Sandbagging

March 5th, 2010

My service in the Kentucky Air National Guard involved some logistics which might be considered wasteful of taxpayer’s money. The most I can say is that these events were not at my request or instigation.

Shortly after joining the Air National Guard, probably 1948, I was “hanging out” one day at the Guard center at Standiford Field, Louisville. While there, a helicopter flew in – a rarity at that time (1948). It had a pilot and a passenger. The pilot’s destination was Fort Knox, but the passenger’s final destination was Louisville. The pilot asked if we could provide him with a sandbag or similar weight to balance his helicopter for the flight to Godman Field.  It was an early model Bell chopper (Model 47, or military H-13 Sioux) which couldn’t fly safely with all the load over on one side.Early Model Bell Helicopter

They couldn’t come up with anything suitable, so one of my pilot friends said, “Norm, why don’t you fly with him to Fort Knox, and I’ll come down and pick you up in an AT-6 (two-seat trainer.)” I agreed to substitute for a sandbag, and experienced my first helicopter ride. As we were leaving Standiford Field, I saw my friend warming up the AT-6 Texan. I thought he would pass us going to Fort Knox, but he didn’t. We flew fairly low, and it was fun to see people rushing from their houses and pointing at us. Perhaps their first helicopter sighting.

At Godman Field, I said goodbye to the ‘copter pilot, having performed my counterbalance duties well, and stood and waited for my ride home. Eventually I saw a C-47 land, and was surprised when it pulled up beside me, and I was invited to “hop in”. It turned out that a pilot who wanted to get a bit of flying time in the C-47 had called my friend back from the AT-6 to co-pilot the C-47.
During WW II, when I was trying to become a fighter pilot, I read that ”by the time you are 18, you are beginning to be too old to be a fighter pilot” . But now those same WW II pilots were in their late 20s or early 30s and were still our frontline fighter pilots., and some of them would serve in the Korean war and beyond.
The National Guard was required to serve two weeks of active duty each year, for training and to maintain proficiency. This was before flight simulators were widely used, and the fighter pilots needed actual “stick-time” to remain proficient.
One of these active duty periods took us to Lockbourne Air Base near Columbus, Ohio. There I was introduced to the high-pressure aircraft maintenance required to keep the planes available for flight. Yet P-51 Mustangs were relatively simple aircraft. The ratio of maintenance hours to flight hours was nowhere near as high as with today’s jets.
A memorable event during the Lockbourne exercise was that we burned down the mess hall. But we kept the planes flying.
Another two-week activation took us to Godman Air Base at Fort Knox, Kentucky. For this, I pleaded to be excused, because I felt that I couldn’t afford to miss two weeks of college at this point in my studies. They offered me a deal. I would attend the lecture classes in the mornings, then skip the laboratory classes in the afternoon sessions. The ANG would fly me from Louisville to Fort Knox around noon each day. This required a dedicated flight by a C-47 and two pilots.  Again, they justified this procedure by the fact that they needed a certain quota of flight hours each month to maintain their flight proficiency.
During our active-duty tour during the Korean War, we enlisted men were moved about on C-46 Commando transports. These, were larger than the C-47s, and were often fully loaded. On one occasion I was pressed into duty as a loadmaster. We had a lot of equipment and toolboxes to move, and didn’t have scales to weigh them. So with a couple of helpers, we “hefted” each item and estimated its weight. We loaded the plane close to it’s weight limit, The flight went smoothly, and I wondered how well the load limits were observed during the WW II period.
One of our war games exercises took us to “Operation Southern Pines” at Laurenberg-Maxton Air Base in North Carolina. This involved various disciplines, including some paratroopers. One day, a buddy and myself talked ourselves into going along as “observers” on one of the drops. There were at least a couple of dozen paratroopers on the plane, as we approached the drop zone. Suddenly, they were all jumping, and my buddy and I were the only ones left in the C-46 besides the pilots.. He asked, “Where did everybody go?”

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POST MORTEM

February 27th, 2010

About 1963, one of my early assignments after transferring to the Douglas Long Beach plant was as a member of an accident investigation team. Douglas had produced the C-133 Cargomaster transport plane for the Air Force, powered by four turboprop engines. Fifty of these planes had been built, and most of them called Dover (Del) Air Force Base home.

Douglas C-133 Cargomaster

Douglas C-133 Cargomaster

During the year or so before my assignment, a couple of these big planes had crashed at sea shortly after leaving Dover for Europe. The authorities were baffled as to the cause of the losses. When another C-133 at Dover suffered damage which made it unrepairable, our team of investigators was invited to examine that airplane with a fine-tooth comb, disassembling any parts we thought relevant, to look for anything which might be implicated in the accidents.

