Supercruise & Engines
7pap...@spcvxb.spc.edu
Supercruise????
A few weeks back, the DISCOVERY channel on WINGS focussed on the
Russion SST. They mentioned that the fuel economy was terrible
because to sustain supersonic speeds the afterburners needed to
be always on.
A POSTer then mentioned, a few weeks back, that the Concorde's
Olympus (sp?) engines have supercruise and need no afterburner
for supersonic cruise so fuel economy is far better than the Russian
SST.
Is this a situation of the Olympus Engines producing more thrust
without afterburner -or- is Supercruise something different?
I noticed an article in Aviation Week that said the F-22 can
supercruise. This also due to greater thrust overall?
thankyou, edward
Simon Lam
: Russion SST. They mentioned that the fuel economy was terrible
: because to sustain supersonic speeds the afterburners needed to
: be always on.
True, the Russian SST did keep the AB on during cruise.
: A POSTer then mentioned, a few weeks back, that the Concorde's
: Olympus (sp?) engines have supercruise and need no afterburner
: for supersonic cruise so fuel economy is far better than the Russian
: SST.
You shouldn't say the ENGINE has supercruise. You should say the aircraft
is capable of supercruise. The entire aircraft contributes to
supercruise. In case you don't know, supercruise is the capbabiltiy of an
aircraft to maintain Mach 1 using only dry thrust.
Remember, the Concorde still requires burners to pass Mach.
Does anybody know if there is another civilian aircraft with
afterburners? Does the BD-10 have burners?
Simon Lam
It's the man, not the machine.
(But it often helps)
Jacob M McGuire
Engines by Lee Green MD MPH@umich.e
> Supercruise isn't something an engine "has", but just the ability to fly
> supersonically without afterburner. The difference between the Tu-144's
> engines and the RR Olympus is simply that the Olys produce more dry
> (without afterburner) thrust. Both are relatively fuel-inefficient
> turbojets. The Concorde cruises without reheat, but must use burner to
> get past the Mach.
I thought that the Tu-144 had turbofans, hence the need to fly around
in afterburne all the time. I also thought that turbojets were more
effecient at high speed than turbofans, but am still not quite sure why.
Are both of these things correct, or not?
+------------------------------------+------------------+
| Small towns in western Germany are | Jake McGuire |
| usually about ten kilotons apart | mcgu...@cmu.edu |
+------------------------------------+------------------+
Matt
I have a very basic understanding of the jet engine, and have a
good background in basic physics. I want to know the differences
between turbofans, turbojet, ramjet, scramjet, and any other jet
types out there. Does anyone know of a good book that is a
beginner's guide to jet engines? If anyone wants to share their
knowledge, that would be great too.
Thanks
Matt
David Siebert
>
>Excerpts from netnews.rec.aviation.military: 16-Nov-95 Re: Supercruise &
>Engines by Lee Green MD MPH@umich.e
>> Supercruise isn't something an engine "has", but just the ability to fly
>> supersonically without afterburner. The difference between the Tu-144's
>> engines and the RR Olympus is simply that the Olys produce more dry
>> (without afterburner) thrust. Both are relatively fuel-inefficient
>> turbojets. The Concorde cruises without reheat, but must use burner to
>> get past the Mach.
>
> I thought that the Tu-144 had turbofans, hence the need to fly around
>in afterburne all the time. I also thought that turbojets were more
>effecient at high speed than turbofans, but am still not quite sure why.
>
> Are both of these things correct, or not?
>
>
>+------------------------------------+------------------+
>| Small towns in western Germany are | Jake McGuire |
>| usually about ten kilotons apart | mcgu...@cmu.edu |
>+------------------------------------+------------------+
in gear ratio's in a car. Jet engins work by moving air. A turbofan moves a lot
of air realitivly slowly while a turbojet moves a less of air quickly. A
turbojet is most effecet at high speeds A turbo-fan at lower speeds and the
higher the bypass ratio the higher the effency but the lower the speed. that is
why Turbo props are good at low speed.Take a look at three air craft there
engine selections.
Lockheed Orion 300kts Turboprop
Boeing 757 500kts High Bypass TurboFan
Concord Mach 1+ Turbojet
There are several fighters that use low bypass turbofans it is a comparomise so
that the are more efficent at sub sonic speeds where they spend most of the
time but can still go fast when needed. Plus a figher with a high bypass engine
would looks silly
Bill Huber
>Well, in a nutshell- yes. The _how_ of the F-119 engine being able to put
>out as much in "dry" military power as the F100-PW-220 does in _full
>afterburner_ is pretty amazing. And doing so with the fixed geometry
>inlets, and curved ducts, on the F-22 to boot. Impressive.
>Mark
What is the thrust of the F-119? Both mil and full AB. Or is that
classified?
