Birth of a Bomber

by J I Waddington

Thousands of drawings go through an intricate process before they form a new Halifax for the RAF.

One of the reasons for Britain's superiority in the air over the Luftwaffe is the fact that Britain has never "frozen" her designs. While the Nazi has produced the Messerschmitt Me-109s and Junkers Ju-87s in great numbers, Britain's more recently designed and modified Spitfires and Hurricanes have demonstrated their superiority in speed, maneuverability and fire power.

The British policy of fairly frequent changes of type has one disadvantage which must be weighed against the individual superiority of British aircraft — any change in an aircraft type slows up production.

Britain's theory of changing types has stirred up some talk between the designers and the production engineers. The designer wants his aircraft to have the most recent improvements incorporated into its design, while the production engineer wants as few changes as possible so that he may improve and speed up his production. Britain so far has been able to strike a balance between these two oppositions.

The layman often hears that a certain factory is nonproductive during a changeover from one type of production to another. He cannot understand why the factory cannot stop the manufacture of one type one night and the next morning begin construction on another. For him to understand this lag in production, it is most necessary for him to understand the organization of a factory necessary to produce a new aircraft.

When an aircraft factory takes over the job of putting out a heavy bomber like the Handley-Page Halifax, when before they had manufactured light ones, all designs of the plane are completed — but not the production planning.

The parent or design-drawing firm submits to the planning office of the manufacturer all the actual drawings of the aircraft (which in some cases may be as many as 18,000 or so in number).

Poring over these drawings, the production office staff consider their interpretation for actual use in the shops. They are analyzed for different production processes, the designing of jigs, tools and other fixtures on which parts and assemblies are made and finally assembled into a complete aircraft. They must also draw up specifications on all types of materials used in the aircraft and the quantities of these materials which will be needed.

One of the first jobs of the production crew is to break down the drawings under four different headings:

  1. Planning Sheets: defining the operations necessary for the manufacture of details, subassemblies and assemblies; and
  2. Tool Instruction Sheets which are issued for each tool or jig required for manufacture; and
  3. Parts List which is a schedule of the details and subassemblies required to produce a complete modification; and
  4. Material Schedules which are a summary of all the quantities and specifications of all the necessary raw materials.

Before and after all this activity in the production department, the Ministry of Aircraft Production has suggested a program of production for the factory based on its previous capacity and asks for an accelerated quota of aircraft per month up to a certain maximum. The Ministry's suggestions are discussed by the heads of the material, production, planning and material control departments and are either agreed on or amended before the final agreement is drawn up.

During this discussion, the factory men consider in detail the amount of work involved in tooling, the manufacture of details and subassemblies and other factors involved in preparing a plane to "fly-away." Also discussed is the question of obtaining raw materials and additional equipment.

Following the decision of this board and a deadline being set for the completion of the first aircraft, the scheduling department produces a program which will provide for a continuous flow of tools, materials, and subassemblies and an eventual production flow of finished planes. Deadlines are established for the delivery of raw materials and finished items. If the planning engineer has decided to subcontract certain items, each is given a deadline which must be adhered to.

The tooling department's work determines the rapidity with which the plane production can be gotten under way. This department issues a tool instruction sheet for each tool or jig required in the production. In the case of turning out this heavy bomber, there are 28,000 separate tools needed. Orders are placed in the tool room for all the items which they can produce and others are obtained from outside sources. As is the case with all other parts and assemblies, deadlines are set for the tool deliveries.

The planning sheet and parts lists are issued to the works order department, who in turn put out work orders to the various shops. Planning sheets are also sent to the rate fixing department, where labor costs are established, and also the inspection department.

Material schedules are broken down by the material control department into raw material needs. Here a decision is made on which parts are to be produced outside the plant. The material department having completed its schedule, then issues orders on the buying department. deadline is established for each item.

Time schedules are carried out from the first order of the plane, as the orders pass through the various shops and are broken down into more complete lists Deadlines are attached to each so as to insure all deliveries being made when and where needed.

Planning is no overnight job. This work briefly outlined above will take no less than 12 months to complete and often as much as 18 months or two years before production can be started on the firs plane.

It is almost impossible to plan ahead for a new plane — the plane which the factory knows it might be producing next year. The war shows daily where changes can be made and designs change with remarkable fluidity. No two designs call for the same tools or the same amount of raw or semi-finished materials. Then, again, it is never possible to predetermine the ending of one contract or the placing of another for a new type 12 to 18 months before the contract is awarded.

The man in the street does not realize that during this apparent lack of production at the plant, there are key departments working at top speed. The results of this work, however, will show themselves months later in the quality and quantity of heavy bombers which roll from the factory gates in a smooth and continuous line.

This article was originally published in the May, 1943, issue of Flying including Industrial Aviation magazine, vol 32, no 5, pp 36-37, 164.
The original article includes 3 photos: Photographs from British Information Service