Percent power altitude

[Doug[_1_]]

Anyone tell me at what altitude I get 75% and 65% power respctively
(with full throttle, normally aspirated).

[Mitty]

You don't have a POH?

On 10/21/2006 10:33 AM, Doug wrote the following:
> Anyone tell me at what altitude I get 75% and 65% power respctively
> (with full throttle, normally aspirated).
>

[Bob Moore]

Doug wrote
> Anyone tell me at what altitude I get 75% and 65% power respctively
> (with full throttle, normally aspirated).

See the graph at:

http://www.kellyaerospace.com/articles/Turbocharging.pdf

Bob Moore

[Bob Moore]

Mitty wrote
> You don't have a POH?

You know, he might not even have an airplane. He just asked
a question and expected an answer, not a wise crack.

No POH required, answer is not aircraft specific, see:

http://www.kellyaerospace.com/articles/Turbocharging.pdf

Bob Moore

[john smith]

In article . com>,
"Doug" > wrote:

> Anyone tell me at what altitude I get 75% and 65% power respctively
> (with full throttle, normally aspirated).

Depends on the engine, depends on the OAT (density altitude).

[Bob Moore]

john smith wrote
> Depends on the engine, depends on the OAT (density altitude).

Not on the engine as long as it's "normally aspirated' as
specified in the OP.

Bob Moore

[Jim Macklin]

5 and 7 thousand
"Doug" > wrote in message
oups.com...
| Anyone tell me at what altitude I get 75% and 65% power
respctively
| (with full throttle, normally aspirated).
|

[Bob Moore]

Jim Macklin wrote
> 5 and 7 thousand

Running on (faulty) memory again, Jim?

How about 7,500' and about 12,500', ISA of course.

See my previous replies to this thread for a real chart
answer.

The formula answer is:

bhp at altitude equals bhp at sea level times the quantity
(density ratio minus the quantity(1 minus density ratio divided by 7.55))

Works out to 76% at 7,500' and 64% at 12,500', or thereabouts.


Bad information is worse than no information at all.

Bob Moore

[Bob Noel]

In article >,
Bob Moore > wrote:

> The formula answer is:
>
> bhp at altitude equals bhp at sea level times the quantity
> (density ratio minus the quantity(1 minus density ratio divided by 7.55))
>
> Works out to 76% at 7,500' and 64% at 12,500', or thereabouts.

OK, I'm confused. Full throttle, 64%, is 12,500' for any engine?
How come my cherokee 140 couldn't even get to 12,500'?
What am I overlooking?

--
Bob Noel
Looking for a sig the
lawyers will hate

[Bob Moore]

Bob Noel wrote

> Bob Moore > wrote:
>> Works out to 76% at 7,500' and 64% at 12,500', or thereabouts.
>
> OK, I'm confused. Full throttle, 64%, is 12,500' for any engine?
> How come my cherokee 140 couldn't even get to 12,500'?
> What am I overlooking?

:-) The wing, of course. :-)

Bob Moore

[Mitty]

Possibly Cessna and Piper have not seen your chart. I have several POHs here:

An Arrow PA28R-201 POH shows 75% power, full throttle, at 6,000 feet/2400 RPM
and 7,500/2700 RPM. 65% power at about 9,800/2400 and 12,000/2700. (IO-360/200
Lyc.)

A Cessna 182T (T-model, not T for turbo) POH has tables that are a little harder
to read than the Arrow's graphs, but the highest % power they show at 8,000 feet
is 74% and at 12,000 feet 64%. (IO-540/230 Lyc.)

A carburated Cherokee Six/260 shows 75% power, full throttle, at 8,300 feet and
65% power at 11,200 feet. Engine RPM is not stated. (O-540/260 Lyc.)

I also have a tiny and very complicated power chart from Lycoming for the O-540
but I am too lazy to figure it out.

