SR-71

[Wing Nut]

Hey, is it true that the Blackbird uses so much fuel on takeoff, she has to refuel once airborne?

[Mynameisnemo]

Hey, is it true that the Blackbird uses so much fuel on takeoff, she has to refuel once airborne?

just found this for you from http://www.sr-71.org/blackbird/sr-71/

After the SR-71 takes off, it has a rendezvous with a KC-135Q tanker seven minutes later. The SR-71 takes off with a very light fuel load and after this refueling, the plane can fly up to 2,500 miles without refueling. The aircraft then accelerates to speed and altitude which is about Mach 3.2 at 85,000 feet

Is that the info that you require?

[Craig.]

Its not just that it uses alot of fuel. It actually leaks from the skin of the plane i believe.

[Mynameisnemo]

Its not just that it uses alot of fuel. It actually leaks from the skin of the plane i believe.

You are correct in the fuel leaking out

In order for the SR-71 to fly the worldwide missions, it has a special fleet of modified KC-135Q tankers for refueling. SR-71s run on JP-7 fuel, that fills the six large tanks in the fuselage. The component parts of the Blackbird fit very loosely together to allow for expansion at high temperatures. At rest on the ground, fuel leaks out constantly, since the tanks in the fuselage and wings only seal at operating temperatures. There is little danger of fire since the JP-7 fuel is very stable with an extremely high flash point.

[Wing Nut]

Works for me...  ;D

[krigl]

Just passing through....  in the documentation for Richard Barker's Blackbird it has some interesting stuff about the plane... including that the temperature of the windshield grew so hot during flight that the pilots cooked their lunch on it. I read that 52s also do the same thing with refueling shortly after takeoff, simply because with a full fuel load they are too heavy to get airborne...  :)

[Mr. Bones]

Ok, about the fuel stuff. (out of the head after reading several books of former SR pilots) The Blackbird never took off with full tanks because of the weight of the plane. I say never but that isn't really correct. The NASA guys often did it, but normally a Blackbird never takes off with a full load. Shortly after take off, it would refuel to a full load of 80 000pounds. I think they used to take off with 65 000 pounds. It was possible, but not worth the risk in case of an aborted take off.

It's true the fuel tanks leaked while on the ground. The reason is that it was impossible to overcome this because of the many cooling wires that went in and out of the tanks.

About cooking the lunch on the winshield...don't really believe that. The pilots were strapped in in a pressure suit with their helmets closed. They had a bag of water on the inside but as far as I know, they never opened their helmet to eat. They only opened it when they were about to land. I recall reading a text about a pilot who was talking about his longest mission, 11 hours. For that time, he was breathing pure oxygen inside his suit, his eyes became very dry. On final, his lost his vision. Don't really know how to say this, but he managed to press a tear out of his eyes to make them humid again. After that, he vision returned so he could make an uneventfull landing.

Another fact about the Blackbird is that because of the extreme heating, the airframe became stronger after each flight.

Another one: during cruise, a Blackbird never flew level. When it burned fuel, it became lighter so the optimal cruise altitude always had to be a little bit higher. Therefore, the jet always cruised at a rate of climb of 100ft/minute.

You want more facts about this amazing jet? When some pop up in my head, I'll post them here.  ;)

[ozzy72]

http://www.sr-71.org/blackbird/manual/index.htm some light reading for you Kevin

[Craig.]

and here i was expecting it to open with.
Welcome to your brand new SR71.

[ozzy72]

And today in our used plane lot we have.....

[Gary R.]

Just caught this old thread.  Very interesting.  Some of the facts I already knew.  I know the 71's records will probably not be exceeded for years to come yet.  I also suspect that the plane was never flown at it's absolute limits when setting these records due to the fact that the U.S. government wanted to keep the published limits in line with the preformance.  No doubt, the plane could easily best it's own records.  I say this because in Xplane 7 the blackbird there does perform better than the real world published capabilities including altitude.  I've had it over fl 100.  I know Xplane's flight modeling is very exact but I just wonder if it's advanced enough to calculate the compressor stall altitude of any given engine?  I do know I lost control surface resistance when I exceeded fl100.  

[Mr. Bones]

I guess you mean FL1000. FL100 = 10 000ft which even a C172 can reach.  ;D

Not sure about the Blackbird though.

[Gary R.]

Oh gee, i forgot that last 0. DOH!!!  Anyway, I would highly recommend Xplane for their SR-71 alone.  Actually, it's worthwhile for any exotic plane because there is no altitude limit as in FS.  Also, the sky does get very dark up that high and the suborbital scenery depiction looks a lot like space shuttle shots.  Very nice.  Til you get in an uncontrollable yaw at least  because there isn't any air to work against the control surfaces.

[Boss_BlueAngels]

I read someplace that the jet also grows about 3 inches due to thermal expansion and changes color from black to a very dark blue.  

[congo]

The SR-71 is a "Devil Plane", dripping with the blood of the arch-angel's after heavenly and holy combat......... God won and grounded the fleet. See photo evidence below.

http://www.sr-71.org/photogallery/black ... 930-12.jpg