| From: | Jeffrey Mach <mach@****.CALTECH.EDU> |
|---|---|
| Subject: | Re: Arrow |
| Date: | Thu, 5 Mar 1998 19:25:07 -0800 |
> >Well, if we are talking fighter craft, let's not forget the US project that
> >has been dubbed "Aurora." While it's name might be something totally
> >different, it's clear that the US Gov. has *some* sort of bleeding-edge jet
> >that it's been testing for several years now.
>
> The really neat thing is that this includes NASP, the X-31, the NASA
> aerospike engine, and lots of other high-speed stuff...
Huh? What does the defunct National Aerospace plane, a thrust-vector
test-aircraft (already obsolete--see the VISTA F-16 or ACTIVE F-15
projects if you want to get closer to SotA), and Rocketdyne's engine have
to do with Aurora?
> There may be a hypersonic reconnaisance aircraft, it's been discussed
> for some years: even here in the UK there are claims of sightings off
> Scotland, of landings at Boscombe Down, et cetera.
Normally, I am a cynic when it comes to conspiracy theory, but I have seen
the data on sightings of "Aurora" (even though the name has been traced to
belonging to the Tier 3- Darkstar scout drone) and I am quite convinced
something "is out there." Fact is the F-117 was kept a secret for about a
decade, hell, I was even later relieved to find out about them after a
dark and silent triangular shape flew over my house a few months before
the press conference (my house is on Beale AFB's flight-path, the guy was
probably on the way to a KC-130). Fact is, seismographic sensors have
detected high-frequency pulsed detonations traveling over the Southern
California desert at many times the speed of sound. Caltech tried to ask
the USAF what it was, since it was bugging their seismographic sensors and
were brushed off. Fact is, around the time, weird contrails were
photographed and even videotaped. They look like a straight contrail with
doughnut shaped "puffs" around them. Best guess as to what could cause
it: pulse-detonation ramjet. Paul's already adressed that. Manned or
unmanned, reconnaisance vehicle or hypersonic testbed, nobody either knows
or is willing to tell.
Only comment on what Paul had to say was that the SR-71 hedges the
supersonic intake problems a bit by having the "cones" at the fronts of
its engine nascelles be retractile, to keep the shockwaves at bay, as well
as allow the engines to convert from turbojets to ramjets once up to
speed. They had to simply because the engines couldn't survive being run
as turbo-jets at the speeds that they wanted the Blackbird to cruise at.
Of course in all the pictures you see of the Blackbird, the cones are out
because at speed, the only aircraft that can easily photograph a Blackbird
is another Blackbird. =) Of course if you look at the pictures closely,
in many of them, the wings of the SR look "wet." That's fuel. Since the
frame heats up so much when the aircraft is at speed (to the point that if
you land right after a full-speed run, you can't get out of the aircraft
right away, the aircraft is too hot) that they had to design the fuel
tanks with gaps that would seal as the metal expanded. Why do I know so
much, see above Beale AFB comment. The SR's basically the main reason I
am getting my Master's in Aerospace Engineering. Now _there_ is a plane
that was ahead of its time.
> >It's
> >rumored to be extremely fast.
>
> Mach 5 or thereabouts.
I've heard claims that the propulsion system should be good to about Mach
8, but the body probably isn't. Trying to survive the incredible pressure
and worse thermal stresses on an aircraft at these speeds is a _major_
materials problem. A seriously hot topic right now. Since the problems
geometrically increase the faster you want to go. Reentry is bad enough,
but you typically don't spend much time in the hypersonic regime, and at
least in the case of the shuttle you end up replacing quite a bit after
you get done with a few flights. Now, you want to cruise at these speeds?
Good luck.
--Catch you later
Jeff
