Ground speed control with leaning

In article , Michael wrote:
"Roger Long" wrote
I had an idea today which worked well and I wonder if anyone sees a
downside. I always operate our 172 N on the ground leaned to the max.
Instead of using the brakes this morning, I just leaned some more until the
engine sagged and controlled my speed that way. Turning the vernier knob
didn't seem much more work than pushing the throttle in and out. Running
super lean like that must be good for the plugs.

There is no downside whatsoever to your idea. You can't possibly hurt
your engine by overleaning at these power settings.

Not only that, you'll prevent yourself from trying to take off after
forgetting to push the mixture control back in because the engine will
probably quit if you try.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

"Roger Long" wrote in message . ..
I like to keep RPM in ground operations just over 1000 to minimize fouling.
This is always a compromise with brake usage however. Controlling speed by
riding the brakes is a clear no, no. One suggestion a CFI made to me
recently is to just leave the throttle alone, apply brakes briefly, let the
plane pick up speed again, repeat as necessary.

I had an idea today which worked well and I wonder if anyone sees a
downside. I always operate our 172 N on the ground leaned to the max.
Instead of using the brakes this morning, I just leaned some more until the
engine sagged and controlled my speed that way. Turning the vernier knob
didn't seem much more work than pushing the throttle in and out. Running
super lean like that must be good for the plugs.

The first year I owned my Mooney IO-360 engine I had the plugs cleaned
3 times. The next year I took the advice that if increasing throttle
causes an increase in RPM, you are too rich in taxi. Since then I've
not cleaned any plugs outside of annual. I also bought an EDM with
fuel flow. I now can lean in cruise much better. Flying a Mooney in
cruise with full rich mixture can cause it to burn almost as much gas
as a Bonanza (i.e. Chevy Suburban )



-Robert