Interviewer(s): Rebecca Wright
Interviewee(s): Earl R. Keener, Malinda Alves

Earl R. Keener: My memories go back to a friend of mine that started building model airplanes. That got him involved, and it helped me to understand the word “aeronautics.” Instead of building models, I got interested in wind tunnel work.\n\n For school I needed to write two English papers, so I decided to look at the history of aeronautics, of flight, up to the World War II. In order to carry that out, in order to get more acquainted with it somehow, I went to the back of the stacks of libraries, and lo and behold—found out about this place called NACA, National Advisory Committee for Aeronautics.\n\n What I learned was there was a group, a NACA group at Langley [Research Center, Hampton, Virginia], and there were other groups. These men were looking ahead and at what was ahead. It was growing, also, with the time. So, instead of a model airplane, I built a model wind tunnel. It would do about 27 miles an hour. I had a lot of fun, building that. I was never able to completely have a satisfactory measuring system, which is an area all to itself.\n\n It’s important I go back before World War II, and the airplanes—the pursuit airplanes, the high-speed airplanes. These were expanding towards the end of the World War II. The importance of this is because we were losing airplanes and we didn’t know why. They would flip up and crash. There was an effort for supersonic flight.\n\n When I was a senior in high school, I first got acquainted with a graduate of Kansas University. He was planning ahead for an engineering college. He found there was a wind tunnel up in our science building, up in the attic. He prepared the tunnel so that he could take data on models that were of interest to the Air Force. I got interested. That occurred after World War II. Later, he was busy buying up used equipment from the war buildings—surplus buildings and a machine shop. I looked him up, and met him in the machine shop; he was a good machinist. This was a young man that was captured by the Japanese, and the Japanese tried to file his teeth down. I don’t remember his name, but I talked to him many times.\n\n It was around this point, I had to answer the question of where I should go to college. I had to make a decision between MIT [Massachusetts Institute of Technology, Cambridge], or go towards the West Coast to Caltech [California Institute of Technology, Pasadena], or stay with the Municipal University of Wichita. I chose to stay in Wichita where I have many fond memories of Dr. Melvin Snyder, who encouraged the students tremendously, myself included.\n\n In college, I spent some time in the aeronautics school, just making myself available. I joined up with another engineer from Boeing; his dad was one of the designers for Beechcraft [Aircraft]. He had big plans to build a wind tunnel. He got together with one of the technical people—they designed a wind tunnel and proceeded to test a small and a large tunnel.\n\n Then, I didn’t know much about certification and that kind of thing. At the time [Kenneth] Razak developed this school [Wichita State University College of Engineering, Kansas], and I got more interested and finally decided to go to school there. He started classes and I started going. His engineering school developed, and a whole Ph.D. program. I graduated in the College of Aeronautics. I was in aeronautical engineering class number two, and Bob [Robert Burnham] was in number one, class number one. Very good engineer. I knew his father and his father was one of the [Beech Aircraft] designers. In fact, they designed a racing plane and won the annual meet that they had with the Air Force.\n\n I was ready to graduate, and I had been hearing stories about this X-1 vehicle. They [NACA] didn’t have recruiters, but I saw tacked on to the [school] bulletin board, a standard government employee job offer from Langley and also at Lewis [Research Center, Cleveland, Ohio]. I was really into the possibility of working for NACA, National Advisory Committee for Aeronautics. There was an actual committee. This was in my senior year, I got a return [on my application for the job]. It came from Langley; it was offering a job, but not at Langley. It was for the Flight Research Base [Muroc (now Edwards), California]; they had a group there. Most, I think, were at Langley, but they sent out an offer, then, for the Flight Research Center. One of the interesting things was that they offered jobs directly out of school, and that highly irritated some congressmen.\n\n They sent me an offer to go out to Edwards, but I would have done anything. My soon-to-be wife was very accommodating, and I don’t know of any other girl who would have gone out to Edwards. They did have some women in mathematical work.

Malinda Alves: Who was that? Wasn’t it my mom?

Earl R. Keener: You’re right. See what I mean? (laughter)

Malinda Alves: You went back to Wichita and married her, and then took her out.

Earl R. Keener: Yes. I went ahead. I’m conservative, and I went out there to Edwards, and they expressed an interest, then we went.

Rebecca Wright: Can you tell us about your first task? What did they ask you to do when you got out there to work?

