HI
the tach is very useful to me -,at the beginning of every days flying-, i fly only two stroke glo , i always set the -low end RPM -based on the wind speed-, the idle speed must fly the plane to the ground-3000 RPM no wind is my base line-some wind 3200-,stronger wind 3500
every days out i run my engine to max RPM and back off 2-,300 RPM - (i/4 turn richer than max RPM- )-this run up to max IS A TEST RUN if the engine performs at its usuall RPM- then i know i am good to go fly -if for any reason the RPMS are higher than usuall -( AN AIR LEAK )or lower than usuall time to look for a problem somewere and correct it before you get into the air-prevents dead sticks in most cases and that is a very good thingENJOY BEST REGARDS TONY