> >Being an unreconstructed aerospace nut (and spending way too much time on
> >airplanes), I've followed the Concorde crash story with morbid fascination.
>
> Then you would probably find the following site of interest:
>
> < http://www.airdisaster.com >
The recommended site was enormously informative, Zero, and
I thank you.
Greg -- I share your fascination although I don't perceive it as
morbid. I've no interest whatever in other types of transport
disaster, or in generic disaster scenarios of any kind. It's true
that "nuts" tend to have "morbid" interests, but I would describe
myself as "an unreconstructed aerospace fanatic" so that my
attention, while socially borderline, is otherwise asymptomatic.
Seriously -- how do you interpret this specific interest?
And while I've got you on the line, Greg, please appreciate that
I DO regard serotonin reuptake neuropathy as correlated with
suicide, or an apathy sufficiently profound to justify a diagnosis
of "quasi-neonatal failure to thrive" You see, we really have no
category for this illness [c.f. involutional melancholia] and I
regard the word "depression" as a metaphor rather than a
satisfactory diagnostic category, supposing that phrases such
as "neurochemically induced mood disorder" [in endogenetic
cases] not only more accurate, but less prejudicial. One may
consider this disorder as analogous to diabetes, either of
which may or may not contribute to the death of an otherwise
viable person.
My regards,
Bob
------------------
I think Concorde can in some way be compared to the SR-71. Two unique
highspeed aircraft that will never be replaced, each have millions wanting
or wanted them scraped, each are an excellent demonstration of what brains
can achieve when you want them to!
As Kelly Johnson once said (wearing a very dodgy plaid jacket!) "It'll be a
long long time before they make another airplane that goes faster and higher
then the SR-71" He said that in the 70s and its still true!!!!
-------------------
Provided we have enough brain-power and sufficient resources we can accomplish
almost anything we set our minds to. If we wanted to we could develop a quiet
and economical SST to replace the Concorde and possibly many subsonic
transports. However, it is not in the industry's interest to do so, especially
given the huge investment they would have to make which would be considered very
risky and thus unprofitable. This aversion to risk has already been devastating
in some respects. Our inability or unwilingness to innovate will come back to
haunt us some day.
Sam
--------------------
> <> Despite having suffered through a transatlantic flight more times than I
> can now count, I can't make myself believe that an SST with current
> technology makes sense. It seems to me that the disruption of one's schedule
> from crossing 6 or 8 time zones in 3 or 4 hours is just as great as doing it
> in 9 or 10 hours. Heck, just going back and forth between the US Middle and
> Left Coasts is enough to kill the better part of two whole days for me. With
> the ability to keep a laptop computer running throughout the usable portion
> of the transatlantic flight now, I've come to actually be able to make
> productive use of the trip if I want or need to.
>
Actually I've read many businesspeople coming from Europe take the Concorde
over (arriving in US around same time of day that they left), do their
biz here, and then grab a normal slower flight back to sleep on. In that
case I can see that it makes sense.
-------------------
According to this article America is not soooo unwilling to pursue new
technologies
in that field...
Timothy
http://38.247.214.215/FRheft/FRH9911/FR9911g.htm
AMERICAS X-PLANES
By Christopher Hess
No other aircraft program illustrates the USA's strong will for the
leadership in aerospace technology better than the X-Planes. In more
than 50 years since the first supersonic flight of the Bell X-1, the X
designation aircraft have become the technological spearhead in
developing new aircraft and spacecraft.
Including a few classified projects there are currently 12 active or
planned X programms which will fly in the medium term. However,
this number includes single projects, such as Boeing's or Lockheed
Martin's Joint Strike Fighter prototypes (X-32 and X-35) which are
not X-Planes in the classical sense of technology driven experimental
vehicles.
The X programm was initiated at the end of the Second World War as
a joint effort from NASA (back then NACA, National Advisory
Committee for Aeronautics) and the US forces. The goal of the
project was the exploration of the back then still unexplored speed
region of high subsonic (transsonic) and low supersonic.
