Posted on 03/07/2008 4:27:01 AM PST by MNJohnnie
Some of us in the 456th AEMS were asked for TDY to the 9th SRW to work on the SR-71. OH Hell yes I said to the shop chief. My "work" consisted of doing a R&R of my black box while having several rifles pointed at me. Great fun.
I love the Blackbird.
In other words, the engines had three settings; acceleration, idle, and off. The engines will keep accelerating until they fail (explode) so no one really knows what the top speed is.
How cool is that. Man I love American ingenuity.
I guess that explains his rather cryptic reference to 'surpassing their previous MACH numbers and showing "scary" MACH numbers'.
He was already talking about M3.5; Wonder where, in his experience, "scary" came into play?
Man, I would love to have the re-release limited edition with his RSO's book "Untouchables", but dang, I can't afford the $500+ bills for it.
later
Like the author, I too graduated in 1966, from Oroville High School ( a small town roughly 25 miles north of Marysville/Beale AFB). I worked at a local supermarket bagging groceries and would often get home late, heat something up and watch a little TV at my parents home high on a hill with a pair of huge vista windows facing south. One evening just before I sat down I noticed a bright light in the sky out the window and for a year or so though I’d seen a UFO that lit up the sky and climbed so rapidly I thought surely we didn’t have aircraft that could do that. A year or so later as I sheepishly recounted my experience to a guy I met at Yuba College (just down the road from Beale) who was an Air Force brat with a father in the Air Force at Beale, he proceeded to tell me that I undoubtedly had seen the new SR-71 Blackbird. So once more I considered myself completely sain again. In the months that followed we frequently saw the Blackbird flying around the area and after JC at Yuba I decided that the Air Force was for me in 1968. And even in an era of anti-military, spit on baby killers I was, and still am proud to have served. Next to fathering and raising three fine children I consider my Air Force service the finest thing I ever did. I’ve often thought, in the last seven years, what I pity I’m too old to be of much use but I still feel I could help in some way if there was but a plan for guys like me. Oh well, I ‘m off on a tangent again. God Bless pilots like this, Kelly Johnson and the Skunk Works!
WOW!!!
Wish I could tell you all something about how much trouble we had at reading out and exploiting the vast (understatement) amount of imagery (photos for you non-intel types) from the SR-71. But if I tried, I might get arrested. I don’t know if some of those cameras and sensors are still being used. Likely they have all gone digital and realtime. Those were the days to get rich by owning Kodak stock.
She was/is one sexy beast!!
They went to the end of the runway, got airborne, stood on their tails and went straight up disappearing in a minute. When they came in they made a seemingly slow silent circle around the base and landed without much sound until they were on the ground.These things were the stuff of SciFI big-time.
We called them all Habus. 6990 SS Kadena 1970.
I thought just the ones on Kadena were called Habus. But I’ve been mistaken before. My husband was 6927 SS at Onna Point and then 6990 SS at Torrii Station. We had a great tour over there.
I have no idea if it's true, but I've read a similar story where the pilots are are asking Air Traffic Control for ever higher altitudes until an SR-71 sled driver calls in asking for Flight Level 60.
ATF responds that he can have it if he really thinks he can get to that high altitude. Of course the sled driver calmly responds that they'll be *descending* to Flight Level 60.
The major, and really only, effect is temperature. But temperature varies with altitude. (Aircraft and engine performance depends on pressure as well, but we are just talking the velocity corresponding to Mach 1 at a particular altitude/temperature).
On a standard day (59 degrees Fahrenheit (15 degrees Celsius at sea level, the speed of sound is 1116 fps or 761 mph. Using a "standard atmosphere" temperature profile. The following gives the ratio of the speed of sound at altitude to that at sea level.
Altitude in feet Speed of Sound ratio
Sea Level 1.00
5,000 ft 0.9827
10,000 ft 0.9650
15,000 ft 0.9470
20,000 ft 0.9287
25,000 ft 0.9100
30,000 ft 0.8909
35,000 ft 0.8714
40,000 ft 0.8671
50,000 ft 0.8671
60,000 ft 0.8671
(temperature is constant above 37,000 feet (-69.7 deg F, -56.4 deg C). The speed of sound is proportional to the square root of the absolute temperate (that add 460 deg to the F or 272 to the C temperate to get the value above absolute zero)
As you can see the speed of sound actually drops with altitude, so a particular Mach number represents a slower speed.
Thus the Mach 3.5 at 80,000 feet (bet they were really higher. :) ) would be 761 mph * 0.8671 or about 660 mph, or 3387 feet per second.
Consider the the muzzle of velocity of the standard M-16 cartridge (M855) is only 3,100 fps, there were really humming along. Considering also that at 300 meters that's down to 2,115 fps, and they were really really humming along.
At 80,000 feet, or any altitude above 37,000 feet, 2250 mph is Mach 3.4. As the story says, well above Mach 3.2.
I did not know that mach varied with altitude. Nice impromptu lesson there. Thanks.
de Nada.
However Google is my friend. I knew it dropped with altitude, but I thought it both a temperature and pressure effect.
It's probably not true that temperature is constant about 37,000 feet, even in the standard atmosphere. But I suspect it's constant up to any altitude an air breathing engine would function at. After all, it has to drop to effectively zero at some point, since sound does not propagate in the vacuum of space.
bump
You got that right.
Gato - Thanks for the lesson! I knew someone would come along with the science to prove this out.
El Gato es muy inteligente
Gato - Thanks for the lesson! I knew someone would come along with the science to prove this out.
El Gato es muy inteligente
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