[Spaceships] [Alternate GURPS] Building a Hovercraft . . .

[vicky_molokh]

Greetings, all!

So, I decided that I want to, instead of using the one from Ultra-Tech, design a hovercraft using Spaceships/Alternate GURPS/Pyramid Vehicles rules. I thought, the AG article is so good with all the additions, surely I'll be fine with just a couple of tweaks. But now, it seems not that easy.

Now, a hovercraft basically has two systems that are interesting, and seem simple from a gaming standpoint . . . at first sight.
These are the turbine/rotors used for lift (and the attached skirt) and the rotor for horizontal trust.
Turns out, there aren't any thrust propellers that can be installed in the rear. There are jets, but those have a nasty exhaust, and eat fuel directly (thus making elctro-motor versions impossible). The closest thing I found were various Ether Screws, and those are definitely not in any way like the real thing.

Now, in desperation, I looked at Helicopter Rotors, but I'm not sure. They provide wonderful lift for just a single system, and, interestingly, a top speed that is more-or-less similar to the one of UT hovercraft. But what should be gained by 'downgrading' those from a full-flight rotor to a ground-effect-skirt-only rotor?

Perhaps there are other considerations for hovercraft?
Thanks in advance!