I spent 48 years with Douglas Aircraft and its successors. Some people have asked, “Didn’t you get bored doing the same old thing?” The answer is that it wasn’t the same old thing. There were always new challenges.
Starting in 1952 at the El Segundo plant,, where we built Navy fighter and attack airplanes, I was assigned to the Hydraulics Design Group, and within that, to the test group. I was told that this was probably a temporary assignment, as hydraulic systems would soon be replaced by electrical and pneumatic systems.
Aircraft hydraulic systems were undergoing growing pains, having transitioned from WW II designs which operated at 1200 or 1500 PSI, and part time at that, to 3000 PSI full time systems. Temperatures and pressures went beyond former operating limits. I participated in improving the hydraulic seals by (1) refining the O-ring groove design, (2) improving the back-up ring design, and (3) facilitating improved quality control of the O-rings themselves. This work was spread over several years.
Harder working hydraulic systems produced more wear particles due to hydraulic pump and motor wear, O-ring wear, and more. These particles can cause the pumps to wear out or control valves to misbehave. Lab tests I performed helped in the development and validation of new high-performance filtration systems which the suppliers were offering. Field testing I did for the Navy hastened the time when these improved filters were specified for new military aircraft and soon after for commercial aircraft.
Our chief piping engineer, Frank Hanback, was constantly trying to eliminate rubber seals, believing they were the weak point of a hydraulic system. When the Navy explored brazed-joint tubing systems, Frank picked up the ball and ran with it. I was in the right place at the right time, and became deeply involved in the brazing process, the brazing tool design, and the tube fitting designs.
A related area in which I did substantial testing, though little original design work, was the use of flexible coiled metal tubing in lieu of rubber or Teflon hoses where motion of the tubing was required. I did contribute to the use of titanium flexible pipes. The later Navy A-4 Skyhawk airplanes had hydraulic systems which were virtually rubber-free, and were very reliable.
Transferring to mostly commercial aircraft, the game changed somewhat. A military plane might be ready to be scrapped after 5000 fight hours. A commercial airplane could fly 4000 hours per year, for 10 years or more. Some DC-9s achieved over 30 years of service. We learned to emphasize designs that were maintenance free and corrosion free (as near as possible) with minimum cost of ownership (eg., minimum number of overhauls during the life of the airplane.) Some of the design concepts we had pioneered on military airplanes proved to be very well suited for the commercial airplanes.
I was occasionally called upon to go abroad to do design coordination and/or educational duties with customers or with partner enterprises.
For many years I was the Douglas (Long Beach) representative to the SAE committee G3, which creates industry standards for tubes, fittings, hoses and clamps. In this capacity, I authored or modified several industry-wide hydraulics system standards. This enabled me to travel to committee meetings all over the US, and sometimes to Europe. Eventually, as the company came on hard times, it’s support of this activity was withdrawn.
With the completion of the DC-10 design, I sat down with the chief of the Hydraulics design group and explained why our next new airplane should have a 5000 PSI hydraulic system. He accepted my arguments. However, as it turned out, we never designed another all-new airplane at Long Beach.
We did have a new MD-12 in preliminary design, cancelled when Boeing bought MacDonnell-Douglas. The MD-12 would have had a 5000 PSI system, which is now the standard for new airplanes like the Airbus A-380 and the Boeing 787.
During a lull in commercial airplane design activity, I was assigned to help in the “weapons delivery” section (bombracks). Originally intended to help with some qualification tests of new bombracks for the F/A 18 Hornet airplane – a St. Louis product – I later became the cognizant design engineer for the BRU-32 and BRU-33 bombracks, but not during the original design phase. In a way, these racks were”hydraulic”, except that in place of high-pressure liquid, they were operated by high-pressure hot gas generated by discharge of a pyrotechnic cartridge.
Working with weapons systems was not my preferred career path, but I had to admit that they probably involved more high-powered engineering than many projects I had worked on. What I originally perceived as ”a dumb little machine with a couple of hooks” turned out to be more like a giant Swiss watch, with loads in tons rather than milligrams.
At a time when the design and production problems for the bombracks were under control, the hydraulics design group leader, Bob Madison, retired. I was asked whether I wanted the job, and immediately accepted. For a time this involved more or less routine work on our production airplanes, the MD-90 and the MD-11. Before long, however, a new variant of the twinjet line was proposed, to be called the MD-95. The hydraulics group was split, and I became the cognizant design engineer for MD-95 hydraulic systems.
While the MD-95 design was taking shape, Boeing bought the company. After some uncertainty as to the status of the project, Boeing decided it would continue , except that it would be redesignated the Boeing 717.
My design group –usually about ten engineers -consisted entirely of foreign-born engineers. I was the only “Anglo”. One day Mikhail, our Russian, came into my office and said “We need some help with an English word, and there’s nobody out here but immigrants.”
This group got along very well, assisting each other as we transitioned into computer drafting. The FAA had made me a “Designated Engineering Representative”, or DER, to assist with the certification of the airplane. There was a lot of coordination with the flight test division and with the FAA to establish what testing would satisfy the Federal Air Regulations.
It takes hundreds of engineers to design, test, and certify a commercial airplane. I’m proud to have been a part of the 717 team.