There were four of us, and we boarded a DC-6 or DC-7 bound for Philadelphia, with intent to take a Greyhound bus to Dover. As our plane neared the East Coast, however, the pilot announced that “ Due to the weather, we have been diverted to Dulles airport at Washington DC.” There was a blizzard in progress.
When we reached that vicinity, we circled about for a very long time, until our fuel reserves must have been very low. We could see that we were in a severe snowstorm, but occasionally we could make out things on the ground. Eventually, we descended and made a pretty rough landing. As we rolled to a stop, the pilot announced, “Surprise! We’re in Baltimore.”
They have snow emergency laws there, which say that all private vehicles are banned from the highways. The only things permitted to move are emergency vehicles, and Greyhound busses. We were able to get tickets on a bus to Dover Air Force Base.
We arrived at the bus station near the air base at about 2:00 AM, a bit behind our schedule of 6 or 7 PM. There was no transportation available to get us to the motel where we had reservations. But we had the name and phone number of the resident Douglas representative at Dover. Our team leader called him to ask if he would pick us up and drive us to the motel. He had almost closed he deal, when the sleepy voice on the other end said, “Who did you say you were?” Turned out we had a wrong number.
The right number was dialed, and we persuaded the Douglas rep to come get us. I’m not sure why he was allowed on the road, but he wasn’t challenged. We were a bit late getting to bed.
The next day (actually the same day) we got to work. The carcass we were to dismember was a C-133 which had the right wing burned off in a fueling accident. I had purchased one of those adjustable inspection mirrors, and proceeded to minutely inspect the hydraulic system. Every tube and hose, every fitting, every actuator, every valve.  The other guys studied other systems, structure, etc.
The first evening there, I fell into conversation with a Colonel who was a C-133 pilot. He asked why we were there, and when I told him, he said, “You guys are wasting your time. These pilots have just been stalling the airplanes during the climb to altitude. They climb out at an airspeed just above the stall speed when they are heavily loaded. It’s possible for some turbulence or wind shear to reduce the speed just enough to stall the airplane. And the effectiveness of the elevators is such that they can’t pull out of a dive if it happens at a low altitude”
I knew the airplanes had a stall-warning system. I asked about that, and he said, ”Yes, they have stall warning systems, but when the alarm goes off, they just reach overhead and pull the circuit breaker.” In other words, they turn it off and ignore it.  Big mistake.
I reported this conversation to our team leader, but it was received skeptically. We continued with our physical examination of the C-133. I found nothing which was a potential danger to the airplane. I interviewed mechanics, “crew chiefs”, who maintained the hydraulic systems, and learned of no concerns by those who had day to day hands-on experience with the airplanes.
We finished our post-mortem on the airplane, and submitted our findings. They were all analyzed and combined with input from our aerodynamicists. The final report was written a few weeks later. The conclusion? The pilots were ignoring the stall warnings, and stalling the airplanes at an altitude too low to permit a recovery.

