NASA HEADQUARTERS NACA ORAL HISTORY PROJECT

EDITED ORAL HISTORY TRANSCRIPT

CHRISTOPHER C. KRAFT, JR.

INTERVIEWED BY REBECCA WRIGHT

HOUSTON, TEXAS – AUGUST 5, 2014

WRIGHT: Today is August 5, 2014. This oral history session is being conducted with Chris 

Kraft in Houston, Texas, as part of the NACA [National Advisory Committee for Aeronautics] 

Oral History Project, sponsored by NASA Headquarters History Office. Interviewer is Rebecca 

Wright, assisted by Sandra Johnson, and we thank you for agreeing to come and talk to us this 

afternoon.

KRAFT: My pleasure.

WRIGHT: We’d like to talk to you about your time at NACA, and actually, even before that, 

when you were still at VPI [Virginia Polytechnic Institute, (Virginia Tech), Blacksburg, 

Virginia]. I remember in your book that you talked about using and learning from those NACA 

reports during that time. Can you talk to us about that experience of what you learned from 

those reports, and actually, what you learned about NACA and why you thought that might be a 

place to work?

KRAFT: What I said there was an overstatement, so I have to back up a little bit. When you 

study aeronautical engineering in 1944, when I graduated, what we were studying was basic 

aerodynamics, basic physics, basic things that you would eventually use in aeronautical 

engineering. Our capabilities, our teachers, were not very versed in the problems of aeronautics 

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of the time. There was a lot of reasons for that. A lot of the research was confidential, so they 

couldn’t know it. NACA reports were confidential, so we couldn’t know it. As an example, it 

was obvious that the use of wing sweep was going to be a major part of the future airplanes of 

that age, and all of that was confidential. The Germans were doing it. You could almost get as 

much data out of the German reports as you could NACA reports because if you had their 

reports, it was okay, but to have the NACA reports, you had to put them under lock and key. 

Things like turbulence, the first NACA report was about turbulence, flying through 

turbulence, believe it or not. The early reports were basic. A lot of things on structures, a lot of 

things on wing shapes, on air flow shapes. There were a number of books that were published by 

NACA that were just hundreds and hundreds of cord shapes, of wing shapes—cusp and flares 

and all that kind of fancy stuff that you could do to change the basic stability of the wing as 

opposed to the lift of the wing. They were published, and those were almost catalogues, and they 

were fundamental to the designer of the times—the designers, remember now, being late 30s, 

early 40s. That’s what I was referring to, really.

As I was trying to design a small, light airplane, which was one of my classes, I wanted 

to get what the wing shapes were, the effects of aspect ratio, things like that, which I knew little 

about. The types of airfoils that were the most efficient and give you the least drag, and would 

couple generally with a light airplane. That’s what I was referring to. On the other hand, 

structures, as an example, was something that was coming on at that time, and we had a heck of a 

good airplane structures prof [professor], and I learned a lot from him, and so did NACA when I 

got there, because I had had that background. 

The books were pamphlets, big, thick pamphlets put out by a couple of the aviation 

companies. They were very, very informative. That’s where I got my early knowledge. I really 

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have to say, I was not very smart. I didn’t know how NACA went about doing their work. I 

didn’t know how they went about publishing their information. I didn’t know that their product 

was reports, basic writing. I’m pretty glad I didn’t, as a matter of fact, because NACA reports 

were very dull. One of the first reports I wrote at NACA was on the [Republic] P-47 

[Thunderbolt] airplane. It was a lousy airplane from a flying qualities point of view and, really, a 

control point of view, and I said that. In the beginning of my report, I wrote that down. The 

editorial office says, “You can’t say that.” 

I said, “It’s a classical example of what you should not do to design an airplane.” 

They said, “You can’t say that. You can say what it is, but you can’t say what you said.” 

They were kind of dull, but fundamental.

All the fundamentals were catalogued by NACA. As you know, the cowling, as an 

example, was an invention of NACA, and it changed the look of modern airplanes in those days. 

It changed the drag, eventually, and increased the efficiency of the engine, as a matter of fact. 

NACA was very prominent in anything that aviation did. Later, after I got there, and airplanes 

started to go high subsonic, supersonic, those airplanes were actually designed in the NACA 

tunnels. The [Vought] F8U was a classic example. That airplane, which is the first Navy 

supersonic airplane, which I was in charge of for NACA in flight test, not as it came through the 

tunnels, but every nuance on that airplane was an NACA nuance. That was quite impressive. 

Go someplace else—talk about the [Bell] X-1, as an example.

WRIGHT: NACA wasn't your first choice to work.

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KRAFT: No. I was going to work for Chance Vought [Corporation], and I don’t know, can’t tell 

you why. I was a young student out of college; I didn’t know where I was going. I said, “NACA 

is right next door to me, I’ve been living here all my life, why don’t you go someplace 

different?” I couldn’t get hired. You read that in my book. They wouldn’t hire me. I had two 

job offers. One was with NACA, one was with Chance Vought. I could have probably had 

more, if I wanted them, but I just took Chance Vought, and so I didn’t even mess around with it. 

I did take the one from NACA as a backup, and fortunately, that was a good thing to do. 

