And what country can preserve its liberties if their rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms. The remedy is to set them right as to facts, pardon and pacify them. What signify a few lives lost in a century or two? The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants.
Those are excess hydrogen burnoff igniters. They burn off gaseous hydrogen that might accumulate near the engine bell or base of the shuttle just before main-engine ignition. It basically mitigates the risk of a large-volume hydrogen detonation at liftoff.
Company I worked at, got to weld tube assemblies for those engines, NASA engineer that followed the parts thru our shop had some interesting anecdotes, one that stuck in my mind was how much power the hydrogen pumps ran at, 7million shaft horsepower, the main hydrogen feed is 5ft inside diameter, can't remember now, they consumed some ungodly amount of tonnage a second at lift off. The resonance from the volume of liquid H2 running thru that feed would cause hundreds of cracks to form on the inside face of the material. And they figured for all that. Incredible engineering and design talent. The NASA guy was extremely particular on how you went about working on his parts, carried a small ball peen hammer in his back pocket, had a bottle of red DYKEM too, these parts where all titanium alloy, had them on wheeled carts, bring them to each person working on them. One requirement being no bare hands, we wore white cotton gloves whenever handling a parts, the specification being fingerprint oil cause stress cracks, (which is true, technical term is Alpha Case, tiny surface imperfections, cracks etc, cause of the stress heat vacuum etc the parts are subjected to in flight), of course some knuckle head put a big ol thumbprint smack on top of a flat spot on one of the fuel manifolds waiting for X-ray. Out comes the ball peen hammer, fellow puts dents all over the part, paints it red and red tags it. They never found out whose thumb it was, it was painted red and too smeared before a photo was taken. It was a lot of money turned into scrap metal.
My father was government inspector at Allison in Indianapolis (now split between Rolls Royce North America and independent Allison Transmission) where the fuel tanks for the Command Module and Lunar Exclusion Module were made, also out of titanium. Welds had Xray film laid on them, then exposed, then long meetings examining the results for welding imperfections. Long arguments over whether microscopic bubbles were too close together, risking formation of a crack. That meant scrapping a part, maybe an entire fuel tank.
How they count porosity, gas bubbles really, depends on size, and how many in a given length or diameter. .005 inches is max allowable size, how much porosity depends on weld classification, Allison has very tight specs, on say their fuel manifolds, their spec's for outside contractors exceedingly so. At the shop I worked at, many fusion weld qual tests used Allison ClassIIIA specifications, if you can pass those you pass most other company qualification specs.
It was never dull tell you what. Got to work on really awesome stuff, lot of rocket engine parts, mostly RL10 engines, (PrattFlorida), the long bleed air tubes on the SR71, oxygen lines on space suits, STS engine parts, Lockheed booster parts, the suit line where crazy complicated flexible metal hose with 4 different alloys in one joint, had one specification, no defects permitted, using a 50 power loupe on the X-ray film read. Got in on a bunch of experimental parts. One night, box truck pulls up literally to the back door, there's a Pratt engine experimental for the YF22-YF23, on a pallet. Pratt asked if we could fabricate every master tube for it. That was the first engine using single crystal growth turbine blades and BLIMP sections, only way back then to create hit section blades for the critical high temps needed for no afterburner super sonic cruise modes. Very secret at the time, and they dropped it off in our employee parking lot, only a PrattWhitney truck driver to guard it. We put it on a engine dolly rolled it to a bare spot, got to work, anyone could have walked in any time, we never locked the doors, no security cameras, not a guard in the place. Supposedly, rumor had it, that single crystal growing method at the time was the most secret tech secret in the US .gov. Coolest looking engine I ever looked at. It was very very advanced, nothing like it. Still pretty clever engine. Those guys at Pratt do some amazing stuff. An American version of RollsRoyce, quality like nothing else. What I seen of their products anyways. They use a lot of high nickel hardenable alloys, like 70-80% nickel, it will dull a file hardened, tougher than woodpecker lips, its how it was made possible how they where able to produce great jet engines. That RL10 rocket engine, its b/p's had the date of March 1956, two tiny revs on the prints, designed by slide rule, up till 96-98, we built a prototype bootleg system for the regenerative cooling engine bell manifold, till I think it was in the 90's the only reliable re-start able in vacuum engine, it worked right from the drawings first go. Smart folks down there at PrattFlorida. still widely used, goes on lots of geo sats due to its very high vacuum impulse and reliability. That bootleg was claimed to be valued at 4 billion dollars in saved satelite time due to higher impulse it got, simply by dividing the fuel/cooling circuit distribution in two. Basically provided more balanced evened out flow, more fuel efficient that way, more fuel to maintain correct orbits.
very powerful steam engine
ReplyDeleteThat’s one way to look at it. 2 H2 + O2 = 2 H2O plus E lots ‘O E. A lot of very hot water.
