Part of the problem that started this discussion is that lifters just magically appear on ships and have no cost independent of the hull in MgT2e post Starship Operator's Manual.
Like I mentioned previously, we were limited by the scope of the SOM, but if you really want to reflect it game-mechanically, you can simply assume that 'non-gravity hull' = 'No lifters'; you halve the cost-per-ton of hull and halve the power consumption.
T5 does something similar in that, by opting out of having lifters, you recoup some of the cost you were spending on your hull (T5 isn't as granular about power as MgT2 though, so no word on that on their end).
So what distinguishes a Lifter from a Maneuver-0 drive with the 'Orbital Range' restriction? Would a 'Budget' (requires exactly one disadvantage) Man-0 with the 'Orbital' limitation (2 disadvantages) be able to take the 'Energy Efficient' (1 advantage) to bring it to the required 1 net disadvantage?
It never got into the final SOM, but we did think about equating M-Drives with the Limited Range disadvantage with G-Drives from T5, as both are M-Drive-esque devices with a range of 10 Planetary Diameters.
As for what distinguishes them, the Lifter works as described in SOM, it has a field envelope area and it accelerates everything within said field away from it – the acceleration is tiny, in the order of the centi- or even milli-G, but there's just so much
stuff inside the field that the total force is enough to counteract the planet's gravity.
A G-Drive (read: M-Drive with Orbital Range) on the other hand works like an M-Drive, which is almost, but not quite, entirely unlike lifters. The M-Drive also couples to masses and accelerate them to generate thrust, but it can only couple to said masses if they are within range; the bigger the mass, the larger the distance the M-Drive will still be able to couple to them.
For planet-sized masses, this turns out to be 10 Diameters for the G-Drive, and 1000 Diameters for the M-Drive (as described in T5.
That's the idea, anyway.
[Edit: only now I realise you were asking about the
Orbital Range disadvantage, not the
Limited Range one. Yup, no idea honestly, I shan't lie to you. Maybe it's just an
unfathomably shitty G-Drive?]
Definitive until the next book comes around....
Anyway, right now the definition comes pretty much straight from T5. But even that is subject to interpretation and I interpreted 1D altitude to be 1D from the center of the world, meaning the first half of D gets you to the surface, so you can only go half a D over the surface.
When we got to talk with Rob Eaglestone (and MWM via proxy) while writing the SOM, that was their intention, you can hover up to 0.5 Diameters above the planet's surface; i.e.: 1D from its centre-of-mass.
My only real problem with lifters is that they are a magical property of spaceship hulls. Effectively, in T5 and MgT2e we don't have Lifters. We have gravity resistant starship hulls. Just build a starship hull and it ignores gravity intrinsically.
If you'll allow me to put on my devil horn tiara and don my best sleazy lawyer suit? The High Guard ship construction system is highly abstracted – T5 even more so in some aspects (and weirdly...
not...? in others).
Theoretically the hull itself
must have a volume and
must have a mass, even at armour 0, otherwise your hull is made out of vacuum, which last time I checked makes for a poor construction material.
Both ship construction systems abstract these away, and they do the same with lifters.
Personally, if I were making a FF&S equivalent for Mongoose 2nd (which I would not – I'm literally just a co-author of a fluff book, not a professional Mongooser – and do not want to do [that's what Geir is for!*]), I'd certainly look at Striker, FF&S Senior, and FF&S Junior and include lifters as an actual component that must be bought and tallied and accounted for.
But as things are, this is way below the resolution of the respective editions' design sequences. 'Tis what it is.
*Sorry Geir – I do love your work, though!