When I got to [NACA] Langley [Aeronautical Laboratory (now Langley Research Center), 

Hampton, Virginia], most of the people knew who I was, as a kid. Where I grew up, everybody 

knew, it was a small town business, and everybody knew everybody from everybody else. They 

knew my name, and so they were very kind to me. I remember when I went to see the personnel 

guy, he was very nice to me, and he said, “Well, I think you’d fit best in flight research.” He 

said, “What are you interested in?” 

I said, “Well, I’m not quite sure. I’m not sure I know what I want to do. I’m interested 

in stability and control and things like that.” 

He said, “Well, I think you’d be best fit in airplane flight test.” I didn’t know what that 

meant. He said, “We’ll put you over in the Flight Research Division. They got a bunch of smart 

guys over there that’ll teach you how to be an aeronautical engineer, and I think you’ll make out 

well over there.” He was absolutely right. That was a wise thing for me to go there to work 

because they were working on all the modern airplanes. They could work you on the P-47, the 

[North American] P-51 [Mustang], and the [Bell] P-39 [Airacobra]. They had those airplanes 

flying. It was in the old hangar—they built the new hangar while I was there for the Flight 

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Research Division. It had a Japanese [Mitsubishi A6M] Zero. It was a great place to learn, for 

me.

WRIGHT: I’m sure it’s a great place for those pilots that got to fly all those different airplanes as 

well. You worked close with the pilots.

KRAFT: Yes. Back in those days, at NACA, test pilots were not very prevalent. NACA taught 

several of their aeronautical engineers to be test pilots. Jack [John P.] Reeder, who was one of 

the best test pilots NACA ever had, was just an aeronautical engineer in the full-scale tunnel, and 

they made him into a test pilot. Mel [Melvin N.] Gough was an aeronautical engineer. He had 

graduated from Johns Hopkins [University, Baltimore, Maryland], had a job at NACA and saw 

what was going on, resigned from NACA, went across the river, across Hampton Roads, to join

the Navy to learn how to fly Navy airplanes, and came back to NACA as a test pilot, and 

eventually became their chief test pilot. 

Those guys were not too unlike me. I was a young, wet-behind-the-ears aeronautical 

engineer and didn’t know tiddlywinks about airplanes. I was a baseball player. I wasn’t an 

engineer, and airplanes didn’t interest me. I’d been there all my life, watched them fly over me 

and go to the air shows and so forth, but I never was interested in airplanes. That professor at 

Virginia Tech got me interested in airplanes.

It was a great place to learn. NACA was a really great place to learn, and I’d learned 

about flying qualities that [Robert R.] Gilruth had written [Requirements for Satisfactory Flying 

Qualities of Airplanes, NACA Technical Report 755]. I went to class at night, at Hampton High 

School, had classes at night in various elements of aeronautical engineering. [William] Hewitt 

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Phillips, who was my boss, taught flying qualities. I would go there two or three nights a week 

and learn what flying qualities was. I realized how great a man Gilruth was. He and Mel Gough 

had developed flying qualities, and that was the Bible for how to build an airplane from a 

standpoint of flying it, and it was the Bible of how to test an airplane. 

The Army [Air Corps] and the Navy adopted that document as the basis upon which they 

were going to buy airplanes. That put me in the know on what all airplanes were. The 

significant fact that was a part of your teaching, and was knowledge, in NACA in those days, 

was everything was static. When you talked about the forces that operated on an airplane, you 

were talking about the static conditions. What were the balancing forces? You measured those 

forces in as static a condition as you possibly could. This was before anybody even thought 

about doing a dynamic analysis. You’d write the equations of motion for an airplane, it was just 

the static forces you were dealing with. 

By a year or so after I got there, the biggest thing about the dynamics of an airplane was 

what is the time to damp to half-amplitude? You do a step input with the stick or with the rudder 

or with the ailerons and see what happened. You would see how it damped. In other words, if 

you pull back on the stick, if it damped in 1.5 cycles, that was the test. That was the only 

dynamic test. 

Within a year, I was writing equations of motion in the airplane. It was all dynamics 

because it was obvious to NACA, particularly, that as you approached higher speeds, the 

dynamic aspects of the airplane were equally important as the static aspects of the airplane. All 

the wind tunnels, all the flight tests began to look at the flight dynamics, as opposed to balancing 

forces. Of course, that changed all the mathematic analysis, also. 

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When I was in college, I’d never heard of a Laplace transform. I took operational 

calculus, which is all I needed when I got to NACA because that’s how you wrote the equations 

of motions of the airplane, but wasn’t too long after that, that the dynamic parameters which you 

left out of the equations of motion had to be considered. They became as predominant a force on 

the airplane, naturally, as just doing it as a balance stick. The wind tunnels, everything started 

becoming interested in dynamics instead of balancing.

The other thing, however, was that, as I alluded to, it was obvious that in order to get to 

the problems that you were having at high subsonic speeds—as the Mach number began to 

increase, most airplanes at that time period, the high-speed airplane was about 550 miles an hour 

and Mach 7/10. If you increased the speed, increased the power, and the jet engine was not 

going to allow you to do that, get a lot more power and efficiency out of a jet engine than you 

could with props, and propellers were limited in their aerodynamic design as well, it was obvious 

that you were going to be flying at higher Mach numbers. What is the airplane going to have to 

do to deal with higher Mach numbers? 