Earl R. Keener: I did go out, and the first on the job was, as you might expect, had to do with research on stability and control. That was the chief job. We all met with the chief research engineer, who was De E. Beeler at that time, he was making the assignments. We were such young engineers.\n\n Going to my assignment, then, a very unique thing occurred that I didn’t know until later, that had to do with [Chuck] Yeager’s X-1. Yeager’s X-1 had a rocket, or had rockets, actually four of them, so it couldn’t collect much data. Here was my assignment—this airplane. It was subsonic, and they needed somebody—or some people—to run tests, subsonic, to fill in, I guess you could say, the gap. It was important; we needed a vehicle that would do flight research.\n\n There are ways that’s common in flight research: you pull up and take data while you’re pulling up, and then record it. Had a system that worked with the ladies [mathematicians] who were working up the data with a lot of plotting; then they had a remarkable machine for integrating the data. The results ended up in a report. A lot of data is in there, and I chose to put a lot of the description in the title. It is possible, I think, that the title itself then ended up being a description of what was in each report.\n\n They needed a vehicle that would fill in Mach number and flight and that vehicle did not have to be supersonic. The X-1 supersonic data was highly restricted because all he could do is go that-a-way and then pull back. Somebody, maybe from Langley—that was a brilliant decision—they would design that airplane that would fill in most of that gap. This is with the D-5581.\n\n When I came aboard, I worked with pressure measurements. It turned out that every one of us, within a year, were up to date with the research, the control, particularly of stability, that kind of control. The pressure measurements, somebody set it up to measure pressures on the full-scale airplanes; mine was one of them. A lot of my career was the pressure measurements. I chose to do more than just record it and send it back—I made a research effort out of it so someone would have to analyze the data. I preferred to do it myself.

Rebecca Wright: Tell us about what you thought when you arrived at the Center.

Earl R. Keener: I was introduced to the vehicle, D-5581, a Douglas [Aircraft Company] design. I was able to fill in, so to speak; the pressure measurements were mainly on the wing. Of course, the stability and control people were marching through, doing stability data. Douglas also designed a supersonic. It was a combination of rocket and jet. They could actually switch these. I wasn’t personally assigned, but we made some pressure measurements for that test. The D-5582, then, was a supersonic vehicle. This was gradually developed.

Rebecca Wright: That was a Navy plane?

Earl R. Keener: It was a Navy design. I got the impression—I wasn’t on the inside—that there was a planned approach. [A. Scott] Crossfield was assigned to run—they must have dropped him from an airplane like they did the X-15. I don’t think that that type would take off and land. My work had to do with pressure measurements. He proceeded, in a planned program, to try to get to Mach 2. He made many flights. They’d go up and come down, and he was trying, trying, trying to get Mach 2 out here. Finally, I remember being there, listening; he finally made it to Mach 2.\n\n Then, Yeager came along. They had upgraded the X-1 and a couple of things like the escape hatch to get out of the airplane; he would never make it, if anything had gone wrong. Made Mach 2.5 a week later. He paid for it because he got up to about 30,000 feet and the airplane went into a tumble. Tumbling was not necessarily a problem, but after a few moments, he was going down in altitude, and so he was able to control it just from the air.

Rebecca Wright: How close did the engineers work with the pilots when you were out at the Flight Research Center? Did you work closely?

Earl R. Keener: That’s an interesting question because I personally didn’t have much contact with them, yet I followed the flight. I’d like to get over to the test; one of the airplanes was a delta wing. They would plan, and then I’d make measurements. The Air Force, [XF] 92-A was a delta wing, was a flat delta, you know what I mean? The wings were flat. I measured the pressures, and I really didn’t know what was going on until later. There was also one, I’ll just throw in that there was a one of these vehicles had variable sweep wings. I think the administration or our planners found that there was an engineer in Germany that discovered the swept wing. There was a lot of discussion of that. This X-5 had a variable control on sweep.\n\n Ames was interested in seeing whether you could fly an airplane without a horizontal tail. The director of Ames got interesting in that project, and so, that was the X-4. The X-5 was the variable sweep. There was no X-8. There was an X-3—unfortunately, it tried to get to Mach 3 and it crashed.

Rebecca Wright: Were you there when it crashed?