Bill Huber
Paul F Austin
>From: gre...@umich.edu (Lee Green MD MPH)
>Subject: Re: Supercruise & Engines
>Date: Thu, 16 Nov 1995 22:21:54 -0500
>> Is this a situation of the Olympus Engines producing more thrust
>> without afterburner -or- is Supercruise something different?
>> I noticed an article in Aviation Week that said the F-22 can
>> supercruise. This also due to greater thrust overall?
>Supercruise isn't something an engine "has", but just the ability to fly
>supersonically without afterburner. The difference between the Tu-144's
>engines and the RR Olympus is simply that the Olys produce more dry
>(without afterburner) thrust. Both are relatively fuel-inefficient
>turbojets. The Concorde cruises without reheat, but must use burner to
>get past the Mach.
<snip>
>The F-22 uses a low-bypass turbofan, optimized for supersonic flight.
>It's much more fuel-efficient than a turbojet. It also produces enough
>dry thrust to not only cruise at, but to accelerate to, supersonic speeds
>without reheat. This is "true" supercruise, one could say.
Supercruise in a fighter-size aircraft requires a combination of technologies
that come together in the F22 (and F23). Not only do the engines's dry thrust
level need to be high enough (20-25Kpounds) to drive the airframe at
supersonic speeds but the engine T/W ratio has to be high enough and airframe
structure light enough to allow enough internal fuel storage to have
meaningful range.
As an example, F22 has a _lot_ more internal fuel than an F15C as well as
having engines 40% more powerful, in the same size airframe.
Charles Holzer
as looking 'silly' at all. Go figure. Chuck-7MY
David Siebert
>
>David: The SR-71 uses two high bypass J58 engines. I never considered it
>as looking 'silly' at all. Go figure. Chuck-7MY
>
The term High Bypass is pretty vauge the 747 uses something like a 7to1 Bypass
ratio I doubt that the Bypass ration on the SR-71 is anything close to that.
Alexei Gretchikhine
> Just a quick note: Supersonic flight in dry thrust is already
> possible. The first aircraft to do it was the YF-17 in 1974. Also, the
I wonder where all Britons go:) Someone should say a word about
Lightning...
Can't do it from the top of my head, but since you mention first and YF
(not being a service a/c), there were probably some Mikoyan
experimental designs capable of supercruise as well, well before 1974.
--
Alexei Gretchikhine agr...@opie.bgsu.edu
http://ernie.bgsu.edu/~agretch/
Russian Aviation Page http://ernie.bgsu.edu/~agretch/RAP.html
--
MARK DONALDSON
> Just a quick note: Supersonic flight in dry thrust is already
>possible. The first aircraft to do it was the YF-17 in 1974. Also, the
>latest F-15's and F-16's equipped with the P&W F100-223 engines can
>achieve supersonic flight with dry thrust in certain areas of their
>flight envelope.
> I don't think a real supercruise capability (supersonic cruise) will
>be achieved until the F-22 goes into service, though.
The designation of the engine is slightly off, it's P&W F100-229. The F-15E
has supercuised before but it was likely a clean bird. The F-22 should be able
to do it in the course of a mission because there won't normally be any drag
imposing "accessories" on it (like bombs, external tanks, etc).
Corsair
__________________________________________________________
CAG of "The Jolly Rogers" Simulation Squadron
__________________________________________________________
Web CAG of The Unofficial "Jolly Rogers" Site
http://www-home.calumet.yorku.ca/mdonalds/www/home.htm
__________________________________________________________
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Mark Van Alstine
gski...@gpu4.srv.ualberta.ca (George Skinner) wrote:
>
> Just a quick note: Supersonic flight in dry thrust is already
> possible. The first aircraft to do it was the YF-17 in 1974. Also, the
> latest F-15's and F-16's equipped with the P&W F100-223 engines can
> achieve supersonic flight with dry thrust in certain areas of their
> flight envelope.
I don't believe it was in level flight, but in a dive. That limits how far
one can "supercruise" before experiancing a "ground intercept," I would
think? };->
> I don't think a real supercruise capability (supersonic cruise) will
> be achieved until the F-22 goes into service, though.
Correct. (Unless you count the YF-22 as a _different_ aircraft....) };->
Mark
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right through every human heart--and all human hearts."
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Richard Sails
Message-ID: <467204...@sails.demon.co.uk>
Date: Tuesday, Dec 05, 1995 22.09.47
Organization: None
Reply-To: ric...@sails.demon.co.uk
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X-SMTP-Posting-Host: sails.demon.co.uk [Tue, 5 Dec 95 22:39:04 GMT]
> In article <49v7su$a...@pulp.ucs.ualberta.ca> (George Skinner) writes:
>
> I don't think a real supercruise capability (supersonic cruise) will
> be achieved until the F-22 goes into service, though.
>
> The F-22 should be able to do it in the course of a mission because
> there won't normally be any drag imposing "accessories" on it
> (like bombs, external tanks, etc).