They began to look what the Germans were doing. The Germans were sweeping their 

wings. Immediately, NACA started sweeping wings and seeing what that did to the wind tunnel 

and how that changed the dynamics of the machine, how that changed the drag, how that allowed 

them to prolong, put off a swept wing. All you’re doing is you take the angle of the sweep, and 

multiply that times the speed. You find that, well, the force is coming along the cord, and so that 

allowed you to design the airplane to fly at Mach 9/10 while the wing was going to 0.75. Just 

that simple aerodynamic feature. The Germans figured that out pretty quickly, I guess by rote, 

by trial and error, because I don’t think they had the wind tunnel capacity NACA did.

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As soon as we started mucking around with sweep, we found out that was a very 

prominent thing that was going to be in the new airplane. The other thing was that [Richard T.] 

Whitcomb—Whitcomb was an aerodynamicist of my age, maybe a little older, not much, he just 

died recently. I think it was the [McDonnell] F-101 [Voodoo] and the [Convair F-]102 [Delta 

Dagger], one was a delta wing and one was a straight wing, and they found that the doggone drag 

was a lot higher than they thought. They had drag interference between your fuselage and the 

wing, interference drag, they call it. 

Whitcomb figured out that if he slimmed the fuselage down where the wing came in, that 

the drag went down. They didn’t understand that, but it worked, and then he figured the math 

that went with it. That’s how he became famous. At that time, those two airplanes would not go 

high subsonic, into the transonic range, and they put the Coke bottle shape in there, and lo and 

behold, they reduced the heck out of the drag and they were able to get a lot, almost 1/10 of a 

Mach number higher, speeds out of it. That’s the kind of gimmicks we were getting to, to try to 

get close to the transonic range. We all knew that the one block that we were facing was, what 

did we call it? When you get to Mach 1?

WRIGHT: The sound barrier?

KRAFT: Sound barrier, right. Everybody said, “Well, we got the sound barrier right there,” and 

all the math said that drag became infinite at that speed, and of course, it didn’t. We knew that 

bullets would go through the speed of sound, but we didn’t understand the math. We didn’t 

understand the design. The wind tunnels that we had would not measure the forces in the throat 

of the tunnel because they got these shockwaves coming off of the wing, and that screwed up the 

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flow. The flow became turbulent. If you know anything about aerodynamics, at any speed 

you’re flying at, the air is not only worried about what’s there, but it’s sending out signals in 

front of it. It literally sends out a signal that I’m coming, and tells the molecules of air what to 

do. The closer you got to transonic and high supersonic speeds, the signal wasn’t there anymore. 

It was just a flat shockwave coming off the flat plane of the wing.

That fact, you put a configuration in the wind tunnel and the shockwave would come off 

and the flow would be destroyed. All the measurements you would make on the wing or the tail, 

on the whole airplane, were in error because the flow was wrong. It wasn’t what you were going 

to see when you actually got flying in free air. That’s where John Stack became very famous at 

NACA. John Stack invented the throated tunnels. What he did was put a force outside the 

tunnel and suck that air off, suck the turbulence off, so that you could measure things at 

transonic, supersonic speeds. 

We people in flight tests were trying to come up with, well, what can we do—Gilruth was 

thinking about those kinds of things—to measure what’s happening to the airplane at transonic 

speeds? He came up with these two techniques that we were using, which is what I started 

working on, almost from the time I got to flight research. That is, we would take a high fineness

ratio body and put a wing on it, and sweep the wing to various angles, put the wing at various 

locations before and after the max [maximum] diameter of the fuselage, take it up to 35,000 feet, 

drop it from a [Boeing] B-17 [Flying Fortress], initially, and we had a balance inside the fuselage 

to find the high fineness ratio body, and we put telemetry in there. 

Nobody had ever used telemetry before. We tracked it with radar as we’d drop it, as it 

fell. That way, you got into free air to measure the aerodynamics, and with the radar, we could 

measure the velocity very accurately. We could do all kinds of configuration testing. We could 

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express our measurements on the body, on the high fineness ratio bodies, and you could locate 

the wing at different positions back and forth. Lo and behold, there was the Coke bottle.

We found, hey, we put the wing behind the maximum diameter of the body, the drag 

decreased because it reduced the interference drag between the fuselage and the wing. That was 

a big invention of the time. Sweep, high fineness ratio bodies, and location of the wing relative 

to the fuselage. A lot of airplanes then started using that to get through transonic speeds. The 

theory said that what happens as you approach those Mach 1 is that you get separation of flow. 

If the air separates from the wing or the tail, either, it loses its effectiveness, and you don’t know 

what that is. You can’t measure it in the tunnel, and we can’t predict it. We can’t write the 

equations which predict what’s going to happen. That promoted the thickness of the wings and 

the tail. 

Up till that time, their initial thought was, “Well, you got to have thick wings because it’s 

got to be really strong to withstand these forces that you’re going to get;” high Q forces that you 

were going to get at high speeds, but that was wrong. What we needed was thin wings, so that 

makes sense, doesn’t it? Thin wings are going to have less drag, and that’s what happened.

We didn’t know what kind of controllability we would have, or whether we could predict

[the controllability] in order to design the stability and control of the airplanes. We didn’t know 

what that was going to be. We’re all searching for how to measure the forces that acted on the 

configuration you had at transonic speeds. Gilruth came up with body over a P-51 and the drop 

technique, and then he took the rocket, put the bottle on the end of the rocket, and then you could 

get to Mach 3 easily, by firing it on the end of a rocket. 

