I’m not sure as to why the clock style display was chosen, it probably explains it in one of my references so I’ll have a wade through.
My only guess is that because the system is universal; when setting the system up in an aircraft you alter the end points for the EVG depending on the aircraft, for example the 109G’s are from about 1230 to 0450-0430, however in an E with 601A it’s 1230 to 0250-0230, with a clock with no face markings you can display both these sets of information on the same instrument, I don’t think a linear display this information as clearly. The other thing is that the pitch required to maintain a given engine RPM depends upon the aircrafts speed (true airspeed-TAS) and so the pitch needed at 200kph to maintain 2600rpm (for example) would not be the same as that required at 400kph, I think the unmarked clock face reflects the dynamic nature of the relationship between required prop pitch and TAS without being confusing.
As some sort of compact display instrument was required that had to be universal non confusing and unambiguous the clock style seemed a good choice. My guesses!
Matt
Sign In