Earl R. Keener: Yes. There was a lot of discussion because it was not a supersonic design as such. They were using the forces from a rocket in order to try, and I think he made Mach 6, but everything came apart. I hadn’t thought of that for a long time.\n\n The delta wing, that was a very interesting program. I don’t know who started it, but I was asked to lay out pressure measurements. It was an Air Force project. It was intended to reach about 1.4. They did some wind tunnel testing on it, not in the 40 x 80, but the 1.5 wind tunnel. The reason I’m smiling is the [aviation company] is trying real hard to get supersonic, and they’re not quite making it. So, they send their Ph.D. there. He was in a room with me and two others, and one of the others came up with this riddle: there was an old engineer, he had so many data points, he didn’t know what to do. (You know what least squaring is? It’s a way you can take a bundle of data points, and it’s a mathematical way of selecting which ones to go, what the best fairing is.) He least-squared them all, but then had the gall to fair through only two. He had quite a reputation for being humorous. I can’t quite put it together, except that here we are with one or two, an initial test of an airplane.\n\n They kept flying. It wasn’t the only thing wrong. It turned out the engines were not the right engines. We had trouble with that quite often out at the Flight Center, with the design. They tried to design an airplane with proper engines, and there always seemed to be something wrong with it, and they can’t use the engines that they designed.\n\n There was an engineer back at Langley that was well known for developing a way of designing the airplane, the delta wing, and it was to remodel and clock the cross-section of the airplane. When they did that, they realized that in the center was a pump. He got the idea of that pump being related to Mach number. His theory then was to smooth out the cross-section. When he got through, the cross-section developed by that method, and we got to calling that the “Marilyn Monroe” section because it had the hour-glass shape. The company was able to modify what we had in the 102. They called it the 102-A, I think. They added a little bit here and then took away a little bit and reduced that pump, and sure enough, it went supersonic. Then, the engines weren’t capable of 1.4, so that was kind of the atmosphere that we were exposed to.\n\n Also, you get various responses to various models, and this would be in the category of a pursuit airplane. We got into a study with Lockheed—Lockheed had a hypersonic tunnel. We developed a relationship with him, and this was a medium. We had a model. Some of those models were $1,000,000 or so.\n\n Here’s an example of what I did with this data: you see I’ve got the chordwise pressure distributions, but when I cross-section, we had, I think through Ames, developed some flow conditions that occur on a delta wing. You can see this change in here, very likely with a shockwave. I cross-plotted all of this, and this is what we came up with.\n\n This is where there would be a very large change, in along the leading edge. The interesting thing, somebody thought of—we called it conical camber because the leading edge is dropped and you go to the root, the camber is zero, but it grows. They designed it to be conical shaped, gradually increasing. I studied the flow over the wing, and our interest in flight was this sort of thing, was it still there at Mach 1.5 and 2? We wanted to trace the Mach number. Of course, this was one of the things that I was most interested in. The delta wing and the Marilyn Monroe shape.\n\n I can jump ahead a little. As you know, there was a complete change with NASA, and those of us with our heads still back in NACA, we had to find new work. That’s a whole era.\n\n We were looking at Langley’s wind tunnel work. First of all, the project for the delta supersonic airplane—it was supposed to have so many passengers. The British airplane was the Concorde, Mach 2. Our computational people that made these, they were designing different ways and means of flying. By this time, they had good support from computational, and so, they were trying to develop what type of shape would give the least drag. I came in on that. I had, down at the Flight Center, I’ll just describe it—a company had designed skin friction measuring. That applied the way to look at the boundary layer surveys and all of that. I learned that this company had designed a skin friction balance, they had a fluid dynamic—actually, fluids have viscosity. Ames had, what it is, is very, very good accuracy, and it tended to go downstream. We measure that tendency, I think, is a way to say it.\n\n We would determine how much drag there was in this. They had a technique in designing the supersonic transport. Part of the project, they needed to calculate the drag. The designer people thought of drag in terms of passengers. That was a big thing, then, was to make a comparison on the basis of number of passengers that could—you could look at it at either plus or minus the number of passengers that could fly at that rate. That skin friction balance, which balanced a floating element in the center. It was very carefully designed. I was aware of a smaller one that had brought into the Flight Research Center, so I brought it into Ames. We started making measurements of drag. In the meantime, the designer people were heavily into design before they finally canceled it, due to the sonic boom.\n\n By the way, I heard the first sonic boom down at Edwards. We had been hearing these noises, and the farmers, particularly the ones that were raising minks, they called in and they’d say, “Well, there’s been an explosion out here, my way,” and they’d never find it. I don’t know exactly the steps in how they recognized what they were listening to. That’s a very famous thing, the sonic boom, in aeronautics. It would sure wake us up in the middle of the night. The pilots learned to do that, and those shockwaves were strong. They had some show going on that actually created a very heavy shock and broke some timber, some of the walls of the aircraft in a part of Palmdale. They found that it could do some damage, so they set up a test—“they” being, I think, the administrators of whatever was going on. They had a pilot fly at, I think, 30,000 feet, and perform what would be a shock and boom. They rigged it up so that we could hear the conversation with the pilots, and they were talking back, letting us know when we should have it. A sonic boom travels at something like 5,000 feet? It caused a lot of discussion about what would happen.\n\n Another interesting thing, I lived in Mojave—right then, they were testing the atomic bomb. I can remember driving to work and seeing the plume from Mojave and Lancaster—just over the mountains. It turned out that was about 400 miles from there. Some people would go up into the mountain, hike up into the mountain so they could watch that. The most spectacular thing is they rigged one up so that they could hear it in Los Angeles, from Lancaster. It was all set up on what you could hear. They had a countdown, and all of us saw it. The whole light, the whole area just lit up, and real intense light from Lancaster. That was part of our technology, I guess.