Everybody was looking at those kinds of techniques. Then, that further exacerbated the 

stability and control problems, the dynamics problems, and that’s when everybody started 

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working on automatic stability and control. How can we provide stability and control when we 

know the configuration, but even if we don’t know the configuration, we could measure what’s 

happening and we could use that information to provide forces to correct the forces which are 

about to send you off somewhere. 

Now, about 1951, ’52, ’55, that’s where, in that period, automatic stability and control 

became prominent. You mix wing sweep, new ideas about drag, and artificial stability and 

control together, that’s the modern airplane of the time. That developed at the NACA from ’46 

to spaceflight. Everything that we were doing at NACA was going in that direction. It was 

slow. 

The other thing I’ve forgotten, did not talk about much, is the jet engine. With the jet 

engine, you’d get reduced drag, and so, therefore, how can we get high, efficient jet engines? 

That’s the other thing that NACA began to get into, was how to reduce the fuel consumption of a 

jet engine. The first jet engine airplane was a Bell [XP-59A Airacomet], Bell Aircraft built one, 

a low-wing monoplane. I think it could only fly about 30 minutes, was highly inefficient. 

Everybody jumped on that, to try to improve the jet engine. 

We had all these bi-flows and air flow changes and prop design inside the jet engine, the 

vanes inside a jet engine. That became also a requirement of the NACA, to improve the 

efficiency of the jet engine. All those things were coming, being driven by the jet engine; you 

could get to the speeds you wanted to get to, but you couldn’t fly there. The F8U airplane would 

fly at supersonic speed for 6 minutes and run out of fuel, so you needed to improve the 

efficiency, needed to improve the drag, you needed to improve the stability and control, and you 

needed to invent automatic stability and control. Those were the design requirements that 

developed in the time period when I grew up in that age.

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WRIGHT: Can you explain to us how all of you that were working on these projects exchanged 

information?

KRAFT: We had this exchange of information between the divisions, we had meetings, we had 

high-level management meetings, but the other thing we did was our product was reports. 

Everything we did, we had to write about, describe in detail how we got there, what the math 

was, what the measurements were, if we had any, and then write the results of it, the effects of it, 

in the English language. What we did then was if I wrote a report, then it was sent to the other 

organizations at NACA that were similar to what I was in, flight research and stability and 

control, and it went to the wind tunnel people, it went to the structures people, and they would 

appoint an engineer to be a reviewer of the report. 

You would send them the report, they would read the report, they would comment on it, 

both technically and the writing, and improve not only what the writing was, but make sure it 

was technically correct. You would have these meetings and they would come in with their 

comments. You, the author, had to take those comments and justify what you had said, or 

correct it on the basis of what they said. Everybody was feeding off of that information, 

continuously. That’s where I learned that the easiest thing in my life I ever had to do was 

criticize somebody else’s work, which is true. You learn a lot that way, a heck of a lot.

WRIGHT: Were you working with Ames [Research Center, Moffett Field, California] and people 

with Lewis [Research Center, Cleveland, Ohio] as well?

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KRAFT: We didn’t have that close a relationship as I just described with the reports, but there 

was, yes, a similar transfer. Not as great because of the distances, but yes. We had an NACA 

conference, eventually twice a year, where the whole universe of the aviation industry would 

come to NACA. We’d have it one time at Ames, one time at Lewis, one time at Langley, 

rotating, and we had these vans that would take all of these people, and we’d be about maybe 

500 people. We had to set up these stations around all of Langley, and we’d have an engineer 

who’s responsible for making a presentation at every one of those stops. 

They’d divide these people up into groups of 25 or 30, and you would have to make that 

spiel about 10 or 12 times a day. That would take about three days. We did that every year, with 

the NACA conferences. Start out in the morning, where they would go to the main auditorium 

and the head management and the head of the various divisions would make a presentation, 

probably the most significant of the presentations, to the gathered group, and then we’d split 

them all up and send them out in these little groups to review the work. 

That, plus the reports—now, here comes all these NACA reports—the time scale on 

those was lousy. It took too long to get it through the editorial office and get it through this 

process, but eventually, and we had several classes of reports. If it was for the services, we had 

these preliminary reports that we would put out, which were not edited, that just presented the 

data, and sent them out. They sent us an airplane, and we would give them the results of those 

tests that we had done, various phases. We’d send them a report, which was undisciplined, I 

suppose, so they would have the data within several weeks after we had obtained that. The 

actual report itself took another six months. That was just a confidential report, and then we 

wrote technical notes. To get a technical note took probably four or five years to write because it 

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was fancy graphics and fancy writing and highly centered and highly edited. The editorial office 

was as important as the engineering offices were. It was a good product.

WRIGHT: You had some support with math, as well? I think you’ve mentioned this before, it’s 

your first dealings with the computer was during that time, but you also had all the math 

equations to work out.

KRAFT: My highest math was operational calculus when I was at Virginia Tech, but as we got 

into dynamic analysis, as we got into an analog computer, which you mentioned the REAC 

[Reeves Electronic Analog Computer], then that was a whole new world to get into. Because 

none of us knew that kind of math and none of us knew that kind of analysis technique. That 

was cumbersome and it took a long time to evaluate because if you write the equations of 

motions and you do all this math, you get one single point at one single point in time. What you 

want is a time history of what happened to the airplane for the next 25 seconds, as an example. 