EF2000 will easily go well above supersonic without using REHEAT while
carrying four AMRAAM's and two ASRAAM's! ~~~~~~~~~~~~~~~~~~~~
I don't know if it has been released yet just how fast, so I'am not
saying.........
--------------------------------------------------------------------
Richard Sails Personal EMail: ric...@sails.demon.co.uk
~~~~~~~~~~~~~ Work EMail:Richard....@warton.bae.eurokom.ie
Telephone (Home) UK: 01772 792039
Telephone (Work) UK: 01772 852866
This golden age of communications means everyone talks at once.
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I do not speak for my employer (other people are paid much more
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MARK DONALDSON
>It has been reported that a stock MiG-21 (clean, of course) is capable of
>supercruise AFTER using a short burst of burner to get it past the sound
>barrier. At this point, the burner could be turned off and the aircraft would
>maintain supersonic flight. This isn't too much of a stretch as an unloaded
>(but pretty damn useless) 21 has an exceptional airframe.
Hey "Jolt Boy" :)
Supercruise is defined roughly as flying supersonically without afterburner
but afterburner is not needed to reach that supersonic cruise. For example,
the Concorde regularly flies supesonically, but only after using afterburners
to achieve supersonic flight. Supercruise means you can achive that cruise
without using the greedy afterburners.
Charles Greig
>> Just a quick note: Supersonic flight in dry thrust is already
>> possible. The first aircraft to do it was the YF-17 in 1974. Also, the
>
>Lightning...
>Can't do it from the top of my head, but since you mention first and YF
>(not being a service a/c), there were probably some Mikoyan
>experimental designs capable of supercruise as well, well before 1974.
It has been reported that a stock MiG-21 (clean, of course) is capable of
supercruise AFTER using a short burst of burner to get it past the sound
barrier. At this point, the burner could be turned off and the aircraft would
maintain supersonic flight. This isn't too much of a stretch as an unloaded
(but pretty damn useless) 21 has an exceptional airframe.
Life's short, so what the hell... Drink Jolt! -- Twice the karma!
``Opinions expressed are mine alone, but as soon as I figure out how
to force everyone to accept them, I will.'' - Disclaimer
cs93...@ariel.cs.yorku.ca - www.lookup.com/Homepages/61642/home.html
Richard Sails
>
>The first aircraft to do it was the YF-17 in 1974.
>
Am I wrong or did Concord do it before 1974 ?????????
Mach 2.2 with dry thrust!!!!!!!!!!!!!!!!!!!!!1
MARK DONALDSON
>Am I wrong or did Concord do it before 1974 ?????????
The Concorde uses afterburner to get over "the number" so to speak and then
cruises dry. That doesn't meet the requirements of supercruise though. The
F-22 will cruise supersonically without use of afterburners at all.
Joseph P. Hillenburg
>(doesn't neccessarily mean it didn't happen though). WAPJ claims that the
>F-15E did it with the -229s. I'm only speculating but it is my belief that
Are the -229s really that great? In Tom Clancy's book "Fighter Wing",
the F-16 pilots make a huge deal about how the -229s improved the
aircraft. Anyone have the scoop?
Can the revision of a single engine over the life of an airframe make
that much of a difference? How about F100 vs F110?
--
Joseph P. Hillenburg
Email: mailto:johi...@indiana.edu
WWW Page: http://copper.ucs.indiana.edu/~johillen/
MARK DONALDSON
>I don't believe it was in level flight, but in a dive. That limits how far
>one can "supercruise" before experiancing a "ground intercept," I would
>think? };->
I'm not sure I agree with this. Supercruise only refers to the ability to get
to supersonic cruise without afterburner. For instance, Concorde uses
afterburner for only a short time to get above "the number" and then cruises
supersonically in dry thrust. It is doing this in level flight because it
would never make the hop over "the pond" if it were constantly diving. The
Concorde doesn't supercruise though because of the limited use of the
afterburner.
A lot of aircraft have achived mach speed in a dive without AB but this has
never counted as supercruise either. It seems that the term supercruise is
very tightly defined as getting past Mach 1 without afterburner in level
flight. I can't attest to the VF-17 doing it because I never heard that
(doesn't neccessarily mean it didn't happen though). WAPJ claims that the
F-15E did it with the -229s. I'm only speculating but it is my belief that
they would mention if a dive was used rather than use the term "supercruised."
That however, is only my speculation though.
Douglas Byerly
220's. There is a similar increase in dry thrust, but I don't know the
exact numbers. Pilots love the extra thrust (of course). Both the F100-
PW-229 and the F110-GE-129 were designed to meet a 29K lb thrust
requirement, but I think the GE engines exceeded it by 1 or 2K.
I have always been told that a clean F-15 could supercruise with -220's,
and the -229's let you supercruise with some externals. However, this
was probably not without using AB first, so it may not meet the strict
definition. I am pretty sure that an F-16 cannot supercruise, regardless
of engine configuration. If this is wrong, please let me know (since I
get paid to know this sort of stuff.)
