Need Information To Do A 150 Hp Conversion On My C-150

: Any idea How do I get my 182 to cruise along at 5.5 GPH? (without
: burning something up cause it's leaned out too much? or falling out of
: the sky) It's a 1957 and real light for it's size and got a STOL kit.
: Getting hard to afford gas for it, but don't want to give in to my
: husband and get one of those old-fashioned taildraggers.

Don't know what altitude you're talking about but at 7500 and 20 squared
you are looking at 9 gph. At 15 inches and 2000 you will get about 6.5
gph. At this point the nose will be pretty high and you will only be
getting about 95-100 MPH IAS. To get to 5.5 gph wouldn't be any fun at
all. If you have to have 5.5 then sell the plane and get something that
can reasonably do that.



It also might be worth taking a look at some lean-of-peak information. Bottom
line: below max cruise power, it's impossible to damage your engine with the red knob
alone.

On the big bore Continentals you need to be below 65% before you try
that. Plus having a carbed engine makes LOP impractical.

"Newps" wrote in message
...
On the big bore Continentals you need to be below 65% before you try that.

No. You don't.

Karl
Gami Serial# 19

In rec.aviation.owning Newps wrote:
: Don't know what altitude you're talking about but at 7500 and 20 squared
: you are looking at 9 gph. At 15 inches and 2000 you will get about 6.5
: gph. At this point the nose will be pretty high and you will only be
: getting about 95-100 MPH IAS. To get to 5.5 gph wouldn't be any fun at
: all. If you have to have 5.5 then sell the plane and get something that
: can reasonably do that.

He didn't ask how to make it fun... just if it was possible to fly a 182 at
5.5 gph. I answered that it most likely was. Truth be told, if you're after pure
fuel economy, you'd want to run oversquared as much as possible, too.

: On the big bore Continentals you need to be below 65% before you try
: that. Plus having a carbed engine makes LOP impractical.

LOP on a carb'd engine is difficult/unlikely. Running at peak (as long as
your CHT's aren't high) is fine as well... as long as your power is low.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Max Conrad (ferried Pipers all over the world in the 40s and 50s) ran
fully leaned & with full carb heat when he was in his max range mode.
Do you know of any reason not to, assuming a low power setting? It
would improve the mixture distribution, something the O-470s are
notoriously poor at. It would also reduce the inlet air density,
allowing things to operate with less pumping loss.

nrp

In rec.aviation.owning nrp wrote:
: Max Conrad (ferried Pipers all over the world in the 40s and 50s) ran
: fully leaned & with full carb heat when he was in his max range mode.
: Do you know of any reason not to, assuming a low power setting? It
: would improve the mixture distribution, something the O-470s are
: notoriously poor at. It would also reduce the inlet air density,
: allowing things to operate with less pumping loss.

Unless the CHT's get too high in that configuration (causing poor valve
cooling and cylinder badness), there's not much that says it's bad except:
- No filtration of the air with carb heat. Shouldn't be a big deal in cruise (unless
you have a *really* dirty cowling).
- If flying in cold enough weather, you could get carb ice when normally ice crystals
would flow through unmelted. (I generally don't like to use carb heat until I know
it's necessary)
- Sudden power requirement will cause the engine to falter... get used to a quick red
knob, then throttle.

The real disadvantage of the arrangement on my fixed-pitch plane is 65% is
only obtainable at that mixture up to about 7000-8000'. "Best power" of 50 ROP will
get you 75% or so at that altitude.

-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

In rec.aviation.owning wrote:
: The real disadvantage of the arrangement on my fixed-pitch plane is 65% is
: only obtainable at that mixture up to about 7000-8000'. "Best power" of 50 ROP will
: get you 75% or so at that altitude.

Cory, this I don't understand. You don't have to run WOT to use LOP. Or, are
you saying that you can't get over 65% LOP above 7000'? The maximum possible
power from a non-turbo engine at 7000' is 75%, perhaps that's what you're
saying?
--
Aaron C.

nrp wrote:

Max Conrad (ferried Pipers all over the world in the 40s and 50s) ran
fully leaned & with full carb heat when he was in his max range mode.
Do you know of any reason not to, assuming a low power setting? It
would improve the mixture distribution, something the O-470s are
notoriously poor at. It would also reduce the inlet air density,
allowing things to operate with less pumping loss.

On the 470's, in cruise, you give it whatever carb heat gets you a carb
temp of 40-45F. Running at full carb heat makes no sense whatsoever.

Newps wrote:
On the 470's, in cruise, you give it whatever carb heat gets you a
carb
temp of 40-45F. Running at full carb heat makes no sense whatsoever.

Why not? Using full carb heat would seem to promote better mixture
distribution. The reduced charge density would allow you to run a
higher manifold pressure for the same mass flow, reducing the pumping
loss for a given power setting.

Obviously aggressive leaning probably to at least peak would be
desirable, although who knows where the non-instrumented cylinders
would be running.

I'd be a little concerned running partial carb heat as there would
possibly be a considerable temperature gradient in the air intake
system, given how the carb heat is crudely modulated with that
humongous flapper valve. In other words, some cyls might get a hot
mixture, and some might get cold mixture.

This is assuming the purpose of all this is to reduce the fuel
consumption to get maximum endurance or range under low power settings.
I don't think cyl temp would be a limiting factor.

I don't normally fly my 172M this way (w carb heat always on), but if
it was a question of making it or not, I'd sure use it.'

Thoughts of others?

Most pilots don't know how to get the absolute maximum range or
endurance out of their aircraft.

In rec.aviation.owning nrp wrote:
: Max Conrad (ferried Pipers all over the world in the 40s and 50s) ran
: fully leaned & with full carb heat when he was in his max range mode.
: Do you know of any reason not to, assuming a low power setting? It
: would improve the mixture distribution, something the O-470s are
: notoriously poor at. It would also reduce the inlet air density,
: allowing things to operate with less pumping loss.

I find that I can run my Cherokee's O-360 LOP quite effectively using full
carb heat. Attempts to do so without carb heat lead to unacceptable engine
roughness. With the carb heat on, I can reduce the RPM down several hundred
RPM from peak RPM with good smoothness. Without the carb heat, the RPM
peaks as the mixture gets leaner, then as the RPM begins to drop the engine
gets progressively rougher.

I have not run the engine LOP for any appreciable length of time as I have
no CHT or EGT instrumentation. I have done it for a minute or so to see if
it is possible.
--
Aaron C.

wrote:



LOP on a carb'd engine is difficult/unlikely. Running at peak (as long as
your CHT's aren't high) is fine as well... as long as your power is low.


You need to be at 65% or less if you're going to run at peak.