To do that, you had to compute what the airplane was doing maybe, probably initially, every 10 

seconds in time. Whereas if you had a computer, you got a continuous readout of it. We didn’t 

have a computer—what we had was a Marchant and Friden machine. Have you ever seen one of 

those?

WRIGHT: I have seen one, yes.

KRAFT: You sit there and crank that damn machine. Took me three months to get one time 

history of an airplane response. If you pull back on the stick on a fighter airplane, it will go like 

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this and damp out and get to 2 Gs [gravitational force]. In order to do that mathematically, it 

would take you maybe three months on a Friden calculator or a Marchant. 

On a REAC, you could do it in real time, but you had to convert the forces in your 

equations of motion to electronic terms, as opposed to force terms. In other words, you had to 

interpret your equations of motion into an electronic circuit, which then would respond to the 

way your airplane would respond. Does that make sense? REAC was nothing but—it was a big 

panel, about that big [gestures], with hundreds of knobs on it. Those knobs would change the 

resistance, the capacitance, and what’s the other term, in the electronic simulation of your 

equation of motion. 

When I first started doing that, I didn’t know what the hell I was doing in the first place, 

but I got an electrical engineer to help me construct this equation of motion into electronic terms, 

but then I need somebody to teach me how to use the various parameters that I had on that 

computer to simulate what that equation of motion was. You’d have to go away, and in order to 

show you the answer was right, you’d have to do it mechanically, first, do a time history of the 

response of the airplane, and then compare that to what you were putting into the REAC. 

Of course, if you got to be an expert in that, after a while, that was the right way to do it. 

Fortunately, the card machines came along, digital machines came along instead of analog, and 

instead of recreation, electronic recreation. That’s what NACA had bought, was card machines. 

Didn’t take long to get rid of them because it was a monster—the whole damn base was covered 

with cards. These big banks of cards, do you ever remember that?

WRIGHT: I’ve seen those, yes.

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KRAFT: Banks and banks of cards would have been describing this equations of motion of what 

you were dealing with. That was driving me nuts—I hated it because I couldn’t understand it. 

When I wrote an equation on the airplane, using quadratic equations and eventually, operational 

calculus, that was pretty straightforward for me. When you got to Laplace transforms, that was 

not the case. Laplace transforms is a fancy mathematical technique—it’s really a logarithm, like 

a logarithm, so you could describe the airplane’s response, together with its automatic pilot—it 

had its own dynamics—and Laplace transforms allow you to do that. 

MIT [Massachusetts Institute of Technology, Cambridge], they were the godhead of 

automatic stability and control, and they wrote these books. I remember the math book. I tried 

to teach myself that math, I’d work at it and work at it. My boss, Hewitt Phillips, was a genius, 

and I’d work for weeks trying to figure out the derivation of my work. I’d do it and then I’d take 

it in and show it, discuss it with him. He’d look at it for 5 or 10 minutes, and he’d say, “Why 

didn’t you do it this way?” It used to really piss me off. He was that smart. He knew how to do 

that damn high math. He had graduated from MIT, it’s where he got his teaching. 

Bob [Robert G.] Chilton, I don’t know if you know that name or not, but he came into 

our stability control branch about a year and a half, two years after I got there. He taught us all 

how to do it. He came directly from MIT. They called it the Instrumentation Lab [Laboratory] 

back then. Now, it’s called the Draper Lab. That’s the reason we hired Draper to do all of our 

analysis, eventually, as we got to spaceflight.

WRIGHT: I know that the NACA did a lot of evaluation of the aircraft that was being built by 

contractors, and at times, I’m sure the NACA found some issues that they had to discuss with the 

contractors.

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KRAFT: Eventually, we got the third airplane of any new airplane out of the military. It was sent 

to NACA, the third airplane built, for flight tests. The aircraft company themselves were doing 

the initial flight test, then the Army was doing the flight test, and the Navy, and then NACA was 

doing similar flight tests. We got together with their flight test people, with their flight test 

engineers with their test pilots. They would come to see us or we would go to see them. They

were at various places. 

The Navy had a flight test center on the Patuxent River, called [Naval Air Station] 

Patuxent [River]. We would do these flying qualities tests, various maneuvers that you do to 

measure the airplane response, and we put instruments inside the airplanes, and got the answer 

on film. It was a mechanical process, light-driven sensors connected to a potentiometer, as an 

example, to tell you where the drill surface was, or the stick is. Then, we had devices for 

measuring rates and accelerations. We’d measure all that and put it all together. That’s where 

the girls came in to play. When I first got there, I was doing it myself. You would actually take 

the film and a plastic scale and measure the deflection of the trace, and from that, you could tell 

what the numbers were. This is where the elevator is, this is where the stick is, this is what the 

rate is, as you do this maneuver. NACA was very efficient at that, very good at that, and very 

accurate at that. 

That’s where I spent half my time, calibrating instruments. If you got a vane or the 

position of the surface, I go there and have to put it here and see what the film said. I’d calibrate 

the potentiometer that was on the surface, just a rotating thing, electronic signal going to my film 

box and film measuring, tell me what the deflection was. We knew what the calibration of the 

measuring device was, and then we’d calibrate the surface itself, or whatever it was. It appears 

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to be that that’s pretty tedious, but it wasn’t tedious at the time because that’s the only way we 

could do it. Now, you wouldn’t do it that way, but nevertheless, that’s the way we did it. 

