Thread

NASA asked several former SR-71A staffers to help secret restart

327 points · 403 comments · ilamont

0xbadcafebee · 1790728000 · focus · HN ↗
To give you an idea how ridiculous this is: to start each engine, they made a cart out of two Buick V8 engines tied together - so four V8 engines to start the plane. Those V8 engines were long since out of production, so at one point they went around the country, to every junkyard, buying up every one of those V8s they could find, so they would have spares to start planes up in different places. If an SR71 had an issue and landed at an unusual airport, they had to fly the start cart and other equipment to that airport to start the plane again. Everything about this plane is expensive and one-of-a-kind. It's a hot rod that goes to space.
1. AnimalMuppet · 1790729766 · focus · HN ↗
  Rather than re-engineer the cart to use a different block? I mean, I guess when a part reaches end-of-life, your first move is to buy as many as you can, before you try to re-engineer things so it isn't needed, but... horsepower is horsepower. Torque is torque. It shouldn't be that hard to replace...
  1. jauntywundrkind · 1790734548 · focus · HN ↗
    They did eventually replace the Buicks.
    > 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.
    <a href="https://www.thesr71blackbird.com/Aircraft/Engines/starting-the-sr-71-blackbirds-j58-engines-ag330-start-cart" rel="nofollow">https://www.thesr71blackbird.com/Aircraft/Engines/starting-t...
    And eventually the start carts themselves got replaced.
    > 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.
    m4rtink · 1790761297 · focus · HN ↗
    Yeah, big car engines is actually not that impressive, rather surprisingly primitive. Modern jets have external APUs for starting, usually via compressed air, that have compact yet powerful gas turbines inside.
    Sure, less impressive than a contraption with a bunch of car engines but much more powerful.

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