R. M. R. Years at Varian
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  Ray: Your account of political intrigue at UTPB has a somewhat
familiar ring. I have some similar, yet distinctly different,
experiences in some ways. I was Grievance Chair for the real
estate board for 4 years and had numerous occasions to plumb the
depths of human depravity in that role. If I ever run short of
raw material, all those records are up in the attic.

I am more interested in the foibles of technological
development and D.O.D. procurement procedures. In these cases,
the players are rarely motivated by raw greed or maliciousness. 
As a rule, everyone wants to meet the goals set out, but they
have honest (more or less) disagreements as to how to go about
it. The following account is a case in point. 

A GENTLE SAFARI INTO THE R&D JUNGLE

I got my Master's Degree in EE in 1951 while holding an
assistantship in the EE Department at Ohio State University in
the Vacuum Tube Laboratory. Vacuum tube technology was at the
core of radar, navigation, and communications technology during
WWII and consolidating the gains already made while keeping on
the frontiers of research in Vacuum Electronics was a high
national priority. Shortly after I came to Ohio State in 1950, I
went to a seminar in the EE lecture hall to hear Jack Morton,
from Bell Telephone Laboratories, tell us that new discoveries in
Solid State Physics were going to make vacuum tubes obsolete, and
that sooner rather than later. He had a primitive transistor
with him and gave a demonstration in which he prepared a simple
battery consisting of a penny, a nickel, and a piece of blotter
paper dampened by his tongue and he used it to power a transistor
oscillator which could be heard clearly throughout the
auditorium. 

Prof. Boone, my thesis advisor, told his class afterward
that transistors would, indeed, make inroads into the vacuum tube
business, but it would not happen overnight and it was very
doubtful that they would ever be able to take over all of the
functions of vacuum electronics. He had told me earlier that the
thing which fascinated him so much about vacuum tubes was the
breadth of technology required to work effectively in the field. 
Sooner or later the vacuum tube brought everyone who worked with
them face to face with every known law of basic physics, and
there would always be a market for people who knew the basics. 
This was inspiring to me, since I was primarily interested in
basics of all kinds.

My interest in basic principles has got me into a lot of
trouble over the years. During the war, I went through radar
school where the emphasis was on diagnosing malfunctions in
electronic equipment by studying the symptoms and, from a deep
understanding of how the thing was supposed to work, coming up
with a precise fix... usually the replacement of a small
component like a vacuum tube, a resistor, or a capacitor. More
often than not, the apparent symptoms were not enough to pinpoint
the problem, but they did indicate further tests which should
lead to a convergence and precise diagnosis. The Chief Petty
Officer to whom I reported at my first duty station after school
didn't think much of this approach. His method was to replace
large modules until he found the one with the trouble. The bad
module would then be put in a box and stored in a warehouse and
either forgotten or shipped to Seattle, Washington where there
was a repair depot. If there was not a good module on hand, he
would order one and wait until it arrived. On rare critical
occasions he might suggest testing all of the vacuum tubes and
replacing any found to be bad or marginal.

Glass blowing, welding, and machining were as basic to
vacuum tube technology, in my mind at least, as electromagnetic
theory and electron dynamics. My senior advisors, however, were
unanimous in telling me that this was an unfortunate mind set on
my part. My employers in industry would not be happy to see a
highly paid theoretician doing work which would normally be done
by less well educated and lower paid technicians. My hope was to
learn these manual skills while still at Ohio State, but after a
year toward my studies for the PhD I met the girl of my dreams in
1952, got married and went to work in industry at Bell Telephone
Laboratories. I had been told that academic freedom at Bell was
absolute, perhaps even moreso than might be found in academia,
and while I found this to be true enough it was still clear that
some of my more mundane interests did not find favor with the
people I worked for. I nevertheless found opportunities and
managed to become reasonably skilled in most of the manual arts
required in vacuum tube fabrication, although more than once I
felt like a pair of brown shoes at the Tuxedo Ball.

In 1956, one of my senior associates at Bell, Will Yost,
took a job as an R&D supervisor at Varian Associates, a vacuum
tube manufacturer in California, and he made an attractive offer
to me to join him. It was past time for me to move on, so the
family and I came west. My skills as a machinist, welder, and
glass blower found immediate application, at least until we could
hire some technicians to do these jobs. Engineers were not
allowed to operate machines in any of the larger R&D or
production shops, but a number of departments had a lathe and/or
a milling machine for small jobs which anyone could use, subject
to the approval of the department supervisor. I soon accumulated
a professional machinist tool box on a tea cart and almost all of
the small tools I might need. I was using an ancient lathe in
the plant maintenance facility one day when Sig Varian, one of
the company founders, stopped by and introduced himself. He said
that he was delighted to see a new engineer who could operate a
lathe and he told me how the machine I was using had been with
the company from the beginning and how he had personally all but
worn it out. Both Sig and his brother, Russel, the recognized
inventor of the klystron and company founder, were said to be as
common as old shoes. I got to know both of them reasonably well
and can testify to the truth of that sentiment. The grunts on
the shop floor absolutely loved Russ and Sig, who made it a point
to be on a first name basis with as many of their employees as
possible, but I got the impression that at least some upper
management people spent a lot of time trying to figure out how to
ignore them or work around them. 

Roughly speaking, the organization of the company in those
days was divided into Pure Research, Research and Development,
Pilot Production, and Manufacturing. Pure Research meant company
sponsored projects which served to satisfy the curiosity of
someone in top management and might or might not lead to a
product for the market. There was not much activity under this
heading as a rule, although there was some on occasion. Most
management people preferred to wait until someone at nearby
Stanford University or elsewhere had done all the heavy lifting
in this regard and then hiring the essential people to bring what
they knew of value to the company. R&D projects tended to be
closely associated with an existing product or to build upon
existing technology somehow with the intent of coming up with a
marketable product. It was often said that it was better to make
your own products obsolete in house, rather than waiting until
your competition did it. R&D projects could be funded in whole
or in part by company funds, but there was often customer funding
as well, particularly when the customer was the government. 
Pilot Production's charter was to take ideas demonstrated in
principle in R&D or elsewhere and re-design them for ease of
manufacture once a market had been found. When the bugs had been
worked out in Pilot Production, the product was turned over to
Manufacturing where it was apt to be re-designed again to use
inexpensive mass production methods. 

This machinery rarely, if ever, worked as intended. Pilot Production people complained bitterly about R&D people that their results were so much garbage while the R&D people might bemoan the lack of sophistication on the part of the Pilot Production
people. The Manufacturing people complained bitterly that Pilot
Production didn't get all the bugs out of the product, while Pilot Production people complained bitterly that the
Manufacturing people had changed everything important without any
thought to the fundamental operation of the device.  Communications were invariably strained at all jurisdictional
boundaries and suspicion of motives often prevailed.