You can do it by all kinds of crazy ways, now. Electronic devices can allow you to do 

that. The tunnels had certain sets of instruments and manometers to measure the pressures and 

velocities and flow. They had their own set of instruments. They were highly accurate, highly 

expensive, and very difficult to calibrate, but that’s what they did. Then, of course, they began to 

get computers. We called them “computers,” but very pioneer devices, that eventually, they had 

high-speed information also, but it took a long time to get there. That was what NACA was 

doing when the space program came along.

WRIGHT: Sputnik [Russian satellite launch] changed a lot, didn’t it?

KRAFT: Yes, it did.

WRIGHT: You want to talk about that? Your thoughts when you first heard about the satellite?

KRAFT: I remember I was in Washington [DC], at an automatic stability and control meeting, 

and we read about it in the paper, I think. Talked about it at the meeting. A couple of weeks 

later, I was up there when Vanguard [rocket] flew. I remember being in a taxi, and the taxi 

driver said, “Hear what happened this morning?” 

I said, “No.” 

“Had a rocket blow up down there at Cape Canaveral [Florida].” That was the Vanguard. 

Came up off the bed and exploded. That was the country’s first attempt to put up a satellite. It 

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immediately got everybody thinking, well, in the first place, about orbital mechanics. I didn’t 

know a damn thing about orbital mechanics. Immediately got people thinking about highaltitude pressures and temperatures and ways of measuring the environment and ways of putting 

instruments into zero gravity in a perfect vacuum. Of course, people immediately—I wouldn’t 

say immediately, probably close to it—started thinking about, well, can man survive in that 

environment? Can he survive at zero gravity? How do you keep him alive? That’s a whole new 

ballgame.

Our high-speed airplanes that were going to 50-60,000 feet were using g-suits and 

pressure suits already, but not space suits. They had means of supporting the body from an 

acceleration point of view, and namely means of providing oxygen at the upper altitude, upper 

levels of where they were flying, up to 60-70,000 feet, but they didn’t have a space suit per se. It 

initially started out being g-suits as compared to space suits. The initial test pilots sucked on a 

tube to get oxygen before they had masks. Back when I first went to work, if you flew at 35-

40,000 feet, you did have a mask, but you also had a backup tube of oxygen. All the early test 

pilots used a tube in their mouth, but that progressed pretty rapidly, too. 

The Army Air Corp was in the lead at Akron, Ohio, where they had a test facility. All 

that kind of equipment was being developed there, in consultation with the flight test people, 

where I was. That was a whole industry in itself. We began to think about what the problems 

were of stability and control, of reentry, of thermal protection that we hadn’t ever thought about 

before, and Gilruth and several of his engineers started thinking about how to put a man into 

space. 

I remember that Chuck [Charles W.] Mathews—whom I worked with very closely in 

different things, and eventually he was in charge of what I was doing—four or five of them that 

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started thinking about putting a man in space. The Air Force was thinking about it also; they 

called theirs the MIS Program, Man in Space Program. I was not in that group. 

Chuck Mathews and Max [Maxime A.] Faget and Caldwell [C.] Johnson and Aleck [C.]

Bond were all working for Gilruth in the Pilotless Aircraft Research Division, and he got a bunch 

of those guys to start working and thinking. Mathews was a very smart engineer, and so, Gilruth 

got him to come work on it. I knew that they were working on something about space, but I 

didn’t know any of the details until he asked me to go to work on it. As you discerned here, I 

was not very happy with being a mathematician, as compared to being an aeronautical engineer, 

or eventually, an aerospace engineer. That was a welcome request. I’d get the hell out of that 

math. I was good at it, but I didn’t enjoy it. I did not look forward to doing that the rest of my 

life. 

As soon as I went to work there, I had at least 10 things to do every hour. Different 

requirements that dealt with tracking or communications or geography or control, and how was

the body affected by it, how do we get information back, and how do we do that in real time? 

What could you do? That was where my thoughts immediately went.

WRIGHT: Were there significant changes with the transition from NACA to NASA that affected 

your job during that time period after Sputnik?

KRAFT: No. The changes were different in that our relationship with the aerospace industry 

changed, yes, but I don’t think that in terms of internal to NACA and the organizational aspects 

of NASA; NASA was still the NACA. They had just had additional duties called “Space.” 

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Now, it didn’t take long for us to be different because our jobs were so different. Now, 

we were responsible for the hardware like the Air Force and the Navy was responsible for their 

hardware. That was a different relationship for us, and that may have been one of the reasons 

that Gilruth wanted me to go to work in that area, because I did have that kind of experience, 

where I worked with the airplane contractors pretty closely in the flight test of airplanes, and I 

was pretty good at it. I was pretty rough with them, pretty straightforward with them. I don’t 

know whether he knew that or not, to tell you the truth. 

As in any organization, back in those days, they sort of protected themselves. They were 

always trying to protect their ass, so to speak, and it was my job to ferret that out. That

particularly came true on the F8U airplane, where I found out a hell of a lot of wrong things with 

that airplane. Sometimes it took a lot of doing. I had the airplane grounded, and they didn’t like 

that. Grounding an airplane was the last thing anybody ever wanted to do because it took it out 

of the hands of the operators. 