I am no fluid dynamicist (and may be about to prove it), but my dim
understanding is that the Reynolds number has a major effect on fluid flow and
in its calculation there is a density term. Certainly the mixture velocities at
various points in each different intake system would be different. Velocity is
also a term in the Reynolds number calculation. So (leaping) it does not
surprise me that intake systems with different geometries would perform at least
slightly differently at different altitudes. Exhaust systems, too, I'd guess.

Possibly I should have been more diplomatic in how I suggested that the OP
needed a POH but that still seems to me to be the case.

On 10/21/2006 12:46 PM, Bob Moore wrote the following:
> Mitty wrote
>> You don't have a POH?
>
> You know, he might not even have an airplane. He just asked
> a question and expected an answer, not a wise crack.
>
> No POH required, answer is not aircraft specific, see:
>
> http://www.kellyaerospace.com/articles/Turbocharging.pdf
>
> Bob Moore

[Jim Macklin]

Yes, after age 60, my recall gets muddy.


"Bob Moore" > wrote in message
. 122...
| Jim Macklin wrote
| > 5 and 7 thousand
|
| Running on (faulty) memory again, Jim?
|
| How about 7,500' and about 12,500', ISA of course.
|
| See my previous replies to this thread for a real chart
| answer.
|
| The formula answer is:
|
| bhp at altitude equals bhp at sea level times the quantity
| (density ratio minus the quantity(1 minus density ratio
divided by 7.55))
|
| Works out to 76% at 7,500' and 64% at 12,500', or
thereabouts.
|
|
| Bad information is worse than no information at all.
|
| Bob Moore

[Jim Macklin]

Leaning and density altitude (performance altitude).



"Bob Noel" > wrote in
message
...
| In article
>,
| Bob Moore > wrote:
|
| > The formula answer is:
| >
| > bhp at altitude equals bhp at sea level times the
quantity
| > (density ratio minus the quantity(1 minus density ratio
divided by 7.55))
| >
| > Works out to 76% at 7,500' and 64% at 12,500', or
thereabouts.
|
| OK, I'm confused. Full throttle, 64%, is 12,500' for any
engine?
| How come my cherokee 140 couldn't even get to 12,500'?
| What am I overlooking?
|
| --
| Bob Noel
| Looking for a sig the
| lawyers will hate
|

[Doug[_1_]]

As a first approximation, it should be the same for any normally
aspirated engine (and yes it would be based on DENSITY altitude). The
engine develops 100% HP only at sealevel. As the altitude goes up what
changes? The density of the air decreases and in response the fuel
delivered decreases (from both the carb delivering less fuel and the
pilot leaning the mixture). This is the same for all the normally
aspirated engines.

Now at somewhere around 65-70% power it becomes impossible to get
excess EGTs and CHTs due to overleaning the engine. So run the engine
at that altitude and lean for max rpm and note the EGT. This is
guaranteed to be a safe EGT! Now use this EGT for leaning at ALL
altitudes. Thus you have found 100 or so degrees rich of peak without
ever having to run the engine at peak (which is too hot and hazardous
in itself).

Doug wrote:
> Anyone tell me at what altitude I get 75% and 65% power respctively
> (with full throttle, normally aspirated).

[Bob Moore]

Jim Macklin wrote
> Yes, after age 60, my recall gets muddy.

Hmmmm....at 71, I must have missed that stage. :-)

Bob

[Ron Natalie]

Bob Noel wrote:

> OK, I'm confused. Full throttle, 64%, is 12,500' for any engine?
> How come my cherokee 140 couldn't even get to 12,500'?
> What am I overlooking?
>

Because 64% of whatever HP you have isn't enough to get you there/
hold you there.

I've got 300HP in an airframe designed for 185. At 65% HP I'm
doing better than they can do with WOT at sea level.

[Jim Macklin]

Note, I did say MY recall. I sleep like a baby now. Go to
bed, wake up every hour or two, cry and go to the bathroom.

I my defense, I'm not perfect.