Every so often a "manufacturing specialist" would come on board to reorganize that function and institute proven mass production methods. These people might come from a background in glass receiving tubes or television picture tube production, or
perhaps breaker boxes or automobile parts. Essentially all of them started from the premise that specific knowledge of vacuum electronics technology was irrelevant. All failed to improve the efficiency of the manufacturing operations, although some no doubt made personal fortunes of their own during the course of
their endeavors. 

The vacuum tube business is unique, in my humble opinion, and does not lend itself to comparison with other industries.  Jack Morton was right in predicting the demise of low power low
voltage vacuum tubes due to competition from transistors and
other solid state devices, but almost 50 years later there are still a number of functions in high energy physics and high power microwave generation where only a vacuum device is practical.  Megawatt klystrons are a good example. These are used to drive
particle accelerators and radar systems for air traffic control and military applications. There are no solid state substitute,
nor is there ever likely to be due to fundamental considerations like heat transfer and weight, not to mention cost and reliability. These tubes are very expensive and are required in small numbers, typically 2 or 3 per month. Travelling Wave Tubes capable of generating several kilowatts over an octave bandwidth are made in greater numbers, perhaps in the 100's per month, but never in quantities comparable to mass produced items like TV picture tubes or auto parts. Every TWT is hand made by highly skilled people. Every one is unique, at least in the fine details of its characteristics. The use of Statistical Process Controls and mass production techniques like Just In Time are entirely inappropriate. I recall one  incident in which we had contracted to deliver one tube per month for a total order of 24 tubes. We were also required, by contract, to use Just In Time methods in order to keep the parts inventory to a minimum, so we
had to pay the machine shops for 24 set-up times and 24 sets of parts instead of one set-up time and 24 sets of parts, plus a few spares. Each set-up time cost 10 times as much as a set of parts, but we did perhaps realize a few cents savings not having
to stock parts before we needed them. "Give me ten men like Inspector Cluesau, and I can destroy the world."

When I came to Varian, my first assignment was in R&D on a
project to develop a high power TWT to replace a klystron used as the transmitter in an established radar system. The klystron developed roughly 1 megawatt over a narrow band of frequencies.  There was reason to hope that the TWT could be made to develop the same power level over a wider frequency bandwidth, a decided benefit, without any modification of the system hardware. The term Form, Fit, and Function, or FFF, was applicable. The outline drawings were identical as between the klystron and the TWT and the power requirements were the same in every aspect. I have seen this specification on numerous occasions over the years, but I have never seen it fulfilled completely. There are those with more experience than I have who tell me that FFF is a reasonable goal, even attainable on occasion, but every time I have been involved with it the project tends to get hung up on some point where it would make far more sense in the overall scheme of things to modify the end equipment than to comply fully with FFF wholly within the vacuum device. 

I was 31 years old in 1958, and still a little wet behind the ears, but with enough practical experience now in the real world to be able to make a modest contribution. I had become increasingly unhappy with the R&D project, which was running over a year past the original goal with no end in sight, because of an impasse over technical matters with Will, the issue being FFF.  We were beating our heads against a brick wall trying to meet a trivial specification which all parties, including Will and our customer, agreed was best addressed by making minor modifications to the system. The sticking point, it seemed to me, was a matter of saving face somehow... we had all made a commitment which seemed reasonable at the outset, but now seemed all but impossible. No one wanted to admit to this lack of foresight.  My discomfort came to the attention of at least one of Will's like numbers in another department. This worthy, one Leo, courted me with some fervor for several weeks with flagrant disregard for the code of etiquette which made it poor taste to recruit talent from your fellow manager down the hall. I was flattered by the attention and took the opportunity to get out of what I saw as an increasingly oppressive situation. I don't think Will was too upset by this turn of events because he took over my duties for himself and did things his own way without any carping from me.

Leo was the manager of Pilot Production for Small Tubes, and he had a hot job waiting for me and a raft of great ideas to share as to how we should go about it. The situation was that, less than a year ago, a solid state device had replaced a vacuum tube he was building for an important military system, but the performance of the new device was less than satisfactory so far.  In the meanwhile, continued effort in our research department had come up with new technology which should allow us to produce a new vacuum tube with performance superior to the highest claims of the solid state device. The sales staff, in the person of one Murray Kohl, had sold an R&D contract to the manufacturer of the system in question to build a prototype of this new tube to be tested in the system. There was a real possibility here to buck the trend by taking over a solid state function in favor of a vacuum tube function. Leo had most of the required technology well in hand and this job would naturally come to his department, but he needed to find a suitable project engineer. This is where I came into the picture. I was transferred to Leo's department a week or so before the formal contract was issued and had to charge my time to his overhead, but it was full steam ahead on the new project right from the start.

As soon as I came on board, a meeting was held with Murray and the research staff to bring Leo and me up to speed on what they had learned and how they thought we should proceed to make a working model which could be put into production. I was in full concurrence with everything I was hearing. A few days later the full contract with a 40 page list of specifications and a charge number was in place. It bothered me a little that I was never a
party to the negotiations over the terms of the specification document, but that was apparently normal procedure. It was
certainly the case on the project I had just left. I assumed that Leo or at least Murray was on top of all of the spec items and had the opportunity to speak up during the assembly of the
document, but I didn't have anything like a clear picture of the way it all worked. Leo gave me a copy of the specification
document without comment and I dutifully took it home and read it
from cover to cover. I understood most of it, but there were
several points which were not at all clear to me.

The research boys got a copy as well and one of them came to
sit with me over lunch in the cafeteria and to go over a couple
of items. He said that Murray had signed us up for a lot of
grief over a couple of points that were of little or no
importance to the overall operation of the system as well as one
specification which was probably a physical impossibility. I
asked him if he had talked to Leo about these matters. He had
not nor did he have any plans to do so. He said that Leo tended
to ignore the finer points in specification documents on the
theory that these were merely "wish lists" which he would
certainly do his best to fulfill, but in the end the customer
would always have to settle for the results of his best efforts. 
If his competition could do better, then he would somehow find
out what the other fellow was doing and match him or best him. 
By and large, though, Leo had a reputation for being the man to
beat in any head to head competitive situation. In this case,
there was no competition other than the manufacturers of the
solid state device we were trying to supplant.

Leo still had a lot of parts on hand used to build the
previous version of this tube and most of them could be used
without modification. While he made drawings for the new parts
required and saw to their being made in our machine shop, I
rounded up the bits and pieces needed to make a power supply and
test equipment and had it all ready and waiting for the first
tube to come off the pump. We were a couple of weeks ahead of
schedule when testing began and it was apparent right off that we
had a winner, at least when it came to the critical
specifications. Our customer sent an engineer from their
facilities to come out and twist the knobs for himself. He was
duly impressed, but he also pointed to several minor shortcomings
which neither Leo nor I had ever heard emphasized, but which were
variously alluded to in the specifications. The items the
research engineer had expressed concerns over did not seem to be
problems, while the physically impossible matter was quite
possible after all.

