Properties and preparation of ceramic insulators for spark plugs

Silsbee, F. B., Honaman, R. K., Fonseca, E. L., Bleininger, A. V., Staley, H. F.
naca-report-53
1920


Report describes in detail the preliminary experiments which were made on the conductivity of spark-plug insulators in order to develop a satisfactory comparative method for testing various spark-plug materials. Materials tested were cements, porcelain, feldspar, and quartz.

An Adobe Acrobat (PDF) file of the entire report:
http://naca.central.cranfield.ac.uk/reports/1920/naca-report-53.pdf