Slide Rule (10 page)

An incident in the early days at Howden confirms this. At that time there was some unemployment among ships’ riggers at Hull, and a rigger turned up at Howden for a job. Jimmie Watson, our works manager, asked, “Can you climb?” The man said he could climb anything.

We had a number of fire escapes at Howden to reach up from the ground to the structure of the ship, and one of these was being overhauled that day and stood fully
extended in the shed. Jimmie said, “Well, hop up to the top of that.” Now a big fire escape is a horrible thing to climb when the top is free and not resting against a wall; I hated them till the end of our time at Howden, and never climbed one if I could avoid it. It is about ninety feet long, and by the time you are halfway up the base carriage is behind you so that there is nothing but the concrete floor below, and you feel that every movement that you make will overturn the thing and send you crashing down to death. As you go up the ladder sways with every movement, so that at the top each step upwards sets it swaying three or four feet in space. With your intellect you know that it is safe, but I know nothing more terrifying in the air or on the ground.

The rigger got up halfway, and stuck; Jimmie called to him to come down. The man came down very crestfallen; he said that he had been out of work some time and needed the job badly. We couldn’t take him on unless he could climb, but the men were sorry for him, and Jimmie took him into the canteen and stood him a beer before sending him away. After his beer the rigger asked if he could have another shot at that bloody escape. So they sent him up again, and that time he got three quarters of the way up before he stuck. So they had him down and gave him another beer, and so strengthened he got right up to the top, and got his job. Within a week of starting work he was perfectly all right and able to climb anything, without the beer.

It was not possible to heat the huge shed at all. Howden stands upon low ground; in winter there is standing water on the aerodrome and in the height of summer water is found two feet below the surface of the earth. In consequence the air is always humid; a more unsuitable locality for airship manufacture would be difficult to find. Very frequently the shed was filled with a wet mist so that every
girder became coated in water; mould attacked the fabrics in the store, and the corrosion of duralumin became a serious matter. We became experts in corrosion. Halfway through the construction it became evident that the structure of the ship was being seriously attacked, and Wallis took the bold step of deciding to revarnish every girder of the ship by hand. It took thirty men three months to do and probably added the best part of a ton to the tare weight, but when the ship was finally demolished in 1931 the structure was in a very perfect state. On winter mornings it was not uncommon, after a heavy mist and frost, to find the girders sheathed in ice, stopping all work upon the ship that day on account of the danger in climbing.

The labour difficulty was always grave. We were three miles from the little town of Howden and twenty-five from civilisation in the form of Hull. It was difficult to get skilled aircraft hands to work upon the ship however high the wages that were offered; accommodation for workmen of good class was almost non-existent. In Howden fourteen of our men slept in three rooms of a small pub.

We employed a large percentage of our labour in the form of local lads and girls straight off the farms as unskilled labour, training them to do simple riveting and mass production work. The lads were what one would expect, straight from the plough, but the girls were an eye-opener. They were brutish and uncouth, filthy in appearance and in habits. Things may have changed since then—I hope they have. Perhaps the girls in very isolated rural districts such as that had less opportunity than their brothers for getting in to the market town and making contact with civilisation; I can only record the fact that these girls straight off the farms were the lowest types that I have ever seen in England, and incredibly foul-mouthed. We very soon found that we had to employ a welfare
worker to look after them because promiscuous intercourse was going on merrily in every dark corner, and we picked a middle-aged local woman thinking that she would know how to deal with problems that we had not contemplated when we started in to build an airship. But the experiment was not a success. I forget how we solved the problem; probably we never did, because as the job approached completion the need for unskilled female labour was reduced and we were able to get rid of the most jungly types.

Still, the ship grew. For three years the work in the shops came hard upon the heels of the design; the progress of the design regulated the speed of the work. Looking back upon that time, I think that an inferiority complex plagued us more than we quite realised. We knew in our hearts that the work that we were doing was good and that we were building a fine ship, but there is no denying that the incessant publicity of the competing staff had its effect upon our spirits. At times it seemed that every newspaper we picked up had a column describing the wonders of R.101, ending up with a brief sentence that R.100 was also being built at Howden. Our puny efforts at a counterblast could not compete with the Air Ministry press department; moreover we had little energy to waste on matters of that sort. We carried on with our designing and construction, wondering what the end of it all would be.

And there were times when we had much to wonder at. News of the progress of the Air Ministry ship was scanty and hard to come by; by virtue of their official position they knew all about our ship but we knew little about theirs. We gleaned our technical knowledge of R.101 from patent specifications, from popular articles in the press, and from hearsay. Early in the design our calculations had disclosed a curious aerodynamic feature in the stability of these huge ships; not only could they both
easily be steered by hand without the assistance of a servo motor, but no balance area was required upon the rudders although they were over a thousand square feet in area. At a comparatively late stage in the design we learned on sure authority that R.101 not only had balanced rudders but had servo motors fitted at great weight and cost to assist the helmsman in the steering of the ship. Out flared the inferiority complex; we suspended work on the rudders and spent three days in checking through our calculations to find our mistake. At the end of that time we knew that our figures were correct, and we were left dumbly staring at each other. Either these ships could be steered by hand or they could not; it was impossible that we could both be right. There
must
be something in this that we did not understand.

