SR-71 Speed
 

Brian Shul has a great story about requesting GS from ATC in his Sled Driver book. Basically, there's a strong tail wind and requests for GS start from a Cessna, one-upmanship begins with a corporate, then a military fighter, then finally Shul's backseater requests GS for "Aspen 20". Long pause from the controller, uuuuum Aspen 20, I show 1700 knots GS. There were no other GS requests that day.

Hmmmm....... ATC wasn't allowed to do that. No Cessna would even hear an SR71 on UHF. The SR-71 did not use VHF. Even its UHF was a discrete frequency for the SR. The transmit button for ATC wasn't armed unless they were actually talking to an SR. The altitudes were coded, and changed regularly. Oh, and what tailwind is at 80,000 feet? They didn't spend a lot of time below 60,000.

I call BS on that one (whether its in the book, or not).

Definitely in the book, but your points are obviously valid. Pilots wouldn't embellish a story would they?:)

10% rule applies

Interesting. Didn't know that about the Blackbird.

But Tony, you're a total buzzkill on this one.:p

Tony are you speaking from first hand knowledge? Very few military a/c are limited to only UHF.

RB-57F had VHF, UHF and HF. Some had an additional UHF radio.

Who talked to ATC ? We filed radar vectors to VFR on top above 60,000 ft, went about our business, and contacted ATC when it was time to come down.

We did monitor Guard Freq.

Yes, from the ATC side of the mike. We certainly dealt with more than one type that only had UHF (or UHF/HF) back "in the day".

Never talked to an SR71 on anything but the discreet UHF frequency assigned to each ATC center specifically for this use.

Of course, Guard is monitored. In UHF, VHF, or both.

I thought it was rule of three's ;)

At the risk of Lawyers.............
 

Here's the text from the book verbatim. Thanks Major Shul for signing both "Sled Driver" (9-Jun-92) and the "Untouchables" for me. They are wonderful books. (6-9-92??? crud, I'm old, but at least I remember the important stuff)

"We were monitoring various radio transmissions from other aircraft as we entered LA Center's airspace. Though they didn't control us, they did monitor our movement across their scope. I heard a Cessna ask for a readout of it's ground speed. 90 knots, Center replied. Moments later a twin beech required the same. 120 Knots, center answered. We weren't the only one proud of our speed that day as almost instantly an F-18 smugly transmitted. Ah, Center Dusty 52 requests groundspeed readout.. There was a slight pause, 525 knots on the ground, Dusty. Another slight pause. As I was thinking to myself how ripe a situation this was I heard the familiar click of a radio transmission coming from my back seater. It was at that moment I realized Walt and I had become a real crew, for we were both thinking in unison. "Center, Aspen 20, you got a ground speed read out for us? There was a longer than normal pause...... Aspen, I show one thousand seven hundred forty two knots. No further inquiries were heard on that freq." :)

Well, the speed is about right. Call sign Aspen or Pinion is right, also. NASA flew those birds for a while after the Air Force, and I don't recall what freqs were used then. It didn't last long.

It's the same time frame that I was working the center (Oakland instead of LA). I really can't believe that a controller actually broadcast that info, but hey, stuff happens. Whether the SR actually had been equipped with VHF then, all I can say is that I never once communicated with them on VHF.

Just to give you an idea of the sensitivity in those days, we had a controller ask an SR to verify some info. Keep in mind, even the flight plan filed airspeed was "secret", and showed that way in the FAA computer. The pilot declined to broadcast the info (which makes it even stranger that these alleged shenanigans were going on) and the controller, "Skip", persisted; even going as far as to come off all the other VHF and UHF freqs, except the discreet SR freq, and then informing the pilot that he was off all the other freqs, would he please provide the info?

The facility got a visit from the U.S. Air Force. The pilot did not talk.

Skip was not the same guy who asked a F-117 to squawk standby (to see if the primary radar would pick it up). This was when the flight plans on these were shown as A7 aircraft, and they only flew very late at night.

Yes, ATC didn't normally assign the altitude above FL600, UNLESS there were more than one up there. The clearance was simply, "climb and maintain at or above flight level six zero zero".

We still had to have 10 miles, and 5000 feet separation, however, about 600. VFR-on-top was not valid separation (according to an operational error at Oakland Center, but that's another story).

