Ja-Moo wrote:
That's very cool!
Thanks John, I know you are a plane nut of sorts, thought you would like this.
Dad's first job was in West Palm Beach at Pratt and Whitney, I will let him describe it in his own words from a journal I found after he passed (it's long but a cool story........). I also donated his engineering notebooks to Lockheed Palmdale, they still maintain an archive for the SR-71 as it was so advanced, several current programs are considering use of the engine technology for hypersonic weapons.......
"I learned that Pratt & Whitney in West Palm Beach, Florida were hiring. After the initial contact, they showed considerable interest and invited me down for a job interview. The plant was located several miles west of the east coast in the Everglades. This location offered security advantages and remoteness where engine test noise would not cause complaints. I talked with several people at PW, but mainly, it was Bob Hurley who decided I should be made an offer. Bob headed up the compressor analytical design group, which at the time only had two people in it, Jack Sammons and Bob Schiller. When I learned they were going to extend me an offer I was overjoyed.
What a job it was. PW were in early development of a large, afterburning turbojet engine – the largest in the world - and its nine-stage compressor was in need of a lot of design work. Bob confided to me that he had hired me specifically because of my working experience with the NACA data and relationships, and needed to apply it to their design as quickly as possible. We started developing design relationships that could be programmed into the computer design routines. There was lots of overtime work as the programming matured and was used to develop new aerodynamic blade shapes for redesign of the compressor. It was very exciting because we weren’t just doing paper machines here; we are going to build and test this huge compressor after we demonstrate some of the high technology in smaller, single-stage rigs. I learned a lot about my job and the analyses, but nothing about the actual engine for which this huge compressor was destined. It was interesting that we analytical aerodynamicists were also responsible for the structural design of the compressor blading, which meant we had to be familiar with materials and vibration properties as well. A special dynamics group, who would critique and change each design as they examined it, did the actual vibration analysis work. This was a highly important process, for if the parts vibrated uncontrollably, the machine would be destroyed. The dynamics group was managed by an uncompromising genius named Herb Rubel, who brooked no foolishness and accepted only perfection from his workers. Unfortunately, he was not very well liked by his group, but somehow, Herb and I always seemed to hit it off OK. The compressor design was an iterative process of repeated trial and error reduction between aerodynamics and blade shape and material properties. The iteration would proceed through the design groups and calculations until the error was reduced to within our accuracy to determine, and the resulting design change would be tested for verification. If successful, the change would be incorporated into the design of the large, multi-staged compressor for the mysterious J-58.
The West Palm Beach PW plant had been built in 1958 to serve as the company’s government research and development facility. The plant was deeply involved in the large mystery engine with the nine-stage compressor, and some very exotic rocket engine development work. It was 1961 now, and the large engine had been in development for about three years, and a few complete engines had been built. We always seemed to be under time pressure, like there was an urgency to get this engine working properly. However, no one seemed to know what the engine was for. We were aware of some pretty exotic altitude and Mach number design conditions, but were cautioned not to discuss them or question the use of the engine. The entire project was cloaked in security classification that was rigorously enforced. Each employee wore a company badge displaying his photo, name, designation of areas cleared for access, color code for level of security clearance and employee number. New hires were only allowed into the analytical office areas where they worked; they could not go to production, assembly or test areas unless escorted at all times.