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A Fluid Situation

December 6th, 2009

In my career as a hydraulics engineer I had constant, and sometimes trying, involvement with hydraulic fluid. My first ten years were primarily with Naval aircraft which used a petroleum-based fluid (MIL-H-5606). It was similar to kerosene and its flammability was always a concern. It was sometimes responsible for fires, particularly when overheated hydraulic wheel brakes were involved.
About 1951,  chemical company produced a water-based hydraulic fluid called Hydrolube H2. It contained about 30% ethylene glycol, so was pretty much like anti-freeze in your car radiator. The Navy thought it was the answer to their fire concerns, and mandated it’s use on new airplanes delivered to the Navy.
A good hydraulic fluid is also a good lubricant, is anti-corrosive, anti-foaming, and resists degradation caused by pumping at high pressures. Our chemists were not convinced of the anti-corrosion or the lubricity. Our chief engineer Ed Heinemann resisted the Navy’s mandate for airplanes we already had in production. We were preparing to use Hydrolube on the new A2D Skyshark airplane.
One day the Admiral of the Pacific Fleet sent a message to Naval Headquarters, “Don’t send me any more airplanes with Hydrolube!” Planes from other manufacturers were experiencing corrosion within their hydraulic systems. That essentially ended the experiment with Hydrolube, and Douglas, not having delivered any planes with Hydrolube installed, came out smelling like a rose. The A2D Skyshark never became a production airplane.
Commercial aircraft went down a different road. They used the petroleum-based fluid into the 1950s. Then a Douglas employee who whose hobby was chemistry, came up with a fire-resistant fluid based on phosphate esters. It initially had problems with viscosity at low temperatures, but when formulated with the right additives, it met goals for lubricity, anti-corrosion, anti foaming, anti-oxidation, and above all, fire resistance.
The new fluid was licensed to Monsanto Corp. and dubbed “Skydrol”. The FAA was happy to endorse this safety improvement, and required all the large commercial airplanes to use it.
We proposed to the Navy that we supply A4D Skyhawk airplanes with Skydrol. I was involved in preparing a study concerning costs, weights, maintenance practices, etc, and the Navy seemed very interested in achieving it’s long desired goal of fire-resistance. However, there were two major stumbling blocks: (1) All the O-rings and other rubber seals in the hydraulic system would have to be replaced, and (b) Skydrol attacks most paint. In the end, the Navy decided not to take us up on our offer.
Skydrol was priced at $17 a gallon in the 1960s, and Douglas received a royalty when a Boeing or Lockheed airplane used it. The formulation was changed periodically, and when I became involved we were using Skydrol 500A (which reflected the viscosity in centistokes at low temperature.)
Airplane fight-control valves are high precision spool-type assemblies, with clearances of about .0002 to .0005 inch between slide and sleeve to minimize leakage. We didn’t understand that with the filtration of the day, the fluid was loaded with tiny  particles (metal and O-ring wear, airborne dust particles, etc.) which tended to clog up those clearances and reduce the leakage to near zero when the valve was in neutral. It only took 2 or 3 seconds.
I was up to my neck in efforts to introduce ultra-fine fluid filtration to hydraulic systems at Douglas, and the filter manufacturers were pushing it at our competitor Boeing and at British firms. In the early 1960s a new phenomenon appeared. Control valves were being eroded to the extent that they soon had unacceptable rates of leakage.
I spent a lot of time examining eroded valve parts under microscopes, and trying to ascertain the cause of erosion. It seemed probable that electrostatic discharges were responsible.
The British developed a commercial airliner called the Trident. Their test airplanes passed their hydraulic system tests readily, but production models sometimes showed excessive valve erosion, even before being delivered to a customer. Why the difference? Detective work revealed that on the test airplanes, the hydraulic fluid had intentionally been contaminated with the maximum allowable water content (about ½ of 1%) to evaluate how detrimental that was to the airplane. Unexpectedly, the presence of the water seemed to protect the valves from erosion.
The next formulation of fluid was Skydrol 500AW, where the W stood for water. It worked for us. Boeing proclaimed it was all a hoax to sell more fluid, even though they had a backyard full of airplanes they couldn’t deliver because of valve erosion, and these were the first airplanes they made with high efficiency fluid filters. Cause and effect were there for those who looked.
Lab testing at Douglas and at Monsanto showed that the erosion was an electrochemical reaction due to static charges built up by the high velocity fluid escaping at the valve metering edges. Our new filters removed the particles which formerly impeded the leakage flow. Monsanto chemists eventually established the degree of conductivity of the fluid needed to dissipate the static charges and avoid the erosion (0.4 micro-ohms). Later they found another less corrosive additive to replace the water. Problem solved.
Boeing always chafed at having to pay Douglas a royalty for using the fire-resistant fluid, and as the Douglas patents were about to expire, they induced two other chemical companies to develop competing fluids. The competitors started with a lower density phosphate ester base stock (about 7% lighter), resulting in a fluid which saved a substantial amount of weight, particularly on a plane as large as a Boeing 747. This forced Monsanto to develop a similar fluid to remain competitive; Skydrol LD, for Low Density. There was a slight reduction in the fire resistance, but it was judged acceptable by all parties involved. The DC-10 was in development, and we had an “iron bird” in our lab with the three full-scale hydraulic systems installed. We put a different brand of fluid in each system, and evaluated them for a year. The biggest problem was with mixtures of these fluids, and in particular, maintaining the required conductivity.
The low density fluids caused increased O-ring swelling, We thought for a time this might be a show-stopper, but our year of iron-bird testing eventually proved it to be acceptable.
One day when I came to work, the sales representative for one of the fluid manufacturers was waiting for me with his feet on my desk. He demanded to know what “friction locks” we had in our hydraulic systems. The answer was none. This came as a relief to him. It turned out that Boeing 747s with his brand of fluid installed were having landing gear doors come open in flight. These doors were held closed by friction locks, and his fluid had an additive which greatly reduced friction when under pressure. But the upshot of this episode was that his company withdrew from the aircraft hydraulic fluid business.
With inflation, these fluids now cost much more than the original $17 a gallon, but Douglas, which has been absorbed into Boeing, gets no royalty. We reduced the system leakage, and through better filtration, reduced the replacement of fluids due to degradation, so the airplanes require less “makeup” fluid than formerly. Monsanto spun off this now lower-profit product line to a new company called Solutia.

