WESTERN737800
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Question For SR-71 Pilots

Sun May 24, 2009 12:33 am

Hey gang I was wondering what are the takeoff and landing speeds for the SR-71 Blackbird? I did some research, couldn't find anything. Thanks in advance.
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474218
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RE: Question For SR-71 Pilots

Sun May 24, 2009 1:15 am

You can find the information at:

http://www.sr-71.org/blackbird/manual
 
HaveBlue
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RE: Question For SR-71 Pilots

Sun May 24, 2009 6:55 pm

Around 200 knot take off speed, around 155 to 165 knot landing speed.
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SEPilot
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RE: Question For SR-71 Pilots

Tue May 26, 2009 10:19 pm



Quoting 474218 (Reply 1):
You can find the information at:

http://www.sr-71.org/blackbird/manual

Thanks for posting this; it is fascinating (the SR-71 is just about my all-time favorite aircraft.) I was interested to read that the maximum altitude is 80,000 ft "unless otherwise authorized". I had a friend who had worked on the DEW line in Alaska as a radar operator; they normally would get notice to turn off their radars at certain times but not why. One day my friend was on duty and observed an inbound aircraft well above the height limit of his radar (which was about 120,000 ft), and just about the same time he got a blistering call from a general somewhere telling him to "get your *%&$# radar off my bird." He had not received notice to turn off the radar, and was never told what the "bird" was, but at the altitude and speed it was going it could only have been an SR-71. The point is that he could read altitude up to 120,000 ft, and this bird was well above that.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
474218
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RE: Question For SR-71 Pilots

Tue May 26, 2009 10:27 pm



Quoting SEPilot (Reply 3):
Thanks for posting this; it is fascinating (the SR-71 is just about my all-time favorite aircraft.)

Mine too, the SR-71 was the first aircraft I ever worked on, right out of tech school, in April 1966.
 
Flighty
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RE: Question For SR-71 Pilots

Wed May 27, 2009 6:50 am



Quoting SEPilot (Reply 3):
The point is that he could read altitude up to 120,000 ft, and this bird was well above that.

Interesting story. I have never ever heard anything like that. I wonder if anybody cracked Mach 4 in the SR-71. Something I read online suggested that with modern materials on the engine inlet, the aircraft could today hit Mach 5 or 6 with few or no additional changes. We have much better materials now.
 
connies4ever
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RE: Question For SR-71 Pilots

Wed May 27, 2009 8:59 am



Quoting Flighty (Reply 5):
Interesting story. I have never ever heard anything like that. I wonder if anybody cracked Mach 4 in the SR-71. Something I read online suggested that with modern materials on the engine inlet, the aircraft could today hit Mach 5 or 6 with few or no additional changes. We have much better materials now.

Doubtful. Yes, we have better materials now in terms of heat resistance and so forth. But at M=5 or 6 I'd bet the combustion process in the engines would quench as the JP-7 fuel just can't burn fast enough to maintain a flame front. You'd need something more like methane or LH2 -- much bulkier which would require more volume for a given range -> ergo, new design.

Absent that, the design as it existed was optimised for the regime in which it was intended to operate, i.e., M=3.2-3.5. Going much beyond that would I think introduce elasticity issues in the wings. Hypersonic vehicles IIRC tend to favour short straight thin wing sections (see X-15).

That said, a remarkable achievement for its' time, and a very snaky looking beast.
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SEPilot
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RE: Question For SR-71 Pilots

Wed May 27, 2009 12:29 pm



Quoting Flighty (Reply 5):
Interesting story. I have never ever heard anything like that.

I cannot vouch for its authenticity; my knowledge of the event is strictly limited to my friend's account, and I did not know him well enough to be totally sure that it was accurate. But I have long believed that the SR-71 flew a lot higher than anybody who knew acknowledged; the only figure publicly revealed has been 80,000 feet, which the U-2 could also achieve. I have always believed that the SR-71 could fly a lot higher than the U-2. By the way, the public statements are that the SR-71 never actually flew over the Soviet Union; I do not believe that either.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
HaveBlue
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RE: Question For SR-71 Pilots

Wed May 27, 2009 1:39 pm



Quoting SEPilot (Reply 7):
the only figure publicly revealed has been 80,000 feet,

I have seen 100,000' in print a lot. Operationally it may have been used to 80-85,000' and that may have been optimal for the cameras or until fuel burned off, but its ceiling was certainly higher. Just as the F-15 probably doesn't often cruise at 50,000'... but it can.

Also one of my favorite quotes in regards to the speed of the Blackbird was made by one of its pilots. Asked what we do if the Soviets broke the SR-71's speed record his reply was "we'd just go up and press a little harder on the gas pedal" or something very close to that effect.

From everything I read its not the materials or fuel that limited the true top speed of the Sled, but rather the shockwave. Much over 3.2/3.5 and... from what I've read... the shockwave wouldn't be positioned right and the engine would flame out. But I'm a romantic and I much prefer to believe it could indeed go faster.  Wink

And the Blackbirds (SR-71, A-12, YF-12) are in my top 3 of airplanes too... them and the XB-70 and the F-14. And I've been lucky enough to see all 3 variants at one place or another.