A quiet, brilliant man, Hal Stetson, came down from Hartford to head up the aeroanalysis group, and Bob Hurley’s compressor team became part of it. Hal moved my desk close to his office because he decided I was to be his ‘shock troop’. I became one of the mainstays of the small compressor design group and, in addition to my analytical work, had to observe tests being conducted. My first visit to the test area was pretty exciting. The test area was located about three miles further west from the main facility, and was accessed by a two-lane road through the Everglades with its saw cabbage, slash pine and alligators. The test facility was pretty big. When I first got there they had three or four outdoor engine test stands, a test rig facility, a very large air facility for provision of simulated altitude and Mach-conditioned air, and several rocket test stands with assorted tankage and bunkers for the corrosive fuels. Imagine, all this exotic stuff out here in the middle of the Everglades with the ‘gators. The air facility and a high-pressure steam turbine for mechanical drive supported the compressor test stand. It could simulate compressor inlet conditions as high as 100,000 feet altitude and Mach number 3.2 - over three times the speed of sound. The mechanical drive could provide up to 30,000 horsepower. This was BIG stuff. Conducting and observing tests was interesting, but also time consuming, and often done at off-hours. We made progress and design changes were being incorporated into the engine compressor as we gained improvements. I’ll never forget the first engine test I saw, and heard! In afterburner, the JT-9D (P&W’s designation for the J-58) produced over 32,000 pounds of thrust. That’s a hell of a lot of sound power and a hellish streak of fire out the back of the engine which extended sometimes forty feet. The noise is literally unbearable, your chest cavity vibrates, your shoelaces dance, you want to get away! Those of us who visited the test area frequently learned how to minimize the impact of the environment - usually by waiting until things abated a little. Sometimes though, an engine was on endurance test - long hours - and you just had to get exposed to the fierce conditions. We became very skilled at quickly opening and closing the heavy test bunker double doors, for when they were open it exposed all those in the test control room to the hell outside.
More J-58 engines were being built, they were being shipped too, but we knew not where. Extensive development work was being done on every engine component, particularly the afterburner system. Afterburner tests were frequent and frustrating. Many test failures were experienced because of the high combustion load necessary for the proper thrust augmentation. There were also main combustion section problems manifested by turbine durability failures. It turned out his time that the compressor was the culprit. The airflow pattern leaving the compressor varied widely between sea level and altitude engine operation. This variation was intolerable to the combustor and turbine, the components that followed the compressor. I devised a rotor blade change to the last stage of the compressor that evened out this variation and significantly increased the durability of the engine. The change was thus quickly incorporated into the engine. It also gained me credibility with my peers and superiors. About the same time, the combustor guys had come up with a liner for the afterburner that had some durability, and expanded the flight envelope over which the engine could be utilized.
One day Herb called me over to his desk and showed me some circular figures which had some lines on them like a weather map. He explained that these were pressure contours of the airflow entering the engine at various conditions of flight. It was called inlet distortion. I asked Herb, “Where did you get these contours?” He said, “Never mind where I got them.” Because I had never known anything about an aircraft this engine was used for, I asked, “Are they from a model test?” Herb replied, “Yeah - a VERY good f------ model; don’t ask me anymore where I got them.” This was the first time I suspected that an aircraft using this amazing engine was actually flying. It was about 1963. What Herb wanted, was to know if us compressor guys could come up with a way of simulating these pressure contours with a device that could be used for compressor and engine testing here at the test facility. I thought it could be done easily by overlaying different wire screen densities on a support grid in the airflow duct upstream of the test engine or compressor. I spent the next few months working up a material list with test engineers and constructing such a device. The proof of the experiment had to be demonstrated at a high Mach condition for which the engine or compressor inlet temperature was in excess of 700 degrees Fahrenheit. Myself and another engineer spent several hours many nights working in a test stand inlet chamber which had been just run at 700 ºF wearing flameproof, insulated suits, clipping screen and wiring it to support grids. But we got the job done and ran probably one of the very first inlet distortion tests ever on an engine compressor in a controlled environment.
During this time, the infamous Bay of Pigs fiasco occurred and south Florida was overrun with troop trucks towing guns and lots of military activity. Many of people considered moving north away from the Cuban proximity; but we just watched the news and stayed on. Work was getting interesting and there was more urgency, because of the Cuban missile crisis. My frequent visits to the test area led to being the “contact” as to how engine testing was progressing so our analysis group could better keep abreast of development progress. We had known now for many months that the engine was the USAF J-58 afterburning turbojet, and that it operated at extreme conditions of speed and altitude. We did not, however, have any idea what aircraft it was being used in. Keeping the status on engine testing was a real treat, I had unlimited access to the test area and saw many engine test firsts and bloopers. For a short time, the engines which were running accumulated hours for endurance testing were coming apart at the middle at max power scattering parts all over the place. The heavy turbine wheels would climb walls and bounce over buildings when they broke from the running engine with so much stored energy. And there was almost always a fire, which would cause extensive damage to the test facility. Fortunately, fires were not as common as with most engine tests because the heavy fuel, JP-7, had very low volatility and would not readily burst into flame. It was so hard to light, the engine used a pyrophoric chemical, tri-ethyl borane (TEB) for starting; normal electric ignition systems would not provide a hot spark in the rarified upper atmosphere. Engine starts and afterburner lights were always characterized by a brief flash of green flame as the TEB was injected into the engine combustor. Night tests were spectacular with the green flashes; 40 foot afterburner plumes and cherry red tailpipes. The noise was indescribable and could be damaging. On a calm night, the engines could be heard on the coast in Jupiter, over twenty miles away.