So the drill for ATC was to call ahead to any adjacent sector/facility and "APREQ" (Approval Request) the SR before attempting a handoff via automation. The reason was simply that the planes were moving so fast that any turn radius was measured in percentages of the size of a typical U.S. state, and getting the altitude reports and assignments took time.

So, if you were the controller who had an SR in the sector, and the next guy called and said he APREQ'ing another SR, you had to get your SR's coded altitude from him, and get the coded altitude from the other SR, relayed through the controller at the other facility. These guys are talking on crappy UHF radios in space suits, too.

The coding for this day might be that 60,000 feet is Alpha, 70,000 ft is Bravo, etc. Your SR might report "Alpha plus 5" and the other guy might be Alpha plus 8 (or Bravo minus 2). Now, you had to either find out if the other guy could climb up 2 thousand feet, or you guy had to come down two thousand.

Very cumbersome.

Once all that was figured out, then you had to assign the altitudes to each, to ensure 10mile/5000ft separation.

The most I ever saw was two SR's and one U2 in one sector above FL600. That U2 was like a stationary target for the other guys to run into !!

thanks Tony
 

Thanks for the info from the other side of the mike.

Aspen was the sled call sign and Pinon (as in pinon pine tree) is for the U-2.

Good stuff...I was fly into LAX about a year ago and Pinon 72 was on Freq (we could only here ATC's side). They got descent clearance from FL600 - FL420. Sounded like ATC was trying to get them into an airport like Edwards...but not sure. The PNF asked ATC who they were and we were immediately give a frequency change ;)

Since this thread mentions Shul, here's another interesting story copy-pasted from elsewhere as it pertains to the SR-71 speed. A tad more interesting I think. Apologies if it's already been posted;

"What was the slowest you ever flew the Blackbird?"
Brian Shul, Retired SR-71 Pilot, via Plane and Pilot Magazine

As a former SR-71 pilot, and a professional keynote speaker, the
question I'm most often asked is "How fast would that SR-71 fly?" I can
be assured of hearing that question several times at any event I attend.
It's an interesting question, given the aircraft's proclivity for speed,
but there really isn't one number to give, as the jet would always give
you a little more speed if you wanted it to. It was common to see 35
miles a minute. Because we flew a programmed Mach number on most
missions, and never wanted to harm the plane in any way, we never let it
run out to any limits of temperature or speed. Thus, each SR-71 pilot
had his own individual high speed that he saw at some point on some
mission. I saw mine over Libya when Khadafy fired two missiles my way,
and max power was in order. Let's just say that the plane truly loved
speed, and effortlessly took us to Mach numbers we hadn't previously
seen.

So it was with great surprise, when, at the end of one of my
presentations, someone asked: What was the slowest you ever flew the
Blackbird? This was a first. After giving it some thought, I was
reminded of a story I had never shared before, and relayed the
following:

I was flying the SR-71 out of RAF Mildenhall, England, with my
back-seater, Walt Watson; we were returning from a mission over Europe
and the Iron Curtain, when we received a radio transmission from home
base. As we scooted across Denmark in three minutes, we learned that a
small RAF base in the English countryside had requested an SR-71
fly-past. The air cadet commander there was a former Blackbird pilot,
and thought it would be a motivating moment for the young lads to see
the mighty SR-71 perform a low approach. No problem; we were happy to do
it. After a quick aerial refueling over the North Sea, we proceeded to
find the small airfield.

