Oerjan said:
The grav trailer needs its own near-full-sized grav engine. Simply
providing the lifting force isn't enough; it also needs the
side-to-side maneuvering capability as well or it'll whip out in every
curve the main vehicle makes (imagine driving with a loaded trailer on smooth
ice,
with smooth tyres... then remove the ground friction :-/ ).
==> I concur, though you may find because you're hauling it behind, if you
were going at speed, drag would possibly keep is straight behind you (think
dragging a glider behind a plane).
The only
thing which keeps a usable grav trailer from being a straight-up
robotic vehicle is that it'd take its maneuvering commands from the
main vehicle instead of from an on-board computer brain. GEV trailers
have exactly the same problem.
==> Well, yes and you don't need to wire big perceptual brains into them
either...
> Maybe the AG unit (or GEV) unit in the trailer is powered by some
That assumes a *seriously* over-sized powerplant on the main vehicle,
though. Very unlikely, unless the main vehicle is purpose-built for
towing
grav/GEV trailers.
==> Unlike modern military wheeled tow vehicles? Have you noticed many of them
have an awful lot of overpower to tow heavy trailers... and they've got to
drag them versus friction on the surface (yes wheels aren't too bad... but an
air puck has to be better). So if the lift energy can be supplied, the energy
to pull might be less.
==> And if you are towing it behind something with the same kind of powerplant
that can lift a 250 metric ton main battle tank (aligned crystaliron armour, a
200 gigawatt pulse laser, a GMS, and multiple smaller armaments, plus an ECM
suite) but which has no armour (ie a grav truck or tractor) or which only has
minimal armour and some engineers aboard
(CEV),
this seems quite believable to me. That mass of armour you sacrifice on the
tank is probably enough for any two trailers....
==> But, YMMV. It all boils down to how abundant your power is, how
efficient your AG and GEV propulsion/lift systems are...
> Barclay, Tom wrote:
> Oerjan said:
If you go *straight ahead* at speed, the trailer will stay straight behind you
thanks to air drag. If you brake, or turn, it won't stay there any more than a
glider will stay straight behind a towing plane which slows down or turns.
(Which is to say "not at all" even at supersonic speeds, unless the glider
also has a full set of maneuvering surfaces *and* either a pilot of its own or
is remote controlled from the towing plane.)
> The only thing which keeps a usable grav trailer from being a
Modern UAVs and cruise missiles don't have big perceptual brains either, but
they're quite capable of following routes determined by
someone else. They do, however, need full-sized propulsion and
maneuvering systems.
> Maybe the AG unit (or GEV) unit in the trailer is powered by some
You mean that modern military wheeled tow vehicles are *not*
purpose-built for towing trailers? (OK, they're purpose-built to tow
anything that needs towing, not just trailers...)
> Have you noticed many of them have an awful lot of overpower to tow
John's original post allowed *all* vehicles to tow trailers... including MBTs
and SPGs. No, I haven't noticed any awful lot of overpowering on MBTs or SPGs;
in fact most tankers and artillerists I've talked to complain that their
vehicles are *under*powered.
> and they've got to drag them versus friction on the surface (yes
1) Unless you're going extremely fast, the energy required to lift the thing
is very much larger than the energy required to move it horisontally. We're
talking multiple orders of magnitude of difference here.
2) An air puck requires less energy than a wheeled vehicle to start moving at
all, but it requires a lot *more* energy when you want it to *stop* moving as
well as when you want it to start moving in a different direction from where
it is currently going because you don't have any ground friction to help out.
In FT terms, the wheeled vehicle
uses Cinematic movement while the grav floater uses Vector movement :-/
> ==> And if you are towing it behind something with the same kind of
See above. John's original proposal allowed *that very 250 metric ton MBT with
200 GW laser and ECM" to tow *exactly the same trailer* as the
PURPOSE-BUILT tractor I noted as an exception to the "seriously
overpowered" rule.
Regards,
> ==> I concur, though you may find because you're hauling it behind, if
If you go *straight ahead* at speed, the trailer will stay straight behind you
thanks to air drag. If you brake, or turn, it won't stay there any more than a
glider will stay straight behind a towing plane which slows down or turns.
(Which is to say "not at all" even at supersonic speeds, unless the glider
also has a full set of maneuvering surfaces *and* either a pilot of its own or
is remote controlled from the towing plane.)
***Adrian: Hang on a sec, though. A glider is on 250' of 5/8"
polypropylene rope (give or take). A trailer is on a wee little
hitch...
There is a lot of difference between how you tow a glider and how you tow a
trailer, and an awful lot could be done with clever *hitch* design, I'd think.
I'm sure with some careful thought and good engineering, you could
design a hitching mechanism that used hydraulic/pneumatic/electric
actuators to damp out unwanted swaying/pivoting of the trailer, such as
when decelerating, but still allow enough flexibility to accomodate bumps,
etc. Damp out unnecessary turns, and then allow turns when appropriate
-
wired into the brain of the vehicle (or doing it automatically with gyros
> --- Oerjan Ohlson <oerjan.ohlson@telia.com> wrote:
> > ==> Unlike modern military wheeled tow vehicles?
Not really. My experience with US Army trailers has
been with M113A3 APCs towing -105 trailers and with
both M113A3s and M48/M60 AVLBs towing MICLIC trailers.
Not designed as a trailer-hauler per se, except in
that they have a trailer pintle.
> >==> I concur, though you may find because you're hauling it behind,
[Bri] But then you are adding weight and control mechanisms to the
towing vehicle. Such an elaborate set up would require additional cost (DS2 or
value SG2) to the towing vehcile. I agree with statements made earlier, a
Grav, Hover, Walker, or VTOL trailer would require an engine of it's own.
Obviously wheeled or tracked do not because the physical supporting structure
does not require power. On tracked or wheeled trailers, I agree that the cargo
capacity should be increased, but I would suggest that it only be 2 cargo
units (8 capacity points) per size. Grav, Hover, Walker, or VTOL trailers
would not gain this bonus because they would still need to