I remember November 22, 1963. President Kennedy was assassinated in Dallas while we were working. At the time, some of us in the expanded compressor design group were reassigned temporarily to help design the liquid hydrogen pumps for the XLR rocket engines used in the Atlas Centaur second stage vehicle. It was weird working our design codes with a liquid; they worked pretty well if the proper fluid constants for specific heat, etc. were inserted into the program. The rocket test area was spacey with its big spherical liquid hydrogen tanks and their lightening rods, the huge test control-room computers and timing exactness. They also ran tests on some smaller rocket engines that used hydrogen fluoride as an oxidizer. Real nasty stuff. The leak detection system was simple enough; they just wound a single wire around everything and ran a current through it. As long as current flowed, no leaks. If a leak occurred, the HF would immediately corrode the wire and break the circuit. It was effective, but cleanup was a mess after an HF leak.
The hydrogen-oxygen XLR engine test set up was very clever. Since it was a second stage engine which only operated outside earth’s atmosphere, some way had to be devised to simulate the vacuum and extreme cold of space. The test stand was designed such that the test engine acted as an ejector pump, which evacuated the space surrounding the nozzle exit area. Each test was preceded by a “cool down”, where liquid nitrogen was circulated through all the pumps and lines until a low temperature condition was reached uniformly; then, the engine was fired for the test program. The procedure was very exacting and the entire test sequence was programmed and controlled by computer, and all data was recorded automatically by computer- real gee-whiz stuff for 1963.
When President Lyndon Johnson revealed to the media in early 1964 that USAF had developed a super spy aircraft that flew so high and fast that it was beyond interception we all put it together and realized we had been working on the engine for that unique aircraft: the A-11, built by Lockheed’s “skunk works”, which developed into the famous SR-71 “Blackbird.” We also learned that the factory we were working in was not only the development center for the engine, but its production facility as well. We felt very proud to be a member of the free world’s only “Mach 3 team”. This was the reason that the test area had expanded to include seven engine test cells, two of which were simple thrust beds on which endurance tests were conducted. Now of course, Congress took a great interest in the program. I remember their first big visit. We cleaned the area for days, and great effort was exerted to get enough engines running so all seven test stands would be going with operating engines when they came to the test area to observe. Well, I was at the test area going on my rounds when the limousines arrived. All the test stands were thundering with engines either at military or afterburner, the din was terrible. There were three limousines and the first one drew to a stop just in front of me and the others also halted. It was a hot day and the cars were all closed up with the air conditioners going full blast. The front passenger door of the first car opened about half way - and then abruptly slammed shut. The cars sat there for about a minute, then moved out of the area toward the gate back to the main plant. The politicos were afraid to get out of the car and expose themselves to the noise! I don’t think an entourage this large ever visited the test area again. Of course, all the guys in the test cells were greatly relieved and got a big laugh out of it.