When Chuck Yeager broke the sound barrier on 14 October 1947,
such accomplishing the near-term program goals, the flight
experiments did not stop but were intensified. Most interestingly the
original XS aircraft designation (for eXperimental Supersonic) was
changed into X already at the very beginning of the program.
The continous research of supersonic flight gave the Americans an
immense Knowledge about the flight in the high-speed region,
cumulating in the X-15 that reached a speed of more than six times the
speed of sound and an altitude of more than 100 km.
This high-speed research was only the beginning. In the past 50 years,
the most different aircraft configurations were tested under the X
designation. The spectrum reaches from a tailsitting vertical lift-off
plane via a nuclear powered bomber and a gyro copter to the
spaceplane of the future. Engines used in the projects include jet,
propeller and rocket motors.
Today, the role of the X-planes has changed significantly. While at
the beginning their purpose was mainly to give the US a technological
lead (especially in the military aircraft sector), today's experimental
aircraft must have a commercial perspective as far as the potential
application of the tested technology is concerned. There is an obvious
shift from aviation to spaceflight in the research activities.
The USA see a big market potential in spaceflight. But in order to
exploit that market, the cost of transportation must be reduced
considerably. However, the necessary technologies are not yet or
only little tested. Here, the industry needs support to take the
technological risk. This is the part the X-Planes must play today.
NASA has developed the Future-X concept in the frame of its Space
Transportation Program. According to this concept, new technologies
are tested with demonstrator vehicles in two classes. First the
pathfinder class vehicles which are focus on a very narrow
technology. Accordingly, these demonstrators are designed for a very
short development time of less than two years from program start to
flight tests. Also, the program costs should be less than 100 million
Dollars.
One example for such a pathfinder technology demonstrator is the
X-34 which is currently undergoing integration tests with its
Lockheed TriStar launch aircraft at NASA's Dryden Flight Research
Center. The X-34 is supposed to start suborbital flights next year,
reaching Mach 8. The technologies to be demonstrated include an
autonomous flight control and landing system, as well as, an
integrated health monitoring system that is supposed to allow quick
turnarounds between flights.
While the pathfinders are focusing on specific technologies, larger
vehicles, the so called trailblazers, will be used to validate the
integration of various technologies and systems. These experimental
demonstrators almost look like the real vehicles. For example, the
X-33 is a half-scale VentureStar which Lockheed projects as one
possible successor of the Space Shuttle. The X-33 already features
several design components of the VentureStar, such as new
Aerospike rocket engines and a metal thermal protection system.
With this approach, NASA together with the industry is making its
way towards the next generation of new space transportation systems.
This also includes cost-sharing aspects of industry and government.
Meanwhile, Europe has recognized the new X-attitude of the USA.
With its Future Launchers Technologies Programme, which includes
small and large technology demonstrators, the European Space
Agency wants to create a technological basis for a competitive and at
least partially reusable space transporter.
From page 12 of FLUG REVUE 11/99
----------------------
> <> I understand why the engines have to be in closed nacelles tucked in
> tightly to the body and wing, but why not on TOP of the wing, where debris
> from an exploding tire wouldn't be a problem?
A few reasons come to mind. The intake has access to less turbulent
air {and so higher pressure} if they are below the wing, and secondly
having the engines above the wing would raise the center of gravity, which
is bad for stability. Further, if the center of thrust were above the center
of pressure, then getting on the gas would push the nose down instead
of up. The way it is, a pilot can control the aircraft in a hydraulics-out
sitch to a certain extent as was demonstrated by the pilot in the Sioux City
crash a few years ago.
The high mounted engines would still be vulnerable to exploding tires,
perhaps less so. Rubber frags would be thrown forward and ingested by
the screaming engines on takeoff.
spike
-------------------
My question is this:
Repeated news reports talk about the Concorde having difficulties
with tires exploding on landing gear.
