Mike Busch at OSH 2021

[Colonel]

Above is what I do in an aircraft that has all the data - eg a modern engine monitor.

However, 99% of aircraft do not. What to do?

I used to fly a lot of different aircraft, and a lot of different aircraft types. They had
little or no engine gauges, and their output was suspect.

I am a simple person. How do I lean junk that I jump into, like a 172 or Cherokee?

Most people just leave the red knob all the way in, all the time. But my problem is
that we're burning fuel we might need later, just short of the destination.

So, I lean for max airspeed in cruise. Doesn't matter carbureted or fuel injected or fixed
pitch prop or constant speed.

Max airspeed is best power. This makes Mike Busch run screaming for the door, yammering
about "red boxes". He thinks I am an infidel because I don't buy into his LOP religion.

Hogwash. I've been flying for a lot longer than him. Leaning to best power works just fine -
I've used it for decades. It uses a lot less gas than full rich, and it gets me where I'm going
as fast as possible, which is important to me, because I get really fucking bored in straight
and level flight. I honestly have no idea what the attraction is.

My idea of a perfect flight is 0.2 on the tach - pull vertical at the end of the runway and do
surface acro directly overhead, spending 10 minutes pulling and pushing as much G as you
can stand. You land, panting and sweating with blood vessels blown on your face. You do
that once a day for ten years, you're good to go. Air Canada might not hire you, but they pay
shit and the flying sucks and the management is worse.

[Squaretail]

Max airspeed is best power. This makes Mike Busch run screaming for the door, yammering
about "red boxes". He thinks I am an infidel because I don't buy into his LOP religion.

Playing with airplanes that do have the individual cylinder read outs though, If its normally aspirated, its hard to get the "red box" if you're cruising at any sort of altitude. The engine just isn't making enough power to run that hot, combined with the generally cooler outside air temps at altitude. Realistically I see most beating on the engine happen in climbs and descents. Pilots generally being an impatient lot frequently will climb at best rate regardless of whether a cruise climb will be more efficient. Combine this with how way too many pilots have been trained to obsessively put the mixture rich on descent, its the two worst places for sudden temp changes. Mike's slides regarding leaning are well taken. Engines are designed to be heated from the inside and cooled on the outside, if you cool it excessively on the inside (dump excess fuel into it suddenly) or cause it to heat on the outside (insufficient airflow to cool it) you're going to cause it the most amount of harm. Outside of running it too hot in cruise - which is hard to do without a turbo - ROP or LOP hardly makes a difference, though in most airplanes is hard to get a smooth run LOP especially with a carburetor. Maybe if you were running around at sea level all the time.

I would say as well that his advice about running "over square" are reasonable as well. Not sure where that originates from, but a lot of pilots get taught it.

[TwinOtterFan]

So why do they teach us to go full rich before making any type of attitude adjustment? I get it for climbs, but why for descents?

[Colonel]

his advice about running "over square" are reasonable as well

Absolutely! Lycoming says you can run 5 more inches of MP than RPM.

I believe Lycoming. And Continental, for that matter. They know a lot.

why (lean) for descents?

Really bad technique, taught to the lowest common denominator. See, on the
offchance that you have to overshoot, they want you to have the mixture rich
already so you don't forget it.

See, pilots are too dumb during an overshoot to select mixture/prop/throttles
so long before final, just in case they have to overshoot, they select mixture
rich and prop full fine, often on downwind. Which makes me cry at night.

You want the mixture leaned in the descent. It keeps the engine warm and
stops the cylinders from cracking (phone TCM to find out why - fascinating).

On more than one occasion in the winter, I have seen pilots stop the prop
on final. Not intentionally. Keeping the engine warm in the descent is not
just an academic concern about engine life.

Lean the mixture at all times on the ground for max RPM. If you have to
wait and idle on the ground, do it at 1100 RPM (ask Lycoming why).

I'm not very bright, but I lean for desired CHT in the climb and cruise regardless
of density altitude, if I have the equipment. If the hottest cylinder is just under
400F, I'm not hurting anything, and I'm getting the lead out the exhaust port in
gaseous form, instead of condensing on the exhaust valve guide stem, which
causes sticking valves down the road. See Lyc SB 388B and SI 1425A.

Don't get me wrong. Mike isn't right about everything. He's not wrong about
everything. In fact, more times he is right than wrong which in aviation is doing
pretty darned well. But at the risk of offending Mike, he is not God and does
make mistakes, sometimes. Even I do (gasp).

Mike is like a professor at school. Strong on theory, but if you look at his
hands (you can learn a lot by looking at someone's hands) you will see a
lack of grime under his pristine manicured fingernails, and his hands and
forearms aren't all torn up. His theory is terribly important to him. It is only
important to me, in how it impacts my practical life.

[Squaretail]

So why do they teach us to go full rich before making any type of attitude adjustment? I get it for climbs, but why for descents?

Because instructors and lawyers are terrified of the idea that an engine might quit if it is too lean, and especially that a pilot might need to go around and not have enough power because they would be too stupid when the engine sputters to not add some mixture. As Mike says, this is not the case, when the throttle is back the engine can be leaner and not quit. Everyone fantasizes that they will have to do something drastic in flight and be too deer in the headlights to think of the mixture and instigate disaster. Its an unfounded fear.

[TwinOtterFan]

That seems silly considering you are already taught to do almost the same thing with carb icing.

[Colonel]

Ok. On an overshoot, most pilots can remember to push in the throttle, but
the carb heat is often forgotten, as are the flaps.

Many, many times pilots have attempted overshoots with full flaps. This
is actually a certification requirement.

Reallly, no one gives a shit about the mixture control, and there are consequences.

Similarly, misuse of carb heat can bite you badly.

[CpnCrunch]

Here is Lycoming's guidance for leaning in flight training operations:

https://www.lycoming.com/sites/default/ ... ations.pdf

They recommend leaning in the climb above 3000ft, and setting 1000rpm with leaned mixture while waiting for takeoff clearance in order to avoid plug fouling.

[Squaretail]

Here is Lycoming's guidance for leaning in flight training operations:

https://www.lycoming.com/sites/default/ ... ations.pdf

They recommend leaning in the climb above 3000ft, and setting 1000rpm with leaned mixture while waiting for takeoff clearance in order to avoid plug fouling.

Unfortunately, a lot of people don't read that bit. It is my experience that if you want to hide something from most pilots, put it in a book.

[CpnCrunch]

Some more info about lead fouling:

https://www.shell.com/business-customer ... 71600.html

https://aslcamguard.com/wp-content/uplo ... 1-to-3.pdf