While Leo and I were putting our heads together addressing
the shortcomings of our new creation, Murray was busy getting us
into a deal of trouble on a far grander scale. The Air Force was
flying higher and faster than ever before and our adversaries
were doing their best to keep up and, if possible, to defeat our
best efforts. This was in the days of Sputnik when the Russians,
a backward agrarian society mired in a degenerate political
philosophy, had leapt ahead and launched a satellite ahead of us
and we were in a desperate game of catch-up. Electronic warfare
was forever on the move and the uses of space for spying was a
vast and unexplored frontier. Each measure was met with a
counter measure as quickly as possible. Radars and anti-aircraft
missiles with radar guidance and jammers against them were barely
operational before they were made obsolete while vacuum
electronic devices were, and still are in 1997, indispensable
components of many such systems. 

Murray dropped by one Friday before lunch to tell Leo and I
of a new application which would mean a great deal of business
for us and, most likely, one of our competitors. He had a 100
page specifications document he wanted to go over with Leo and I
over the next couple of hours. The specs had been prepared by a
systems manufacturer in response to the stated needs of the Air
Force. There were perhaps a dozen companies in the NATO
countries with vacuum electronics capabilities adequate to
compete in this arena, with only half as many in the USA. All of
the US companies had been offered the opportunity to bid for an
R&D contract to develop a prototype tube meeting the
specifications, but Murray was pretty sure that only our company
and one competitor were going to respond. The final design would
be the property of the Air Force and they could let manufacturing
contracts out to any or all qualified bidders at the lowest
prices. Being one of the developers had its advantages and
disadvantages. It was possible, in theory, to make a profit
during the development process, but competition was likely to
make this an occasion of net investment for the company in the
hope that they would have a strong edge in terms of proprietary
knowledge when the time came to bid in the manufacturing phase. 
There was also the benefit of the fallout technology likely to
come as an inevitable by-product of the effort. To Leo and I,
this last item was a major factor. It meant that he and I and
the technicians on the project could hone our skills further and
no doubt learn a number of valuable lessons along the way. 
Management tended to take a much dimmer view of this prospect. 
They had little enthusiasm for investing in the education of
employees who might very well take these benefits elsewhere
sooner or later, most likely to a competitor. It was greatly
preferred rather to hire people already educated at someone
else's expense. In any case, my experience over the years is
that R&D contracts of this sort almost always show up on the
debit side of the ledger and bring a measure of grief and anxiety
to the accounting staff which is never shy to share its
discomfort through frequent comments such as, "when are you going
to deliver a full spec tube?"

Murray went over the specifications item by item making
notes of Leo's comments. This was still during the period of
negotiation leading up to a final document to be agreed upon by
all parties. A number of the specifications were beyond the
state of the art in that no one had ever demonstrated the
technology. In some cases there was a theoretical basis for
believing that the thing was possible while in other cases there
was no theory either way. In still other cases there was theory
to suggest that the thing desired was not possible under the laws
of physics as we understood them. All three categories were
evident so far during this reading. 

We broke for lunch about halfway through the list of specs. 
I took the occasion to ask how this all worked because I had
never been in on the early stages of this process, but I was
quite familiar with being beaten about the head and shoulders by
customers who could not seem to understand why you were unable to
meet performance standards someone else had committed you to. 
Murray was all too happy to enlighten me. All R&D contracts he
was familiar with had provisions which turned out to be either
physically impossible or simply not attainable under the various
constraints, like time and money, although later advances in the
state of the art might bring such goals well within the range of
practicality. An R&D contract was essentially the customer's
wish list which we and our competitors would agree to fulfill to
the letter without regard to the state of the art or physical
limitations. If one company would agree to do a certain thing,
all of his competitors had to agree to do likewise if they wished
to be players. This usually meant that they all had to agree to
do certain things they didn't necessarily believe they could do. 
Leo went on to explain that during the course of the contract a
number of things would likely become apparent and things
originally thought to be difficult or impossible might turn out
to be feasible after all, while other matters thought to be
trivial might sometimes rise up to bite our backsides. The time
would come, however, when the truth about such matters would be
evident and the survivors would then hammer out a new definition
of the problem and rewrite the specifications in terms of what
they knew they could do. Until that time came, all players could
expect to have their feet held to the fire with no quarter being
given. Put this way, it all sounded fairly reasonable to me and
I was looking forward to the campaign ahead.

After lunch we returned to Leo's office where Murray
finished going though the specifications with Leo and me. He
then left to return to the negotiating table, but he said he
didn't expect to get any significant concessions since his
impression was that our sole competitor had already agreed to go
along with all of the provisions in the document.

While Murray was away, Leo and I learned that the company
who made the solid state device our other project was in
competition with had made a breakthrough and we were unlikely to
regain this socket even if we could successfully address every
shortcoming now evident in our product. Leo and I went to a
meeting where our superiors reluctantly gave us another month to
fix everything with the aim of putting the device in the catalog
to see if there were any other customers out there.

A week or so later I came to work on Monday morning to find
Leo working at his drafting table. There were dark bags under
his eyes and he looked as though he had neither slept nor bathed
nor shaved for several days. The floor was littered with
cigarette butts and the waste paper basket was full of candy
wrappers and coffee cups from the vending machine down the hall. 
Leo had evidently been working around the clock over the weekend. 
He told me that Murray had come by with the contract late Friday
after I had gone home and he had spent the weekend preparing
drawings for the routine parts so he could get them to the
machine shop without delay on Monday morning. He was as jubilant
as one could be under the circumstances, but he was about to drop
from sleep deprivation. As soon as the foreman of his small
prototype shop came in, Leo went over the stack of prints with
him and urged him to get on with making the parts without delay. 
Then he went home to get some sleep.

I had long since recognized that Leo was an intensely
competitive animal and this was one of his traits that I admired
up to a point. There were half a dozen managers on his level in
the company and I was vaguely aware of some of the rivalries
among them for favor in the eyes of upper management. My sense
was that Leo was the top dog in this league and had been for
several years, but now there was another hot shot, one Zachary, a
relative newcomer, hot on his heels. Leo, Zach, Will, and I took
lunch together in the company cafeteria from time to time or at
one or another of the better eateries near the plant. We were
all still friends, but it was understood and accepted that
vigorous competition was a welcome sport and good for all
concerned. It was also clear that my ambition was in the
direction of technical competence and that I had no managerial
aspirations whatsoever. My competitors were the 2 or 3 PhDs in
Pure Research, even though I had only a Master's degree. 