It turned out that the technology learned in the aircraft program whetted the appetite of the commercial world, and evoked the political advantage it would be if the US developed a supersonic transport larger and faster than the Anglo-French Concord. A design team for a brand new engine was selected from the J-58 program to start work on an engine system for the US SST. Preliminary cycle analyses had been completed and the engine design selected was a duct-burning turbofan engine that would develop about 60,000 pounds of thrust at take-off rating. I was selected to do the analytical design of the huge fan and got to work very closely with Herb and his dynamics guys. It was a fun job, high priority, overtime and the run of the plant and computer preference as well. These were the days when a several day turn around for a computer run was the norm. The SST analyses got on and off the computer almost on demand. The J-58 engine had given us confidence in working and designing with titanium, and with supersonic rotor blade airflow analysis. The dynamics group had also gained experience in blade vibration analyses dealing with mechanical damping systems, pre-stress fits, and cold assembly requirements. The compressor designer’s big job was to prepare the final “blade books” which dimensionally defined the blade shape, which had to be machined out of the large titanium forgings. Forging technology had advance to the point where the blade shape could be finish-forged. The dovetail, blade cut-off and mechanical damper surfaces had to be machined from billets left on the finished blade form. I defined the final airfoil shape; Herb’s guys took care of the dampers. We worked many weeks on the fan design and finally, one Saturday we reached the conclusion. The computer button could be pushed to print out the final blade books. I spent a good part of the day getting them prepared and packaged for express shipment to East Hartford where they would be fabricated. The fan stage blades were about four feet in length and had a system of two vibration dampers at midspan positions. These would be the largest and by far the most expensive fan blades ever made for any engine. I was happy the job was done. Heh-heh; I came in Monday morning and found I had made a minor mistake in one of the computer settings and all the blade book information I had rushed off to East Hartford on Saturday was wrong! That feeling of being dipped in boiling water came over me and I almost fainted. Nothing to do but admit the mistake and get it corrected. I went into the design supervisor’s carpeted office and told him I had to see him - it was really important. What a neat guy. When I told him what had happened he didn’t bat an eye, just asked me: what did I need to make the correction. Then he called Hartford and told them that the books were wrong and we would be sending another set up to them that day. That’s all there was to it. I thought I was going to be fired. I’ll never forget the man, Walt Ledwith. The program didn’t even hiccup; the change went smoothly and we all got a little laugh out of the screw up.
My memory is a little dim on the SST engine designation, I think it was the JT-12D. It was an amazing accomplishment. Pratt & Whitney went from a clean sheet of paper and an engine cycle definition to a complete, running engine on the test stand in just over nine months! It was an exciting time monitoring the fabrication of this exotic engine, and keeping up with the constantly changing SST mission profile. As we talked about the upcoming very first test, one worry became paramount - would the engine start first time? We were told horror stories about the problems P&W had with the prototype TF30 duct-burning engine and everyone was concerned. I didn’t have any familiarity with the TF30 program, so I didn’t appreciate the concern. We all watched the day grow closer when the engine was scheduled for its first test. Only selected project people were allowed on the test stand that fateful day, I think it really turned out to be at night. Anyway, we heard the next morning that, amazingly, the engine started the first time and stabilized at idle! Everybody was surprised. In fact, they were surprised to the point that they reviewed the whole start procedure and test stand connections, etc. We were told that they found the start bleed system had been cross-wired, and if it had been properly connected they might still be on the test stand scratching their heads with an engine which wouldn’t start. It seemed that ‘Murphy’s Law’ had backfired this time. As a friend once said, “Engine testing is not a job, it’s an adventure!”
I was one of the fortunate few to be on the test stand to watch the JT-12D run up to full power the first time. I got to watch the thrust stand meter needle climb to 60,000 pounds of thrust! This take-off power was reached when the duct burner was at maximum fuel flow. A duct burner is really an afterburner wrapped around the core of the engine in a concentric duct, instead of being attached separately at the rear. When the duct burner was lit and at full power, the entire titanium duct around the engine undulated like something inside was alive. It was almost scary to watch.
As the months wore on, the dispute regards the SST flight profile mounted. At issue were the unknowns about community noise, upper atmosphere pollution, mission profile fuel burn efficiency, and political opinion. High-speed flight narrows options tremendously because of the enormous amount of fuel burned, and the type of engine has a large bearing on this amount. If the flight profile, or mission, is mostly supersonic, then the most efficient engine cycle is a turbojet with an afterburner, which was the type of engine our competitor, General Electric, was developing. If the mission contains a large percentage of subsonic or transonic speed operation, the most efficient engine cycle is a bypass engine with a duct burner - like our JT-12D. Boeing and Lockheed were both developing SST aircraft designs. They were also each biased differently toward a different mission profile. It was kind of a mess because nobody really knew how the politics and technology were going to weigh out. Technically, a true SST was the best solution. Politically, it might not be, because of overflight noise concerns and the unknowns with regard to pollution. To make matters worse, the airplane designs kept growing in gross weight trying to meet a cost per seat mile target that favored larger and larger aircraft. If this sounds like a hopeless situation it was. The US SST program was abruptly terminated late in 1965 and all assets were either destroyed or put in dead storage. A week later it was as though the program had never existed. What a shame.
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