It was a whole new relationship then developed between the NASA government and the 

aerospace industry. The Air Force and the Navy did not have the technical competence that 

NASA had. The NASA engineer was a very different animal than the people in the services that 

were telling the aerospace industry contractors what to do and what they wanted, what the 

requirements were, and how they measured the contractor’s performance. It was a very different 

relationship. We knew technically as much about what they were doing as they did, and in some 

instances, more. Some instances, less, but our background, having been in the aerospace

industry ourselves, was pretty good. 

That was a new relationship that had to develop as we wrote the RFPs [requests for 

proposal], evaluated the RFPs, and then contracted for it and then built it. Building it and testing 

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it and proving its systems evaluations, etc., that was a whole new set of engineering 

circumstances that we at NACA did not have. We had to learn how to do that. We had to 

develop a working relationship with the industry, which I thought, it was difficult, but after we 

got it going, it was extremely profitable, from a hardware performance point of view, I thought. 

I’m right—I think that was unusual, but it was beneficial to both sides, both the contractors and 

ourselves, and I think we probably saved lives, the truth of the matter is. That created a new set 

of engineers, which are called flight controllers.

WRIGHT: You never had a hesitancy when Bob Gilruth asked you to come to the Space Task 

Group? Did you think twice?

KRAFT: I thought about it for at least a couple of hours. I didn’t know what I was looking for, 

but I knew it was a new opportunity, and I knew that I would be given an opportunity to lead, or 

to be a leader in that field, and I guess that’s what I wanted. I’m not sure I knew I wanted it at 

that time, but I liked doing that when I was a kid, so I guess that’s where that came from. We 

needed some leaders, and we got a lot of good ones. Got a lot of bad ones, too, but they get 

sorted out, after a while. 

WRIGHT: Do you feel like a lot of, or some of, the lessons that you learned, or some of the 

experiences that you had at NACA followed you on through?

KRAFT: Hell, yes. I knew what an instrument was, and I knew what a good instrument was, and 

I knew how you measured the response of an instrument to know what you were measuring on 

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the thing you were trying to measure. I know that’s a lot of nonsense I just said, but I knew how 

to do that, and I learned that at the NACA. I learned that from a guy named Piggy [Alfred E.] 

Alexander, who was an instrument mechanic, but I learned how to do all that. I saw when 

people started talking about the response of an instrument, or the responses and the inputs that 

had to the design of a system, they came up against a guy like me that knew what the hell he was 

talking about. That was unusual. 

The Air Force guy that had that responsibility in the past to them didn’t have that 

capability. He didn’t have any technical background. The NASA engineer had a heck of a 

background of various kinds that he had accumulated as a pure engineer. It was hard on 

McDonnell Douglas when they first started working with us, but after a while, we became a 

pretty good team.

WRIGHT: When I’ve read about people working within the NACA, what I always found very 

interesting, and I think very—“nurturing” is not the right word, but it’s the best one I can come 

up with the moment—was that the exchange of knowledge you got was not just from your 

bosses; it was pilots, it was machinists, it was, as you mentioned, the technician. Everyone very 

much collaborated in sharing that information to a large degree.

KRAFT: Very much so. When I designed a model of the X-1 and put it in the shop to be built, I 

designed it on the drawing board. I put the device in it to make it work, to get the data I wanted. 

I designed that and then I took it to the drawing board and designed that, and then I took it to the 

machine shop, and they built it. I was the guy that interfaced with the machinist, the chief 

machinist, not the guy on the lathe, but the guy that was their boss, making that piece of 

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hardware. You get that in the industry, too. If you were building a spacecraft at North American 

and you were a North American engineer, you interfaced with the shops. I had that experience 

as an NACA engineer. Then I had to flight test it. I had to think about what to do to test it, and 

then I had to do it, and then I had to write about it. I was sort of cradle to grave about the 

operation of some piece of equipment or some flying piece of hardware. We had a lot of 

experience. I don’t think we were any smarter than anybody else—we just had the experience, 

and we knew what questions to ask. After a while, we started figuring out a lot more about it. 

A mission rule, as an example; we would run these simulations and we’d come up against 

some problem that a system had, and we’d say to ourselves, “Well, we better write that down. If 

this thing happens in space, then we better write it down, and we also better write down what the 

hell are we going to do about it.” If this breaks, if this thing deviates, if this becomes a problem, 

what are we going to do about it? Why do we want to do that? We want to remember it, in the 

first place, and the second place, we want everybody else to know that’s what we’re going to do. 

You started sending this stuff up to the management, and they’d get this stuff—“What the 

hell is this?” Eventually, they wanted to know, what are the mission rules, what are you going to 

do? If the fuel cell fails, what the hell are you going to do? As I looked at that myself, I said, 

“Hell, I want everybody to know what I’m doing. If I’m going to bring this thing down, if I’m 

going to bring it out of the air, if I’m going to abort it, I want them to know this is what I’m 

going to do if it happens.” 

We started writing all that stuff down, and that led you to asking more questions. Here’s 

an instrument measuring the flow of oxygen out of this tank, and you look at the answer, and it 

doesn’t look normal. It looks abnormal. Why? Is it something wrong with the tank, or is it 

something wrong with the instrument? If it’s not real, it’s as bad as the damn thing failing. If 

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you want to know that that instrument is telling you the truth, and if it isn’t telling you the truth, 

why isn’t it telling the truth, and if it is telling you the truth, what is happening in the system 

that’s causing it to give you that answer? 

