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Blackbirds Myth & Fact

SR-71

So how fast does the SR-71 really go.......?

The fastest published speed of the SR is Mach 3.5. There are several factors thatlimit the speed of the SR, one is the shock waves generated by various parts ofthe plane, at around Mach 3.6- 3.8 the shock wave off the nose of the aircraftnarrows enough to go into the engine, while there is the inlet spike (which slowsthe air to subsonic before it enters the engine), the shock wave bypasses thespike and causes the engine to unstart.

Second is the heat generated by the plane moving through the atmosphere, eventitanium has it's limits, and the heat generated by the SR brings the fuselage tothe brink. Just recently I found out that during a Lockheed Skunk Works studyto see how much money and development it would take to get the SR to gofaster than it's designed top speed 3.2- 3.5, the designers discovered (amongother things) that the metal divider between the windshield was heating up somuch above mach 3.5 that it was affecting the integrity of the windshield, and atthat point they had stretched the glass technology to the max! So Mach 3.2 to amax of 3.5.

Now according to Richard Graham: "The design Mach number of the SR-71 is3.2 Mach. When authorized by the Commander, speeds up to Mach 3.3 may beflown if the CIT limit of 427 degrees C. is not exceeded. I have heard of crewsreaching 3.5 Mach inadvertently, but that is the absolute maximum I am awareof."

How high does the SR really fly, and do the Pilot and RSO get astronaut

wings after flying the SR?

The SR doesn't fly quite that high, the highest altitude I've heard attributed to theSR was 100,00 ft (18.93 miles), all the Air Force and Lockheed admit to is

above 80,000 ft. To get astronaut wings you have to fly at least 264,000 ft (50miles). Which the SR (even though it's a fantastic aircraft) doesn't get close tothat altitude!

Richard Graham contributes: The SR-71s engines require a sufficient quantity ofair in order to operate. The maximum altitude limit is 85,000 feet unless a higheraltitude is specifically authorized. Again, I have heard of crews inadvertentlyreaching 87,000 feet, but no higher.

So what does it cost to fly the SR-71?

There are lots of numbers floating around about how much it costs to fly the SR,I've heard figures over $100,000 an hour to fly the SR-71, and a $1,000,000 a

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picture. The figures are all over the place, it's especially hard, because you canfigure it so many different ways....do you include Tanker support, flight

proficiency ops (SR "B" model and T-38), and numerous other expenses. I liketo figure it as what it actually costs to fly the airplane itself, no training, tankersupport, etc. So with that said.....The numbers that I've been told by people that

know is $38,000 per flying hour. The costs can be lower to a rock bottom priceof $27,000 per hour if the annual flying time gets above 300 hours total. So theactual cost is probably somewhere in between 38 and 27 thousand an hour.

Well after the latest Wings episode "Spyplanes" on recently, some interesting errors!Well here goes....

"The SR takes off with almost dry tanks"

Well not exactly empty, the SRs tanks hold 80,000 lbs. of fuel, the SR-71usually takes off with 45,000 lbs. of fuel on board. Not what I call almost dry!

The SR takes off with either 45,000 lbs., 55,000 lbs., or 65,000 lbs. of fuel.Almost all flights are refueled by KC-135Q's (now "T"), there are a fewexceptions though... one was called the "Rocket Ride", which were flown fromKadena AB, Okinawa and then on to Northern Korea, on 65,000 lbs of fuel. Theonly SRs that launched with a full fuel load were the test flights from Palmdale,CA.