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Hypersonic

December 3rd, 2009

There was a period of a few weeks in 1963, after the majority of the Douglas El Segundo people had transferred to the Douglas Long Beach plant, that I was still practicing my profession at El Segundo. The test lab facilities at El Segundo had not been fully reborn at Long Beach, so some work continued at the old location.

For me, the project was the “fast-acting gate valve”. Douglas had a research facility located near the El Segundo plant, Douglas location A-10, which was developing a hypersonic wind tunnel, in which a small test model would be fired like a bullet into a chamber where the aerodynamics would be recorded by Schlieren photography (interferometry). This is a technique whereby a high-speed image is recorded showing air densities, shock waves, etc. The whole test lasts milliseconds.
A necessary feature was the fast-acting gate valve, which was to open to permit the test model to pass, then close to prevent the combustion products of the “light gas gun” from entering the test chamber. Less than the blink of an eye.  One of our top designers, Harold Groebe, designed the gate valve, which had about a ten-inch diameter opening. I was assigned to do tests firings. A small explosive charge (electrically fired squib) was used to trigger a slide valve, which in turn controlled compressed air to move the valve gate.
I was to report to my superiors at Long Beach, weekly or more often, what progress had been made. The El Segundo division had been reduced to a few machinists, lab technicians and engineers. I was in the Hydro-Mechanical Engineering group. My weekly report was a typed newsletter entitled “Hydro-Mechanigram”, and subtitled “The Truth from an Outlying Facility”.
As the machining and assembly of the gate valve progressed, I designed instrumentation which would allow us to measure valve position vs. time to verify that the valve was meeting its’ specifications. The first test showed that the position measuring instrument wasn’t adequate. It failed early in the open-and-close cycle. I calculated that it would take about 3000 Gs (G = Force of Gravity) to cause the failure. I confessed in the next Hydromechanigram that I had no idea that Gs went that high.
A revised design worked. But another problem surfaced. The small squib-powered actuator was good for one shot. A rubber O-ring on the piston suffered fire damage and had to be replaced after each firing . I tried substituting a steel piston ring, of the type used on model airplane engines, but this proved less than satisfactory. Finally I redesigned the piston to put the O-ring farther from the piston face exposed to flame. The flame had to travel through an .002 inch diametral clearance between cold steel parts for about 3/8 inch to reach the rubber O-ring, and was effectively quenched along the way.
With development testing completed, the gate valve assembly was delivered to the wind-tunnel people, who reportedly used it successfully for many hypersonic wind tunnel tests.
During this period, a building which provided our main entrance/exit to Aviation Boulevard was leased to the Mattel Toy company. Soon it was equipped with a variety of toy-making machines, and we Douglas employees entered the premises and exited via a walkway between those machines.  After a couple of weeks, chain link fences appeared on each side of the walkway. We learned that the purpose was not to protect military or Douglas-company secrets. It was to protect the Mattel’s toymaking secrets (for the next Christmas season) from the prying eyes of Douglas employees.

SIDEBAR: We  had a photgraphic group at El Seguondo which was kept fairly busy documenting our test setups and results.  One of the photographers, named Milo, had on his own initiative educated himself in the use of Schleiren photoraphy.

One needed a government SECRET clearance for access to the wind-tunnel facility but due to some friction with his boss, Milo’s application for clearance had been “lost”.  As the time came for that skill to be used in the new hypersonic facillity, Milo was instructed to teach his fellow photographers to do Schleiren photography.  Milko said “No”.

He was called before a labor relations board, as time was getting short.  The arbitrator asked, “Is this procedure a Douglas secret, or a military secret?”  ”No.”

“Is it described in textbooks which are generally availab;e?”  ”Yes.”

“OK, Milo you don’t  have to tell them a  thing.”  Milo’s SECRET clearance was ready within two days.

