On 23Aug2022 1527, kaladorn at gmail.com (via tml list) wrote:
> That's interesting, yet a bit odd just as stated. I can understand an
> air-ram mode in atmospheres of sufficient density and if your ship is
> flying quickly enough. That part is makes some sense.
>
> The parts I would wonder about:
> 1) The description is a bit sloppy. It says it works in non-breathable
> atmospheres. Fine and good, but don't call it 'air'. It's atmosphere or a
> gas mix or whatever, but air should only apply to either only breathable
> for human atmospheres or some other definition, but a methane atmosphere
> ain't air in any sense I've ever heard.
> 2) The system supposedly rams in atmosphere at flight speeds and compresses
> them (hence the ram effect). It heats it with the reactor. Okay, if it's an
> earth like atmo, it may have some humidity in the lower layers. Flash heat
> that in and you get steam and a big expansion inside the engine, not so? If
> you want atmo to flow very fast through the system, wouldn't that shake the
> ship severely? What about other gas mixes that have low temperatures of
> ignition and a lot of brisance? Hydrocarbon explosions might ensue. I'm
> sure some other atmospheric components might, when rammed, undergo
> reactions such as combustion or even a chemical change perhaps.
> 3) I'm curious how this 'doesn't use fuel'. If true, that would seem to
> make it the perpetual motion machine.... methinks some kind of fuel is
> being used. Reactor is doing something to produce heat in high enough
> volumes to meaningfully heat the reaction mass (rammed atmo) enough to
> eject it out a venturi or some such to get a meaningful thrust. That uses
> fuel to run. And to get your ship up to the point where it can ram atmo,
> fuel has to be expended. So it isn't like no fuel is going to be
> expended... once you get into a sufficient velocity to ram enough atmo
> through and superheat it, then maybe you can ride that up and out of atmo
> or even just around to travel inside the atmo at a sufficient speed.
> 4) How do you maneuver at slow speeds like when starting out or heading in
> for a landing? You can't be ramming air in enough volume in that phase.
> This would be where an auxiliary propulsion system would be, not so?
>
> TomB
It's probably a turbo-ram, so works like a turbojet at 'low' velocities
and a ramjet once the vessel is moving fast enough for the ramjet effect
to function.

As for 'fuel' - the engine has a nuclear reactor of some sort built in,
so while it will be using fuel it's at a very slow rate that can be ignored.

--
Rupert Boleyn <xxxxxx@gmail.com>