Thanks;
Doogie
F100 Engineer
Kelly AFB, TX
Simon Lam
: gski...@gpu4.srv.ualberta.ca (George Skinner) writes:
: >
: >The first aircraft to do it was the YF-17 in 1974.
: Am I wrong or did Concord do it before 1974 ?????????
: Mach 2.2 with dry thrust!!!!!!!!!!!!!!!!!!!!!1
Remember, burners are needed for the Concord to hit Mach.
Does anyone have an offical definition of "Supercruise"?
--
Donny Chan
MA>Newsgroups: rec.aviation.military
MA>Subject: Re: Supercruise & Engines
MA>Date: Wed, 6 Dec 1995 21:40:34 GMT
MA>Organization: Calumet College, York University
MA>Supercruise is defined roughly as flying supersonically without afterburner
MA>but afterburner is not needed to reach that supersonic cruise. For example,
MA>the Concorde regularly flies supesonically, but only after using afterburners
MA>to achieve supersonic flight. Supercruise means you can achive that cruise
MA>without using the greedy afterburners.
After reading the article "EF2000 - from the cockpit" in the 12/95
issue of Aerospace Magazine, I was about to ask in this newsgroup a
definition of "supercruise." I was wondering if a supercruise-able
aircraft needs or doesn't need afterburning ("reheating" to Brits) to
achieve supersonic speed before it can supercruise at supersonic
speed with military power, ie, without further afterburning.
Unlike your opinion, the author of the article, Chris Yeo (Director
of Flight Operations, BAe Military Aircraft Division) defines
"supercruise" as: "it will maintain supersonic flight in dry power
once it has accelerated in reheat with EJ2000 engines. It does not
have that performance with the RB199s currently fitted to the first
two prototypes, although I must say that the supersonic performance
is very good indeed."
Now, my question is: can a supercruise-able aircraft achieve supersonic
speed without using afterburners at all?
---
* DeLuxe2 1.21 #6922 * U of Toronto * Mechanical Engineering 9T3+1 * ERTW
Chris Douglas
>
> In <mdonalds.3...@calumet.yorku.ca> mdon...@calumet.yorku.ca (MARK DONALDSON) writes:
> >F-15E did it with the -229s. I'm only speculating but it is my belief that
>
> the F-16 pilots make a huge deal about how the -229s improved the
> aircraft. Anyone have the scoop?
>
> Can the revision of a single engine over the life of an airframe make
> that much of a difference? How about F100 vs F110?
>
Certainly it can make a big difference! Compare the TF30-engined F-14A's to the
GE F110-engined F-14B's (and D's, though the D has many other improvements).
I doubt the difference between the F110 and F100 is quite so profound, but the F110
is slightly more powerful, isn't it?
--
-----------------------------------------------------
Chris Douglas - cdou...@origin.ea.com
Production Designer/Animator - Origin Systems, Inc.
-----------------------------------------------------
The mindless corporate entity for which I work has
no opinions. Those expressed must be my own.
-----------------------------------------------------
Mark Van Alstine
mdon...@calumet.yorku.ca (MARK DONALDSON) wrote:
> In article <mvanalst-051...@lin.rbi.com> mvan...@rbi.com
(Mark Van Alstine) writes:
>
> >I don't believe it was in level flight, but in a dive. That limits how far
> >one can "supercruise" before experiancing a "ground intercept," I would
> >think? };->
>
> I'm not sure I agree with this....
It's a JOKE! (Sheesh...)
> ...Supercruise only refers to the ability to get
> to supersonic cruise without afterburner. For instance, Concorde uses
> afterburner for only a short time to get above "the number" and then cruises
> supersonically in dry thrust. It is doing this in level flight because it
> would never make the hop over "the pond" if it were constantly diving. The
> Concorde doesn't supercruise though because of the limited use of the
> afterburner.
>
Perhaps we are misunderstanding each other here? It was noted that the
F-15 supposedly achieved "dry" supercruise by exceeding Mach 1 in a
(slight?) dive. The Concorde exceeds Mach 1 by using AB. In neither case
do the they exceed Mach 1 "dry" in _level_ flight. The definition of
"supercruise," as I understand it, is the ability to exceed Mach 1 and
sustain Mach 1+ velocities in level flight _without_ using AB.
Modern combat aircraft like the F-14 and F-15 can exceed Mach 1 by using
AB. The problem is that it takes a lot of fuel to do this, thus decreasing
their combat radius significantly. (Or in the case of the COncorde it
affects it's transit radius.) The F-22 can exceed Mach 1 _without_ using
AB and thus have a larger (non-refueled) combat radius. Not having to
constantly "sip" from a tanker also allows for faster response times and
better battle management when on station.