Deletewhat is the fluid being sprayed from the left and right towers, and what is it for?
ReplyDeleteThose are excess hydrogen burnoff igniters. They burn off gaseous hydrogen that might accumulate near the engine bell or base of the shuttle just before main-engine ignition. It basically mitigates the risk of a large-volume hydrogen detonation at liftoff.
ReplyDeleteWatching in cabin films, you see the moment the main engines ignite and run up to full power, bounces and throws everyone into their straps.
ReplyDeleteCompany I worked at, got to weld tube assemblies for those engines, NASA engineer that followed the parts thru our shop had some interesting anecdotes, one that stuck in my mind was how much power the hydrogen pumps ran at, 7million shaft horsepower, the main hydrogen feed is 5ft inside diameter, can't remember now, they consumed some ungodly amount of tonnage a second at lift off. The resonance from the volume of liquid H2 running thru that feed would cause hundreds of cracks to form on the inside face of the material. And they figured for all that. Incredible engineering and design talent. The NASA guy was extremely particular on how you went about working on his parts, carried a small ball peen hammer in his back pocket, had a bottle of red DYKEM too, these parts where all titanium alloy, had them on wheeled carts, bring them to each person working on them. One requirement being no bare hands, we wore white cotton gloves whenever handling a parts, the specification being fingerprint oil cause stress cracks, (which is true, technical term is Alpha Case, tiny surface imperfections, cracks etc, cause of the stress heat vacuum etc the parts are subjected to in flight), of course some knuckle head put a big ol thumbprint smack on top of a flat spot on one of the fuel manifolds waiting for X-ray. Out comes the ball peen hammer, fellow puts dents all over the part, paints it red and red tags it. They never found out whose thumb it was, it was painted red and too smeared before a photo was taken. It was a lot of money turned into scrap metal.
ReplyDeleteMy father was government inspector at Allison in Indianapolis (now split between Rolls Royce North America and independent Allison Transmission) where the fuel tanks for the Command Module and Lunar Exclusion Module were made, also out of titanium. Welds had Xray film laid on them, then exposed, then long meetings examining the results for welding imperfections. Long arguments over whether microscopic bubbles were too close together, risking formation of a crack. That meant scrapping a part, maybe an entire fuel tank.
DeleteHow they count porosity, gas bubbles really, depends on size, and how many in a given length or diameter. .005 inches is max allowable size, how much porosity depends on weld classification, Allison has very tight specs, on say their fuel manifolds, their spec's for outside contractors exceedingly so. At the shop I worked at, many fusion weld qual tests used Allison ClassIIIA specifications, if you can pass those you pass most other company qualification specs.
DeleteGood story.
ReplyDeleteIt was never dull tell you what. Got to work on really awesome stuff, lot of rocket engine parts, mostly RL10 engines, (PrattFlorida), the long bleed air tubes on the SR71, oxygen lines on space suits, STS engine parts, Lockheed booster parts, the suit line where crazy complicated flexible metal hose with 4 different alloys in one joint, had one specification, no defects permitted, using a 50 power loupe on the X-ray film read. Got in on a bunch of experimental parts. One night, box truck pulls up literally to the back door, there's a Pratt engine experimental for the YF22-YF23, on a pallet. Pratt asked if we could fabricate every master tube for it. That was the first engine using single crystal growth turbine blades and BLIMP sections, only way back then to create hit section blades for the critical high temps needed for no afterburner super sonic cruise modes. Very secret at the time, and they dropped it off in our employee parking lot, only a PrattWhitney truck driver to guard it. We put it on a engine dolly rolled it to a bare spot, got to work, anyone could have walked in any time, we never locked the doors, no security cameras, not a guard in the place. Supposedly, rumor had it, that single crystal growing method at the time was the most secret tech secret in the US .gov. Coolest looking engine I ever looked at. It was very very advanced, nothing like it. Still pretty clever engine. Those guys at Pratt do some amazing stuff. An American version of RollsRoyce, quality like nothing else. What I seen of their products anyways. They use a lot of high nickel hardenable alloys, like 70-80% nickel, it will dull a file hardened, tougher than woodpecker lips, its how it was made possible how they where able to produce great jet engines. That RL10 rocket engine, its b/p's had the date of March 1956, two tiny revs on the prints, designed by slide rule, up till 96-98, we built a prototype bootleg system for the regenerative cooling engine bell manifold, till I think it was in the 90's the only reliable re-start able in vacuum engine, it worked right from the drawings first go. Smart folks down there at PrattFlorida. still widely used, goes on lots of geo sats due to its very high vacuum impulse and reliability. That bootleg was claimed to be valued at 4 billion dollars in saved satelite time due to higher impulse it got, simply by dividing the fuel/cooling circuit distribution in two. Basically provided more balanced evened out flow, more fuel efficient that way, more fuel to maintain correct orbits.
DeleteBest place i ever worked at.