Leo and his wife had no children and she seemed quite
content to manage the household and their investments and
generally to support his ambition. I, on the other hand, had a
wife and two small children and soon after I came to Varian I
found myself flying back east frequently to hold hands with our
customer. One time I awoke from a nightmare in my motel room on
one of these trips and found that I could not recall the sounds
of my children's voices. I was prepared at that instant to take
up another trade that did not involve such separation, but
fortunately there was another fellow in my group who leapt at the
chance to take over this role. When I saw Leo that Monday
morning wholly consumed with this new project, I told myself that
no job, no salary, no house, no lifestyle, no set of toys, no
nothing was going to get in between me and my family. I was
willing to work hard and take work home on occasion, but I was
determined to be available to my wife and kids come hell or high
water. This mindset cost me somewhat in salary and advancement,
but it was a bargain I was very comfortable with. I watched a
number of my associates wrestle with this issue over the years. 
Some resolved the matter by divorce while still others found a
way to divide the labors with the woman staying home, raising the
kids, keeping the home fires burning while the man always had his
bags packed and was on the road half of the time, or more. The
modern way wherein both parents are on the road much of the time
and with the kids raised by surrogates is, in my view, an
unmitigated disaster for all... the kids, the parents, and the
society as a whole. I prepared myself to tell Leo to go to hell
if he ever indicated that he expected me to go without sleep and
a bath over a weekend, but he never did.

Our new project was to develop a high power TWT to operate
in the very thin air to be found at 60,000 feet. Heat transfer
was to be by forced air convection. One of the most formidable
specifications was that the hot spot on the external surface must
not exceed 300 DgC. It was possible that the air surrounding the
device could become contaminated with jet fuel vapor and this
spec was intended to prevent the possibility of an explosion. My
degree was in electrical engineering, but I also had a keen
interest in heat transfer. Back at Bell Labs there were several
senior people who relied on me for thermal analysis in connection
with their projects. They could have done the analysis
themselves, of course, but they took no joy in it and were happy
to have me take this chore off their hands. In exchange I could
tap them for personal attention whenever I had a problem in
electromagnetics or electron dynamics. My past experience in
heat transfer, however, did not include forced air convection at
high altitude, so Leo hired a consultant to address this and all
of the other relevant heat transfer problems. I watched with
interest out of the corner of one eye, but I was kept pretty busy
wrapping up the previous project. Whenever there was a lull in
that effort, as happened on occasion, I was pressed into service
as a machinist making parts for the new tube.

A decision was made to quit spending money on the previous
project and to put the device in the catalog based on
characteristics we had demonstrated at one time or another, but
not all in the same tube at the same time. The idea was that we
could work all that out if and when the market showed any
interest in the product. I don't think it ever did. In any
case, I was soon released to spend full time on the new TWT pilot production effort. Leo put me to work on the input and output
windows and transmission lines... a relatively straightforward, though non-trivial, assignment.

Travelling Wave Tubes, TWT's, are electron beam devices wherein a beam of electrons is made to flow in vacuum through a long helix or other suitable microwave propagating network. The
beam is confined by a magnetic field along the axis of the device. A small signal is introduced onto the microwave network which induces a growing plasma wave on the electron beam. This
wave becomes a surf delivering a large signal to the output transmission line. The spent electron beam flows into a collector which tends to get very hot unless it is effectively cooled somehow. TWT applications vary from satellite communications to radar jammers and numerous other variations.

The magnetic focusing field for the electron beam in Leo's TWT was to be provided by a solenoid shipped as an integral part of the microwave power module. Andy Mervyn, a supervisor at
Leo's level in Varian's Magnet Division, was responsible for producing the solenoids. I had worked with Andy on several occasions and had the highest respect for him as a first rate
mechanical engineer. I think he had a similar opinion of me as an electrical engineer. Several weeks after the start of this project, Andy came by my desk and invited me to go to lunch with him. He had just come from a meeting where he and Leo had made a progress report to upper management and he was troubled by certain aspects of the way things were going. He told me that
the amount of forced air cooling available was far from adequate
and there was no way to meet the hot spot temperature requirement
unless a lot more air was provided. After lunch we went to his
office where he gave me a concise lecture on heat transfer to a
moving air stream along with a review on fans and blowers. It
all seemed pretty basic to me and I could find no fault with his
arguments, but I told him I would have to go over the material at
my leisure to become completely comfortable with it. Over the
next several days I read his text books and worked the problems
at the end of the relevant chapters and came back to him for
further discussion. 

My review of this material brought to mind an incident from
my college days at the University of Florida. I was working
during the summer between my Junior and Senior years at a job
which involved painting and yard work and general maintenance
around a large old Victorian mansion on 10 acres about 40 miles
from Tampa. This property and all of the neighbors were beyond
the water mains and everyone had their own well. Our water
system included a check valve and a centrifugal pump driven by an
electric motor and a water tower tall enough to supply gravity
feed to rooms on the third floor of the old house. One day the
pump motor gave up and getting a replacement became the first
order of business. The name plate indicated that the motor specs
were: 110 volt; 1 hp; 3550 rpm. It was too late to drive into
town, but several telephone calls revealed that there was at
least one 110 volt 1 hp motor available in Tampa, but the rated
speed was only 1770 rpm. A close neighbor and long time friend
of my employer worked at a frozen food operation nearby as a
plant maintenance supervisor. He was consulted on the matter
when he got home from work and said that the rpm was irrelevant,
so long as the hp rating was OK. I had my doubts, but he had a
great deal of practical knowledge regarding pumps and motors
while I had nothing but my intuition. I had earned an A in
Dynamics in the semester just ended, but the subject of
hydraulics had been mentioned only in passing and I was not
prepared to go head to head with this fellow. I kept my mouth
shut at this point. 

Between supper and bedtime I racked my memory trying to
recall what I had read about hydraulics and the difference
between a static head and a velocity head and how the sum of
these two numbers was perhaps a constant. When I woke up the
next morning I had a nearly complete recollection of everything
that had transpired when this subject came up in class. The
problem our instructor had discussed had to do with the velocity
of a stream of water from a garden hose and how high we could
expect the water to go in terms of the static pressure when the
water was turned off. There was also some mention to the effect
that the static pressure in a centrifugal pump could never exceed
the velocity head at the tips of the impeller blades. The
available pressure was directly related to the rpm of the pump,
the maintenance supervisor was flat out wrong, and I so informed
my employer of my reasoning. He suddenly found himself in that
awkward position familiar to all laymen... namely what to believe
when the experts disagree. The only solution to that dilemma I
have ever found is to learn the truth for myself somehow, but in
this case he had to go with experience over theory. I would have
done the same thing, and would probably do the same today. I
think of myself primarily as a theoretician, but I fully
recognize that there is no substitute for experience and hard
data. My employer drove to Tampa and bought the 1770 rpm pump.

By the time he got home with the motor, I had remembered
that the velocity head was given by the product of the fluid
density times the velocity squared, all divided by 2. I also
knew that the no-load speed of a 60 cycle 2-pole induction motor
was 3600 rpm, while the no-load speed of a 4-pole motor was 1800
rpm. A rough calculation led me to suspect that the maximum head
for the centrifugal pump we had was less than 20 feet above the
water table, not enough, if the motor speed was 1800 rpm. I saw
nothing to be gained by sharing this result and so kept my mouth
shut. The mounting holes were not exactly where they needed to
be so I spent an hour or so enlarging them with a round file. 
When the assembly was complete we turned on the power, but there
was no water coming into the tank. When the maintenance supervisor came home he dropped by to see how we were doing. His diagnosis was that the check valve below the pump was leaking and we were having difficulty priming the pump. We took the check valve apart and could not see any obvious fault with it. Well past dark and after several attempts to prime the pump with water carried over by the bucket from a neighbor failed, we gave it up for the evening. After a morning of total frustration my boss got on the phone and finally located a 3550 rpm motor in Tampa and went to get it. We had the system working properly before the maintenance man got home. I am reasonably sure he was never told what had happened and there was certainly no discussion with me about it either.

