SR-71 top speed...

I did a google search tonight to see if the government have finally declassified this information and I came across this forum. I also see that they have not declassified the SR-71's top speed. Since I happen to know aproxemately what it is, I thought maybe you all would like to know as well.

I have two sources for this information, and both sources are independent of each other. They were both stationed at Edwards Air Force Base but at different times.

One source was a mechanic on the F-111's at Edwards in the late 60's or early 70's and he told me that in addition to the regular JP-5 jet fuel, he would regulary see SK-4 rocket fuel being pumped into the SR-71's on base. This led him to belive that in excess of mach 5 was possible.

The second source I met while at a New Years party with my dad. He was an Air Force Captain, who also worked at Edwards. This was in the mid-80's. He was an assosiate of my father's who at the time had dealings with both the C.I.A., and MI-6. I don't know why the Air Force officer told me this, maybe he thought I was just a harmless kid, but he told me that the SR-71 could go well in excess of Mach 5.

Now I don't know if these were special variations of the SR-71, or if they could all do it, but considering that not one SR-71 was ever shot down, I would tend to belive that Max speed is in excess of Mach 5.

I haven't done any research on it, but if one were to look up the top speeds of all the Soviet SAM's up until the retirement of the SR-71, you'd at least be able to rule out any speed less than that.

On a side note:

NASA used the SR-71 to measure the effects of time travel and relativity. At speeds aproaching the speed of light, time slows down. Using highly accurate atomic clocks, one onboard the aircraft and one on the ground, NASA was able to measure the different times on the clocks when the aircraft landed - proving that time does indeed slow down at extremely high speeds. Those pilots, in effect, aged a fraction of a second less than the rest of us on earth. I don't know why they did this with the SR-71 instead of a rocket, but whatever...

Mahalo,
-Roach-

Originally posted by Roach131313
NASA used the SR-71 to measure the effects of time travel and relativity. At speeds aproaching the speed of light, time slows down

Roach, I doubt that the SR-71 can approach the speed of light needed to test Einstein's thory. Listed speed for the A-12 was about Mach 3.35 according to most sources avalible in literature. Figure a bit faster than that but not much. The heat generated would far exceed the ability of the fuel on board to cool the airframe.

Originally posted by FredT

Roach, I doubt that the SR-71 can approach the speed of light needed to test Einstein's thory. Listed speed for the A-12 was about Mach 3.35 according to most sources avalible in literature. Figure a bit faster than that but not much. The heat generated would far exceed the ability of the fuel on board to cool the airframe.

He said 'approaches' which doesnt actually mean 'gets anywhere close to'

The experiments include adding an payload to the SR-71 which includes an atomic clock (clock A) that has been synced to a second atomic clock which remains on the ground (clock B) and a third atomic clock that acts as the control (clock C) - all of these clocks are 100% in sync and telling the same time.

Clock A is then accellerated to whatever speed, but the higher the better. Einsteins theory about relativity doesnt have a line which says 'cross here and effects start happening', they happen at any speed. Yes, when you get into a car and accelerate to 100mph on the freeway/motorway you will experience time slowing down - but you wont notice it because the effect is so small on you.

When they bring clock A back down to earth, its lagging both clock B and C in telling the time, because its experience time dialation. The pilots wouldnt have noticed anything because the difference is in 1000ths of a second. This experiement has also been tested in the Shuttle and Mir, both of which travel at speeds MUCH faster than the SR-71 can ever reach, and results have been consistent in that the difference in time settings between clocks were more pronounced.

At higher speeds, the effect is more 'noticable' with the correct instruments but you dont have to be going at anything like a percentage of the speed of light to notice the effects (with the right instruments of course .

Richard do you a link for these experiments? Its the first I have heard of them and i have spent alot of time researching and reading about the A-12/SR-71's???

FredT, unfortunately I do not have any credible web links at the moment for you, but the experiments were conducted in the early 1980s with support from NASA. The experiment was a repeat of one done in 1971 with cesium clocks and commercial jet airliners.

Four cesium beam clocks flown around the world on commercial jet
flights during October 1971, once eastward and once westward,
recorded directionally dependent time differences which are in good
agreement with predictions of conventional relativity th eory.
Relative to the atomic time scale of the U.S. Naval Observatory,
the flying clocks lost 59+-10 nanoseconds during the eatward trip
and gained 273+-7 nanoseconds during the westward trip, where the
errors are the corresponding standard deviations. These results
provide an unambiguous emperical resolution of the famous clock
"paradox" with macroscopic clocks.

Source and confirmed here

In the interests of your research, I have put the question to Google Answers for a small sum of money, and if any weblinks can be found, they will find it I shall post the answers here if and wehn someone comes up with any.

This is one of those times where stuff happened before the web came along and noones really seen fit to post the information on a relaible website (i can find a lot of uncredible sites ( crackpots mostly) and forum boards, but I *know* the experiment took place, Im just not willing to quote these type of sites)

Richard, thanks for verifing what I posted about the NASA experiments. Honestly I don't remember where I heard about them, but knowing me it was probably on the Discovery Channel or PBS or something like that. Maybe a Discovery Wings episode.

I wonder if you could also verify the SK-4 being used as a fuel source? My source swears it was used, but a second opinion would make it better.

-Roach-

Originally posted by Roach131313
I.