"Bob Moore" > wrote in message
. 122...
| Jim Macklin wrote
| > Yes, after age 60, my recall gets muddy.
|
| Hmmmm....at 71, I must have missed that stage. :-)
|
| Bob
|

[karl gruber[_1_]]

It depends predominantly on your mixture.

Karl
"Curator" N185KG



"Doug" > wrote in message
oups.com...
> Anyone tell me at what altitude I get 75% and 65% power respctively
> (with full throttle, normally aspirated).
>

[karl gruber[_1_]]

"Doug" > wrote in message
oups.com...
> altitudes. Thus you have found 100 or so degrees rich of peak without
> ever having to run the engine at peak (which is too hot and hazardous
> in itself).
>
What makes you think that?

Karl
"Curator" N185KG
Gami ser# 19

[Thomas Borchert]

Doug,

> Thus you have found 100 or so degrees rich of peak without
> ever having to run the engine at peak (which is too hot and hazardous
> in itself).
>

Come again? That part in parenthesis is completely wrong.

--
Thomas Borchert (EDDH)

[Stan Prevost]

"Doug" > wrote in message
oups.com...
> ever having to run the engine at peak (which is too hot and hazardous
> in itself).
>

For my 1999 Saratoga TC, all the cruise performance charts are given for
peak EGT, including the ones for maximum performance cruise.

[John R. Copeland]

"Thomas Borchert" > wrote in message ...
> Doug,
>
>> Thus you have found 100 or so degrees rich of peak without
>> ever having to run the engine at peak (which is too hot and hazardous
>> in itself).
>>
>
> Come again? That part in parenthesis is completely wrong.
>
> --
> Thomas Borchert (EDDH)
>

Thomas, I think you snipped away an important part of Doug's post.
He was trying to stress the need for leaning to a temperature limit.
Stainless steels approach their softening points above 900C (1650F).
Doug's "too hot and hazardous" remark referred only to the peak EGT
reached at a high power setting, where the peak temperature is high
enough to enter the softening region of the exhaust collectors.
Doug's advice about never leaning above a safe temperature
is well advised, and it's exactly what I've followed for 25 years.
In fact, I found that leaning to RAM's recommended 1550F
still results in a little exhaust-system distortion, and I've held to
1525F max for the last ten years or so, with better results.

[Allen[_1_]]

"John R. Copeland" > wrote in message
.. .
Doug's advice about never leaning above a safe temperature
is well advised, and it's exactly what I've followed for 25 years.
In fact, I found that leaning to RAM's recommended 1550F
still results in a little exhaust-system distortion, and I've held to
1525F max for the last ten years or so, with better results.

I believe their recommendation at 75% power is 100 degrees rich of "peak",
not 100 degrees rich of 1650 degrees. Most engines will peak at a
temperature less than 1650 degrees.

Allen

[John R. Copeland]

"Allen" > wrote in message et...
>
> "John R. Copeland" > wrote in message
> .. .
> > Doug's advice about never leaning above a safe temperature
> > is well advised, and it's exactly what I've followed for 25 years.
> > In fact, I found that leaning to RAM's recommended 1550F
> > still results in a little exhaust-system distortion, and I've held to
> > 1525F max for the last ten years or so, with better results.
>
> I believe their recommendation at 75% power is 100 degrees rich of "peak",
> not 100 degrees rich of 1650 degrees. Most engines will peak at a
> temperature less than 1650 degrees.
>
> Allen
>

OK, let me try to rephrase what Doug already said correctly...
*At the higher power settings*, say about 70% and above,
the peak EGT *will* rise above steel's softening temperatures.
If your EGT gauge is calibrated for temperature,
never lean above 900C/1650F, except for very brief time.
Preferably, lean directly to the desired temperature and fuel flow.
RAM recommends operating at 850C/1550F, but my experience says
that's slightly too high, and I lean to about 25F cooler than that.
My penalty is less than 5% additional fuel flow above RAM's figures.
Yes, avgas is expensive, but replacing exhaust parts is expensive, also.