Charlie Whitaker
mvan...@rbi.com (Mark Van Alstine) wrote:
>(slight?) dive. The Concorde exceeds Mach 1 by using AB. In neither case
>do the they exceed Mach 1 "dry" in _level_ flight. The definition of
>"supercruise," as I understand it, is the ability to exceed Mach 1 and
>sustain Mach 1+ velocities in level flight _without_ using AB.
>
>Modern combat aircraft like the F-14 and F-15 can exceed Mach 1 by using
>AB. The problem is that it takes a lot of fuel to do this, thus decreasing
>their combat radius significantly. (Or in the case of the COncorde it
>affects it's transit radius.) The F-22 can exceed Mach 1 _without_ using
Concorde uses afterburners (reheat) to pass both M1 and M2 before reaching
a dry level cruising speed of around Mach 2.2 at 50,000 ft or so.
'Supercruise' is the raison d'etre of the plane: it was designed around the
concept.
This ability, incidentally, makes Concorde the world's most efficient
passenger vehicle in terms of people x miles for fuel (energy) expended.
Unfortunately, this efficiency does not seem to be reflected in the price
of the tickets.
Charlie.
Samir Sudhir Roy
From what I have read in his group and elsewhere they seem to be as good
at performance but not as long lived as US planes .
Is it true ? or is it a reflection of the ways they service thier engines
.At least that is what I understood from a Article in this group from a
guy in Russia .
Mark Van Alstine
char...@easynet.co.uk (Charlie Whitaker) wrote:
The world's most efficient passenger vehicle? Care to explian that in more
detail? I've heard the Jumbos were more fuel/passenger efficient and the
new generation of Boeing passenger jets even more so. All the Concorde
seems to do is get you there faster using more fuel per passenger/mile.
Which, coupled with low production runs (higher aircraft/maintenance
costs?), is likely why the tickets costs what they do. If you have studies
that show otherwise I'd be interested in reading them.
Dennis Jensen
>Concorde uses afterburners (reheat) to pass both M1 and M2 before reaching
>a dry level cruising speed of around Mach 2.2 at 50,000 ft or so.
>'Supercruise' is the raison d'etre of the plane: it was designed around the
>concept.
>
>This ability, incidentally, makes Concorde the world's most efficient
>passenger vehicle in terms of people x miles for fuel (energy) expended.
>Unfortunately, this efficiency does not seem to be reflected in the price
>of the tickets.
>
>Charlie.
>
Where did you come up with this one. Do you seriously contend that the
Concorde gets better fuel mileage per passenger than the A320 say? No, I
didn't think so!
Dennis
Anders Pettersson
> In article <ACF4FF5F...@charlie1.easynet.co.uk>,
> char...@easynet.co.uk (Charlie Whitaker) wrote:
>
> > mvan...@rbi.com (Mark Van Alstine) wrote:
> >
> > >(slight?) dive. The Concorde exceeds Mach 1 by using AB. In neither case
> > >do the they exceed Mach 1 "dry" in _level_ flight. The definition of
> > >"supercruise," as I understand it, is the ability to exceed Mach 1 and
> > >sustain Mach 1+ velocities in level flight _without_ using AB.
> > >
> > >Modern combat aircraft like the F-14 and F-15 can exceed Mach 1 by using
> > >AB. The problem is that it takes a lot of fuel to do this, thus decreasing
> > >their combat radius significantly. (Or in the case of the COncorde it
> > >affects it's transit radius.) The F-22 can exceed Mach 1 _without_ using
> >
> >
> > a dry level cruising speed of around Mach 2.2 at 50,000 ft or so.
> > 'Supercruise' is the raison d'etre of the plane: it was designed around the
> > concept.
And why must it use AB to pass M2 ?? I understand M1 passage, but M2 ??
/Anders
email: Anders.P...@eua.ericsson.se
Paul Tomblin
>This ability, incidentally, makes Concorde the world's most efficient
>passenger vehicle in terms of people x miles for fuel (energy) expended.
>Unfortunately, this efficiency does not seem to be reflected in the price
>of the tickets.
I read a book about Concorde a long time ago that stated that it had the best
"passenger miles per hour per gallon", which is the stupidest spec you can
ever come up with, but which tries to hide the fact that it is a gas guzzler
of unprecedented magnitude. I believe you could carry the same load of
passengers, each one in his own Gulfstream bizjet, for less fuel per mile.
--
Paul Tomblin, Contract Programmer.
I don't speak for Kodak, they don't speak for me.
(Email that is not work related should go to: ptom...@canoe.com)
"You are in a twisty maze of Motif Widget resources, all inconsistent."
Charlie Whitaker
mvan...@rbi.com (Mark Van Alstine) wrote:
<snip>
>> Concorde uses afterburners (reheat) to pass both M1 and M2 before reaching
>> a dry level cruising speed of around Mach 2.2 at 50,000 ft or so.