Rebecca Wright: Tell me about this picture here, with these points.

Earl R. Keener: We heard from Langley that you could make, we called them four-bodies, in the front end of an airplane. The Langley people—it was one of serendipity, I think they call it. They were just testing a probe of some sort, and found that it would create a side force. We were looking for something to do, and Langley told us about there, and we realized that this was a whole area, a whole, complete area of aerodynamics. We joined in, and there were some questions: one was conical, and it created quite a side force; tangent ogive created a side force. What I was interested in was, what happens if we blunt the nose of the vehicle and the side force diminished? We did quite a bit of work with that.

Malinda Alves: My mom was telling me that scientists from around the world were working on the nose shape of airplanes. My dad was involved in completing the statistics on that, then they went out and actually started blunting the noses of the airplanes. He was involved in all of that.

Earl R. Keener: We did quite a bit. Why I emphasized that is high angle of attack used to be up to 15-18 degrees, but when we went in there, it was ±90 degrees, and we were making measurements. You’ve seen them shoot a rocket off of a submarine, and if you look closely, the rocket goes off and goes like this and recovers and goes off. We didn’t know whether it would recover or not because of the side force. We did quite a bit of research on that.

Rebecca Wright: Did you publish a paper about the blunt nose? How was that received?

Earl R. Keener: Yes. They were major papers at that time on that subject. I had some important people. The professor was such a big help to me. He would walk around Ames with his library in each hand. I hate that I can’t remember his name. [He was] out of the Illinois University, I think it was. He was well known at the Center, there. He would talk to us. He was really great on unsteady. He pointed out that these flows are not steady, and most of my research was based on steady flows. That brought another part that opened up the unsteadiness, and what it might have.

Rebecca Wright: Tell me about why this picture tells us so much.