My engines certainly will peak above 1650F at high power settings,
but not so when operated down around economy power settings,
which would typically be below 65%.
I normally cruise my TSIO320s at about the 50% power level,
and even there, my peak EGTs remain above my personal target of 1525F.

From my cockpit, I can see down through louvers in the tops of my
engine nacelles, into the areas around the turbochargers.
I've had passengers at night ask me why I have yellow-orange lights
turned on in the engine compartments. :-/
When you've seen your exhaust components glowing in the dark,
you get a better appreciation of the stress they endure hour after hour.
They are more than red-hot, they are nearly yellow-hot.
Don't abuse your exhaust system any more than necessary.

[Jim Macklin]

Very true. On a turbocharged airplane the EGT is calibrated
and called a TIT [an a jet it is ITT or TPT]
The turbo has designed temperature limits and because it is
rotating at 35,000 to 120,000 rpm it needs very good
strength to stay in one piece. It also needs to be cooled
at a moderate idle speed for 4-5 minutes to allow it to
spool down, cool off and have good oil pressure. A closed
throttle idle doesn't supply enough oil volume to cool the
turn bearing, and a fast idle, particularly a simple fixed
waste gate type won't let it slow down enough.

Bottom line, RTFM for the particular model and serial
number.



"John R. Copeland" > wrote in
message . ..
"Allen" > wrote in message
et...
>
> "John R. Copeland" > wrote in
> message
> .. .
> > Doug's advice about never leaning above a safe
> > temperature
> > is well advised, and it's exactly what I've followed for
> > 25 years.
> > In fact, I found that leaning to RAM's recommended 1550F
> > still results in a little exhaust-system distortion, and
> > I've held to
> > 1525F max for the last ten years or so, with better
> > results.
>
> I believe their recommendation at 75% power is 100 degrees
> rich of "peak",
> not 100 degrees rich of 1650 degrees. Most engines will
> peak at a
> temperature less than 1650 degrees.
>
> Allen
>

OK, let me try to rephrase what Doug already said
correctly...
*At the higher power settings*, say about 70% and above,
the peak EGT *will* rise above steel's softening
temperatures.
If your EGT gauge is calibrated for temperature,
never lean above 900C/1650F, except for very brief time.
Preferably, lean directly to the desired temperature and
fuel flow.
RAM recommends operating at 850C/1550F, but my experience
says
that's slightly too high, and I lean to about 25F cooler
than that.
My penalty is less than 5% additional fuel flow above RAM's
figures.
Yes, avgas is expensive, but replacing exhaust parts is
expensive, also.

My engines certainly will peak above 1650F at high power
settings,
but not so when operated down around economy power settings,
which would typically be below 65%.
I normally cruise my TSIO320s at about the 50% power level,
and even there, my peak EGTs remain above my personal target
of 1525F.

From my cockpit, I can see down through louvers in the tops
of my
engine nacelles, into the areas around the turbochargers.
I've had passengers at night ask me why I have yellow-orange
lights
turned on in the engine compartments. :-/
When you've seen your exhaust components glowing in the
dark,
you get a better appreciation of the stress they endure hour
after hour.
They are more than red-hot, they are nearly yellow-hot.
Don't abuse your exhaust system any more than necessary.

[Doug[_1_]]

I agree I didn't say it right. But the procedure has some value. You
lean to peak at 10000', you are leaning to a safe EGT. THAT EGT will be
well rich (or lean) of peak at "dangerous" power settings (like 75% or
more) and you have found this rich (or lean) of peak by never leaning
all the way to peak.

That is what I meant. Sorry about the poor (actually incorrect) wording.

[John R. Copeland]

Beechcraft, for example, calls it "TIT" instead of "EGT".
Some others still call it "EGT" on turbocharged airplanes.
But they all mean the same measurement.