Andy told me that the blowers the customer planned to use were supposed to produce a static pressure head at 60,000 ft altitude sufficient to support a column of water 1 inch high, but on the basis of his calculations he could expect no more than 0.25 inches. The aircraft power system operated at 400 cps so the maximum speed for a 2-pole induction motor was 24,000 rpm. I repeated the type of calculation I had made in the case of the water pump and came up with the result that 1 inch was the  appropriate head based on the velocity of the tips of the fan blades. When I showed my results to Andy, he argued that I had calculated the maximum velocity in the direction of rotation, but this was not the whole story since the direction of air flow was in the axial direction and I had neglected to take the pitch angle of the fan blades into account. This sounded reasonable enough to me, but again he had a lot more experience in this regard than I did.

I found Andy's arguments quite persuasive, but I was keenly
aware of a lack of hard data, so the question remained as to how
Leo, who was very smart, came to reject them and how his expert
heat transfer consultant had not smelled a rat. Andy was not
sure about Leo, but he said that the consultant had, no doubt,
been given a faulty set of parameters to work with. The
specification spelled out that the system would provide a plenum
pressure sufficient to press a column of water in a manometer to
a height of 1 inch at 60,000 feet. That was all the consultant
needed to know.

Andy suggested that I approach Leo on the matter once I had
satisfied myself as to the soundness of the arguments. Several
days later I did just that. Leo replied that I must have been
talking to Andy Mervyn. I said that I had, but that I had also
made a study of the matter myself, found considerable merit to
his case, and was curious as to Leo's understanding and the facts
of the matter. Leo said that fluid dynamics was not his strong
suit, nor was he very interested for that matter, and while he
had a great deal of respect for Andy he was familiar with more
than one occasion where Andy was flat out wrong. As if to settle
the matter, he took out the specification document and showed me
where the customer agreed to provide a forced air cooling system
with a plenum pressure of 1 inch of water. Next he produced a
brochure from the blower manufacturer which indicated that their
blower would deliver that pressure at altitude. He had hired a
recognized expert consultant to design the heat exchangers based
on that specification. If that was all wrong, then the customer,
and not Leo, had a problem. Leo's ass was covered. 

This line of reasoning disturbed me very much. It seemed to
me that it was essential to find the truth of this matter as soon
as possible in the interest of a successful program and that
playing a blame game later when things didn't work out was bad
business and bad politics, but then I was a new kid on the block
and a novice as to how the game was played by the big boys. 
Perhaps it was as Leo said, that we must concentrate on the
immediate problems before us and work out the sticky matters
later on. I had plenty of other work to do on this project and I
turned to it with due diligence, but in my off hours I read the
text books and made a number of calculations for my own
edification. All of my studies and calculations supported the
idea that Andy was right all along, but there was still no hard
data and I had known for some time that one measurement is worth
a thousand calculations. 

In due time, in fact ahead of schedule, we had a working
tube in test and the overall electrical performance was very
impressive. There were a few minor bugs which were not too
surprising and, if past experience was any guide, these would be
successfully addressed in the next few tubes. Environmental
testing usually discloses more troublesome flaws which are not
generally foreseeable. Production models must be able to survive
all manner of shock and vibration standards, extremes of heat and
cold and humidity, and in this case, high altitude. We had most
of the environmental test facilities in our plant, but the
altitude chamber was back at the customer's facilities. Our
first tube disintegrated during shock and vibration testing, but
the autopsy indicated a set of fixes. These were incorporated in
the next tube which passed both electrical test as well as shock
and vibration. It was packaged and sent to the customer where
these tests were to be repeated. The customer would also use the
tube to test his system for the first time. When everything that
could be learned at this stage was learned, the entire system
would be tested in the high altitude chamber. 

Within a week we learned that the tube failed after 15
minutes in the altitude chamber because of excessive temperature
at one of the heat sensors. The precise location of the hot spot
was not clear, but the data showed that all of the heat sensors
were indicating a rising temperature and none of them had reached
steady state. Andy dropped by to invite me to lunch and to come
over to his shop afterward and go over the data he had received
from the customer. The most telling was the focus coil voltage
which was a measure of the resistance, and thus the average
temperature, of the copper windings. Andy had done a lot
analysis regarding the heating and cooling cycles for the focus
coil and he was reasonably confident that he could infer the
effectiveness of the forced air cooling for the coil from this
data. The results were more dire than he had suspected. 
Following his methods, I did a similar calculation with regard to
the heating cycle for the collector and came to a similar
conclusion. I did not bother to share any of this information
with Leo because the work he had assigned to me did not include
this matter and it was, strictly speaking, none of my business. 
He did, however, call in his heat transfer consultant and spent
several hours with him.

Several weeks later our competitor delivered their first
tube to the customer and the plot thickened. Murray had learned
that the electrical characteristics of this tube were not as good
as ours, but it survived for several hours in the altitude
chamber. In theory, the customer was not supposed to relay
detailed information between the competitors, but each always
managed somehow to find out what they needed to know. Murray was
able to tell us that the competitor's tube had failed due to a
sever arc in the gun region which would certainly have ignited an
explosion had there been jet fuel vapor in the environment. The
gun, in both tubes, was the region where a hot thermionic cathode
provided the electrons which were focused into a beam, the active
element in all TWT's. It was necessary to encapsulate the high
voltage leads and terminals in this region using some form of RTV
(Room Temperature Vulcanizing) compound. All known RTV products
would decompose at elevated temperatures, so it seemed most
likely that this effect was at the root of the problem here. 
Murray was also able to tell us that the collector on the
competitor's tube was running much cooler than ours and had
reached steady state before the tube failed.

This last bit of information, if true, cast serious doubts
on Andy's and my calculations. I was willing to believe it if I
could oversee the whole process including the taking of the data,
because it is basic to me that theory always has to yield to the
evidence. I didn't have to ask Leo or Andy if they believed it
was true.

Ever since I left college to work in industry, I have been
in the habit of making a more or less formal write-up of any
technical problem which I have studied in any depth. This was a normal part of my college work and I found the practice very useful when I had occasion to refer to the material again. It turns out that similar problems often come up again and again and referring to these write-ups is a very convenient way to get up to speed in a hurry. I went through my lab notes and wrote a concise summary of the reasoning that Andy and I had been through. I gave a copy to Andy and several others with whom I had discussed the matter, but I saw no point in bothering Leo with it. He nevertheless knew about it and that I had done it on my own time at home. 