The engine installation was another one. An airship requires engine power to go astern to check her way as she approaches the mooring mast and in R.100 we had arranged for two of our six engines to drive their propellers through a reversing gearbox for this purpose. As R.101 approached completion we were astonished to hear that her reversing propellers had proved a failure, and in consequence four of her five engines were arranged to drive ahead and the fifth one would only go astern. The fifth engine apparently was to be carried as a passenger on all her flights solely for the purpose of going astern for a minute or two at the start and finish of each flight, and with its power car it weighed over three tons. Again we were left staring at each other, speechless. It is the greatest mistake to under-rate your competitor, and in spite of their past record it was incredible to us that our competitors should perpetrate such childish follies. There
must
be something in this that we did not understand.

As the years went on the same perplexities came to us very frequently on one point or another.

The conditions imposed on the two staffs by their respective organisations provided an interesting comparison. With our capitalistic organisation we could go to no great expenditure upon experimental work; we were supposed to know our job and to be able to build an airship as a bridge might have been built. On the other hand we had freedom to change our minds and to make rapid alterations in policy and design if circumstances should require it. As an example, we changed our engine policy three times during the construction of the ship. At first it seemed expedient to design a special engine for R.100 running on hydrogen and kerosene. After a year’s work it became evident that this engine would not be fully developed before it was required for installation in the ship. The work was stopped, the design and work in progress was sold off in the most economical way, and we decided to fit diesel engines of the type that were being developed by the Air Ministry for R.101. That phase lasted for six months; it then became clear that the diesel engines would be grossly overweight and unsuitable in other ways for use in our ship. At this stage we cut clean through our difficulties and decided to use aeroplane engines running upon petrol in the normal manner. Six Rolls Royce Condor engines were selected, and the engine installation gave us no further trouble.

At Cardington the circumstances were entirely different. A large expenditure upon research and experiment was permitted to them; if they asserted that certain research was desirable before their design could proceed, that research was invariably put in hand. In this way they built an entire experimental section of the ship, and made innumerable experiments on such accessories as gas valves, servo motors, steam heating of the passenger quarters, evaporative cooling of the engines, etc. All these researches were admirable in themselves, but unnecessary
for the production of a successful airship; we bought our gas valves for R.100 from the Zeppelin company and if airships had gone on we would have made them under licence. On the other hand, it appeared that once they were committed to a definite policy with regard to R.101 it was difficult for them to change their minds; if public money had been spent upon an article for the ship, into the ship it had to go. A few months before the first flight of the R.101 her designer urged his superiors to fit petrol engines in the ship as we had done in R.100, on account of the excessive weight of the diesel engines. This petition was refused by some high civil servant in the Air Ministry whose name is now forgotten, perhaps fortunately; the diesel engines had been developed for R.101 and they had to be used. It is interesting to note these relative restrictions imposed on the two staffs; our work was hampered by the paucity of research dictated by the fixed price contract, and theirs by the inflexibility of the official system.

My own work in the calculating office led at times to a satisfaction almost amounting to a religious experience. The stress calculations for each transverse frame, for instance, required a laborious mathematical computation by a pair of calculators that lasted for two or three months before a satisfactory and true solution to the forces could be guaranteed. To explain this for the benefit of engineers, I should say that each transverse frame consisted of a girder in the form of a stiff, sixteen-sided polygon with the flats at top and bottom; this girder was twenty-seven inches deep and up to a hundred and thirty feet in diameter. Sixteen steel cables ran from the centre of the polygon, the axis of the ship, to the corner points, bracing the polygonal girder against deflections. All loads, whether of gas lift, weights carried on the frame, or shear wire reactions, were applied to the corner points of the polygon, and except in
the case of the ship turning these loads were symmetrical port and starboard. One half of the transverse frame, therefore, divided by a vertical plane passing through the axis of the ship, consisted of an
encastré
arched rib with ends free to slide towards each other, and this arched rib was braced by eight radial wires, some of which would go slack through the deflection of the arched rib under the applied loads. Normally four or five wires would remain in tension, and for the first approximation the slack wires would be guessed. The forces and bending moments in the members could then be calculated by the solution of a lengthy simultaneous equation containing up to seven unknown quantities; this work usually occupied two calculators about a week, using a Fuller slide rule and working in pairs to check for arithmetical mistakes. In the solution it was usual to find a compression force in one or two of the radial wires; the whole process then had to be begun again using a different selection of wires.

When a likely-looking solution had at last been obtained, deflection diagrams were set out for the movements of the various corners of the polygon under the bending moments and loads found in the various portions of the arched rib, and these yielded the extension of the radial wires under load, which was compared with the calculated loads found in the wires. It was usual to find a discrepancy, perhaps due to an arithmetical mistake by a tired calculator ten days before, and the calculations had to be repeated till this check was satisfied. When the deflections and the calculated loads agreed, it was not uncommon to discover that one of the wires thought to be slack was, in fact, in tension as revealed by the deflection diagrams, which meant that the two calculators had to moisten the lips and start again at the very beginning.

The final check was to take vertical and horizontal components of the forces in every member of the frame to see
that they equated to zero, that your pencil diagram was not sliding off the paper into the next room. When all forces were found to be in balance, and when all deflections proved to be in correspondence with the forces elongating the members, then we knew that we had reached the truth.

As I say, it produced a satisfaction almost amounting to a religious experience. After literally months of labour, having filled perhaps fifty foolscap sheets with closely pencilled figures, after many disappointments and heartaches, the truth stood revealed, real, and perfect, and unquestionable; the very truth. It did one good; one was the better for the experience. It struck me at the time that those who built the great arches of the English cathedrals in mediaeval times must have known something of our mathematics, and perhaps passed through the same experience, and I have wondered if Freemasonry has anything to do with this.