Military aircraft, the SR-71 in particular are considerably smaller
than the Concorde but travel in similar regimes.
So why would the Concorde have tire difficulty and you never hear
about tire problems on other supersonic aircraft. Yes, they are
smaller but you get the idea. Since the Concorde is a civilian
airliner perhaps it's more noted. Most military craft don't
report to the media that there were issues.
The news this morning discussed a "cow catcher" on the landing
gear coming loose, puncturing the fuel tank thus causing a leak
and thus the fire.. Big ouch but it also appears that the British
saw an issue with this and devices a leash to keep the catcher
affixed to the landing gear in the event it did come loose, a novel
idea but one the french evidently didn't adopt.
I read Dan Zinngrabe's excellent article on Brilliant Buzzard on
his old website and it talked about very large aircraft having
landing gear requirements where manufacturers didn't want to have
to re-invent the wheel if they didn't have to, thus re-using
landing gear designs for other aircraft.
I'm curious if indeed the Concorde used an existing design or
if it was unique to that aircraft. Might be an interesting read
even though it's off-topic.
Thoughts?
-------------------
You cannot compare military and civilian aircraft like that.
As I understand it, the Concorde's flaw has to do with the placement of the
landing gear in front of the engines. In the event a tire explodes, debris from
the explosion will end up puncturing the skin and or being ingested by the
engines, causing FOD (foreign object damage) and possibly disabling one or more
engines, which is what apparently happened in this case.
In the SR-71's case the engine intakes are far away from the landing gear and
the gear is aft of the engines anyway (the engines are rooted in the wings).
In most military aircraft the landing gear is well aft of the engine intakes or
is placed far enough to the port or starboard of the intakes so that it does not
pose a risk to the engines or any critical parts of the airframe.
> So why would the Concorde have tire difficulty and you never hear
> about tire problems on other supersonic aircraft. Yes, they are
> smaller but you get the idea. Since the Concorde is a civilian
> airliner perhaps it's more noted. Most military craft don't
> report to the media that there were issues.
>
> The news this morning discussed a "cow catcher" on the landing
> gear coming loose, puncturing the fuel tank thus causing a leak
> and thus the fire.. Big ouch but it also appears that the British
> saw an issue with this and devices a leash to keep the catcher
> affixed to the landing gear in the event it did come loose, a novel
> idea but one the french evidently didn't adopt.
Yes, it is quite possible.
> I read Dan Zinngrabe's excellent article on Brilliant Buzzard on
> his old website and it talked about very large aircraft having
> landing gear requirements where manufacturers didn't want to have
> to re-invent the wheel if they didn't have to, thus re-using
> landing gear designs for other aircraft.
It is common practice to re-use existing landing gear assemblies on new designs.
However this does not necessarily impact the placement of those assemblies on
the airframe (placement is usually impacted by other factors such as
load-factors and balance and center of gravity issues).
> I'm curious if indeed the Concorde used an existing design or
> if it was unique to that aircraft. Might be an interesting read
> even though it's off-topic.
I don't know if they used an existing design or whether they designed one from
scratch, although I suspect they may have done so, since the Concorde "probably"
had rather unique requirements.
Sam
------------------
I couldn't tell from the video or front shot with at
least 1 engine on fire where the main landing gear was
in relation to the nacelle's inlets. It did seem like
they "about even" with each other so if an engine blew
some pieces out some might hit the tires. I believe it
is more likely that tire blowouts would have an
unfortunately good chance of being ingested by the
innermost engine or both.
Also I didn't know that the Concorde takes off at
250mph!!! That's pretty damn fast! I believe the
SR-71's usually rotated near 150 mph and got airborne
before reaching 200 mph. It's tires are pretty tough
but someone mentioned that new tires are put on after
10 flights...or sooner if major wear "flat spots" are
discovered. I have read that if one SR-71 main tires
fails, the other 2 will fail also because the loads
are too high for just 2 tires. And usually the plane
just grinds down the wheels and starts on the struts
next!! I believe these tires, which are very expensive,
are rated for a maximum of 249 mph.