As the design parameters became more and more firm with each tube, Leo's organization moved into high speed pilot production.  My contributions diminished to the point where Leo had to find other things for me to do. One of the serious problems still bugging the project seemed to be a lack of consistency in the beam focusing. It was necessary that the electron beam should fit very closely within the helix without actually touching it because the beam power density was so high that any significant amount of interception would cause excessive heating and there was often evidence of this. We needed better quality control on the focus solenoid, Andy's responsibility. Leo talked to Andy and it was agreed that I would give whatever assistance I could to him. Andy and I worked in close collaboration for several weeks and the shortcomings of the solenoids went away. Andy was on top of the matter all along and would have done the job without my help, although it may have taken him a while longer.

Being in constant touch with Andy, he and I honed our common understanding of the thermal problems with this project. He had a lot of knowledge regarding heat transfer in general, much of which was new to me, while I had a lot of basic understanding of electromagnetic phenomena as well as electron dynamics which he was familiar with only in vague generalities. During the time we worked together, each of us learned quite a lot from the other.

Also during this time, Leo shipped a new tube every two or three days and each of them failed in the altitude chamber due to overheating. There were weekly meetings attended by representatives from top management and supervisors at Leo's level where successes and failures were openly discussed during brainstorming sessions in the hope that someone would come up with new suggestions to solve the outstanding problems. After one such meeting, Andy told me that Zach was putting the old harpoon to Leo more and more frequently at these meetings. Leo had the miserable task of reporting a lack of progress at solving the overheating problem with his tube for several meetings in a row and Zach was asking more and more accusatory questions, implying that if he were running Leo's show this problem would be history by now. This was a dangerous game according to Andy, because just now Zach's operation had no serious yield problems, but that situation could change overnight and then the shoe would be on the other foot. As things stood, though, Andy was pretty sure that Zach was making the pitch to his superiors that he could take over Leo's duties and solve this nagging problem as well as keeping his own operation running smoothly.

A week or two later, Leo came by my desk with a copy of the memorandum I had written. He invited me to lunch to discuss the issue at leisure. Over a very fine steak and a bottle of superb wine, Leo told me that he had read my summary and could find no fault with it, but some nagging questions remained. How was it, he asked, that the manufacturer of this blower could publish a specification paper in which he claimed that the static head was 1 inch of water at altitude without verifying that result in his laboratory? Furthermore, I had calculated this very result based on the velocity of the tips of the fan blades. Surely the manufacturer had the best facilities with which to make such a measurement while neither we nor our customer had any such facilities. Leo had run the proposition by his consultant and learned that he didn't see the significance of the pitch angle of the blades as Andy had suggested. Then there was the result that our competitor had somehow managed to defy the laws of physics according to Andy and me, because their collectors did not run too hot. Leo put it to me straight up... how did I explain all this? I told Leo that I had no explanation, but I was fully prepared to yield to the evidence. It was a simple matter, it
seemed to me, to measure the static head developed by the blower in the altitude chamber and go with the results. This, he replied, was entirely out of the question. The customer would never allow such a test, nor would Leo suggest it. If we could not reason the matter out from first principles, we should get into another line of work. Besides, the fact that our competitor's tube passed the altitude test so far as the collector temperature was concerned settled the matter. Our problem was to find out what was wrong with the design of our heat exchangers.

I always had the feeling that Leo was a bit put out with me
for paying any heed to Andy, his competitor, but he never came out and said anything. Now, however, the atmosphere was tense with mutual distrust and it was clear that I would have to find another place. As luck would have it, the guys I sometimes played chess or bridge with were coming to a dead end with their project in Central Research. Pure Research, which had been a more or less informal operation in the beginning, had now become Central Research with a VP in charge of a dozen or so PhD's. My friends were working on a research contract to measure the magnetic properties of Yttrium Iron Garnet, YIG. Another group in CR was growing this material in crystal form and there was a need for an instrument to be used in quality control. After Bob Kantor, one of the research team, explained to me in detail what they were trying to do and the difficulties they were having, I suggested a completely different approach. The project leader didn't think much of my idea and had any number of reasons why it wouldn't work, but both of our situations were becoming desperate. Bob and I set up a clandestine experiment to demonstrate the principle and we were successful on the first try. We brought the VP out to the lab for a demonstration and he was duly impressed.

I was invited to give a seminar describing the method at the next regular meeting of the CR staff. This was well received and I subsequently joined CR to develop my invention, the Frequency Shift Magnetometer. Leo and I were both much happier with the new arrangement. After some six months of hard work with Bob doing the heavy mathematics and I building the hardware, we published our results in The Review of Scientific Instruments.  The director of CR sought to reduce the idea to a product, but the instrument was so simple and the demand so limited that everyone who could use one had already built their own. Even so, I found a home in CR for the next 6 years supervising the machine shop and the electronics shop and serving as engineering support for the scientific staff. 

Several months after I joined CR, Leo was fired for failing to come up with a fix to the overheating problem. The company was hemorrhaging money on this program with no end in sight despite the fact that he'd had the heat exchangers redesigned more than once using different experts. His tubes continued to run too hot in the altitude chamber while the competitors tubes did not. The good news was that the competitors tube failed at altitude as well, but in an entirely different way. This fact kept our product in the running and gave us time to solve the problem. According to Murray, we had the superior product in all respects save one and if we could solve that problem, our design would be chosen. There followed in turn at least two hot shot program managers with terrific resumes and track records at other companies, but they were unable to turn this program around. My impression is that Zach was never offered the job, although his star still shone brightly.

Finally Chuck Farmer, the VP to whom Leo had been reporting, took over the project himself. He was a crusty old guy past retirement age who had been building vacuum tubes since the days of Lee DeForest. He and the Varian Brothers had worked at a large company on the east coast during the war building tubes for radar and navigational aids. After the war, Russ and Sig and a number of their associates came to California to start Varian Associates on land leased from nearby Stanford University. Russ had invented the klystron at Stanford and the ongoing vacuum tube research effort there was perhaps the finest in the world. Chuck Farmer had seen it all.

He had somehow heard of the disharmony between Leo and me and the nature of it. This apparently brought him to speak to my new boss, the VP for research, and to arrange for a loan of my services, which was readily arranged. I was looking forward to the opportunity to get to the bottom of things, because there were still a lot of unanswered questions in my own mind and I was hoping for some hard data to satisfy my curiosity. My first meeting with Chuck was not too encouraging because he told me at the outset that he didn't put too much stock in a lot of theory.  He was only interested in facts and he had a few hunches of his own that he wanted me to verify. Varian had since installed an altitude chamber in house where I could conduct the experiments he wanted done. I was serving strictly as his fetch and carry technician, because he had a raft of experiments all formulated in his own mind. He micromanaged my activities to a high degree and did not inquire as to my opinion. I got the impression, in fact, that any attempt on my part to offer an opinion would be met with a strong rebuff. It was a very uncomfortable position, but I was hopeful that I would learn something new that I was not likely to learn otherwise. My alternative was to seek employment elsewhere. 