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STING OPERATION – NFR BIO 2.5

October 23rd, 2009

My father, Onslow Robinson, was an MIT graduate, a registered engineer in two states, but held to the ideal that a family should be largely self-sufficient. Perhaps this was an outcome of the great depression. He read books like Five Acres and Independence, a Handbook for Small Farm Management by Maurice G. Kains. We usually had a large garden, and canned some of the crop for the winter. We kept enough chickens to supply our eggs and an occasional chicken dinner. He had a steel shoe-last to enable him to repair our shoes and get a few extra weeks or months out of them. And at our Shively, Kentucky home we took up beekeeping, I believe even before the WW II sugar rationing which started in May 1943.

Not in a big way. We had up to four hives, and we all became amateur apiarists, somewhat expert in tending the hives. We received surprisingly few stings, and learned to remove the stinger immediately to minimize the venom. We got hats with veils to protect the face and neck At that time, you could buy a swarm of bees, or an extra queen, from Sears Roebuck.
At some point I read a story, perhaps in a “Tom Swift” book or some other boy’s adventure yarn, which included an episode in which our hero saved the day by capturing a migrating warm of bees which had collected in a tree and was frightening the nearby residents.
This exact scenario soon unfolded for me. Some friends of mine ran a trailer park (it would now be called a mobile-home park) about two miles from our home. They knew we kept bees, so one day we got this frantic call about a swarm of bees on a tree in their park, terrifying their tenants. My father was sympathetic, but had no idea how to help. I told him about the story I had read, and he agreed to give it a try.
On arriving, we sprinkled water on the swarm, because, according to the book, they won’t fly when they think it’s raining. It seemed to work. So far, so good.
Then we took a bed sheet and enclosed the swarm, tying it tightly to the branch between the tree trunk and the enclosed swarm. Then we sawed off the branch, and took it home in our Ford Model-A truck. I believe we did all this without getting stung.
Fortunately, we had an empty hive ready for them. We had a smoke generator, and used that to stupefy the bees so they could be handled. We found the queen, and temporarily isolated her in a small cage, knowing that the swarm would not move on and abandon their queen. The new residents became a productive swarm, and the trailer park owner, Mr. Parkhurst, was very grateful.
We kept bees for a few years – perhaps until I left for the army. We had honey for ourselves, and sold some to our neighbors. Mother baked a lot; pies, cakes, donuts, etc. She learned to substitute honey for sugar in her recipes.
I doubt that the whole enterprise could be called profitable, but with free labor (myself and my brother Albert) it helped us to overcome the WW II sugar shortage, and perhaps move in the direction of family self-sufficiency.

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WEATHER OR NOT

September 5th, 2009

This post involves a few of my encounters with weather. It has nothing to do with engineering, but I thought a few of my weather-related adventures might be of interest to some, perhaps stirring up similar memories.

As a second or third grader- perhaps 1934- I lived with my parents and grandparents on Martha’s Vineyard in a two-story seven bedroom house allegedly built about 1730. It was known as ‘The Old Great House”, and the story goes that when a young couple in Chilmark married, they would often set up housekeeping in one of those bedrooms while they were building their own house. We had moved back in with the grandparents during the great depression.

One afternoon we heard (by radio?) that we should expect a “tempest” that evening. That was the terminology for thunderstorm at that time and place. We had a large room which served as kitchen and dining area, and that evening  we ate supper accompanied by lightning and thunder. When the meal was finished, my mother and grandmother washed the dishes. At a moment when my mother had stepped to one side of the kitchen sink while drying dishes and grandmother had stepped to the other side to put some dishes away, lightning struck.

A large fireball appeared, apparently from the water faucet, danced around in the sink for a few seconds, then disappeared down the drain.

Still deafened by the thunderclap, I could barely hear myself shouting ,“Is the house on fire, is the house on fire?” Dad had already taken off running to check that out. The only fire he found was in a can of gasoline drippings from our electrical generator. We were connected to a recently installed public power system, but still retained the generator, anticipating power outages. He put that out, then returned to wait for the storm to end.

When it had abated somewhat, we heard a pounding on the door. It was Eva Look, our neighbor from across the road, encased in  yellow oilskins and sou’wester. Eva was a deaf-mute, but my mother and grandmother were both proficient in sign language. The three of them were talking, and to me their hands were a blur of motion. Eva had seen the lightning strike, and she told us that it was three-pronged, striking the house, the garage, and a power pole in front of the house. The next day, we were able to verify her story; there was damage in all three places.

Years later, about 1949, I was returning to Chilmark by Greyhound bus for a Christmas vacation from college in Louisville.  The grandparents had now passed on, and my parents lived in a house on the South Road in Chilmark. A major blizzard hit New York and New England, and when the bus arrived in New York City, only a couple of lanes of the main street had been ploughed out. As we cruised down Broadway, all the side streets had an unbroken blanket of about 17 inches of snow. But I changed busses and departed for New Bedford, and the roads were passable, And the Island steamship was running.