"Jim Macklin" > wrote in message ...
> Very true. On a turbocharged airplane the EGT is calibrated
> and called a TIT [an a jet it is ITT or TPT]
> The turbo has designed temperature limits and because it is
> rotating at 35,000 to 120,000 rpm it needs very good
> strength to stay in one piece. It also needs to be cooled
> at a moderate idle speed for 4-5 minutes to allow it to
> spool down, cool off and have good oil pressure. A closed
> throttle idle doesn't supply enough oil volume to cool the
> turn bearing, and a fast idle, particularly a simple fixed
> waste gate type won't let it slow down enough.
>
> Bottom line, RTFM for the particular model and serial
> number.
>
>
>
> "John R. Copeland" > wrote in
> message . ..
> "Allen" > wrote in message
> et...
>>
>> "John R. Copeland" > wrote in
>> message
>> .. .
>> > Doug's advice about never leaning above a safe
>> > temperature
>> > is well advised, and it's exactly what I've followed for
>> > 25 years.
>> > In fact, I found that leaning to RAM's recommended 1550F
>> > still results in a little exhaust-system distortion, and
>> > I've held to
>> > 1525F max for the last ten years or so, with better
>> > results.
>>
>> I believe their recommendation at 75% power is 100 degrees
>> rich of "peak",
>> not 100 degrees rich of 1650 degrees. Most engines will
>> peak at a
>> temperature less than 1650 degrees.
>>
>> Allen
>>
>
> OK, let me try to rephrase what Doug already said
> correctly...
> *At the higher power settings*, say about 70% and above,
> the peak EGT *will* rise above steel's softening
> temperatures.
> If your EGT gauge is calibrated for temperature,
> never lean above 900C/1650F, except for very brief time.
> Preferably, lean directly to the desired temperature and
> fuel flow.
> RAM recommends operating at 850C/1550F, but my experience
> says
> that's slightly too high, and I lean to about 25F cooler
> than that.
> My penalty is less than 5% additional fuel flow above RAM's
> figures.
> Yes, avgas is expensive, but replacing exhaust parts is
> expensive, also.
>
> My engines certainly will peak above 1650F at high power
> settings,
> but not so when operated down around economy power settings,
> which would typically be below 65%.
> I normally cruise my TSIO320s at about the 50% power level,
> and even there, my peak EGTs remain above my personal target
> of 1525F.
>
> From my cockpit, I can see down through louvers in the tops
> of my
> engine nacelles, into the areas around the turbochargers.
> I've had passengers at night ask me why I have yellow-orange
> lights
> turned on in the engine compartments. :-/
> When you've seen your exhaust components glowing in the
> dark,
> you get a better appreciation of the stress they endure hour
> after hour.
> They are more than red-hot, they are nearly yellow-hot.
> Don't abuse your exhaust system any more than necessary.
>
>

[Jim Macklin]

Not exactly. It depends on whether the gauge is calibrated
to an exact temperature or whether the gauge is used only to
find relative peak and degrees above and below. It also
depends on where the probe(s) are installed. EGT has the
probes about 4 inches past the exhaust valves, TIT has THE
probe at the inlet to the turbocharger. ITT has the probe
located between two turbine wheels in a jet engine.

They all measure the temperature of the combustion process
and thus relate to the fuel/air ratio. But how that relates
to the engine operation will vary. On a turbine engine the
critical temp limit is the start temperature. But in a King
Air for example, some models have the temperature probe in
the tail pipe and some have it in the hot section. With the
tail pipe measurement location the start temp limit might be
only 400°C, but it could run continuously at 650° and in
reality, the engine might actually be at the same
temperature.


"John R. Copeland" > wrote in
message ...
Beechcraft, for example, calls it "TIT" instead of "EGT".
Some others still call it "EGT" on turbocharged airplanes.
But they all mean the same measurement.

