SR-71

On 1-Nov-2007, "Morgans" wrote:

On the same subject, I remember reading that the huffer to start a 71 had
a
Chevy 350 powering it, and that it took every bit of it.

Anyone? True, or not/details?
--

Sort of true. Quoting again from Rich Graham's wonderful book: "Starting the
huge engine was accomplished by a direct mechanical drive to initiate engine
rotation. The large starting cart used to turn the engine over was called a
"Buick" because it originally had two large block Buick V-8 engines, mounted
beside each other, providing over 600 horsepower to rotate the J-58 engine.
When Buick engine parts became scarce, maintenance converted over to using
large block Chevrolet V-8 engines. The "Buick" engines didn't have mufflers,
just 16 straight pipes coming off the exhaust manifold. Through a series of
gears, the two Buick engines drove a vertical shaft, extending upward and
connecting directly to the bottom of the J-58 engine.
The "Buick" start cart was wheeled into position just inside the wingtips
with the vertical shaft directly beneath the engine. An engine access
panel was removed, allowing the vertical shaft to connect directly to the
engine. When the pilot called for engine start, the crew chief gave the
signal to his assistant, standing under the engine, to pull out the manual
throttle on the "Buick" control panel. Applying full throttle to the
"Buick," the noise reverberating inside the hangar sounded like a 3000
horsepower dragster revving up, and at night flames could be seen shooting
out of each exhaust pipe. A sight and sound to behold! The "Buick" turned
the engine over slowly at first, then faster and faster, until the J-58
was ignited and stabilized at idle, about 4000 rpm.
The reason for a direct-drive starter was because their (sic) were no air
starting carts capable of supplying a sufficient volume of air to rotate
the huge J-58 engine. The special lubricating oil used throughout the
engine was so thicjk that it had to be preheated to a minimum of 70
degrees C before the engines could be rotated. Whenever the SR-71 landed
somewhere other than a home base, it was a major task to transport large
and cumbersome "Buick" (about 4 feet by 10 feet) just to start the
engines, thus a portable air start system was developed in the late 1970s.
Eventually the SR-71 shelters (hangars) at Beale were equipped with large
air tanks to store compressed air to rotate the started adapter. Soon
"Buicks" were becoming extinct, and eventually the air start method became
preferred by maintenance."

I saw this air start adapter at Ramstein. 61-7974 flew in for a static
display in January 1984 for a former SR-71 aircrew member's retirement
ceremony. When the Blackbird was ready to leave, they put four AM32A-60
start carts on each side of the jet, eight carts altogether. The four
-60s' bleed air hoses on each side were coupled to a round unit that
obviously contained a turbine that was mounted on the bottom of the engine
nacelle. The turbine evidently drove a starter shaft connected to the same
place the "Buick" would have been. One -60 was sufficient to start an
F-4E, so my friends and I were duly impressed. I got a few nice photos of
974 being started and taking off, if anyone wants to see them I could post
a couple of them on alt.binaries.pictures.aviation. Let me know. 974
later on was the last SR-71 to crash before the program was cancelled. By
the way, there were 49 Blackbirds built, including the A-12, YF-12A, M-21,
and SR-71A and B. There were 20 losses altogether, the majority occuring
early in the program.
Scott Wilson