On Thu, 11 Sep 2003, Ian Woollard wrote:
> >Stir in the availability of turbofans off the shelf, and the desirability
> >of powered landings for operational transport vehicles,
> >
> Yes, but it's an unmanned flyback booster, not a transport vehicle.
An unmanned flyback booster *for what*? It's part of an operational
transport vehicle. That means it wants to make powered landings, to keep
the crash rate down. (By the way, why assume it's unmanned? Making it
manned is probably preferable. Nobody builds unmanned cargo aircraft, and
there's a reason for that.)
> ...you may even be able to use it on the way up too (for a
> small amount of the flight envelope), they have no moving parts...
Those two are probably incompatible -- to get any significant use out of
it on the way up, it will probably need a variable-geometry intake. You
just can't get any significant help from a point-design engine on an
acceleration mission.
> they're more reliable, need much less maintenance...
Modern airliner turbofans don't need much maintenance. It's plausible,
even probable, that a point-design ramjet would be better, but whether
that actually makes a big practical difference is less clear.
> ...and are cheaper to build/buy than a turbojet.
After how big a development bill? Remember, there are no experienced
ramjet development shops left (at least in the unclassified world), and
engines which can't run at zero airspeed need expensive test facilities.
Unless you are talking about a big production run, buying used turbofans
is going to be a whole bunch cheaper.
Henry Spencer
[EMAIL PROTECTED]
_______________________________________________
ERPS-list mailing list
[EMAIL PROTECTED]
http://lists.erps.org/mailman/listinfo/erps-list