"Jim Macklin" > wrote
in message ...
> Very true. On a turbocharged airplane the EGT is
> calibrated
> and called a TIT [an a jet it is ITT or TPT]
> The turbo has designed temperature limits and because it
> is
> rotating at 35,000 to 120,000 rpm it needs very good
> strength to stay in one piece. It also needs to be cooled
> at a moderate idle speed for 4-5 minutes to allow it to
> spool down, cool off and have good oil pressure. A closed
> throttle idle doesn't supply enough oil volume to cool the
> turn bearing, and a fast idle, particularly a simple fixed
> waste gate type won't let it slow down enough.
>
> Bottom line, RTFM for the particular model and serial
> number.
>
>
>
> "John R. Copeland" > wrote in
> message
> . ..
> "Allen" > wrote in message
> et...
>>
>> "John R. Copeland" > wrote
>> in
>> message
>> .. .
>> > Doug's advice about never leaning above a safe
>> > temperature
>> > is well advised, and it's exactly what I've followed
>> > for
>> > 25 years.
>> > In fact, I found that leaning to RAM's recommended
>> > 1550F
>> > still results in a little exhaust-system distortion,
>> > and
>> > I've held to
>> > 1525F max for the last ten years or so, with better
>> > results.
>>
>> I believe their recommendation at 75% power is 100
>> degrees
>> rich of "peak",
>> not 100 degrees rich of 1650 degrees. Most engines will
>> peak at a
>> temperature less than 1650 degrees.
>>
>> Allen
>>
>
> OK, let me try to rephrase what Doug already said
> correctly...
> *At the higher power settings*, say about 70% and above,
> the peak EGT *will* rise above steel's softening
> temperatures.
> If your EGT gauge is calibrated for temperature,
> never lean above 900C/1650F, except for very brief time.
> Preferably, lean directly to the desired temperature and
> fuel flow.
> RAM recommends operating at 850C/1550F, but my experience
> says
> that's slightly too high, and I lean to about 25F cooler
> than that.
> My penalty is less than 5% additional fuel flow above
> RAM's
> figures.
> Yes, avgas is expensive, but replacing exhaust parts is
> expensive, also.
>
> My engines certainly will peak above 1650F at high power
> settings,
> but not so when operated down around economy power
> settings,
> which would typically be below 65%.
> I normally cruise my TSIO320s at about the 50% power
> level,
> and even there, my peak EGTs remain above my personal
> target
> of 1525F.
>
> From my cockpit, I can see down through louvers in the
> tops
> of my
> engine nacelles, into the areas around the turbochargers.
> I've had passengers at night ask me why I have
> yellow-orange
> lights
> turned on in the engine compartments. :-/
> When you've seen your exhaust components glowing in the
> dark,
> you get a better appreciation of the stress they endure
> hour
> after hour.
> They are more than red-hot, they are nearly yellow-hot.
> Don't abuse your exhaust system any more than necessary.
>
>

[Allen[_1_]]

"Jim Macklin" > wrote in message
...
> Very true. On a turbocharged airplane the EGT is calibrated
> and called a TIT [an a jet it is ITT or TPT]
> The turbo has designed temperature limits and because it is
> rotating at 35,000 to 120,000 rpm it needs very good
> strength to stay in one piece. It also needs to be cooled
> at a moderate idle speed for 4-5 minutes to allow it to
> spool down, cool off and have good oil pressure. A closed
> throttle idle doesn't supply enough oil volume to cool the
> turn bearing, and a fast idle, particularly a simple fixed
> waste gate type won't let it slow down enough.
>
> Bottom line, RTFM for the particular model and serial
> number.

John's airplane, a Cessna 340, came from the factory with an EGT (when
installed), not TIT. EGT is located forward of the turbo and actually has a
higher temperature than the TIT. Some airplanes, such as the P-Baron and
58TC have TIT, the probe is actually located in the turbo inlet. I was just
commenting to John that I have never seen RAM recommend any particular EGT,
only the 1650 degree max. I agree with the rest of your post.

