First-Hand:Reinventing the Wheel: Collaboration, Cooperation, and Contention in Engineering


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Submitted by Paul G. Cushman

After graduation from MIT and Middlebury in 1941, I joined the General Electric (GE) Company and stayed with that company for forty-two years and five months. In those days, new engineers at GE entered the "Test Course" where they gained practical experience testing GE products in several different departments. After that, those so inclined could enter, in addition to the Advanced Engineering Study Courses, the Advanced Engineering Program for another one to three years for a series of engineering assignments in various departments.

However, World War II was on and the engineering rotation assignments were forced to stop. The young engineers were "frozen" into military departments. I was assigned to a small group that was designing and manufacturing selsyns and other small electrical equipment. Even though small and low cost, these devices were crucial components in many of the gun directors and gun drives and mechanical computers that GE was supplying to the government.

This assignment was very interesting and instructive. I remember one rather minor event with particular clarity because it was the source of a moment of great technical satisfaction but with an ending of disappointment. GE unions were on strike and we non-union engineers could not get through the picket lines to work. We were getting paid and were told to "think about useful projects" at home.

I spent part of my time analyzing the torque response of selsyn differential motors, which, for reasons not understood, had considerably less torque than expected. The analysis showed that the leakage reactance of the rotor should be increased. This counterintuitive result was not believed by my boss or my associates. But since it wouldn't cost much to try it, my boss gave the go-ahead.

So when the strike was over, I ordered a differential selsyn with a rotor ground undersize but with a thin layer of soft iron wire wound round the rotor to give the desired leakage reactance. Tests revealed an increase in torque of the expected amount. So I submitted a patent docket, fully expecting that the company would certainly patent such a novel idea. But it didn't. Selsyn motors of any sort were not being designed into systems because new accuracy requirements dictated that selsyns be used in their electrical signal mode, with follow-up servos providing the needed mechanical torque. Thus, my patent idea had no future business value, which was much more important to the patent filing decision makers than the novelty of the idea.

The Polaris Project was managed by the Special Projects Office of the Navy. MIT received a contract for the guidance, General Electric (GE) received a contract for submarine based fire control and guidance support, and Lockheed received a contract for the missile structure and propulsion. These were initially development contracts, which were extended to produce hardware. (There were other contracts-for example, submarine, nuclear power plant, and submarine navigation-but these did not interface with GE directly.)

Overtly, MIT, G E and Lockheed cooperated harmoniously. Covertly, there were rivalries. Liaison representatives were exchanged between the three groups. Usually such representatives would attend meetings and take care of their correspondence. But the GE liaison man at Lockheed, Bob Howell, insisted on taking a more active role than that, and was soon running Lockheed's large scale, analog missle trajectory simulation. His findings from these runs were important facts in the system and hardware decisions that were made by Lockheed. In this "triumvirate," it appeared unlikely that I, as Inertial Guidance Concept and Systems engineer, would be allowed to make any significant contribution to the project. As it turned out, I was able to make a contribution, but the acceptance of my contribution required the manipulation of the "politics" of the situation. To a certain extent, my methods might have been labeled unethical, but it didn't seem so at the time.

The guidance steering equations that were proposed by MIT could not be used early in the missle flight. Their use had to be delayed until the missle had been pitched over and had acheived considerable velocity in the general direction of the target. MIT proposed that the early part of the trajectory be achieved by a missle attitude angle program. However, Lockheed soon showed with its trajectory simulation that expected wind conditions could cause mechanical overloads on the missile struture if a fixed angle program were used. So then world wide winds began to be investigated regarding their predictability so that a highly variable set of angle programs could be generated to be used at different launch locations and directions of fire.

This kind of complexity and uncertainty did not please the Navy any more than it did Lockheed. With this dilemma in hand, I spent a few days modifying the steering equations used at the terminal portion of the Hermes A-3 trajectory to the boost part of the Polaris trajectory. The concept utilized the signals from the integrating accelerometers mounted on the IMU stabilized platforms to acheive a highly damped, lateral velocity control for the missle. In such a control, any wind loads are sensed by the accelerometers and automatically compensated by the control response. The calculations that I did were considerably more than "back of the envelope," but needed simulation trails for evaluation.

As industrial supporters to MIT, ideas like these generated at GE should have been disclosed to MIT. However, on the basis of previous contacts with MIT, I knew that ideas from outside that organization were not sought after, and, if offered, would be ignored unless presented with a great deal of supporting data.

So I suggested the idea to Bob Howell for trial on the Lockheed Simulation. The results were immediately favorable. Not only were the required implementations much simpler than even the single, fixed-angle program systems, but the simulation showed that the missile could fly through the worst expected wind profiles with no trouble. As a result, Lockheed forced MIT to incorporate Z-Dot Steering (my nomenclature) into their guidance concept, and this steering was used on the early Polaris missiles. It was a little amusing to me, that nearly thirty years after the concept of Z-Dot Steering for flying though wind profiles had been demonstrated, a shuttle launch was delayed several hours because a "winter wind profile" had been programmed into the guidance computer and the wind on that day was blowing from the opposite direction. It is often said that engineers are prone to "re-invent the wheel." Probably an even greater failing is their tendency to substitute an inferior invention for the wheel.

Most of my previous reports, some of which conceivably might have been candidates for IEEE papers, were classified, as is the case for most work done in a department specializing in military equipment. I served on a workshop group that was considering Standards in Control Systems and for several years, reviewed and commented on Control System Papers that had been submitted for publication.

Most notably, I chaired one of the sessions at the national meeting in Seattle, Washington. I remember that session well because an airline strike was on and three of the presenters in my session did not make it. To partially fill in the time, I presented one of the papers myself. The co-chairman of that session was Mr. N. B. Nichols, the creator of Nichol's Charts.

When reviewing and evaluating a career it is sometimes depressing to remember the frustrations, failures and missed opportunities. It may be helpful for us to bear in mind that only a relatively few can be "rich and famous." One criterion of "success" we can use is the enjoyment our jobs gave us, and our feeling of accomplishment in doing a good job, at whatever level in the "hierarchy" we happened to be.

I fully enjoyed the cooperative tasks with my peers, during which talents and technical contributions were mutually recognized and appreciated. Early retirement was never a consideration for me. Health problems in my family made it necessary to retire soon after the age of sixty-five. Otherwise, I would have continued at the job for several more years.