The first thing Chuck had me do was to install a large number of thermocouples all over the tube to measure the whole temperature profile. This seemed like a good idea to me because up to this time we only knew the temperature at three or four points which were assumed to be the hot spots in those regions.  There were no surprises in the results and the hot spots were pretty much where we thought they would be, but I did manage to take a great deal of transient data I had never seen before.  Thermal transients contain a wealth of information if you have the patience to analyze it all. People often avoid taking such data because they don't know what to do with that much information. Chuck took my data and went over it in private, not sharing any of his conclusions about it with me. I went over it myself and saw nothing to shed light on my outstanding questions.

Over the next couple of weeks I did the leg work implementing and testing a variety of heat exchanger design Chuck had come up with through his own intuition and experience. In all honesty, most of them were superior to the previous designs, but none were able to overcome the apparent fact that there simply wasn't enough air moving fast enough over them. The questions remained, how could the manufacturer of the fans be so wrong and how was our competitor able to do what we could not?  Andy was still firm in his belief that the competition was somehow concealing the true state of affairs, either by design or incompetence. I wanted to make the fundamental measurements of the static pressure head and the flow rate in our altitude chamber, but I was pretty sure Chuck would veto the idea, at this stage of the game anyhow. Sooner or later, though, circumstances would most likely force him to give me a free hand in this regard. Andy and I discussed various ways to take this data and both of us agreed that a simple manometer and a Pitot tube were the proper instruments. These were devices in which either a static pressure head or a velocity head were used to force water up a glass column and one simply observed the relative displacement. Unfortunately, our altitude chamber did not have a glass window to allow us to see this experiment, but the customer's did. There was an electronic readout gas flow meter on the market, but it was expensive and I didn't see how to calibrate it against a primary standard, like a Pitot tube, in our facility and I was not inclined to accept the vendor's word.

After Chuck had run out of ideas for new heat exchangers, he arranged for me to go with Murray back to the customer to see what I could learn there. I noticed, as he set forth this plan with me in his office, that he had been reading my memorandum, but he wasn't offering any comment regarding it. I told him I would want to take a manometer and a Pitot tube with me and make the basic measurements in the customer's facilities. He called the customer on the telephone and made the arrangements. A few days later, Murray was introducing me to the engineers and test technicians at their plant. I brought along a simple homemade manometer and Pitot tube.

We were scheduled to spend 2 days at the customer's
facilities. The first morning was devoted to introductions all
around and I got to meet the overall project manager, who seemed
to be nothing more than a bean counter, and his seconds. One of
these was an electrical engineer responsible for the electronics
of the system and the other was in charge of environmental test. 
During a meeting which consumed the morning, a pot of coffee, and
a large platter of doughnuts and sweet rolls, I learned that the
system had been in unofficial operation for well over a year and
that our design was the superior tube by far. In fact, several
of our tubes had been through a dozen or more missions with no
malfunction while none of the competitor's tubes had come back
from a single mission without a severe arc in the gun potting
compound. The issue of a hot spot igniting jet fuel was
academic, I learned, because this condition could never exist in
normal operation although it might exist in a crash or other
serious malfunction such as the airplane being hit by an enemy
projectile. Still there was a need to find some way to reduce
the temperature of the tube, the focus coil, and the system as a
whole if for no other reason than to extend the life of these
components. There was plenty of evidence of thermal
decomposition in a number of areas and it was well known that
there is a strong inverse correlation between MTBF (Mean Time
Between Failures) and temperature.

After lunch, Murray and I were escorted to the environmental
lab and introduced to the technicians there. The supervisor of
this department had urgent business elsewhere and left soon
thereafter. I explained the measurements I wanted to make and
produced the equipment I had brought. One of the techs went to a
nearby cabinet and brought out some first class store bought
models of these devices. He said he didn't know what they were
used for and, to his knowledge, no one had ever used them. I
spelled out the theory of operation, for which they all seemed
grateful, and together we set up the first experiment I had in
mind. Within an hour I knew that Andy and I had been right all
along because the static head in the blocked off plenum chamber never rose above 0.25 inch at altitude. We let the chamber down to air and set up the experiment to measure the velocity head produced by the unloaded fans. That, also, was 0.25 inch. How, then, I asked, was our competitor able to design a heat exchanger to keep his tube cool with so little air flow? No one had an answer. 

Up to this time I had never seen an example of the
competitor's tube, but a technician went into an adjacent room
and came back with one. There was plenty of evidence of an arc
in the potting compound around the gun, but there were no
temperature sensors on the collector or anywhere else that I
could see. The tech explained that these were connected
separately when the tube was installed in the system module. In
our tube, a thermocouple was brazed to the hot spot as an
integral part of the collector with a pair of external leads
which were to be manually connected to a terminal strip on the
system module. In their case, the thermocouple leads were first
connected to the terminal strip and the heat sensor was manually
inserted between a pair of fins on the collector. This latter
arrangement measured the temperature of the air stream while our
scheme measured the temperature of the metal collector itself
which was, of course, hotter than the air stream. 

It seemed to me that most of this issue had passed over the
heads of the technicians as though they were largely unaware of
the misery these fine points had wrought. I went to the
blackboard and explained the overall picture, as I saw it, and
after I had spelled it all out one of the techs spoke up to ask
why we were beating our heads against a brick wall trying to use
air cooling in the first place. He had installed several of the
modules in the aircraft and had noticed a pair of capped off
nipples on the bulkhead next to the bay for this system module. 
He was sure that this was a hookup to the liquid cooling system
because it was just like those used by several other pieces of
equipment nearby in the aircraft. This said, there was nothing
more for Murray or I to do until what we had learned could be
digested. We managed to get our return reservations changed to a
flight later that evening and cancelled our room reservations. 
When we got to the airport we learned that our new flight had
been cancelled and we spent the night sitting up until the wee
hours when we were able to book a series of milk run flights
taking the scenic route home. I was again reminded why I hated
to travel on these business trips.

Murray was accustomed to the rigors of missed flights and
connections and sitting up all night in airports, but I was not
and was sick in bed for a day after we got home. I called Andy
from my bed and told him what I had learned. He was delighted at
being vindicated by hard data and filled in a clue to one of the
missing links in the story. He said that during the initial
discussions before the contract was finalized, the question of
whether to use forced air or liquid cooling had come up. The
decision to go with forced air was made on the basis that it was possible using these new blowers and it would save time, perhaps 10 minutes, if connecting and disconnecting the liquid cooling pipes could be avoided during replacement of the module. 

Murray and I got together the following day and wrote a
summary of our findings for Chuck Farmer and went to his office to tell him what we had learned. Since his own heat exchangers had not been able to accomplish the desired goals, he was most receptive to the idea that liquid cooling was the only way to go.  He did, however, anticipate a stiff measure of resistance and it might be tough to explain why it had taken us two years and over $1 million in the red to discover this fact. 

