Does anyone have a power setting table for the O-540-J1A5D?
Cheers
Barn

There is one in the Lycoming 540 Operator's Manual if you can get your hands on one. It's kind of a generic manual and covers most of the 540s both O and IO, so if there is another operator near you with one you could copy the chart.

I have a paper copy but nothing in a digital format. When I get more time later I can type in the settings if you haven't found one yet.

Kirk

This is the response I received to a similar question;

"The power settings are in your Lycoming engine ops handbook.
Copy the appropriate graphs and blow them up 150% to read them.
Roughly 45% gives best loiter time, 55% gives best economy, and from there you burn more fuel for the extra speed attained with higher power settings.
With that 2400rpm J engine for work, I used to run at 23MP 2100rpm, or 22MP 2200rpm which give about 68% power on standard temp and a little over 12.5 US gph if I remember right."
_________________
Jeremy
www.maules.com
Maule AK Worldwide

We're looking at a chart for a 235 piper as a base line to work with, found the Lycoming book less than useful for this engine personally.

Thanks guys. I will see what i can track down. Appreciate the info.
Barn

Here's what I got from the Lycoming chart and use for the O540-J1A5D:

Climb power at 2300 RPM: 3000'=25 1/2", 5000'=25", 7000'=24 1/2", 9000'=24"

Cruise power 75% at 2200 RPM: 3000'=24 1/2", 5000'=24", 7000'=23 1/2", 9000'=23", 11,000'=22"

Cruise power 65% at 2000 RPM: 3000'=23 1/2", 5000'=23", 7000'=22 1/2", 9000'=22", 11000'=21" (note the 3000' setting exceeds the limitation of 23" MP below 2050 RPM. I just bump the RPM up to 2050 or just set 23" if I find myself in that range)

Cruise power 55% at 2000 RPM: 3000'=20 1/2", 5000'=20 1/2", 7000'=20", 9000'=19 1/2", 11000'=19"

It's all easier to use if you draw it out into a table which I have done. I wrote the limitations on that table also, so it's easy to see at a glance.

I also try to adhere to a Best Service Life reccomendation I read somewhere: 75% and above CHT435 max, less than 75% 400 max. Also, the sum of EGT plus CHT not to exceed 1825, though that one might be harder to adhere to strictly.

Kirk

Thanks Kirk, thats great info.

Many thanks Kirk.
Very helpful
Barn

A huge engine like the 540 used in a car would run smoothly with 1800 or even 1500 RPM on the highway. It saves fuel and preserves the engine.

So I tried it in cruise flight on my M6-235 on floats: Reducing power to 20 inches and 1800 RPM gives me 103 MPH, the EGT goes back and leaning it the fuel flow comes down to less than 10 GPH from 11 GPH, which the plane burns with 2000 RPM and the same IAS and the same EGT. As far as I understand, the green arc is not a limit for cruise power.

I come from Germany and energy saving is very important to people in Europe. Is it bad for the engine what I am doing?

this is a very good question.

when flying slow (ie- with cubs) i have personally always run power settings around 2100 rpm and 13-16". this nets me 95-100 mph and 8.5-9 gph on the fuel flow gauge. and if i need more power quickly i can just push the throttle in.
since you are already running "oversquare" you must now take time to adjust your powersetting. bring the rpm up and then increase mp in the event of a downdraft or a bird, etc...
what you are doing is similar to lugging your car up a steep hill in overdrive with the gas pedal on the floor. in this example you would actually get better economy to downshift and let the engine turn faster with less stress on it (less cylinder pressures). high cylinder pressures create heat, can be more prone to detonation, and can (in extreme cases) cause damage to the rotating assembly as well as the pistons.
my opinion is to just bring the rpm up and reduce the mp. your engine was made to turn. you are certainly not going to "wear it out" by running 2000 rpm rather than 1800 rpm. actually it could happen just the opposite. you may end up with premature bearing wear from the hammering of high cylinder pressures.
if you are going to continue experimenting with this i recommend full 6 cylinder CHT and EGT and fuel flow instrumentation.

If your an I/O and looking for min fuel burn, run it at 20 squared or so and lean the snot out of it, I can get down to 7.5 gl an hour or so. It will run smoothly at lower fuel flows, just doesn't make enough power to fly.
I do have the Gami's, and I'm sure that helps keep it smoother really leaned out.

UP-M5 wrote:this is a very good question.

when flying slow (ie- with cubs) i have personally always run power settings around 2100 rpm and 13-16". this nets me 95-100 mph and 8.5-9 gph on the fuel flow gauge. and if i need more power quickly i can just push the throttle in.
since you are already running "oversquare" you must now take time to adjust your powersetting. bring the rpm up and then increase mp in the event of a downdraft or a bird, etc...
what you are doing is similar to lugging your car up a steep hill in overdrive with the gas pedal on the floor. in this example you would actually get better economy to downshift and let the engine turn faster with less stress on it (less cylinder pressures). high cylinder pressures create heat, can be more prone to detonation, and can (in extreme cases) cause damage to the rotating assembly as well as the pistons.
my opinion is to just bring the rpm up and reduce the mp. your engine was made to turn. you are certainly not going to "wear it out" by running 2000 rpm rather than 1800 rpm. actually it could happen just the opposite. you may end up with premature bearing wear from the hammering of high cylinder pressures.
if you are going to continue experimenting with this i recommend full 6 cylinder CHT and EGT and fuel flow instrumentation.

I assume this is on wheels. on my m-5 with floats, 0-540, at 2100 rpm and 13-16" MP, im not certain i could even maintain altitude. I can get it down to about 2050 squared (with lower load in plane) and get 110 mph but any lower and the controls get pretty mushy. Fuel at this is about 10 gph. I agree on the RPM comments - tach is marked in green down to 2050 RPM so i assume this is the lowest they want you to go, other than for landing.

garth

gear wrote: I assume this is on wheels. on my m-5 with floats, 0-540, at 2100 rpm and 13-16" MP, im not certain i could even maintain altitude.
garth

garth,

2100/16in gives me around 95mph on floats. 2100/13in gives about 95mph on wheels, and low 8 gph fuel flows. i'm always having to fly this slow to keep up with my supercub and scout-tabria buddies this is with no flaps.

The O540 J and IO540 W engines,
Normal operating range 2050 to 2400 rpm.
Do not exceed 23"MP below 2050 rpm as this a propeller vibratory stress limitation.

Jeremy,
That's prop specific isn't it? Is it for all props, or just the two blade Hartzell?

It was originally written for the two blade Hartzell, but remains in the POH .
There was no POH change called for when we got the McCauleys certified so I would have to scrutinize the STC manuals to see if there is any mention of it when I get a long moment.
The 2050 is not really restricting as one would not normally want more than 23"MP if running below 2050rpm. In a go around the prop control leads the throttle anyhow.
The other entry in the POH is not a restriction as I read it but an advice.
'Normal' operation 2050 to 2400 rpm.