Mixture rich for taxi?

[Capt W E Johns]

Great thread, really enjoying the informed discussion (makes a change on Pprune, eh!).

Not withstanding the professionalism and economy derived from correctly handling engines, Pakeha-Boy makes some valid comments re: the robust nature of modern engines and KISS.

In my line of work I ran into two mutually exclusive aims when instructing on the IO-540. One aim was to have students operate the aeroplane in the absolutely correct manner, the other was the wider aim of preparing them for a profession which would most likely see them never flying another piston engined aircraft.

With that in mind there were inevitably compromises. I didn't want to churn out students who had an intimate understanding of flame-front propagation and detonation at the expense of more applicable lessons (airmanship, rules, blah blah). Those compromises relied on trusting that broad-brush engine handling rules of thumb were 'good enough for government work', and the engines were robust enough to cope with some non-optimal mixture/rpm/throttle management.

It wasn't until some time after I had started teaching on the IO-540 that it became apparent there was 'a better way', and I tried to learn and implement as much as I could. However, I would never have my students learn that stuff - (in my opinion) in the short time they spend at the ab-initio level, there are more important lessons.