Forum: Technology

What is impressive is the fact the Concorde could supercruise for 2 hours or so at MACH 2... :shock:

TEG

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That_Engine_Guy wrote:

What is impressive is the fact the Concorde could supercruise for 2 hours or so at MACH 2... Shocked

TEG

Let's not forget the SR-71Blackbird! Twisted Evil

Well the Blackbirds weren't 'supercruising' at MACH 3+ like the Concorde did at MACH 2.

The Blackbirds used a HUGE fuel capacity in conjunction with extremely high altitudes that kept the fuel-burn low even in afterburner.

TEG

Concorde had turboJETS. That also factors into it.

Pratt&Whitney J58 was a ramjet so there is a slight difference to RR Olympus which was a turbojet
I once read a comment from an aeronautical engineer cant remember when but he said something like this;
If you install 4 J58's into a Concorde and apply full power for M 2,2 at 60.000 feet ,Concord would come down to earth as molten metal ..exaggerated ? I dont know but Concord fuselage would simply not stand the temperatures generated by J58's

Elite 1K Joined: May 26, 2005 - 08:39 PM Posts: 1496

We've had this discussion on this site before, the J58 isn't a ramjet. It's a "bleed bypass turbojet", the SR-71 nacelles combined with the J58 bleed bypass ducts effectively form a pseudo-ramjet at high Mach.

supercruise means NOT using AB... The fist aircraft to do it was the F-104... The concord and the SR-71 do NOT have Supercruse capability..

I beg to differ; from MACH 3+ by Peter W Merlin.

Quote:

In fact, we had a remarkable flight once when we had a very cold day at altitude. Bill Campbell was able to fly at Mach 3 without afterburner. that was a remarkable accomplishment in my book, but it was strictly a function of temperature at altitude.

While that was not typical, this does indicate the Blackbird was most likely well equipped to fly at MACH 1.5 or 2 without afterburner on a regular basis.

As far as the Concorde goes; watch this video:

http://www.iviewtube.com/v/7764/concord ... om-cockpit

Go to 6:20 on the video; as the pilot explains shutting off the afterburners.

Clearly the afterburners are switched OFF at MACH 1.7 / 42K+ feet and stay off for the rest of the flight. (at 8:15 on the video)

But as the pilot states, they 'are still accelerating' at a lower rate.

The Concorde could NEVER cross the Atlantic on AB.

So I would say to you Kamov, the Concorde and SR-71 COULD supercruise with their turbojet engines; given the proper altitude/atmospheric conditions.

Keep 'em flyin' Thumb

TEG

yeah but SR-71 needed 4-5 air refueling in typical mission.

And Concord was a big commercial fail. After 70's oil shock it was pretty much over. Few nickles gas price change/gal means the ticket price changes by a thousand bucks. (ticket price in 2000 was $8000) At current gas price, it would be probably around $12K one way. It wouldn't make it economically no matter how marvelous that plane was. It needed to be 3-4 times more fuel efficient. Even today it's still nearly impossible to do. The shape of the wing is just not efficient for taking off. Think mig-21 or Mirage made out of lead. A supersonic that size probably would be a modified B-1B, with variable geometry wing to increase fuel efficiency during slow speed.

But I think overall supersonic passenger plane is extremely cool. I wish they complete that sukhoi-gulfstream project. It's about time we try fly passenger that fast again.

I remember reading that Concorde was a commercial failure from the aircraft manufacturer point of view, since only 14 production airframes were built, but it was a success for the two airlines operating them. And remember, the Concorde program led to a lot of infrastructure being built at Filton and Toulouse, which could later be used by Airbus.

Anyway, TEG and anyone else interested in Concorde, I suggest reading through this thread here: http://www.pprune.org/tech-log/423988-concorde-question-42.html
At points it does get technical, but that is the most interesting part! Beware, it's a long read, but intriguing...

EDIT:
Here the first page of the thread:
http://www.pprune.org/tech-log/423988-concorde-question.html

bigbird2 wrote:

yeah but SR-71 needed 4-5 air refueling in typical mission., and Concord was a big commercial fail.

Mute point; both could super-cruise as defined today; greater than MACH 1.5 without afterburning.

TEG

Could today's engine technology have brought down operating costs to make it competitive again?

madrat wrote:

Could today's engine technology have brought down operating costs to make it competitive again?