A-12 at the USS Alabama musuem in Mobile, AL
YF-12 at the USAF Museum in Dayton, OH
SR-71 at Eglin AFB, Warner Robins GA, Smithsonian in DC and USAF Museum in Dayton, OH
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SEPilot
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RE: Question For SR-71 Pilots

Wed May 27, 2009 4:04 pm



Quoting HaveBlue (Reply 8):
I have seen 100,000' in print a lot.

I believe I have seen it in unofficial sources, but to the best of my recollection I have never seen any official figure higher than 80,000 ft; it's always been "classified." I find it amusing that the manual just states that anything over 80,000 ft "must be authorized"; I found nothing stating what the actual limitation of the plane was.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
connies4ever
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RE: Question For SR-71 Pilots

Wed May 27, 2009 9:53 pm



Quoting HaveBlue (Reply 8):
From everything I read its not the materials or fuel that limited the true top speed of the Sled, but rather the shockwave. Much over 3.2/3.5 and... from what I've read... the shockwave wouldn't be positioned right and the engine would flame out. But I'm a romantic and I much prefer to believe it could indeed go faster. Wink

I should have remembered the shockwave. It's location relative to the spike is crucial. At speeds approaching hypersonic, would be difficult to position correctly, and could the spike mechanism (jackscrew) respond sufficiently quickly with changing conditions ?

But the fuel would be an issue...
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michlis
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RE: Question For SR-71 Pilots

Thu May 28, 2009 11:02 am



Quoting SEPilot (Reply 9):
I believe I have seen it in unofficial sources, but to the best of my recollection I have never seen any official figure higher than 80,000 ft; it's always been "classified." I find it amusing that the manual just states that anything over 80,000 ft "must be authorized"; I found nothing stating what the actual limitation of the plane was.

And the fact that it is classified (and probably will remain so) will probably keep former pilots from ever speaking about the full capabilities of the aircraft or some of the exotic places that its visited. People who have a tendency to be gabby usually are not afforded the opportunity to fly one of the most awesome aircraft ever built. As for the manuals, I'm sure they've been edited to cull out the sensitive attributes of the aircraft and don't tell the full story.
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SEPilot
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RE: Question For SR-71 Pilots

Thu May 28, 2009 12:59 pm



Quoting Michlis (Reply 11):
And the fact that it is classified (and probably will remain so) will probably keep former pilots from ever speaking about the full capabilities of the aircraft or some of the exotic places that its visited. People who have a tendency to be gabby usually are not afforded the opportunity to fly one of the most awesome aircraft ever built. As for the manuals, I'm sure they've been edited to cull out the sensitive attributes of the aircraft and don't tell the full story.

I think you may be right.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
mrocktor
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RE: Question For SR-71 Pilots

Fri May 29, 2009 7:56 pm



Quoting Connies4ever (Reply 6):
But at M=5 or 6 I'd bet the combustion process in the engines would quench as the JP-7 fuel just can't burn fast enough to maintain a flame front.

Airflow in the engine combustor is subsonic, even for a plane flying at M3. Or M5 for that matter. The variable geometry inlet has the purpose of keeping airflow in the engine controlled throughout the wide range of aircraft speeds.

An engine with a supersonic combusor (i.e. scramjet) is a whole different breed of cat.
 
MrChips
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RE: Question For SR-71 Pilots

Fri May 29, 2009 9:00 pm



Quoting Michlis (Reply 11):
As for the manuals, I'm sure they've been edited to cull out the sensitive attributes of the aircraft and don't tell the full story.

As far as I know, the only thing redacted in that online manual is the section on the ASARS radar; everything else has been declassified. There are a couple of missing pages, but they don't seem to pertain to aircraft performance.

Quoting SEPilot (Reply 3):
Thanks for posting this; it is fascinating (the SR-71 is just about my all-time favorite aircraft.) I was interested to read that the maximum altitude is 80,000 ft "unless otherwise authorized". I had a friend who had worked on the DEW line in Alaska as a radar operator; they normally would get notice to turn off their radars at certain times but not why. One day my friend was on duty and observed an inbound aircraft well above the height limit of his radar (which was about 120,000 ft), and just about the same time he got a blistering call from a general somewhere telling him to "get your *%&$# radar off my bird." He had not received notice to turn off the radar, and was never told what the "bird" was, but at the altitude and speed it was going it could only have been an SR-71. The point is that he could read altitude up to 120,000 ft, and this bird was well above that.

It might very well be true, but I doubt it would be an SR-71. If you look at Figure 5-3 (Limit Speed And Altitude Envelope), by extrapolating the limit lines out to M3.3 (the design limit speed), the very highest they could fly would be about FL870. On a wildly non-standard day, that might translate into a true altitude of 88,000 feet at the most.
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