PA-28-180 Low power query

: Some of the things that might be helpful to specify are the conditions you
: are experiencing this condition. For instance, you mentioned your airport
: is 2100 MSL, but what was the density altitude? What FPM are you getting?
: Are you leaning at all prior to takeoff or during the climb?

: You mentioned EGTs on all cylinders, so I'm assuming you have a full engine
: analyzer. Most of these have a download function. What I suggest you do is
: take a normal flight and carefully note all the conditions of your flight,
: then do a download of the data. You might try shooting an email to Walter
: Atkinson over at advancedpilot.com. Walter participates in a number of
: forums and he's quite helpful.

I doubt that DA is the issue. Of course it has more power at sea-level DA, but still not what it should have as per the static
runup. I've done the DA calculations whenever I'm trying to figure out any true performance as per the book value. I know that few
airplanes match the performance listed in the POH, but they shouldn't be *dangerous* if loaded to gross, and the static RPM should remove
all aerodynamic airframe possibilities (out-of-rig, extra drag, etc).

I do not have an analyzer, but a single gauge and multiple probes on a switch. Also, since I run autogas often, if it were starved
for fuel it would probably have detonated by now. Oh, and yes... I do lean for the DA when necessary (like in the summer when DA can reach
as high as 4500').

Cheers,
-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA *
* Research Associate, Vibrations and Acoustics Laboratory *
* Mechanical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Can you make a static test? Tie tail to large spring scale/load cell,
run it up and observe result...

[This is inspired by my memory of a drag test on the Gossamer Condor;
they used a spring scale in the tow line...]

Then at least you can examine variable without test flights.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:

: Can you make a static test? Tie tail to large spring scale/load cell,
: run it up and observe result...

: [This is inspired by my memory of a drag test on the Gossamer Condor;
: they used a spring scale in the tow line...]

: Then at least you can examine variable without test flights.
: --
I could, but aside from the variable of changing to a different propeller, a static runup will basically tell me the same thing.
Besides, I'm out of ideas on what to try (except for the hydraulic lifters which I meantioned in my first email).

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA *
* Research Associate, Vibrations and Acoustics Laboratory *
* Mechanical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

wrote:
I could, but aside from the variable of changing to a different propeller, a static runup will basically tell me the same thing.
Besides, I'm out of ideas on what to try (except for the hydraulic lifters which I meantioned in my first email).

Have you checked the muffler? A partial obstruction in the muffler
could result in lost power.

(just a shot in the dark...)

Bob Noel writes:

wrote:

I could, but aside from the variable of changing to a different
propeller, a static runup will basically tell me the same thing.
Besides, I'm out of ideas on what to try (except for the hydraulic
lifters which I meantioned in my first email).

Have you checked the muffler? A partial obstruction in the muffler
could result in lost power.

(just a shot in the dark...)


But a good one. I'm still thinking carb but that's without justification.

I've heard of using exhaust gas analyzers to look at the exhaust
for mixture.

I forget, has someone verified the value timing?



--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

: Have you checked the muffler? A partial obstruction in the muffler
: could result in lost power.

: (just a shot in the dark...)


: But a good one. I'm still thinking carb but that's without justification.

: I've heard of using exhaust gas analyzers to look at the exhaust
: for mixture.

: I forget, has someone verified the value timing?

Valve timing? Unchecked, but it seems like if it were out by a tooth on the cam, it wouldn't be able to make static RPM... barely
or not.

Muffler's been replaced as of last year due to other reasons. Performance unchanged.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA *
* Research Associate, Vibrations and Acoustics Laboratory *
* Mechanical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

writes:


Valve timing? Unchecked, but it seems like if it were out by a tooth on
the cam, it wouldn't be able to make static RPM... barely or not.

That's what I'd think on an auto engine; but I'm throwing out ideas,
not claiming they are *good* ones...


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433