>> 'Supercruise' is the raison d'etre of the plane: it was designed around the
>> concept.
>>
>> This ability, incidentally, makes Concorde the world's most efficient
>> passenger vehicle in terms of people x miles for fuel (energy) expended.
>> Unfortunately, this efficiency does not seem to be reflected in the price
>> of the tickets.
>
>The world's most efficient passenger vehicle? Care to explian that in more
>detail? I've heard the Jumbos were more fuel/passenger efficient and the
>new generation of Boeing passenger jets even more so. All the Concorde
>seems to do is get you there faster using more fuel per passenger/mile.
>Which, coupled with low production runs (higher aircraft/maintenance
>costs?), is likely why the tickets costs what they do. If you have studies
>that show otherwise I'd be interested in reading them.
Well, considering that Concorde (peace, friendship, harmony, cooperation)
was conceived, developed and executed in the spirit of international
brotherhood, it would be a shame to see this thread degenerate into a
nationalistic chest puffing-up exercise. Perhaps we shoud leave that to the
French.
While I'm pretty sure about the 'supercruise' part of my previous posting,
I admit the efficiency part was plucked from distant memory and I will go
check the facts. Nevertheless it must be remembered that, although larger
aircraft such as the 747 can carry more passengers aloft for any given kilo
of fuel, they are slower, and the more time you take in getting those
passengers to their destination, the more fuel you consume. So 'getting you
there fast' is important for efficiency (and Concorde goes from New York to
London in under 3 hours). Presumably there is an optimum point between
high-speed/fewer passengers and low-speed/more passengers. Is that point
sub-sonic or super-sonic? More fun if the latter, of course.
My comment about the price of tickets was facetious, of course, as I am
well aware that Concorde was an expensive plane to develop, and this cost
was not defrayed by a large profitable production run. Only 15 production
Concordes were ever built: the plane fell victim to politics, both national
and international. Particularly sad were the whipped-up 'Ban-the Boom'
popular demonstrations on Concorde's inaugural tour. These resulted in a
ban on transonic flights for commercial aircraft over the contiguous US,
effectively killing Concorde's market as anything other than a
transatlantic passenger jet (sonic booms only over the sea). Since the
Boeing SST didn't ever make it into service, this ban is presumably still
in effect!
I cannot comment on maintenance, as I simply don't know anything about
that. I am aware that these planes fly sufficiently few miles per year to
ensure their operation to around 2030. By then I really hope we have
passenger RLVs, otherwise we will be a truly sad species and the aliens
will have to come and nuke us.
Charlie Whitaker
In summary, Concorde has around one third the fuel efficiency of a 747-126.
Oops!
Stroud recorded the flight data for two trips made between London and
Washington DC in September 1984. The first, in a BA Concorde, took around 3
hours, carried 120 passengers and consumed about 78,000 kilos of fuel. The
second, in a BA Boeing 747-126, took around 7-8 hours, carried 350
passengers and consumed about 74,000 kilos of fuel. (All figures are
approximate.)
My thanks to Paul Tomblin for this:
> I read a book about Concorde a long time ago that stated that it had the best "passenger miles per hour per gallon", which is the stupidest spec you can ever come up with
I now no longer have to worry about the origins of my previous claim, as
this most likely covers it.
Since we are now in the business of clearing up misconceptions, here are
some amendments to my first statements about supercruise. Concorde
accelerates in a climb. It uses afterburners to pass through Mach 1 and
accelerate to around Mach 1.6. It then goes to dry thrust while continuing
to climb and accelerate to Mach 2.02 (not 2.2 as previously stated). When
Mach 2.02 is achieved, the 'plane will be at about 50,000 ft. During the
rest of its M2 cruise, it will "cruise-climb" to up to 60,000 ft. Most
airliners cruise-climb, but only Concorde is able to freely do so without
worrying about mid-air collisions.
Some misconceptions posted by others:
- Concorde has a lousy thrust/weight ratio. (This came to me by e-mail.)
- Answer: No, its thrust/weight ratio is better than that of a 747-400 by a
factor of around 1.7.
- Concorde is fuel-inefficient to the point of unprofitability.
- Answer: No, both of Concorde's airline owners make an operating profit on
the 'plane.
- Concorde did not sell because of its fuel-inefficiency.
- Answer: Perhaps, but offensive political/diplomatic actions on the part
of competing nations were also extremely damaging to sales.
Charlie.
Simon Lam
: "passenger miles per hour per gallon", which is the stupidest spec you can
: of unprecedented magnitude. I believe you could carry the same load of
: passengers, each one in his own Gulfstream bizjet, for less fuel per mile.
Yeah, Paul. But at less than half the speed. That's not to say I'm a
Gulfstream basher. I love the Gulfstream and the RR BMW engines, but the
Concord is impressive.
