wrote:
Dave Butler wrote:
: Don't know, but that sounds plausible. Thanks for the correction. The same
: mixture knob controls the mixture at both idle and full power, though.

Yes, but think of the mixture knob as an "absolute" metering adjustment, not a
"relative" adjustment. In other words, setting the mixture doesn't set the air/fuel
ratio... basically just the maximum amount of fuel that can flow. So, to lean on the
ground with the mixture you have to pretty much pull it all the way out. As Deakin
says, if you lean on the ground, doing anything shy of almost cutting it off does no
good, and possibly harm if you forget to enrichen rull before takeoff.

If that's the case, that the mixture control simply meters the absolute amount
of fuel that's allowed to flow (don't know, taking your word for it), then
that's further support for the statement that the mixture control needs to be
able to allow a richer-than-optimum amount of fuel at idle.

Or, put another way, if the mixture is not over-rich at idle with the control at
the full-rich position, you won't be able to enrichen the mixture sufficiently
during climb to provide the necessary cooling. That's the statement I started
with. I think we are agreeing.

Dave
Remove SHIRT to reply directly.