Martha’s Vineyard had it’s own problems. Here, the storm dropped freezing sleet which built up on the power and phone wires until they broke of the weight. My parents cooked on a cast iron stove, originally wood-burning but now fitted with kerosene burners. We had a kerosene powered refrigerator (Servel Electrolux), and they located some kerosene lamps. So life went on. But we learned how much we depended on electricity. Gas stations couldn’t pump gas, many houses including ours had electric water pumps, and those with thermostatically controlled oil furnaces were without heat. We still had a working manual cast-iron pump (after replacing a “leather”), and we provided water for some of our neighbors.

Vineyard Haven had it’s power restored fairly quickly, but up-island, it took longer.  Day by day, we could see the lights on in houses progressively closer to us, and in about a week, our power was restored. The telephone servicemen meanwhile were using the technique I had seen in the army – laying out temporary wires along the roadsides and over snowdrifts. So before I returned to Louisville, life on Martha’s Vineyard had returned pretty much to normal.

Elsewhere in this website I told of the time I waited out a downpour in the cockpit of a parked P-51 fighter plane. Many years later, I had a more serious encounter with heavy precipitation. About 1996, Sally and I were returning to Manhattan Beach. CA from our condo in Mammoth Lakes. As we proceeded south on US route 395 and California route 14, we encountered some rain, but didn’t think it unusual. On other trips, when passing this way during daylight hours, we’ve been treated to the sight of spectacular rainbows.

As we entered the area of the Red Rock Canyon State Park, in the Mojave desert,  the rain became more intense, and we noticed that the usually dry ditch alongside the road was now a roaring river. A bit farther along, where the path of drainage normally passed under the road, the water was also flowing over the road. Traffic had come to a stop.

The driver of an 18-wheeler had decided to move on, and I examined the hydrodynamics of the situation. His tires showed that the rushing water was only a few inches deep above the road. I decided to follow the truck, with Sally yelling “don’t go”. We successfully crossed to beyond the “river” and thought we were good to go. But about half a mile further on, as we reached the top of a small hill, we came to a complete halt, along with a dozen or two cars and trucks..

We were parked there for seven hours, near the settlement of Cantil. The flash flood had deposited mud and debris on the road ahead. There was a report that “a twelve-foot wall of water” had hit Cantil. My question was, who measured that wall of water? In any event, there were no reported deaths.  One woman’s car had been washed off the road, and  a truck driver had rescued her.

As the night progressed, the totally black sky gave way to the clearest star-studded sky you’re likely to see. With the aid of a flashlight, several of us walked on ahead to look at the damage. At the Cantil bridge, one lane of the road was eroded away, and there was mud and debris everywhere.

Finally, at about 2 AM, the Caltrans road workers cleared a path with their bulldozers. They then escorted us out of the affected area – first the passenger cars, then the trucks. We arrived home many hours late, but no worse for the wear.

The next day on TV we saw films of extensive damage to the road at the spot where we had forded the ”river”. It took some weeks for the state to rebuild the road.
We’ve gone back to the condo many times since then, and as we pass the spot where we spent seven hours waiting, someone will say, “Our hill.”

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SCOPE

April 26th, 2009

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.

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Filtration Test Kit

March 24th, 2009

portable fluid testerIn the late 1950s and early 1960s, particle contamination of aircraft hydraulic fluid was a major problem. Adequate filtration to maintain the desired cleanliness did not seem feasible, so to augment filtration the program was to periodically take a sample of the system fluid, filter it through a laboratory “Millipore” filter which would catch anything over one micron, and using a microscope, count the particles.

This was spelled out in a laboratory test procedure SAE ARP598, and when this testing showed excessive contamination, the hydraulic system was to be drained and refilled with fresh fluid.

The Douglas Santa Monica plant was working on an air-launched ballistic missile, the AGM-48 Skybolt (to be fired from a B-52), and they asked the El Segundo Plant to assist in designing a testing kit which would automate the SAE fluid test procedure. I was asked to look into it.

I spent a few days at the Santa Monica Plant, and got several, and widely varied, opinions on how the tester should be designed. I returned to El Segundo and designed a tester as I thought it should be. When finished, I returned to Santa Monica, unrolled my drawings and said, “Here, sign this.” And they did.

(I learned this technique from my father. During WW II he had one frustrating episode trying to get approval of his airport drawings at the Pentagon. The second time he knew which general to see, unrolled his drawing and said “Here, sign this.” And he was in and out of the Pentagon in 30 minutes.)