>
> In the SR-71's case the engine intakes are far away from the landing gear and
> the gear is aft of the engines anyway (the engines are rooted in the wings).
>
> In most military aircraft the landing gear is well aft of the engine intakes or
> is placed far enough to the port or starboard of the intakes so that it does not
> pose a risk to the engines or any critical parts of the airframe.
>
> > So why would the Concorde have tire difficulty and you never hear
> > about tire problems on other supersonic aircraft. Yes, they are
> > smaller but you get the idea. Since the Concorde is a civilian
> > airliner perhaps it's more noted. Most military craft don't
> > report to the media that there were issues.
Perhaps not or maybe only in local newspapers. I get
most of my info from various books and info that is
posted here. I don't remember reading much about tire
failure on the Concordes before the recent crash but
I recall tv reports and articles about a Concorde that
lost a major portion of the tailfin/rudder. I thought
that was attributed to the crew trying to set a speed
record..
> >
..snip...
---------------------
It's also worthy of note that the Concordes have a shield on the gear that
is used to keep spray from being ingested. The British experienced a problem
with the original design shredding and flying up and impacting the fuel tanks
and other areas. They modified all of their Concordes and the problem has not
reoccurred. Although they had the same data, the French chose not to perform
the modification on their Concordes. Parts of the shield, as well as tires
were found on the runway...
---------------------
> > Ja, well Lockheed kicked Boeing butt that time. Of course, they
> > kicked ours in the 747 vs L1011 contest... {8-[ spike
>
> The L-1011 is my favorite air liner. I used to love to fly on them with
> TWA when flying from Seattle to Boston nonstop. The huge legroom that
> coach seats had was incredible (wide seats too).
Mine too. Even my modern standards it is a very comfortable aircraft
for the long haul. If you want an interesting discussion of the L1011
vs its real competitor the Douglas DC 10, Ben Rich discusses it in his
book Skunk Works. The DC10 had the straight thru tail engine, which
forced the rudder to be shorter, which required the wing engines to
be closer inboard so that in a one-engine-out condition, the shorter
rudder could overcome the resultant yaw. The L1011 had the more
expensive and complicated (Lockheed loves to do things this way
whenever possible) S-shaped thrust duct, allowing a longer rudder,
allowing the wing engines to be further outboard, so the passenger
compartment is quieter. The company calculated it would need to
sell 250 of the 1011s to break even, and it sold 246 if memory
serves correctly. spike
------------------
Robin sez:
> I do have a lot of concern that the media tends to grab extremely firmly onto the
> wrong ends of sticks and then worries it to death while the real story gets
> submerged in the mire of obfuscation. Regarding Concorde, at the moment
> there is no real confirmation of anything and there won't be at least until
> the Accident Investigation Board (AIB) has presented its findings. There's
> a huge amount of information to examine before the actual cause of the
> accident can be proposed. In the meantime a fine aircraft with a
> previously excellent safety record is being tarred with accusations
> that it (and by association civil aviation in general) is fundamentally
> unsafe.
>
> Eyewitness accounts are notoriously inaccurate - the existence
> of photographs and video of the event are powerful pieces of evidence
> in the accident investigation, but they are only symptoms of the
> accident, they do not usually point unequivocably at the actual
> cause. In this incident, the engines, in particular a rotor failure,
> was implicated - Rolls Royce would naturally be alarmed to find
> that the incident was blamed on their engines, from design to
> manufacture and maintenance thereof. Ditto the thrust reverser,
> problems with which were hilighted immediately before flight. (The
> suggestion that the maintenance crew "rushed" the repairs -
> implying that they did a botched job - does them a huge disservice.
> Robbing components from a "christmas tree" aircraft is common
> practice and is a perfectly reasonable way to maintain a small
> fleet of aircraft whose spares are in limited supply.)