MARK DONALDSON
>and international. Particularly sad were the whipped-up 'Ban-the Boom'
>popular demonstrations on Concorde's inaugural tour. These resulted in a
>ban on transonic flights for commercial aircraft over the contiguous US,
>effectively killing Concorde's market as anything other than a
>transatlantic passenger jet (sonic booms only over the sea). Since the
>Boeing SST didn't ever make it into service, this ban is presumably still
>in effect!
I think the Boeing proposal didn't go anywhere mainly because of design
hassles combined with what you mentioned above. The Boeing design was to have
a swing wing. However, the mechanism was so heavy that the team told Boeing,
"you can have the swing wing, or you can carry passengers."
Mark Van Alstine
char...@easynet.co.uk (Charlie Whitaker) wrote:
> While I'm pretty sure about the 'supercruise' part of my previous posting,
> I admit the efficiency part was plucked from distant memory and I will go
> check the facts. Nevertheless it must be remembered that, although larger
> aircraft such as the 747 can carry more passengers aloft for any given kilo
> of fuel, they are slower, and the more time you take in getting those
> passengers to their destination, the more fuel you consume.
What about drag? Isn't the drag force (everything else being the same)
porportional to the _square_ of the velocity? Both parasitic and induced
drag should increase rather dramatically the higher the velocity, no? Even
if the Concorde has a low drag coefficient drag at post-Mach velocities
drag should be significant. (Anybody know just how significant as compared
subsonic airliners?) It takes thrust to overcome drag. The more drag the
more thrust needed. This should also effect fuel consumption a bit I would
imagine.
Also what about the engines? Are they a turbojet, turbofan, or a high
by-pass turbofan? Each has thrust/fuel efficiency trade-offs. I'd also be
suprised if the Concorde's engines (unless they have been retrofitted with
newer ones) are as thrust/fuel efficient as high by-pass turbofans on an
subsonic airliner like the Boeing 777. (Anybody know if this is correct?)
Basically, I've always thought the reason almost all commercial airliners
stayed subsonic was _because_ they were _more_ fuel efficient. Given the
airlines' fuel bills (and cutthroat competition) fuel efficiency is rather
important to the bottom line.
Simon Lam
om>
Distribution: world
: What about drag? Isn't the drag force (everything else being the same)
: porportional to the _square_ of the velocity? Both parasitic and induced
: drag should increase rather dramatically the higher the velocity, no? Even
: if the Concorde has a low drag coefficient drag at post-Mach velocities
: drag should be significant. (Anybody know just how significant as compared
: subsonic airliners?) It takes thrust to overcome drag. The more drag the
: more thrust needed. This should also effect fuel consumption a bit I would
: imagine.
I always thought the reason planes like the 747 can't break Mach is
because the amount of extra thrust required to over power the shock
waves. Am I correct? (That's considering they beefed up the structure a
little)
: Also what about the engines? Are they a turbojet, turbofan, or a high
: by-pass turbofan? Each has thrust/fuel efficiency trade-offs. I'd also be
: suprised if the Concorde's engines (unless they have been retrofitted with
: newer ones) are as thrust/fuel efficient as high by-pass turbofans on an
: subsonic airliner like the Boeing 777. (Anybody know if this is correct?)
I don't think there has ever been a high by-pass turbofan mounted on a
supersonic aircraft. The Concorde uses the Rolls Royce Olympus turbojet
with afterburners (reheat) I think it was derived from a 50's bomber engine.
Simon Lam
: a swing wing. However, the mechanism was so heavy that the team told Boeing,
: "you can have the swing wing, or you can carry passengers."
If the swing wings are so heavy, why did they even consider it on the
F-14 where a great payload was demanded? What would happen if we stuck a
pair of wings simular to the F-15 on the F-14?
P. Wezeman
>
> What about drag? Isn't the drag force (everything else being the same)
> porportional to the _square_ of the velocity? Both parasitic and induced
> drag should increase rather dramatically the higher the velocity, no? Even
> if the Concorde has a low drag coefficient drag at post-Mach velocities
> drag should be significant. (Anybody know just how significant as compared
> subsonic airliners?) It takes thrust to overcome drag. The more drag the
> more thrust needed. This should also effect fuel consumption a bit I would
> imagine.
>
> by-pass turbofan? Each has thrust/fuel efficiency trade-offs. I'd also be
> suprised if the Concorde's engines (unless they have been retrofitted with
> newer ones) are as thrust/fuel efficient as high by-pass turbofans on an
> subsonic airliner like the Boeing 777. (Anybody know if this is correct?)
>
> stayed subsonic was _because_ they were _more_ fuel efficient.
different kinds of efficiency are involved.