The tester took a 100 cc sample from an operating hydraulic system, so the sample would be representative.  Then gas pressure (dry nitrogen) was used to drive the sample through a Millipore filter, using a solvent to remove the hydraulic fluid.  Finally, gas pressure alone was used to dry the filter patch, which was then stored for laboratory analysis.  Being a SCUBA diver, I incorporated a SCUBA air regulator  to drive the process.

The test kit worked as advertised, but the air-launched ballistic missile was canceled. The Santa Monica engineers did use the kit – we built four of them – on the Saturn space program until it ended.

I was awarded U S Patent 3,267,723 on August 23, 1966 for the test apparatus. Meanwhile, the Navy asked for proposals to survey its aircraft fleet for contamination levels, and proposals for improvement. We proposed that it be done using our contamination test kit – only a lighter version, which I could carry around the country as a piece of luggage. The Navy said ”go” and I visited about a dozen Naval Air Stations and tested a hundred hydraulic systems. I was on the road for a couple of weeks, including arrival at the Key West Naval Air Station at the height of the Cuban Missile crisis. Imagine the inspection I had to go through.

We looked at aircraft types, filter types, fluid flow rates, geographical areas, age of aircraft, and any other variable we could think of. The Navy seemed pleased with the results, and it influenced the choice of aircraft filtration on new aircraft.

The Ronson company briefly talked of building these test kits under license. I told people I didn’t know which version of the tester they would build, but since it was the Ronson company, it would probably be the lighter version.

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Hydraulic Filters

March 22nd, 2009

The early 1960s was a time of rapid evolution of aircraft hydraulic filters. I was fortunate to attend a couple of industry seminars (one at UCLA) concerning the development of a filter specification (MIL-F-8815) by the Navy, and I gained a reputation as the filter expert in the hydraulics design section.  Then about 1963, the Douglas El Segundo plant (Naval aircraft) was closed, and I was re-assigned to the Long Beach plant where I was soon working on the new DC-9 commercial airplane.

It was soon obvious that the filters used on the earlier DC-8 were inefficient, and the DC-9 was a candidate for using the new technology.  Working with suppliers I had met during those seminars, we came up with a specification for DC-9 filters.  It differed from the Navy spec mainly in that it called for disposable “paper” filter elements as opposed to the re-usable elements which used a twill fabric woven from fine stainless steel wire.  I showed that the throwaway elements provided better and cheaper filtration than did the cleanable elements.

I was supplied with a sample.  However, the design group manager saw no need to change from the type of filter used on earlier airplanes.  In response to my “sales pitches” I was told, in effect, to shut up and sit down.

One day Charlie, the assistant group leader came by my desk and said, “Grab your sample and come with me.”  Soon I was in a small conference room face to face with some old guy who asked what this new filter was all about.  I gave him my spiel about efficiency (particle size removal), non-collapsing at full system differential pressure, an indicator which showed when filter cartridge replacement was needed, and one size throughout the airplane, reducing the airlines stocking problems. The old fellow disputed every claim I made, and seemed unconvinced by my best arguments.  When it was over, as Charlie and I were walking back to the design group, I asked “Who was that guy I was arguing with?”  He said, “That was Harold Adams, our chief engineer.” I was fairly new to the Long Beach plant, and had never met the chief engineer.

The argument had become fairly heated, and I figured that I was on my way out.  For the next few days, I concentrated on my work, and waited for the axe to fall.  Then a design memo from the chief engineer was circulated, telling all about the new high efficiency hydraulic filter we would use on the DC-9.

I learned that Harold loved to play Devil’s advocate, forcing people to present their best and most complete arguments for their proposed changes or design concepts, to counter his objections, and of course to educate himself.  Apparently I had passed his test.  My filter specification continued to be used throughout the DC-9 series, MD-80/90 series and Boeing 717, over 35 years of twinjet  production.

The new filter medium, a thick “paper” composed of resin coated fibers, was so efficient that I campaigned to eliminate the periodic sampling and laboratory tests for particulate contamination. (Contamination by water, solvents, etc, is a whole different story).  I had stared through a microscope for many hours at those Millipore filters, and didn’t like it.  “Let the system take care of itself”. I argued.   “The filters will keep the fluid clean, and the delta-P indicators will tell when you need to change filter elements.” That’s the strategy the aircraft operators now follow.

