This is why we do runups

Elliot, you can expect the leaning police to come and take you away...
Heresy, that's what it is, heresy....
Denny
wrote in message
...
One thing to remember is that for most operations, even at sea level, full
rich is too rich.

Rick, good advice... Everyone operates a bit differently... For a routine
approach and landing I leave the mixture and prop set at cruise the whole
way until shutdown on the ramp... If I need to go around it is a burned in
habit that everything goes to the firewall with one, fingers spread wide,
push....
That will change if I am landing at a fly-in with oodles of traffic or if
the weather is rough and scummy, then I will bring the props up to 2500 and
mixture 90% rich about the time I turn final, since the odds that I will
need to jockey the power are greater in those conditions...

Denny
"Rick Durden" wrote in message
m...
Roger,

You have people who are running the engine full rich all the time. It
was not built for 100LL fuel, so it needs to be leaned in cruise and
in descent

(Rick Durden) wrote in message om...
snip
When you run the prelanding checklist on downwind and pull the carb
heat, that's a pretty good time to go to full rich (if you want to) in
anticipation of a go around. Otherwise, leave it where it is until
you pull it the rest of the way out to shut the engine down as you
park. If you make a go around, push the mixture to rich, carb heat to
cold and apply full throttle. Some folks don't like the extra work
with the mixture at that time, so they go to full rich on downwind,
base or final to be ready for a go around. They lean again after
turning off of the runway to avoid plug fouling.


Argh! This business about going to full rich in anticipation of a
go-around might be OK for flatland pilots, but it is not a good
practice generally. If you are at a high density altitude (could be a
med. altitude airport in the summer), going full rich for landing
might leave you in the trees if you attempt a go around. I've seen
this happen more times than I care to remember.

Rather that repeating the inaccurate landing checklist item,
"mixture - full rich", how about a new one. "Mixture - set
appropriately".

John Galban=====N4BQ (PA28-180)

We try to stay on top of everything on this engine and not begrudge it a
penny. The mags are done every 500 hours and are only a couple hundred out.
We have the basics checked every 100 - 150 hours, pull the lifters, etc.
This has certainly paid off in an engine that has always run like a top with
not even minor plug fouling till now. It starts almost as well in the dead
of winter with a oil pan preheat as it does in the summer. Meanwhile, the
flight school planes are going "grind, grind, grind, grind, grind, grind,
grind, grind, grind..."

--
Roger Long
JerryK wrote in message
...
How long since the mags were overhauled? It is supposed to be done every
500 hours or so.

"Rick Durden" wrote in message
m...

Once you lean the airplane for cruise you need not change the mixture
on the descent. The checklist says to enrichen as necessary to avoid
roughness, so don't enrichen the mixture unless the engine runs rough.

Yes, but that statement should be further qualified by saying that descents
should be made at less than 75% power or else EGT and CHT could exceed
operating limits. 65% power sounds like a good number. Some carbed engines
with good fuel distribution will run smooth when too lean (close to peak,
either rich or lean of peak).

On 20 Aug 2003 12:24:20 -0700, Rick Durden wrote:
park. If you make a go around, push the mixture to rich, carb heat to
cold and apply full throttle. Some folks don't like the extra work
with the mixture at that time, so they go to full rich on downwind,

Depends on the aircraft. On many aircraft, you can push prop, mixture
and throttle forward at the same time with one hand which makes it easier
to follow that practise.

--
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"

(Rick Durden) writes:

It doesn't hurt
to lean it when taxiing as well, but do so very aggressively, so that
if you forget to go to full rich before takeoff it will quit on you
rather than make a takeoff with the mixture other than at full rich.

Rick, I had a talk with my mechanic a couple of months ago about
leaning when idling. He says for my carburator and C-90 engine, and I
suppose many other aircraft engines, leaning at idle doesn't do
anything unless it is nearly at idle cutoff. It is only when the RPMs
are well above idle that the mixture control begins to really control.
So does leaning on the ground--during idle--do anything unless it is
leaned nearly to idle cutoff?

The idea is in fact to lean aggressively on the ground. I lean mine till
it stumbles then turn the vernier in just till it is smooth. That works
out to pretty close to idle cutoff. Leaning this aggressively, the engine
will quit if you advance the throttle, making it impossible to take off
with it still leaned.

Bob Fry wrote:

(Rick Durden) writes:

It doesn't hurt
to lean it when taxiing as well, but do so very aggressively, so that
if you forget to go to full rich before takeoff it will quit on you
rather than make a takeoff with the mixture other than at full rich.

Rick, I had a talk with my mechanic a couple of months ago about
leaning when idling. He says for my carburator and C-90 engine, and I
suppose many other aircraft engines, leaning at idle doesn't do
anything unless it is nearly at idle cutoff. It is only when the RPMs
are well above idle that the mixture control begins to really control.
So does leaning on the ground--during idle--do anything unless it is
leaned nearly to idle cutoff?

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

On Thu, 21 Aug 2003 21:42:44 GMT, "Roger Long"
om wrote:

We try to stay on top of everything on this engine and not begrudge it a
penny. The mags are done every 500 hours and are only a couple hundred out.
We have the basics checked every 100 - 150 hours, pull the lifters, etc.
This has certainly paid off in an engine that has always run like a top with
not even minor plug fouling till now. It starts almost as well in the dead
of winter with a oil pan preheat as it does in the summer. Meanwhile, the
flight school planes are going "grind, grind, grind, grind, grind, grind,
grind, grind, grind..."

I use a progressive maintenance program, but....
I have the mags checked at annual. Only checked. Both have close to
1300 hours on them. I did replace the plugs at roughly 600 hours.
I've never had a problem with plug fowling on the Deb. Compression is
still good.. The vacuum pump is original on the engine at close to
1300 hours so it doesn't have much farther to a Factory reman.

As it has no filter I change oil at 25 hours. At 25 hours it's
difficult to see if the level is down at all. Probably a pint or
less.

It runs smooth and starts easy. I have a Tanis heater on each
cylinder head and on the case. Once the temperatures fall below
freezing the heater stays on 24 X 7 with the entire front of the plane
wrapped in two layers of space age blankets which actually extend well
beyond the firewall.

I get very close to 190 cruise on 13 1/2 to 14 GPH. I always cruise
at 75% unless too high to be able to get 75%.

I've never found it necessary to lean while on the ground except when
I was at Goodland KS and Jefco. There I leaned for takeoff. I either
run 24 X 24, or adjust to one inch over square adjusted for 75%. The
one thing I want to add to the engine are gami injectors and monitor
the EGT and CHTs on all 6.

I have had one complete engine failure and that was due to the
diaphragm in the fuel cutoff valve located in the distribution block
(spider) on top of the engine.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

Chris Kennedy writes:

Rick, I had a talk with my mechanic a couple of months ago about
leaning when idling. He says for my carburator and C-90 engine,
and I suppose many other aircraft engines, leaning at idle doesn't
do anything unless it is nearly at idle cutoff. It is only when
the RPMs are well above idle that the mixture control begins to
really control. So does leaning on the ground--during idle--do
anything unless it is leaned nearly to idle cutoff?

Up here in the mountains we lean to the point of stumbling and try not
to reduce RPMs below 1200 on our O-540 (as does the local FBO with its
O-360). Except on very cold winter days we lean for departure as
well.

As far as I understand, carbureted engines have a separate idle
mixture control that needs to be adjusted with a screwdriver on the
carburetor itself (i.e. on the ground, by an A&P). If that is set too
rich, you can lean during ground idle until the cows come home and
still end up with fouled plugs.


All the best,


David

--
David Megginson, , http://www.megginson.com/