impulse.
Awesome! Except the damn chemical rocket beat it no matter where you dialed it.
Yeah, it was a genius variant on my normal fixed specific impulse ammo/propellant/acceleration chart.
I wish I could link to my Yahoo E-mail list posts, but ... sigh ...
But basically, you've got propellant boxes in rows, where each row is a fixed mass of propellant but the width of the row is how much delta-v it's worth. Pretty intuitive, the rows just get wider the less mass remains...
It also handled ammo consumption nicely - you had a rectangular matrix of ammo boxes. When you consumed/dumped a row of ammo, you also struck through a row's worth of propellant. Thus, it elegantly handled how your acceleration and delta-v improved if you consumed/dumped ammo earlier rather than later...
But extending to variable Isp involved a mind bending switch from each box being a unit of delta-v to each box being a unit of of (delta-v)^2. So each turn, you consumed boxes equal to the delta-v squared. This models how a variable Isp thruster consumes more propellant for a given delta-v the higher thrust you need.
This is for a board wargame. No calculation of formulas for the players to perform. Only (surprisingly simple) formulas for generating the tracking sheets.
Even the calculation of delta-v squared is removed from the player by the use of a ruler that encodes the scaled square calculation in the tick markings.
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