>
> The video and photographs have mostly put paid to the engine failure
> theory in showing that the fire appears to originate from the undercarriage
> bay, which is why the blame has shifted to a tyre-burst that has thrown
> debris into the bay, puncturing fuel tanks and severing control
> lines and triggering a fire away from the engine. This still doesn't mean
> that the engine is entirely off the hook, and it will be examined as if still
> a suspect just to make sure.
>
> Even so, this doesn't actually identify the trigger for the accident, whatever
> caused the tyre to fail in the first place, so we turn to examining such things as
> the brakes. Concorde travelled two-and-a-half miles from the terminal
> building to the end of the runway - a binding brake would have caused
> it to overheat. The heat takes a finite time to soak through into the
> wheel and wheel hub, the wheel and tyre overheating could cause a
> failure of the tyre, which could have happened as the aircraft began
> it's take-off roll applying the final amount of strain to an already overloaded
> tyre.
>
> But (and it's a Big But) this is still all conjecture until the wheels, hubs and
> brakes are recovered and examined, and it still doesn't explain why the tyre failed
> when it did - aircraft tyres are expensive and undergo re-tread procedures.
> Cocncorde tyres are different from conventional civil aircraft tyres, but not
> markedly so. BA inspects after so many landings and allows (AFAIR) 8 retreads
> before scrapping the tyres, AF performs a post-landing check after every flight
> and allows 15 re-treads (again, AFAIR - may have to check the actual figures,
> but it does represent a slightly different approach to tyre inspections by the
> two companies.)
>
> There are also different modification states to the undercarriages between the
> two companies - BA have debris deflectors on their main u/cs, AF do not,
> despite there being a history of tyre failures on Concordes. The deflectors are
> mainly there to protect the engines from ingestion of debris that causes foreign
> object damage (FOD) - in the case of the AF Concorde this may (note "may")
> have penetrated fuel tanks and service lines as well, as indicated by the
> pilot reporting the inability to raise the undercarriage and the roll stability
> control problem (basically, it appears he only had control of the starboard side
> of the aircraft). This is *still* all conjecture until the control systems and
> structure
> can be examined.
>
> It is also possible that Concorde ran over debris on the runway, which may have
> damaged the tyre. This has implications for the operations procedures for
> the airport itself. Again, all conjecture, but may have contributed to the incident.
>
> It takes a long time to properly inspect and sweep a runway, and day-time
> operations mean that it cannot be performed until the evening, or even at night
> when the airport is quiet. Things can be missed, especially when you're more
> concerned with checking a runway when the debris might be on a taxiway or
> the terminal apron. Aircraft safety is down to everybody involved, not
> just the designers, builders and operators!
>
> It could even be something as simple as a flat-spot on a tyre caused by
> accidental heavy braking, in which case the *actual* cause of the accident may
> never be known. The fact that it is possible to check almost every other
> cause is testament to how thorough the AIB's job has to be.
>
> Aircraft designers, manufacturers and operators do not fear the results
> of an AIB. While we hope that they are never needed, when they are their
> findings contribute to the ever-expanding sphere of knowledge as to how
> all machines (not just aircraft) function in adverse conditions. Hazard
> evaluation is part of the safety analysis that is performed as part of the
> design of a new product. We need to find the actual causes of these
> incidents so we can protect against them happening again. We need
> to find the real causes so we don't mislead ourselves into thinking that
> we've fixed the problem when we might have made it worse.
>
> Oops. Sorry. It's turned into a bit of a thesis. Hope this helps, illuminates
> or whatever.
>
> Many thanks,
>
> Robin Hill, STEAMY BESS, Brough, East Yorkshire.
--
Terry W. Colvin, Sierra Vista, Arizona (USA) < fortean1@frontiernet.net >
Alternate: < terry_colvin@hotmail.com >
Home Page: < http://www.geocities.com/Area51/Stargate/8958/index.html >
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