https://www.dekut.com/Technology/rpm-sensor/ The EDM 350 Aircraft engine data manager by J.P. Instruments measures precisely 3.25 square inches i.e. smaller than a standard sized stapler and yet, it this little gadget is packed with electronic chips that analyse over 2 dozen different engine parameters of any 4-cylinder aircraft. The basic 4-cylinder kit starts at just $798 while the 6-cylinder kit is priced at $988. Both representing true value for money. Wed, 14 Feb 2018 04:44:42 UTC en