I was never told the details, but I did learn that the TWT
was redesigned for liquid cooling and that it was a substantial profit center for many years afterward. 

I went back to CR immediately and the only thing I got from Chuck Farmer by way of recognition or appreciation was a joke reinforcing his observation that the only diagnosis worth a damn was the correct diagnosis. It seems that a young doctor was taking over the practice of an old country doctor upon the old man's retirement. The old doctor had but one word of advice... "Always stick by your diagnosis." The first patient arrives doubled up with pain in the belly. The young doctor takes one look at him and says, "Well, sir. In my professional opinion you has got a case of locked bowels." "What do you mean, Doc?", the man protests, "I've got the runs, the trots, I've got the diarrhea." "Oh!, Hmmm!, Yes, I see. Well, in that case what I means to say is that they is locked in the open position." 

I wrote up my findings on this trip as an addendum to my
earlier memorandum, leaving two unanswered questions. One was
how the company which made the fans could have made the mistake
they did regarding the static head at altitude, although I had
learned from Andy a while ago that they had quietly dropped this
claim from their brochures. The other question was why the
competitor's tube ran so much hotter in the gun region than ours
did. A few months after our trip, Murray came up with a likely
answer to this latter question. His information was that the air
flow in our package was such as to bring the coldest air over the
gun region before any heat from the focus coil or the body of the
tube was collected. In the competitor's package, the air was
first heated by the focus coil and the tube body before passing
over the gun. This was certainly an attractive hypothesis, and
probably true.

I came across a plausible answer to the other question some
time later. My boss, the VP of CR, suggested that I attend a
conference in Los Angeles where one of the topics would be YIG
production. I could rub elbows with some important people and
perhaps see how my magnetometer had made a difference to them,
get a few plaudits for myself and make a showing on behalf of
Varian. When I told Andy of this, he suggested that I drop by
the fan manufacturer's plant at the airport within walking
distance of the hotel where this meeting was to be held and see
what I could find out. I asked my boss about this and he made a
couple of phone calls and asked to have someone there receive me
on a courtesy call. The supposed purpose of my visit was to
learn how their fans, of which Varian was a substantial customer
for a variety of applications, were tested. The man responsible
for Quality Control took me on a tour of the facilities while I
expressed my curiosity as to how they measured the performance
characteristics. The QC man was not exactly sure, but he had a
technician who was fully versed in all of the metering problems. 
This fellow showed me a setup wherein the static pressure at the
fan was measured by the displacement of a flexible diaphragm
behind a porus plug to eliminate any velocity pressure crosstalk
and a hot wire bridge downstream to measure the actual flow. 
These two instruments drove an X-Y recorder which would trace out the Pressure vs Flow characteristics as the load was varied from open throat to closed throat. There were some units ready for test and I was given a demonstration.

This test was run on an open bench at sea level, so I asked
how it would be done at high altitude. The tech replied that
they didn't test the fans at high altitude. They did at one time
several years ago, but they got a lot of static from some of
their customers, including Varian, so they stopped doing it. The engineer responsible for the test at that time was no longer with the company, but the tech was pretty sure that he used the same setup in an altitude chamber at the facilities of another company in the area. The tech couldn't be absolutely sure, but he believed that the engineer simply calculated the flow rate based on a well known relationship between density and thermal conductivity as the pressure was reduced. The hot wire bridge used as a flow meter for gases worked on the principle that a moving gas stream removed heat from a wire better than stagnant gas, so the wire elements in the gas stream ran cooler, and thus had lower resistance that the two wires in stagnant gas. An electrical readout registered the cooling effect and thus the velocity of the gas flowing over them. Calibration at sea level was done using a manometer and Pitot tube. The problem in my mind was that I recalled from studies of gas theory in college that the viscosity and thermal conductivity of gases were independent of pressure until the average distance between gas particles was comparable to the size of the containing vessel.  When the gas is dense, there are many carriers of heat or momentum, but they collide with each other so often that the efficiency is poor. As the pressure is reduced, there are fewer carriers, but each carrier is more efficient. This situation prevails until the most likely collision is with the walls of the vessel. Then a reduction of the number of carriers results in a reduction of the thermal conductivity and viscosity. The most likely scenario in my mind was that the engineer, having got the theory wrong, mistook a reduction in mass flow for a reduction in thermal conductivity. Engineers, like doctors, are not perfect in their reasoning and diagnoses.

Some 35 years later, much of it spent diagnosing yield
problems in vacuum tube manufacturing operations, I will make a few observations regarding human nature. Almost universally, the first instinct of people responsible for projects in trouble is to cling to specious theories to account for their difficulties with extraordinary zeal and passion, and they will contrive roadblocks of every description to keep any outsider from learning the truth. We can speculate as to why this is so often the case. Most people with project responsibility were not around when the design parameters were put in place. The designers have moved on and left more aggressive and less well educated people in charge. When trouble strikes, the most likely cause is closely associated with the last change in the production process. This may be a new piece of equipment, a new assembler, a new supplier of raw material, a new incoming inspector at the customer's place. When the cause is found, the fix usually follows close behind, but the fix is rarely exact.  Over the years, the people working on the project develop a working lore regarding what is important and what is not and this lore is priceless, though not infallible. The time comes, however, when some production problem does not yield to any of the standard fixes. Most likely, the only way out of the morass at this time is a fundamental understanding from first principles of the device and its operation. The production and sales staffs are poorly equipped to come at the problem from such a perspective, but they are deeply reluctant to accept the idea that they have lost control.

I was laid off in 1970 when the aerospace industry took a nose dive and spent the next 11 years as a real estate broker and budding house builder. In the early 1980's the S&L crisis hit and took much of the fun out of real estate. As fate would have it, Pres. Reagan decided to build up the military again at this time and people with my experience were now scarce and in great demand. I went back to industry as a production line troubleshooter in the microwave vacuum tube industry. The head honcho of my new company took me to a meeting called to discuss the most critical yield problem in house and relieved everyone there of their responsibility for coming up with a fix. That was my job now, and the boss told them to give me all of the help and information and tools I would request. This was a winning approach. The standard procedure in such instances is to give people the responsibility, but not the authority, to do what needs to be done. I was a very effective troubleshooter for perhaps 5 years, but as the source of power became more and more distant, I found more and more roadblocks in my way until it became clear that I could no longer be effective and I started looking for greener pastures. I lucked out and found one where I spent the remaining years until retirement at the age of 70 years with my intellectual integrity still intact. 

I recently discussed this account with some of the retreads still illuminating the scene and was told that Leo took a job at one of our competitors drawing a substantially larger salary than Varian had been paying him. His new employers hoped to use his experience to get them into the same market with the same product, but again he was unable to deliver after 2 or 3 years and was let go. He was, according to my informant, able to play this same game at yet a third company at a still higher salary.  When I returned to the tube industry in 1981, I heard that he had started his own company and was doing quite well as a vendor to his former employers. -RMR

 
 
 

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