A high-speed engine pressure indicator of the balanced diaphragm type

Dickinson, H C Newell, F B
naca-report-107
1921


This report describes a pressure-measuring device especially adapted for use in mapping indicator diagrams of high-speed internal combustion engines. The cards are obtained by a point-to-point method giving the average of a large number of engine cycles. The principle involved is the balancing of the engine cylinder pressure against a measured pressure on the opposite side of the metal a diaphragm of negligible stiffness. In its application as an engine indicator the phase of the engine cycle to which a pressure measurement corresponds is selected by a timing device. The report discusses briefly the errors which must be avoided in the development of an indicator for light high-speed engines, where vibration is serious, and outlines the principles underlying the design of this instrument in order to be free of such errors. A detailed description of the instrument and accessories follows together with operating directions.

An Adobe Acrobat (PDF) file of the entire report:
http://naca.central.cranfield.ac.uk/reports/1921/naca-report-107.pdf