Meet the SR-72 !!

X-43 & x-51 related?

 

Definitely related.

 

That's quite a challenge...

As I understand it, you cannot get the thing going fast enough with an "off the shelf turbine" to even light the scramjet... all tests so far have used rockets to get it to speed.

Maybe a ramjet/scramjet hybrid after the turbine gets it to M 3 or so?

 

I had a feeling. Skunkworks went back to a design that works, and that is a dual chamber engine system. Only this time, the SR-72 has a door blades that close off one from the other during operation. The mid-point of the door where both engines are taking in atmosphere is where the ramjet must be able to be started. How else could they do it? The old tested and true design off the SR-71, that's how.
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I don't see a cockpit. Without a pilot it's not a real plane.

 

Well...
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That's a ramjet, though. Not a scramjet. Not the same thing.

Can't get the Mach numbers they're talking about with just a ramjet.

 

Scramjets (supersonic combustion ramjets) need a different intake system than ramjets, which must have subsonic flow, like a turbine engine. Combining these cycles is difficult, but theoretically possible. If there is something like that flying, the X-51 has been a pretty good smoke-screen. On the X-43 and X-51, max velocity has pretty much been determined by how quickly the rocket booster is traveling at release. The X-51 did accelerate from about mach 4.8 to mach 5.1, the first time we have seen that in a scramjet test. On X-43, everybody was pretty happy with 12 seconds of engine burn at around mach 10.

Stranger things have happened than an SR-72. The SR-71 predecessors first flew over 50 years ago, so we may have learned a few things since then.

Incidentally, we would probably not name it the SR-72. The SR-71 was named that because a B-71 bomber version of the A-12 was envisioned and the name stuck for the SR.

 

SR stood for Strategic Reconaissance?
Now, SR would stand for what? Scramjet Ramjet?

 

Fantastic! Would love to see new technologic achievements that advance our capabilities. So much trickles down, too.

Still awaiting a return of Mach 1+ commercial passenger AC.

CW

 

It was originally supposed to be RS-71. They re-designated it SR after Lyndon Johnson messed up the name in a public announcement.

 

Gulfstream made a statement last week that until regulations are changed to allow supersonic flight over land it wasn't going to happen.

 

I wouldn't expect the FAA (or any other regulatory body elsewhere) to relax that anytime soon, but I'd think that some of the TransAtlantic and TransPacific/Polar routes might be able to sustain the ticket prices to justify such a service.

I wouldn't expect carriers to operate them at a loss, as they did the SSTs/Concordes, but if there's a way to make the service economically viable, I'd love to see it again.

CW

 

Brilliant political ploy to reveal the drone/airplane. The U.S. enemies will now escalate work on methods to counter the intelligence gathering platform. bravo.

 

Supersonic makes sense on long overwater flights and NASA has been looking at technologies for sonic boom attenuation. The Concorde was too small to be economically viable, even at very high ticket prices. Boeing's and other SSTs carried 2-3 times the number of passengers to break even. Unfortunately, all other factors being roughly equal, sonic boom loudness is proportional to vehicle mass, so land overflight supersonic will not work too well with current technology.

Concorde was also operating in an area of aerodynamic inefficiency, like most supersonic aircraft with aluminum construction. Much more efficient would be around mach 3 in the same flight envelope as the SR-71.

 

I remember when I was working on the Boeing SST project someone asked the British why they were building their SST out of aluminum and the reply was, " Well, we know how to use aluminum." Anything in the higher Mach range would melt it so it was designed to fly under it...at an unprofitable speed and with not enough pax.

 

Bob- Affirmative, the design had built in unprofitability. Much over mach 2.0 for any length of time and you can melt the airframe without titanium leading edges or ceramic thermal protection systems. Or do like the Russians did on the Mig-25, use steel leading edges and build more powerful engines.

 

I remember when a USSR pilot defected in a MiG-25 many years ago... there was apparently surprise to see rust on the wings, according to an article that I read.

 

Concorde was profitable in the hands of British airways once they took over the program from the UK government in the 80s. In fact, on some flights it generated more revenue that the wide-bodies.

There was nothing wrong with using aluminium in Concorde - the fact that it was built and flew safely for 30+ years is a testament to that (can't say the same for the Boeing, Convair or Lochkeed designs) - there was a plan for a follow up which would have seen increased capacity and switch to turbofan engines, but that deal fell thru once the supersonic flight overland was banned.

about the MiG-25

MiG-25 was built mainly out of stainless steel. It also used titanium and aluminium in some areas. They chose steel because it was easier to work with than titanium(later used on Sukhoi T-4 which never entered service but it did flew a couple of times).

 

I didn't know that Concorde cruise speed was inefficient. That's interesting.
On the point of profitability, BA (and AF) may have made money on some of the years they operated the planes. But my understanding is that they didn't pay a true price on the plane (they may even have leased it). When you compare the cost of development with what was charged to the two airlines, it's pretty clear Aerospatiale & BAe had to swallow losses (probably indemnified a way or another by their respective governments).

Still amazing plane, feat of engineering given the time it was designed and impressive operational lifespan (although the crash at the end was horrible). Same can't be said of any of the competing planes.

 

No, the development costs were likely too big for such a small fleet to repay. One must remember than they had more than 100 orders before the overflight ban was enforced and the oil crisis of the early 70s.

I was only pointing out that there was nothing inherently unprofitable about Concorde... it made money for BA once operated properly, sometimes even more than subsonics.

But, then there's also somethin else to keep in mind - the Concorde program paved the way for the formation of Airbus, made many new jobs and helped to keep Europe relevant in the industry. In that regard, the Concorde was a huge success.

 

Concorde was inherently unprofitable by any means of calculating costs and profit. BA essentially received the Concordes for nothing and then only had to pay for operating costs, not amortization of airframe acquisition costs used for any other commercial airline and aircraft. They stopped flying them when operating costs far outstripped any reasonable expectation of profit and the aircraft became unsupportable. So saying they were profitable is really untrue compared to how commercial aircraft are used and costed.

This is not unusual. USAF stops flying aircraft when the cost per flying hour reaches a certain threshold because of difficulty in obtaining spare parts and general wear of systems. Aircraft that bit the bullet for this reason include the B-58, the SR-71, F-117, and the F-111. Some aircraft are replaced because their performance is superceded by newer designs, those listed were not.

 

Program-wise, yes. A fleet of a less than 2 dozen would never repay the development cost. But that wasn't becuse Concorde wasn't profitabe to operate, it was mainly because it was killed by overflight ban, oil crisis and somewhat even by jealousy from across the Pond


On the subject of the SR-72, I fail to see the point. There are already systems that could shoot down Mach 6 high-flying airplanes. Seems like a receipe for another Lockheed-Martin budget overrun.

 

Argosy- No jealousy across the pond and that is a very silly statement. We try to stay above such petty comments here. We all knew Concorde was a non-starter before it was built for all the reasons pointed out above.

If you took pride in it, good for you, but everybody in the US industry knew it was a dead-end as a commercial enterprise. Stage III did not help it, either.