Design

Design

Component Design was carried out by skilled draftsmen working under the guidance of analysis and senior engineers in the drawing office. The draftsman still had to be an extremely competant engineering designer. Some very top staff could both draft, manage and do the analysis – such as Geoffrey Wilde of Rolls-Royce, who began as an apprentice at Rolls-Royce and finished up holding 79 patents and carried working well into the turbojet era, not retiring until 1979.

Staff at Focke-Wulf discuss a fighter aircraft project, often the airframe maker became highly involved with engine development, especially when the turbocharged Fw190 project was in flow.

Design always began with an agreement about the overall direction to follow by the chief designer, and passed down to drafting office managers. Here analysis specialists would carry out extensive calculations by hand to get the design very close to ideal before the prototype was built.

Rolls-Royce Crankshaft Initial Stiffness Calculations

Once the engine was detailed on paper, the actual position of all the components would be laid out, and the speeds and loads on each shaft carefully checked, and the smallest lightest bearings possible chosen.

Daimler-Benz inverted V12 Shaft Drive Layout Drawing

From there the draftsmen would complete individual manufacturing drawings, and 3D concept views of how the finished part would look, like the Turbocharger below:

Daimler-Benz Turbocharger, unlike BMW the Daimler design sacrifices some of the turbine periphery to allow cooling, about 1/3 of the circumference is used only to pass cool air over the blades.

A Daimler-Benz Turbocharger from 1943 shown above in the concept sketches and below as the completed part. Lack of Nickel, Cobalt and Chromium made turbochargers and jet engines very difficult to make reliably in the Second World War in Germany. Therefore Germany was forced to pioneer hollow turbine blade cooling and engineering ceramics, BMW in particular pioneering the hollow turbine blade, which fed cooling air through centrifugally through the hollow turbine shaft then outwards radially through each blade.

The finished turbocharger, the inlet on the far side is for cooling air, the ports on the far left and right are from two exhaust banks of 3 engine cylinders.