b377
Wonder how much of this was learned from the use of the 593s on the 1950s Victor bombers albeit these were not supersonic?
The Handley Page Victor Mk1 was powered by four Armstrong Siddely Saphire turbojets, and was underpowered like hell. The Mk2 was powered by four Rolls Royce Conway turbofans, was a far more capable aircraft and was the fastest of all the V Bombers.
The Avro Vulcan Mk1 was powered by four Bristol Siddely Olympus turbojets, the Mk1 by four Olypus Mk1 1 engines, rated at 11,00lb static thrust and the Mk2 by four 22,00lb thrust Olympus 301 engines. Now allthough the Olympus 593 shares the same name and twin spool turbojet layout, they were in reallity light years apart. The 593, although a development of the earlier engine became an almost total re-design, and was a direct development from the Olymus 320 engine, powering the polititian murdered but absolutely superb BAC TSR2.
Machaca
Thanks for the superb diagrams for the J58 powerplant. The SR71 (one of my top 3 ever favourite aircraft) was without doubt Kelly Johnson's finest creation, and still remains on the record books as the fastest conventional eaircraft ever built. The axisymmetric intake is in fact a potentially more efficient design than the two-dimentional intake used on Concorde, and is really essential for any Mach 3+ design. (The Mig 25 used a two dimentional intake, but was a crap design that only achieved very brief high speeds by use of brute foce and ignorance).
There are two fundimental problems with axisymetrical inlets, that of unstart and also instabily in sideslip conditions. There were many sideslip induced unstart events with the SR71, even aircraft losses occured as a result. There was a club in the SR71 community, known as the 'split helmet club'. This was where as an intake surged or unstarted, as a result of the violent yawing the crew member's bone dome would strike the side of the canopy violently and crack open. To be a member this had to have happened to you. (There were MANY members). I read an article by an SR71 test pilot saying that an unstart was 'like being in a train wreck'.
So you can see that this effect was not really desirable for a passenger aircraft carrying 100 passengers). For a note on unstart we have here another extract from the Concorde Air Intake Control System:
UNSTART
Occurs when the intake shock system is expelled from the intake resulting in almost instant engine surging due to enormous flow distortion. Merely throttling the engine will not resolve the problem, as the shock system will not re-establish itself without movement of the intake surfaces. The phenomenon has plagued almost every variable geometry intake ever flown, with the definite exception of this one.
For these reasons an axisymmetric design was ruled out for Concorde, and it was deemed that the inlet had to be both more or less immune from the effects of sideslip, as well as being a self starting design. (Originally the control laws were tweaked to compensate for side slip disturbences, but eventually an aerodynamic solution was found, and side slip signalling/compensation was relegated to blank lines of code in the system software).
But in spite of the above, I have nothing but respect and admiration for the SR71.
Dude
