Gene Whitt is back on line

You tell us.

If I'm wrong I'd like to know.


"Thomas Borchert" wrote in
message ...
| Jim,
|
| 50 RPM drop on the rich side is too rich at cruise... 50
| degrees rich of peak on the EGT is about right with a
carb.
| With fuel injection, just a little below peak or even at
| peak if the cruise power is set below 70%. At low power
| settings you can run at peak since the actual
temperatures
| will be low. If you have a calibrated EGT (TIT) follow
the
| limits.
|
|
| Ok, kids, now lets count all the misunderstandings and
factually wrong
| statements in that post. Hint: There are at least 5.
|
| --
| Thomas Borchert (EDDH)
|

Jim,

50 RPM drop on the rich side is too rich at cruise...

RPM doesn't matter.

50
degrees rich of peak on the EGT is about right with a carb.

Why? How? 50 ROP is the point of maximum internal combustion pressure.
A point at which you don't really want to be.

With fuel injection, just a little below peak or even at
peak if the cruise power is set below 70%.

below peak on the rich or the lean side? A limit of 70 is artificial.
65 and 75 is mentioned by the engine manufacturers, respectively. Many
say those limits don't mean that much. CHTs do. Many people run their
engines lean of peak (well lean of peak) at 80 percent and more. CHTs
stay well below 380.
There is no difference in leaning technique between carb'd and injected
engines.

At low power
settings you can run at peak since the actual temperatures
will be low.

What temperatures? EGT? CHT? Actual EGTs don't matter anyway. Actual
CHTs are higher ROP than they are at peak EGT. They shouldn't be above
380.

If you have a calibrated EGT (TIT) follow the
limits.

Absolute EGTs don't matter. TIT is a different story, since the engine
is turbo'd.

I really recommend reading Deakin's columns at Avweb - it makes you see
several lights real quick.

--
Thomas Borchert (EDDH)

Jim,

Yes, engine roughness is caused by one cylinder misfiring.

Not at all. Or rather: very rarely. Engine roughness which we normally
encounter during leaning is caused by the cylinders developing
different amounts of power.

Fuel injection is properly calibrated is the same on all
cylinders so the engine runs smooth and balanced.

TCM and Lycoming specs don't at all require that. Which is why
GAMIjectors are such a success. And no, GAMIjectors DON'T calibrate
fuel flow to be the same for each cylinder, since you don't want or
need that. What you need is the same fuel-air ratio in each cylinder.
So those cylinders that get less air need less fuel, too.

Read Deakin, it's all in there.

--
Thomas Borchert (EDDH)

I think we are saying the same thing, basically and to a
degree. A dead mag does not cause a rough engine, a dead
cylinder does. A poorly balanced engine will be rough
because the different weights of the parts moving.
Different power per cylinder will be rough, but as long as
the output is close, most pilots won't notice minor
variations. I used the word misfiring to indicate what was
happening that would be detected.
Certainly, with instrumentation or skill, the pilot will be
able to detect many variations in engine operation with
different throttle positions, mixture settings and rpm.
Volumetric efficiency will vary with RPM, MAP and vary from
engine to engine. A high time engine will be different than
a new engine, carb, single point injection (pressure carb)
or port fuel injection will be different and high quality
parts are better than 50 year old OEM designs.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Thomas Borchert" wrote in
message ...
| Jim,
|
| Yes, engine roughness is caused by one cylinder
misfiring.
|
| Not at all. Or rather: very rarely. Engine roughness which
we normally
| encounter during leaning is caused by the cylinders
developing
| different amounts of power.
|
| Fuel injection is properly calibrated is the same on all
| cylinders so the engine runs smooth and balanced.
|
| TCM and Lycoming specs don't at all require that. Which is
why
| GAMIjectors are such a success. And no, GAMIjectors DON'T
calibrate
| fuel flow to be the same for each cylinder, since you
don't want or
| need that. What you need is the same fuel-air ratio in
each cylinder.
| So those cylinders that get less air need less fuel, too.
|
| Read Deakin, it's all in there.
|
| --
| Thomas Borchert (EDDH)
|

If you set cruise RPM to 2400 and lean the engine, RPM will
increase as combustion is improved and power increases
(fixed pitch prop). Peak power is max RPM, some books
recommend running richer, enough to drop the RPM 50. Ground
idle mixture is set so that RPM increases 20-50 RPM as the
engine goes from rich idle to cutoff and the mixture leans
out.