That was a very different perspective. Apollo 13 is a classic example of that. A guy 

sitting at the console at Cape Canaveral, he looks at this damn thing and he doesn’t have a 

measurement. He says to himself, “The instrument must be broken.” It wasn’t broken. It was 

off-scale high. He didn’t realize that; he thought it was the instrument. Had he realized that the 

problem was in the instrument or the system, then he would have taken the right action. That’s 

what we wanted to prevent in real time. 

It turns out every time we had a problem, it’s like the first time we launched, the rocket 

down on the pad, and all the plugs had pulled out, and first thing you know, the spacecraft is 

interpreting what it sees on its instruments. It’s wrong, but it acts. The first thing you know, you 

got a rocket going out here and a parachute coming out here. You say, “Well, now, why did that 

happen?” We didn’t have a permissive circuit in there that said, “Well, you’ve gone through 

20,000 feet,” and now you can arm that circuit, but until you go through 20,000 feet, you don’t 

want to arm that circuit because you don’t want those things going off when they shouldn’t be 

going off. Those are the kind of things you just don’t think about. You don’t think about that 

when you design it. I think all kinds of things paraphrase that.

As on Skylab, they had these solar panels that were inside a cover on the side of the 

rocket, where the damn thing is ascending. First thing you know, the goddamn cover blows off 

and so does the solar cell. You immediately say, “Why the hell did that happen?” You start 

looking into it, and you didn’t vent the goddamn thing. As you went up, all this pressure builds 

up inside the cover, gets up to a certain altitude, and it damn blows the covers off. They didn’t 

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think about that. The mirror on the Hubble [Space] Telescope, they didn’t do that well. They 

didn’t ask the right questions. They didn’t make the right tests. We only learned that by 

experience.

WRIGHT: You remembered a whole lot more than you thought you were going to.

KRAFT: I didn’t get into NACA very well for you.

WRIGHT: No, you did. Are there other thoughts?

KRAFT: NACA was a very unique place, and it was a different relationship among people that I 

don’t think anybody understood that was inside of NACA. The local people didn’t understand 

the NACA people. They wondered, “What kind of nuts are those? They want to know things 

about this washing machine nobody ever asked before,” when they were downtown buying 

things. They say—I’m not sure this ever happened—they’d see these guys walking around the 

street and they looked like they were in a different world, thinking about what they were doing at 

work. I never saw that for myself, but they’d accuse us of being brain-busters that way.

WRIGHT: I understand some people, when houses would go up, they would watch the unique 

way of building it because engineers were building houses to be very efficient.

KRAFT: I built my own house in Virginia—I was a contractor. I hired the bricklayers and I went 

to a handbook to figure out how to build a chimney, the fireplace, so I wanted to make sure it 

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was the right kind of draft there, sucked flow instead of coming in the house. I designed the way 

in which the walls of the fireplace were to be built—this way, that way, how that got into the 

flue. I hired the bricklayers to do that. I gave them the drawing because I did it myself, and I 

walked in there and they’d finished it. They’d done it like they’d always done it. They didn’t do 

it like I put on that piece of paper. They said, “What’s wrong?” 

I said, “You didn’t do it like I told you to do it.” 

“Well, this is the way we build fireplaces all the time.” 

I said, “Well, it’s not the way you’re going to build mine—tear the damn thing out.” I 

didn’t see those bricklayers for about a month. That’s an NACA engineer, right there.

WRIGHT: You were a close-knit family on the Center itself because you all knew each other so 

well. Your families did things together as well? Did you have activities and things that you did?

KRAFT: Not so much, no. I don’t think that we were that close. Me being a local kid, I didn’t 

have that problem, but now there were a lot of NACA engineers had come from other places, and 

so, they did become very close. They lived together in apartments and things like that, the 

engineers did, and then they built houses close to each other, and they became very close friends, 

yes. That’s very true. I wasn’t one of those. I did get to know a lot of guys that way, but I was 

fortunate enough to be a local rat. NACA people were known to be very strange people. They 

liked them, though, because it was very important to the economy in Hampton, Virginia. 

WRIGHT: I’m sure many became community leaders as well, getting involved with the local 

towns and doing some things within towns.

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KRAFT: Yes, of course. School boards and things like that. We changed this place [Clear Lake, 

area] when we came.

WRIGHT: Yes, you did, definitely.

KRAFT: I’ll tell you that. The education system improved 100 percent the day we walked in 

here.

WRIGHT: There’s this local story of how at that time, the group of old men that always sat 

together at the bank and talked were trying to figure out just how many years NASA was going 

to be here before it left, and then they were going to have to deal with all these problems, all the 

buildings. It’s kind of funny now because people thought five years—until you got to the Moon, 

and then everybody would just disappear.

KRAFT: Unfortunately, that’s beginning to come to roost, isn’t it?

WRIGHT: So many years later. We’re glad you’re a—what did you call yourself, a local rat? 

KRAFT: Yes.

WRIGHT: I’m glad you consider yourself a local person now in Houston. We appreciate you 

coming in and talking with us today.

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[End of interview]

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