Notes: "The E-6B dead reckoning computer, or flight computer, only got its familiar designation when the US military first adopted it in 1940. Within two yeas the military had changed their inventory system and numbering scheme, and it had a different number. That would happen a few more times, but for civilian pilots it was forever the E-6B (or E6-B or E6B, by companies trying to avoid Dalton’s trademark). This one was made by Felsenthal Instruments Co. under a government contract, so it is marked “Type CPU 26A/P. This one is the smaller, “pocket size” version, made of aluminum. "
