Originally Posted by
AlexUM
Mark, Never thought you were
Update on the engine: Student on solo X-C. Went up to 8500ft and leaned out. On the way home forgot about the red knob (checklist?
) and flew a couple of patterns practicing his short-fields before full stop for about 45min. Can this single-time misadjustment be the reason? We need two new pistons and the corresponding valves
Cheers,
Alex
If the student leaned out to max power (something like peak EGT) at 8500 feet. I would have thought the engine would cough splutter and rattle at full power/sea level (it would be way lean of peak on at least some cylinders). The student couldn't help notice this.
HOWEVER, if the student 'sort of leaned' (at 8500 you need quite a bit of red knob back in most planes) they could have gotten to say 150-200 ROP (back to a reasonable performance level). In this case, when doing pattern work, they could have been at full power at peak EGT, deep deep in the Red Box and could have crisped the cylinders in a few minutes let alone 45 minutes.
The engine makes 100% power fairly rich of peak with a lot of partially burned fuel. Same RPM and Throttle setting, but with the mixture set to peak and you will pull much more than 100% out of the engine - and that is not a great idea for longevity