Allen

[Allen[_1_]]

"Jim Macklin" > wrote in message
...
> Not exactly. It depends on whether the gauge is calibrated
> to an exact temperature or whether the gauge is used only to
> find relative peak and degrees above and below. It also
> depends on where the probe(s) are installed. EGT has the
> probes about 4 inches past the exhaust valves,

On single-probe EGT systems such as on John's Cessna 340 the probe is
located toward the tail end of the exhaust riser, well ahead of the turbo
but past the 4" point. This was determined (by Cessna) to be the point
where the exhaust gas is hottest. Cessna POH for the 340 recommends running
at peak for many power settings below about 62%. Cessna designed their own
exhaust systems on their twins, Beechcraft had TCM design their exhaust as a
unit with the engine.

Allen

[John R. Copeland]

"Allen" > wrote in message .. .
>
> ..... I was just
> commenting to John that I have never seen RAM recommend any particular EGT,
> only the 1650 degree max. I agree with the rest of your post.
>
> Allen
>
I don't have RAM's newest engines, but their power charts for the RAM
Series II and RAM Series IV TSIO-520NBs had columns showing EGT's.
Typical row entries are "Takeoff (full rich) - 1450F to 1550F",
"Cruise Climb (85%) - 1450F Calibration Setting",
three different types of "Cruise - 1550F" entries,
"Normal Descent - 1300F min, 1400F ideal", and
"Approach and Landing - 1200F min, 1300 ideal".

[Allen[_1_]]

"John R. Copeland" > wrote in message
...
"Allen" > wrote in message
.. .
>
> ..... I was just
> commenting to John that I have never seen RAM recommend any particular
> EGT,
> only the 1650 degree max. I agree with the rest of your post.
>
> Allen
>
I don't have RAM's newest engines, but their power charts for the RAM
Series II and RAM Series IV TSIO-520NBs had columns showing EGT's.
Typical row entries are "Takeoff (full rich) - 1450F to 1550F",
"Cruise Climb (85%) - 1450F Calibration Setting",
three different types of "Cruise - 1550F" entries,
"Normal Descent - 1300F min, 1400F ideal", and
"Approach and Landing - 1200F min, 1300 ideal".

You may want to call their customer service and get an updated power card.
The one I have justs shows "1650 degrees maximum" for the cruise entries.
They are letting you determine what you want to run at. I think you are
operating them in the proper way limiting the EGT to 1525 or lower.

Allen

[Jim Macklin]

The airframe maker often modifies the engine and
accessories, thus the POH is the authority. STC'd systems
modify that. So, if you and I keep posting sound advice,
perhaps the rest of the group will develop a higher level of
learning.


"Allen" > wrote in message
.. .
|
| "Jim Macklin" > wrote
in message
| ...
| > Not exactly. It depends on whether the gauge is
calibrated
| > to an exact temperature or whether the gauge is used
only to
| > find relative peak and degrees above and below. It also
| > depends on where the probe(s) are installed. EGT has
the
| > probes about 4 inches past the exhaust valves,
|
| On single-probe EGT systems such as on John's Cessna 340
the probe is
| located toward the tail end of the exhaust riser, well
ahead of the turbo
| but past the 4" point. This was determined (by Cessna) to
be the point
| where the exhaust gas is hottest. Cessna POH for the 340
recommends running
| at peak for many power settings below about 62%. Cessna
designed their own
| exhaust systems on their twins, Beechcraft had TCM design
their exhaust as a
| unit with the engine.
|
| Allen
|
|

[Blanche]

Bob Moore > wrote:
>Bob Noel wrote
>
>> Bob Moore > wrote:
>>> Works out to 76% at 7,500' and 64% at 12,500', or thereabouts.
>>
>> OK, I'm confused. Full throttle, 64%, is 12,500' for any engine?
>> How come my cherokee 140 couldn't even get to 12,500'?
>> What am I overlooking?
>
>:-) The wing, of course. :-)
>
>Bob Moore

Perhaps you need to pedal faster?

(*chortle*)