Engine Testing
Specially-Built, Multi-Cell Houses for Routine Tests
By F. C. Sheffield

British aircraft factories’ war production generally afford many excellent examples of efficient organisation that are far too little known, and even less appreciated, in this country or abroad. A typical example is the Rootes layout for aircraft engine testing that forms the subject of this article. The reinforced concrete structure is of “functional” design, in the best sense of that much-abused word. Engines are received, made ready for test, tested, and prepared for dispatch on a smoothly efficient routine under continuous, close supervision. This is made possible by the basic design of the structure that, whilst conserving ground space, provides uncrowded working areas, relatively quiet operating conditions, and comprehensive safety measures.

At the commencement of hostilities, Messrs. Rootes Securities, Ltd., were entrusted with various manufacturing projects and also with the repair and complete overhaul of engines in commission with the R.A.F. Two factories were selected to deal respectively with air-cooled and liquid-cooled types and for each a new test-house was required to be built. To balance repair facilities, eight test-cells were necessary in each case, and in neither was it convenient to erect them alongside the main plant. Accordingly, it was possible to design the test-houses as independently sited, self-contained units.

As power-absorption dynamometers would have been difficult to obtain, and would certainly have been the cause of long delay before the houses could be brought into operation, the method of brake fan testing by running the engine with a calibrated airscrew was adopted. Each cell was to accommodate engines having an output up to 3,000 hp and driving an airscrew up to 16 feet in diameter. In order to conserve ground space, it was decided to build on a “vertical” instead of the more common “horizontal” plan. Houses of this type in the service of Curtiss-Wright, Pratt & Whitney, and other American engine manufacturers, were inspected to check their suitability for the duties required, and the Detroit firm of Albert Kahn, Inc., was commissioned to design an eight-cell building. This firm is possibly the largest organisation of industrial architects and engineers in the world, and has projected and built many gigantic plants in the U.S.A., including Curtiss-Wright at Cincinnati and Willow Run for the Ford Motor Co.