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ENGINEERS WILL BE BOYS

March 18th, 2009

The design engineers at the Douglas El Segundo plant in the 1950’s were a talented and hard-working crew. Their products included the AD Skyraider, the A3D Skywarrior, the A4D Skyhawk, the F3D Skyknight, and the F4D Skyray. At one time, 50% of the Navy’s aircraft dollars were going through our plant. There were other airplane designs which never achieved quantity production, including the A2D Skyshark and the F5D Skylancer. Essentially, Ed Heinemann’s factory produced a new aircraft model every year.

Year after year of overtime work, evoked some eccentricities and practical jokes to lighten up a rather serious environment. Mostly harmless.

One engineer who left Douglas about the time I arrived was John(?) Forbes. He was from Walla Walla, Washington. Mr. Forbes had his first name legally changed to Forbes, so he became Forbes Forbes from Walla Walla. Mr. Forbes drove to work in a second hand hearse, wearing a tall silk hat. I didn’t get to know him, but I was told that he was a very good engineer.

Another engineer drove to work in a Crosley, a minimum car of  pre-WW II vintage. He was also known for leaving work early. On a couple of occasions, several of the engineers surreptitiously went to the parking lot and literally picked up the Crosley and turned it crosswise in the parking stall, so the owner couldn’t leave until one of the cars parked on either side of his had left.  Soon after WW II,  this gentleman obtained an British-built MG, a small but somewhat more robust vehicle. The same crew of jokesters sneaked out with intention of repeating their “crosswise” trick.  They quickly found that an MG is much heavier than a Crosley, and that they didn’t have the strength to execute their plan.  They silently went back to work and didn’t bother the MG driver thereafter.

Aeerospace engineering groups are constantly visited by vendors who want to sell us products or processes, or to build what we have designed, and of course, we needed them. But we could harass them at times when they became a nuisance.
In our hydraulics design section, we had a rejected bracket machined from a steel forging, perched on a cabinet. This bracket, when struck had a distinctive and attention-getting “clang”. Someone attached a nearly invisible steel wire to the forging and put a loop in the other end.

Sometimes when a vendor was engaged in conversation with one of the engineers, a confederate would surreptitiously slip that loop over a button on the visitor’s jacket, then retreat to his own desk. When the visitor moved in the direction which tightened the wire, the forging would fall to the floor, rewarding everyone with a resounding “clang”. After a few episodes, the boss put a stop to that.

We usually had modeling clay available, to fashion component parts of the mechanisms we designed. For some items, this helped define the shape and enable a group critique, before it was committed to a design drawing or machined in metal. We also had ready access to short lengths of hydraulic tubing, so we had very good peashooters with clay pellets for ammunition.

On rare occasions a designer standing and leaning over his drafting board would find himself the target of a clay pellet in his backside. Mostly restricted to those new to the group.

We sat on four-legged drafting stools with metal seats. We also had access to smokeless-powder cartridges used in aircraft ejection seats. Someone found that a few grains of smokeless powder attached to the underside of one of those seats with masking tape would heat it quickly before the victim could react. Someone would light the short fuse behind the premeditated victim, who would urgently move off the stool, emerging from a cloud of smoke. (Well, the powder wasn’t entirely smokeless).

The secretaries weren’t exempt. Among our resources was dry ice (solid carbon dioxide at -109.3 degrees F) used in our many subzero tests of hydraulic equipment. The secretaries’ waste baskets used plastic liners which sealed tightly around the rim.  When  a new secretary would go out to lunch, someone would slip a piece of dry ice into the bottom of the waste basket, between the basket and the plastic liner.  It helpled if the targeted waste basket was already fairly full of crumpled paper.

When the secretary returned, she soon had the contents of the basket slowly rising up and spilling out onto the floor, as the carbon dioxide from the dry ice pushed the plastic liner upward.  The screams of dismay and astonishment were reward enough for our jokers.

One of our test engineers was preparing a fatigue test involving several parts including a complex machined part. When that part arrived, it had a crack resulting from the heat-treatment process. He immediately ordered a replacement part for his test. I was in the lab when the replacement part arrived, and he wasn’t.

I carefully drew on the new part, with a #2 pencil, a duplicate of the crack of the original part. When he arrived and examined the replacement part, he displayed anger, outrage, disappointment, and a few other emotions. When I removed the “crack” with an eraser, our hero was relieved, but less than amused.

I believe this practical joke culture evolved largely from several engineers who were ex-Marines of WW II. None of these pranks resulted in any harm that I’m aware of, but the boss did eventually ask that we call a truce. As far as I know, this practical joke culture didn’t migrate to the Long Beach Division when El Segundo was closed.

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