Who knows? Shrug

Advanced aerodynamics (very low drag) helps with this as well, I'd say it's a 50% split between propulsion and drag.

'Super-cruise' engines need a high velocity exhaust without an afterburner to help. The big thing is this, an engine that is efficient at MACH 2.2/45K feet is not exactly quiet or fuel efficient at most other flight conditions. This is why most jet powered aircraft today use turbofans which are more efficient at their cruise speeds. The closer the engine's exhaust velocity matches the cruise profile of the aircraft it is in, the more efficient the propulsion becomes.

There are NO commercial turbojet/turbofans in production that would push a commercial size transport aircraft available. Engines like the YJ93/GE4, J58, JTF17A-21L, or the Olympus 593 aren't developed anymore; there simply isn't a need. Who's going to spend billions of $$ on an engine that 'might' make the Concorde (or another SST) more efficient. Who's going to risk that amount of capitol?

Today it's all about efficiency; getting the highest amount of passengers, the furtherest distance, with the minimum amount of fuel burned and the least amount of $20M+/each engines. F119 style engines may be able to do this, (like the B-1R proposal) or perhaps even F100-PW-229s and their low BPR and high specific thrust. But even then it would be far more expensive (per passenger mile) than a conventional MACH .85 cruise.

Speed is expensive! No two ways about it. The amount of fuel required to go MACH 1.5, versus .85 is something the public at large isn't going to pay for. This is why Concorde served a niche market to those who could afford to pay for the convenience, not for the masses of tourists who 'just want to get there.'

Super-cruise for the foreseeable future will be reserved for high $$ military programs, or space launch programs. (see also Google for SCRAM Jet engine or PDE/Pulse Detonation Engine)

My Two Cents

Keep 'em flyin' Thumb

TEG

Last edited by bigbird2 on Feb 06, 2011 - 07:06 AM; edited 4 times in total

madrat wrote:

Could today's engine technology have brought down operating costs to make it competitive again?

competitive against what? There is no other supersonic passenger plane. So it's all a question of economics. How many people wants to pay for how much per ticket. BA and Air France claim they made profit on the route. But that's after writing down developmental cost and no more money to upgrade Concorde. Hardly a successful business plan.

Could a Concorde ver. 2.0 be made more efficient? Sure, suppose one put all composite oval fuselage, modern avionic, no drooping nose, reduce flight & cabin crew from 9 to 5, Use F-135 class turbojet that does not need afterburner for nearly all flight need, add more aggressive vortex lift generation wing/reduce wing size, replace heavy and complicated hydrolics with electric actuators, better landing gear, etc.etc... reduce weight, use modern material/manufacturing technique aggressively, new electronics, reduce manpower need, new interior arrangement, fly smarter, better engine, etc.

probably the plane could cut ticket price by half. But that's still a $6000 ticket one way. And you have to sell few hundred of these planes to break even.

Maybe if it can reach cross pacific or fly to latin america from asia the market will be larger.

But definitely government backed/long term business plan situation. 10-20 years type of deal.

Interesting to note, Concorde supposedly only cost $20m/plane to buy. I guess that's not including development cost.

It'll probably look similar to B-1B/Tu-160, if not Concorde.

That_Engine_Guy wrote:

'Super-cruise' engines need a high velocity exhaust without an afterburner to help. The big thing is this, an engine that is efficient at MACH 2.2/45K feet is not exactly quiet or fuel efficient at most other flight conditions. This is why most jet powered aircraft today use turbofans which are more efficient at their cruise speeds. The closer the engine's exhaust velocity matches the cruise profile of the aircraft it is in, the more efficient the propulsion becomes.

The consortium did propose second engine for concorde that can fly without afterburner. Rejected. too expensive. But the technology already exist back then. Concorde engine requirement is at current high end fighter jet.

I think a 10-12 passenger jet powered by two F-414 flying at mach 1.8 is possible. Not sure it meets commercial flying load. The proposed Aerion uses smaller thrust engine. (2× Pratt & Whitney JT8D-219 turbofans, 19,600 lbf (87.19 kN) each)

http://en.wikipedia.org/wiki/Aerion_SBJ

Forum: Technology

Concorde and Supercruise