Earl R. Keener: This was an agreement we had with, what did I say, Lockheed? The agreement was that we’d design one that had this shape, and they would design other. What we’re looking at is the flow with the oil flow. The flow here, it comes to mind, this was the design condition, angle of attack of 5 degrees, and what happens to the flow? What is this Mach number, 4? Not 4, but 9/10. It was decided by the group of us, and then I was assigned to run these tests, so I increased the Mach number to about 9/10.\n\n You see a big vortex, here, that formed. It was of great interest to us. I forgot to tell, I think, one of the most important—some brilliant engineer from Langley, I’d say, probably, that got the idea, I guess I told it, that they could fill in the intermediate area. I think I went through that. The X-1, and then my main job until I left was measuring pressures. There’s a case of conical camber.\n\n For a swept circulation control model in the 6 by 6-foot transonic wind tunnel at Ames, I was asked to set up a test. We got interested in a circuit control. This was to investigate circulation. It was sort of astounding, but they built an airfoil that had a blunt leading edge, they found that they could blow over the leading edge and create lift. At zero angle of attack, they could create lift at this. I just designed a test.\n\n Tested both, un-swept and swept. I ended up being able to corroborate what had been found about sweep. We could sweep it and get the same result at flow that’s approaching at the angle, which was important. And the Shuttle. We had already gone through with this other design group that was looking at that kind of design. They designed the M-2, the lifting body.\n\n The idea was to try to get enough lift, I think this would be just—our tests, I know the model was dropped. They tested down at Edwards before I left, and I got into the wind tunnel testing of it. I didn’t do any of the design of it, but this thing was designed to fit on the head of a Titan missile, and would hold something like eight people, or corresponding. Air Force came along and wanted something longer, so that’s what happened to this project, here.\n\n I was also there when he crashed. Let me tell you about that. This was something. I was in on preparing for the test. I had two jobs. I liked the boundary layer research, and I liked that, but I had the responsibility of just making the wind tunnel test. This was the year before we made the test. I went up on a hiking trip into the mountains, and one of the fellows on the trip was the one that was the pilot on this crash. It was the first time that the outside had photographed. We had a design problem, and so, we asked the pilot not to fly it below angle of attack of, I think it was 5 degrees. They dropped him, and somehow, this was a subsonic relation, there was a helicopter to one side. They dropped him, and I could tell this way, they were following him with the test plane, and this was all un-powered. He was just dropped. I forget where I was. Maybe I might have seen the results of it later. I’m not quite sure whether I was right on that spot. They dropped him, and somehow, he got into this—it’s this kind of thing—instability. I think it was this test that he came in for a landing, but the lake down there at Edwards is very flat, and it has a runway on the lakefront, on the lakebed. He lost sight at the landing strip.\n\n We had a cheapie model, and the landing gear, they decided to design it so that it would just drop by gravity. Somehow in there, he lost his track, and he went into that rolling, since it was a cone, or a half a cone, actually, went into that rolling, and rolled down. It was [Bruce] Peterson, the same guy that was on this camping trip. He said later that he thought he’d hit the helicopter, but he didn’t. He lost his sight on that landing strip, and that probably increased the angle, the angle of attack. They got him out, and knowing after the fact that he had an eyelid, as I understand it, an eyelid cut, I’ve heard a couple of things. He had a helmet, probably helmet problem. I had heard later that if you lose an eyelid, it’s possible to lose your sight, so I tell, you got here just in time, I guess.\n\n Along comes the X-15, and some argument over the design of it actually, a hypersonic shape, the wings would be swept back. That’s it. Langley ran some studies and found that they couldn’t land with a delta shape or nothing because it would be too much force on the nose gear. That caused them to design the X-15 with more of a straight wing.\n\n [We studied] the space plane. Since then, they’ve had many space planes. The idea was that they wanted to take off to orbit. Take off to orbit. I remember [the Illinois professor I mentioned earlier] comment, “Well, at least it’ll have five more years of hypersonic research.” Just like the rest of us, we didn’t believe it at this time. I was getting involved in—the shape of our wind tunnel models is never the same as what is going to be built because the next day, they may change it. We build research models, and this one [shadowgraph photograph of jet plume] is supposed to be right when you turn it upside down because that’s like a wing. It’s like a wing with a rearward surface. We measured the pressure across here. I probably went out on contract for a couple years.\n\n It was the eighties, early nineties. I can’t believe this—this required five different groups. You can barely see the shadowgraph photographs, and then we have the pressures on the body. That led to the possibility of computation. We had a very young, excellent, I think he was under contract, too, for calculation. He ran a calculation on the flow, and it was very close. Depended a lot on whether it’s turbulent or laminar. Partly what was involved is Gary, he was my supervisor, in fact, I had an opening for a job. I went to Gary and he and I had a remarkable relationship. We could talk faster than—you can get a lot more done if you talk faster. He was fascinated by this project. He was on the main committee.\n\n It’s very interesting to trace what the exhaust does on a space plane, or on any of the Shuttle, or what happens. As you increase the Mach number, as you get to higher Mach numbers, the flow can’t flow out of the exhaust as normal. To get into orbit, you have to then use, it’s real simple and very important... They would get some thrust out of, seemed to me, whatever it was they were discharging. That can’t know how to put it, but just by blowing, instead of like a jet, it’s over and above a jet. Releasing oxygen or releasing a jet, or not jet, but fluid, which you don’t normally do, I don’t quite know how to put that.

Rebecca Wright: What was your conclusion about the aerospace plane? Did you think it would fly, when you were working on the study?

Earl R. Keener: You’re talking to someone who didn’t think the X-15 would fly. My record on that, that was a beautiful research, and went up before I transferred to Ames. It was X-15 when we went to Mach 6 on that, pretty fast. They were going to even go higher, but they didn’t make it.

Rebecca Wright: Did you ever want to fly? Did you want to be a pilot?

Earl R. Keener: I joined the Air Force. That doesn’t mean that I wanted to fly. I joined the Army Air Corps, and as a cadet, went in as a cadet, and they closed the system. They closed the program. I think I sat through maybe one or two days. The next day, we were out, just walking around. You don’t do that, normally, on a base. Some lieutenant stopped it, asked why we weren’t marching in concert. I let him know that the program had closed down. I looked for another job on the base, got my trombone out, and joined the band. The base was in Texas, right on the Mexican border.\n\n At any rate, that’s a whole subject on itself because the Chinese, they were training their pilots on two-engine research. We would have some times when the general, the Chinese general, would come. The head of that center was a colonel. He was very happy with the results, and the general was happy, and so the colonel was happy. The colonel told us, “March through the headquarters building, playing your instruments.” We did that, except I had a little problem—to my horror, I had lost my mouthpiece. I played through that without it. I think, a couple of the officers looked rather strangely at my horn—it had dropped out someplace.