Unlike conventional aircraft, all variants of the Blackbird used a very unique starting system that consisted of a drive shaft that was vertically inserted through the underneath each of the nacelles to the engines.  ( THAT IS RIGHT THEY WERE MECHANICALLY STARTED! ) This shaft would spin, thus turning the turbines inside the J58 and starting the aircraft. However, it was not by this simple system alone that the Blackbird was started. The Blackbird also required a shot of TEB or Triethylborane, a catalyst that ignited the fuel. This process was a coordinated effort between the aircrew and the "buddy" crew, those who helped prepare the aircraft for flight.

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Buick Starter Cart at Blackbird Airpark

     The starter carts were in two different variants: the Buick and Chevy carts. In the early days, the Buick-based carts were used. These units were yellow and had twin Buick V-8 engines in them. However, later in the program, these engines were replaced with big-block Chevy engines, thus deriving the Chevy starter cart. The engines in the carts are accessible through opening hoods on the sides of the cart. The exhaust for the engines is routed through an exhaust pipe on the side of the cart (noticeable in the upper right image of the NASA cart). The two engines are connected via drive belts.

     Both starter carts are of the same dimensions although they are distinguishable. Even though the Buick carts are commonly yellow, the Chevy carts have been in a variety of colors: standard olive drab (dull, dark green), black, and NASA's stylish white with the blue stripe.

     There were also other methods of starting the aircraft, two of these were developed for the proposed F-12B program. The Air Force had a requirement that in order for the F-12B to be successful as an interceptor, it would need to be started without delay for a quick launch. This starting system consisted of an attachable unit under the nacelle like any other starter cart, but there was a chemical process that took place in adjacent starting cartridges. This reaction allowed for the spinning of the vertical drive shaft, thus starting the engine. In addition, another process was developed which was turbine-powered. However, these systems proved impractical for the SR-71 and were not used considerably.

     Eventually, these carts were phased out when permanent starting systems were installed in the Beale AFB hangars. This system consisted of compressed air tanks of considerable size that were used to rotate an attached unit. However, the portable carts were still servicing SR-71s at distant operating locations. Nevertheless, when NASA took over a few SR-71s at Edwards AFB, the starter carts were once again used because the aircraft was started and checked before flight out on the ramp.

     It is not known how many of these carts were built, nor how many exist today. Little information is released on this subject simply because it is not a prime area of interest. These carts are on display in various museums around the country. It is also rumored that some are in storage at key facilities like AMARC (Davis Monthan AFB), and Wright Patterson AFB, OH.

 

 

The Buick's

 

 The original start carts were Buick wildcat 401 cubic inch V-8 engines developing 400 horsepower. There were two Buick engines mounted tandem side by side with automatic transmissions. They were coupled together to drive a vertical shaft that was inserted into the starter mechanism on the bottom of the SR-71's engine. On engine launch there was one AG-330 Buick for each SR engine. For the first time observer of an SR-71 launch, the engine starts in themselves were almost indescribable. For one thing there was no mufflers on the Buick engines. As the Buick RPM was advanced, Flames almost three feet long erupted from the side of the start cart. It truly sounded like the beginning of the Indianapolis 500. Combine that sound with the steady increase of SR-71 RPM to engine TEB ignition at 3,200 RPM and then idle aircraft engine speed as the Blackbird comes to life. Then it all starts all over again with #1 engine. It never failed to thrill me to start the Blackbirds engines with the Start Carts. The original design was conceived by two Lockheed Skunk Works engineers who had prior race car engine knowledge. In the mid-1970's, the engines of the start carts was changed to Chevrolet LS-7 454's. The Chevrolet big block engines developed 465 horsepower each. Even so, for many years they were still referred to as the Buick's. In the '80's the AG-330 Start Carts were mothballed and in there place came a Pneumatic Air starting system for the SR-71's. It is true that the start carts were hard to maneuver around. Logistically, a recovery of a Blackbird at another base could be done easier with Pneumatic Air. Garrett Air Research installed the Pneumatic Air starting system in each of the hangers at Beale AFB to accommodate the SR-71 engine starts. The launches were never quite the same without the Buick's or the 454's. Credit should be given to those people that maintained the AG-330's in the 9th SRW Aerospace Ground Support Section. Along with maintaining all support equipment, they took great pride in maintaining the Start Carts tuned and in tip top condition. A job well done

 

 

 

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