Walter had a myriad of sophisticated navigation equipment in the back
seat, and began to vector me toward the field. Descending to subsonic
speeds, we found ourselves over a densely wooded area in a slight haze.
Like most former WWII British airfields, the one we were looking for had
a small tower and little surrounding infrastructure. Walter told me we
were close, and that I should be able to see the field, but I saw
nothing. Nothing but trees as far as I could see in the haze. We got a
little lower, and I pulled the throttles back from the 325 knots we were at.
With the gear up, anything under 275 was just uncomfortable. Walt said
we were practically over the field, yet there was nothing in my
windscreen. I banked the jet and started a gentle circling maneuver in
hopes of picking up anything that looked like a field. Meanwhile,
below, the cadet commander had taken the cadets up on the catwalk of the
tower, in order to get a prime view of the fly-past. It was a quiet,
still day, with no wind and partial gray overcast. Walter continued to
give me indications that the field should be below us, but, in the
overcast and haze, I couldn't see it. The longer we continued to peer
out the window and circle, the slower we got. With our power back, the
awaiting cadets heard nothing. I must have had good instructors in my
flying career, as something told me I better cross-check the gauges. As
I noticed the airspeed indicator slide below 160 knots, my heart
stopped, and my adrenalin-filled left hand pushed two throttles full
forward. At this point, we weren't really flying, but were falling in a
slight bank. Just at the moment, both afterburners lit with a
thunderous roar of flame (and what a joyous feeling that was), and the
aircraft fell into full view of the shocked observers on the tower.
Shattering the still quiet of that morning, they now had 107 feet of
fire-breathing titanium in their face, as the plane leveled and
accelerated, in full burner, on the tower side of the infield, closer
than expected, maintaining what could only be described as some sort of
ultimate knife-edge pass.

Quickly reaching the field boundary, we proceeded back to Mildenhall
without incident. We didn't say a word for those next 14 minutes.
After landing, our commander greeted us, and we were both certain he was
reaching for our wings. Instead, he heartily shook our hands and said
the commander had told him it was the greatest SR-71 fly-past he had
ever seen, especially how we had surprised them with such a precise
maneuver that could only be described as breathtaking. He said that
some of the cadets' hats were blown off, and the sight of the plan form
of the plane in full afterburner, dropping right in front of them, was
unbelievable. Walt and I both understood the concept of breathtaking
very well, that morning, and sheepishly replied that they were just
excited to see our low approach.

As we retired to the equipment room to change from space suits to flight
suits, we just sat there: We hadn't spoken a word since the pass.
Finally, Walter looked at me and said, "One hundred fifty-six knots.
What did you see?" Trying to find my voice, I stammered, "One hundred
fifty-two." We sat in silence for a moment. Then Walt said, "Don't
ever do that to me again!" And I never did.

A year later, Walter and I were having lunch in the Mildenhall Officers'
club, and overheard an officer talking to some cadets about an SR-71
fly-past that he had seen, one day. Of course, by now the story
included kids falling off the tower, and screaming as the heat of the jet
singed their eyebrows. Noticing our Habu patches, as we stood there with
lunch trays in our hands, he asked us to verify to the cadets that such
a thing had occurred. Walt just shook his head and said, "It was
probably just a routine low approach; they're pretty impressive in that
plane". Impressive indeed.

Little did I realize, after relaying this experience to my audience that
day, that it would become one of the most popular and most requested
stories. It's ironic that people are interested in how slow the world's
fastest jet can fly. Regardless of your speed, however, it's always a
good idea to keep that cross-check up -- and keep your Mach up, too.

Funny how the best stories are as just as often about about our screw ups as they are our awe inspiring feats of greatness.

Grumble, my guess is you're a T-45 to F/A-18 guy. Back in the day few tailhook jets had VHF. The Hornet is the first and only one I flew that did.

The F-15A-D were UHF only until the early 2000's...well sometimes HF too...but no VHF for the vast majority of their history.

Don't know about the mudhen's though...

Tony, once you get above 60,000 feet the winds are generally pretty light averaging about 10 to 20 knots as you are above the level of the jet stream.

Ya, that's right. I can't remember the call signs that NASA used on the TR-1 / U2, and their brief stint flying the SR-71.

My point exactly. Same thing at the equator.

RB-57F was "Snipe."

I generally saw winds around 5-10 knots max above 60K

Currently, that would be "NASA 806" & "NASA 809".
And they are ER-2's, not U-2's/TR-1's.
For the record, the TR-1 designation went away in Oct 1992.

Time flies by.............

My father was working for NASA as the director of the High Altitude Test Research at Moffett field. They were phasing out the U-2 c models and was having a hard time getting NASA to fund a new jet. He had talked to Lockheed and they came up with the ER-2 designation, ( Earth Resources -2) and had a production slot but NASA was dragging their feet. He finally got ****ed and thru his Visa card down saying " G-dmit just charge the thing on this". Two weeks later he got the funding and ended up with 2 ER-2's.

As a tanker clown, for those who got to see the SR-71 air refueling charts / turn radii ... it is really freaking cool how far the turns are started in order to marry everyone up.