"Thomas Borchert" wrote in
message ...
| Jim,
|
| 50 RPM drop on the rich side is too rich at cruise...
|
| RPM doesn't matter.
|
| 50
| degrees rich of peak on the EGT is about right with a
carb.
|
| Why? How? 50 ROP is the point of maximum internal
combustion pressure.
| A point at which you don't really want to be.
|
| With fuel injection, just a little below peak or even at
| peak if the cruise power is set below 70%.
|
| below peak on the rich or the lean side? A limit of 70 is
artificial.
| 65 and 75 is mentioned by the engine manufacturers,
respectively. Many
| say those limits don't mean that much. CHTs do. Many
people run their
| engines lean of peak (well lean of peak) at 80 percent and
more. CHTs
| stay well below 380.
| There is no difference in leaning technique between carb'd
and injected
| engines.
|
| At low power
| settings you can run at peak since the actual
temperatures
| will be low.
|
| What temperatures? EGT? CHT? Actual EGTs don't matter
anyway. Actual
| CHTs are higher ROP than they are at peak EGT. They
shouldn't be above
| 380.
|
| If you have a calibrated EGT (TIT) follow the
| limits.
|
| Absolute EGTs don't matter. TIT is a different story,
since the engine
| is turbo'd.
|
| I really recommend reading Deakin's columns at Avweb - it
makes you see
| several lights real quick.
|
| --
| Thomas Borchert (EDDH)
|

"bsalai" wrote in message
...
Matt Barrow wrote:


Standard procedures in many (most?) places says 50 or so ROP...about the
worst place you can run your engine.


That's where I was taught to lean to. I think the reason was that it is a
safe place,

Hardest on the engine is not waht I call safe.

whereas lean of peak has some advantages, but can get you into trouble
with detonation if you are not really careful.

No, you can't really...only if you lag going from ROP to LOP.


Any suggestions?


Here's a start.

http://www.avweb.com/news/columns/182132-1.html
May 27, 2001
Detonation Myths

We've all been taught about detonation in piston aircraft engines. It's what
occurs when combustion pressure and temperature get so high that the
fuel/air mixture to explodes violently instead of burning smoothly, and it
can destroy an engine in a matter of seconds. Right? Well, not exactly.

"Jim Macklin" wrote in message
news:tslKf.100258$4l5.99449@dukeread05...
Yes, engine roughness is caused by one cylinder misfiring.
Fuel injection is properly calibrated is the same on all
cylinders so the engine runs smooth and balanced.


I guess GAMI is selling us a bill of goods, huh? :~)

"Jim Macklin" wrote in message
news:vslKf.100259$4l5.46897@dukeread05...
You tell us.

If I'm wrong I'd like to know.


Red Box = No Fly Zone
At and below about 60% power, there is no red box.
At about 65% power or so, 100ºF ROP to Peak.
At about 70%, 125ºF ROP to 25ºF LOP.
At about 75%, 180ºF ROP to 40ºF LOP.
At about 80%, 200ºF ROP to 60ºF LOP


Makes no difference, carb or fuel injection.

You might have been an A&P for the better part of 35 years, but you're just
parroting "Old Wives Tales"

http://www.avweb.com/news/columns/182155-1.html (Myths about fired valves)

http://www.avweb.com/news/columns/182149-1.html (Detonation myths)

Oh, hell...read the whole series
http://www.avweb.com/news/columns/182146-1.html



"Thomas Borchert" wrote in
message ...
| Jim,
|
| 50 RPM drop on the rich side is too rich at cruise... 50
| degrees rich of peak on the EGT is about right with a
carb.
| With fuel injection, just a little below peak or even at
| peak if the cruise power is set below 70%. At low power
| settings you can run at peak since the actual
temperatures
| will be low. If you have a calibrated EGT (TIT) follow
the
| limits.
|
|
| Ok, kids, now lets count all the misunderstandings and
factually wrong
| statements in that post. Hint: There are at least 5.
|
| --
| Thomas Borchert (EDDH)
|

"bsalai" wrote in message
...
Matt Barrow wrote:


Standard procedures in many (most?) places says 50 or so ROP...about the
worst place you can run your engine.


That's where I was taught to lean to. I think the reason was that it is a
safe place, whereas lean of peak has some advantages, but can get you into
trouble with detonation if you are not really careful.

Any suggestions?

http://www.avweb.com/news/columns/182146-1.html (Series on the right side of
the page), also:

http://www.engineteststand.com/

It all depends, Henry Ford built the "best" car he could
when he built the Model T, a 1962 Chrysler 426 Hemi would
have really seemed like magic to Ford and a modern double
overhead cam engine in a 2000 Acura would really would out
perform that 426 monster cube for cube.
GAMI is better than stock FI which is a very old, low tech
constant flow system on Continental and Lycoming engines.
Your car uses high pressure pumps a fuel rail and solenoid
control metering at the injector, but engine roughness is
caused by __________ which causes __________ vibration.




--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Matt Barrow" wrote in message
...
|
| "Jim Macklin" wrote
in message
| news:tslKf.100258$4l5.99449@dukeread05...
| Yes, engine roughness is caused by one cylinder
misfiring.
| Fuel injection is properly calibrated is the same on all
| cylinders so the engine runs smooth and balanced.
|
|
| I guess GAMI is selling us a bill of goods, huh? :~)
|
|
|
|
|