One: Aerodynamic efficiency. This is the lift-to-drag ratio of the
aircraft. In level flight the drag must be overcome by an equal amount of
thrust. Energy equals force times distance, so the amount of useful
energy required to fly an airplane a given distance equals the weight of
the aircraft divided by the lift-to-drag ratio, this quantity then
multiplied by the distance traveled. Over a longer flight the drag will
not be constant; it decreases in proportion to the weight as fuel is
burned. The lift-to-drag ratio of a modern subsonic airliner at cruise is
16/1 or 18/1 or therabouts. The L/D ratio for the Concorde is about 8/1
at its cruise speed due to parasitic and wave drag. As an aside, the
induced drag generally goes down with increased speed as the wing has
more air to work with in producing lift, although not enough to overcome
the increase in the other components of drag in this case.
Two: Thermal efficiency. This is the ratio between the mechanical energy
of the jet engine efflux (exhaust gas plus air from fan, if any) and the
chemical energy of the fuel burned. This depends on the maximum
temperature reached in the engine, the aerodynamic
efficiency of the compressor and turbine, bearing friction, etc. The
thermal efficiencies of the Concorde's engines and a modern high bypass
turbofan are roughly comparable; the turbofan has improved materials for
a higher turbine inlet temperature and more refined aerodynamic
components, but the turbojet uses the exhaust directly for thrust without
the need for the fan, the extra turbine stages that drive it, and their
associated inefficiencies.
Three: Propulsive efficiency. This is the ratio of the energy of the jet
efflux to the usefull energy delivered as thrust. An engine running on a
test stand has zero propulsive efficiency as long as the stand doesn't
move. In the wake of an aircraft in level flight the prop-wash or jet-wash
causes strong turbulence; this is energy that didn't go into usfull work.
Propulsive efficiency equals 2/(1+R), where R is the ratio of the speed
of the jet efflux (measured relative to the engine) to the forward speed
of the aircraft. Propulsive efficiency approaches 100% as R approaches 1.
The speed of the jet efflux of a high-bypass turbofan is well over 1,000
m.p.h., wheras the speed of a subsonic transport is 600 m.p.h. or less, so
propulsive efficiency is 75% or less. On the other hand, the mach 2+
cruising speed of the Concorde is only slightly lower , proportionately,
than the speed of its turbojets' exhausts, so the propulsive efficiency is
quite high. The figure I remember for the combined thermal and propulsive
efficiency of the Concorde is 40%, said at the time to be greater than
that for any other vehicle, although this may no longer be true given the
greatly improved diesel engines now used in ships. The use of
afterburners gives increased exhaust velocity for greater thrust and
reduces efficiency by increasing the value of R. Note that an
afterburning engine is not necessarily inefficient as such; the SR-71
Blackbird's afterburning turbojets give excellent efficiency at its
cruise speed of mach 3+.
The same gas turbine hot section can be used in a turbojet, a turbofan, a
turboprop, or as a turboshaft in an oil tanker and provide equal
efficiency at all these speeds if matched with the right propulsor.
So, compared to a subsonic transport, the Concorde is a less efficient
airplane powered by a more efficient propulsive system.
Peter Wezeman
Spod
: I don't think there has ever been a high by-pass turbofan mounted on a
: with afterburners (reheat) I think it was derived from a 50's bomber engine.
Correct, the engines in Concorde where (I believe) derived from those used in
the Vulcan (and possibly the other 'V' bombers, I can't remember). The same
type of engine is also used to power the Invincible class carriers.
--
This terminal is my friend - there are many others like it,
but this one is *mine*!
Brad Holt
> Some misconceptions posted by others:
>
> - Concorde has a lousy thrust/weight ratio. (This came to me by e-mail.)
> - Answer: No, its thrust/weight ratio is better than that of a 747-400 by a
> factor of around 1.7.
>
> - Concorde is fuel-inefficient to the point of unprofitability.
> - Answer: No, both of Concorde's airline owners make an operating profit on
> the 'plane.
>
Not true. Operating profits were only generated with creative accounting,
i.e., the airplane was given to the airline. Previous to that they were
subsidized.
> - Concorde did not sell because of its fuel-inefficiency.
> - Answer: Perhaps, but offensive political/diplomatic actions on the part
> of competing nations were also extremely damaging to sales.
>
It is interesting to note that neither Air France nor BA were (or are)
interested in any more Concorde's. I think that says a lot about their
economics - independent of the politics.
> Charlie.
MARK DONALDSON
>: I think the Boeing proposal didn't go anywhere mainly because of design
>: hassles combined with what you mentioned above. The Boeing design was to have
>: a swing wing. However, the mechanism was so heavy that the team told Boeing,
>: "you can have the swing wing, or you can carry passengers."
>If the swing wings are so heavy, why did they even consider it on the
>F-14 where a great payload was demanded? What would happen if we stuck a
>pair of wings simular to the F-15 on the F-14?
If I recall, the F-14 came out before the Boeing proposal. As far as weight
goes, consider you have to account for the airframe, passengers, fuel,
baggage, those damn heavy airline meals <G>. The other thing to consider is
the thrust:weight ratio in relation to both aircraft to understand how much of
a performance margin you have.