One source was a mechanic on the F-111's at Edwards in the late 60's or early 70's and he told me that in addition to the regular JP-5 jet fuel, he would regulary see SK-4 rocket fuel being pumped into the SR-71's on base. This led him to belive that in excess of mach 5 was possible.

The second source I met while at a New Years party with my dad. He was an Air Force Captain, who also worked at Edwards. This was in the mid-80's. He was an assosiate of my father's who at the time had dealings with both the C.I.A., and MI-6. I don't know why the Air Force officer told me this, maybe he thought I was just a harmless kid, but he told me that the SR-71 could go well in excess of Mach 5.

Now I don't know if these were special variations of the SR-71, or if they could all do it, but considering that not one SR-71 was ever shot down, I would tend to belive that Max speed is in excess of Mach 5.

Mahalo,
-Roach-

So, I'm not the only one who has heard from an Airforce officer that the Blackbird could do Mach 5! The Blackbird has many more secrets then we thought.

Tim
ATS Director of Counter-Ignorance

[edit on 10-2-2005 by ghost]

Wasn't the clock experiment done with the Apollo missions to the moon?

As for a mach 5 SR71?
Well as said I think the issue of 'heat soaking' due to the enormous kenetic heating (even at the altitudes it flew) is the limitation no matter how hard a rocket might have (briefly) hurled the plane through the sky.

Anyone got a heat/strength spec for the titanium used in construction and the heat transfer capabilities of the fuel pumping system?
That would settle this once and for all.

Frankly I doubt it, this strikes me as 'boys own' guessing and myth making (people in every airforce do this as so few are really connected to such cutting edge projects.
Go to an RAF association and see the number old silly old sods who have now convinced themselves over the years that they flew Spitfires in the war and see what I mean. ).

I saw a program on the Military Channel yesterday. They were talking about the Soviet T-4 and the comparison to the XB-70. They were talking about the limit for Titanium being around 3.5M where Titanium simply cannot withstand the heat and the sound barrier at the same time anymore. It is probable that the SR-71 use more exotic alloys than pure Titanium.
Also, in the same program I heard about how the air had to be slowed down to sub-sonic speeds in the engine for it to be effective.

Someone I knew once asked Bob Gililand this question, and his response was, "Well, it's still classified, but I can tell you this much: The aircraft will continue to produce power until it disintegrates."

You know, what I have to say clarifies nothing, but an observation I have made:

They openly admit that the aircraft at top speed endures amazing changes in temperature and needed the most exotic paints and materials to handle the changes. Well, if a Foxbat officially has exceeded mach 3 with plain old aluminum skin, I can only imagine that the SR71 traveled much faster to require such an exotic construction.

I would speculate that it easily hit mach 4

I once asked my father (works for Lockheed, on the Raptor) how fast the Blackbird could go... I said Mach 4? He said, "higher", I said Mach 5? he said nothing but gave me the cat that ate the canary look....

I saw in a Discovery special years ago that the oil its used was more expesnive per quart than Dom perignon!! They said thats one of the reason they used the aircraft so sparingly. A flight could easily cost a few hundred thousand dollars.

Not to mention the repairs needed to maintain stealth after each flight....$$$

Originally posted by cljohnston108
Someone I knew once asked Bob Gililand this question, and his response was, "Well, it's still classified, but I can tell you this much: The aircraft will continue to produce power until it disintegrates."

That doesnt say a lot tho, theres quite a few aircraft that have engines that can outperform the airframe (the Canberra for one - it can only go to 75% on the throttles because any higher takes the wings off).

And I seriously doubt it can go much beyond what has officially been released (M3.5 or so), certainly not M5.

Maybe a good thing to look at would be the conditions and reasons behind going for the world speed record? and how much of a buffer they could afford to disclose.

The disign of the engine and the "cones" limit the amount of air coming it. i think there would be a point where they would have to be removed or break off. Therefore there hasto be an upper limi to the egines, and thus the 2nd limiter would be the airframe

Above 4.2 the thermal loading is too great. I believe the number was 4.23 exactly, but it's been forever. For *extremely* short periods of time you can go over this speed.. but EXTREMELY short..

Osiris

I think the clock experiment was done with a 747 that flew around for hours. When it landed the clock on board was a small fraction of a second off from the earth clock. It might not have been a 747 but it was some passengers plane

''In 1975, Professor Carrol Alley tested Einstein's theory by using two synchronized atomic clocks--one on an airplane and the other on the ground. At the end of the flight, the one on the plane was behind the one on the ground. Time had slowed for the clock on the plane--it had traveled forward in time.''

"Princeton professor J. Richard Gott notes in his book Time Travel in Einstein's Universe that the world's most accomplished time traveler is the cosmonaut Sergie Avdeyev, who was on board the MIR space station for 748 days. Gott calculated that Avdeyev, traveling at 17,000 miles per hour for more than two years, traveled into the future by about 1/50th of a second."

www.walterzeichner.com...

hey Roach i do belive i have a begining to the aswer of what type of fule the SR-71 uses this link has a picture and spec. of the Pratt and Whitney J58 Turbojet Engine that was used in the blackbird i am still searching for the fuel type but i have sent some emails and hopeing to get some answers soon www.wpafb.af.mil... note this engin was used in the earlyest of the SR-71's i am sure that the engine was improved over the years

the YF12Aused JP-7 fuel if that is any help i have found this in many web sites but i only have the link to one www.wvi.com...