Internet SR-71 Operators Manual (Declassified)

The manual is already around for quite some years, it is pretty interesting reading. Sadly, it is a bit hard making an Orbiter add-on of it, if you are not good in making complex meshes. Even the simplest indicator in a SR-71 is a piece of art sometimes.
 
RGClark said:
Thanks for that. A question about the SR-71 has been what is its real top speed. Is that mentioned?

Bob Clark
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"Real" top speed? Not that I know in the manual. What is mentioned is its recommended maximum Mach number of Mach 3.2, that you can sustain without engine damage. Mach 3.3 is permitted as long as you watch the EGT.

http://www.sr-71.org/blackbird/manual/5/5-8.php
 
The engines were the weak point of the design, oddly enough. Many Habus (in-house nickname for SR-71 crews) reported that the plane felt like it wanted to go faster, and I have no doubt that with the right powerplant, it would have been possible. Also, significantly colder temperatures at cruise altitude could boost performance. These "temp devs" could sometimes cause missions to be scrubbed because it made the Blackbird fly too fast to make the planned turns!
 
MaverickSawyer said:
The engines were the weak point of the design, oddly enough. Many Habus (in-house nickname for SR-71 crews) reported that the plane felt like it wanted to go faster, and I have no doubt that with the right powerplant, it would have been possible. Also, significantly colder temperatures at cruise altitude could boost performance. These "temp devs" could sometimes cause missions to be scrubbed because it made the Blackbird fly too fast to make the planned turns!
Click to expand...

Yeah, the engines had been pretty special, since they operated pretty much as Ramjet (the jet engine part only had been needed for preventing inlet stall from Mach 2.3 one). It had also been the only jet engine designed for running on afterburner power most of the time. Thus the tendency of the engine to accelerate even at already pretty high speeds, it simply had no mechanic limits there anymore, since no moving parts had been involved for producing thrust. It would simply keep on accelerating if not throttled down until something melts.
 
The J-58 was a masterpiece of powerplant design, even for today. I wonder how much better we could do now with ceramics and new high-temp alloys? I feel we MIGHT get another .2 Mach out of the Blackbird, but that's just me.
 
MaverickSawyer said:
The J-58 was a masterpiece of powerplant design, even for today. I wonder how much better we could do now with ceramics and new high-temp alloys? I feel we MIGHT get another .2 Mach out of the Blackbird, but that's just me.
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I think it could go to Mach 5 if you use kerosene fuel, with modern materials. The main problem would be slowing the air down for subsonic combustion.
 
Ah, but the kerosene would boil in the fuel tanks. They used JP-7 for a very specific reason: the additives in JP-7 dramatically raised the boiling and flash points of the fuel. There are stories of a bucket of JP-7 having a lit cigarette dropped in it, and the cigarette going out!
The fuel was used as a heat sink, as well as a coolant and hydraulic fluid in the engine. Fuel temperatures routinely exceeded 350*F during cruise. Kerosene just won't cut it: If JP-7 was not avialable after an unscheduled landing, and JP-4/JP-8 was all that was avialable, max speed was something like Mach 1.8 or 2.
 
MaverickSawyer said:
Ah, but the kerosene would boil in the fuel tanks. They used JP-7 for a very specific reason: the additives in JP-7 dramatically raised the boiling and flash points of the fuel. There are stories of a bucket of JP-7 having a lit cigarette dropped in it, and the cigarette going out!
The fuel was used as a heat sink, as well as a coolant and hydraulic fluid in the engine. Fuel temperatures routinely exceeded 350*F during cruise. Kerosene just won't cut it: If JP-7 was not avialable after an unscheduled landing, and JP-4/JP-8 was all that was avialable, max speed was something like Mach 1.8 or 2.
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JP-7 is still only slightly better than kerosene in these aspects. Kerosene itself is pretty close to the stuff they burn in ships, because it is a waste product of the gasoline production. :lol: The same lit cigarette story also applies to Diesel (or even RP-1), and I think gasoline would also not ignite that easy, you need some vapors above the surface, or the cigarette would simply drop too fast into the bucket.

The problem would be, that you would need to insulate the fuel better from the hot parts of the aircraft. The JP-7 was also used as hydraulic fluid and cooling fluid, that would need to change for higher speeds. For the SR-71 that kind of hydraulic design made sense because it was best practice for aircraft design.
 
OK, further discussion of improvements can be held here. Please limit further discussion to the DASH-1 ONLY!
 
Since it pretty much gives me no rest today... does somebody know how a map projector operates? Especially, how does it behave, if you would leave the prepared map strip? And could it resume on the map strip?

I know it uses some meters of 35 mm film for storing the map data, and that the strip map was 150 NM wide for the RSO screen (bigger for the pilot, but the pilot had no data film to select). I have seen some drawings of a projected map display, but they make no real sense to me currently.

When looking at the previous mechanism, the paper strip map, it would just keep on moving until the operator stops it or slews it to the correct position. But that looks a bit strange to me.
 
I believe it was tied into the navigation system. However, if you were off the path so bad you strayed off the map (which covered a 250 nautical mile swath), you were either in an emergency or were going to be canned once you landed.
 
MaverickSawyer said:
I believe it was tied into the navigation system. However, if you were off the path so bad you strayed off the map (which covered a 250 nautical mile swath), you were either in an emergency or were going to be canned once you landed.
Click to expand...

Well, you are permitted to add new waypoints and divert from your route, if this is required.

The map projector only received TAS from the navigation system, not the exact position. The pilot MP even used Mach number as reference for in-flight calibration, while operating with TAS data internally.
 
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