Hi Onno, from your explanation, it is very obvious that I screwed up terms in a significant way.
What I meant when I was talking about "vectored thrust" was in fact "reaction less thrusters". Replace all occurrences of "vectored thrust" in my comments with "(vectored) reaction less thrusters" and most of them should make sense to you. And yes, a grav tank with a jet engine for thrust would be worse than a landing helicopter. A Seaking helicopter has about 10 ton at its very max, requiring a rotor with a diameter of 19 m. When such a Jolly Green Giant comes down on an open plane, it is already no fun - and now assume this on a narrow street between houses! (Ok, the street could not be *that* narrow …). And the downwind from a helicopter is just air, it is not hot like the exhaust from a jet engine. 40 ton for the tank is more or less the weight of an F-14. Have you ever stand near behind a starting F-14? Ok, the tank do not need the same terminal speed, but I doubt that the engine power could be much lesser than that for the F-14 … and now that F-14 (or two of them, one covering the other) in the street in front of your house … maybe it is not the hot air itself that damage the building, but your neighbour's car would have some impact on your front door ... And the tanks do not only need the jets for accelerating, they need is for braking, too (or you have to plan for an anchor …). So what will happen if there is a battallion of such tanks fighting in an urban area, when fast moves are necessary to survive? Or the other way round: what sense would make a tank (TANK!) that cannot fight in closer areas? Ruling the open plains might be done easier from above. So I think "efficiency" should always consider collateral damage, too. I think, that's why there had been no real grav tanks at GT TL8 ;-) -- Thomas Thrien Geo 51° 28' 12" N 7° 32' 17" E Es heißt: "Der Klügere gibt nach". Doch wenn die Klügeren immer nachgeben, dann passiert nur noch, was die Dummen wollen ... Am 11.01.2013 um 19:28 schrieb Onno Meyer <[email protected]>: > Thomas wrote: >> A propeller or a jet engine or a like - but would you like stand where the >> jet or propeller that is capable to move (and brake …) a 40 ton vehicle >> is blowing to? So what I should have said is that grav vehicles for the >> mass (as personal vehicle in urban areas) would only make sense with vectored >> thrust because of the desastrous side effects of jets or propellers (that >> can be handled for large mass transports - see our airplanes) or the >> uselessness of "frictioned" motion through pulling beasts or wheels (on a >> grav >> vehicle!). A reactionless thruster would be an alternative, but I categorised >> that under vectored thrust - even if this might not be correct from the >> rules. > > Hello Thomas, > > I think we're misunderstanding each other. Using the default 3E > technology, vectored thrust (VE41) is available for many engine > types. By default, TL11+ reactionless thrusters have no heat or > noise, and since default contragrav appears only at TL12 it > makes a lot of sense to assume reactionless thrusters along > with the CG. But contragrav could come earlier, as in GURPS > Traveller, and then you could have jet engines or ducted fans > with CG. At GT TL8, jets or fans are more efficient than > reactionless thrust. > > And both reactionless or reaction thrusters can be vectored or > unvectored. Vectored thrust means 50% more weight and volume, > so some designs could use non-vectored thrust and extra armor > or payload. > >> A tank is not a personal vehicle, and we know that the military is always >> willing to accept some collateral damage. But I doubt that a battallion of >> 40 ton, jet engine thrusted grav tanks in an urban area would leave >> something worth to defend - even without firing any shot … > > Would it be much worse than helicopters landing in a city? > >> Therefore I think that we can assume that grav tanks will always have >> vectored thrust. This may be different for a gunship ... > > Make it "probably" rather than "always" and we can agree :-) > I'm using vectored reactionless thrusters for my draft grav > tank. > > Johannes wrote: >> The question would be, if additional cost and payload for a turret is >> greater or smaller then for vectored thrust. > > The turret is almost certainly much heavier than the vectored > thrust. So the question remains if the turret brings other > benefits to justify the weight. > >> Regardless which other vehicles become more or less viable due to the >> tanks, i would consider it likely that the tanks will shoot at other >> tanks. > > If tanks just fight tanks, there would be no reason to have > them at all. If tanks wreak havoc in the rear areas or roll > up infantry positions, you need both tank and anti-tank > units. > >> And unless the tanks are forced by something to all operate on the >> same height, that means shooting both upwards and downwards. > > I would guess that the most common altitude for grav tanks > is "nap of the earth". Going higher might make sense for > fast, long-distance flight, but it is a calculated risk if > the enemy has hidden units to hit the unmasked flyers. > > Regards, > Onno > _______________________________________________ > GurpsNet-L mailing list <[email protected]> > http://mail.sjgames.com/mailman/listinfo/gurpsnet-l _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
