Operating O-540 engines in Maules

[Flyin'Dutch']

Question for those with experience with the O-540 engines.

We used to fly the Lance (IO-540) full throttle full fine for take off and after the initial climb leave the throttle full open and just pull back the rpm to 2500.

I can not find anything in the POH to say that a similar technique is not allowed in the Maules.

Full Throttle with 2200 rpm is permissable in the Lycoming table as far as I can see and insures that you get the extra fuel for cooling in the cylinders, something that you would miss if you pull the throttle back to say 25"

Anyone care to comment?

[Kirk]

I have the O540 J1A5D which turns pretty slow. Climb power by the Lycoming tables starts @ 25 1/2 "/2300 RPM.
all that I have read an heard leads me to believe there is no reason to worry about running these engines "oversquare"

Kirk

[a64pilot]

I'm an IO, but I'll leave everything firewalled in the climb, leaning to maintain T/O egt until I get to cruise altitude and then reduce to 2300 and lean to 50 ROP. If I'm travelling, my first throttle reduction is when I let down to land. Firewalled for me isn't but 2400. Why would you want to reduce to 2200 in the climb?
I cruise climb at 100kts. for cooling and to try to cover ground. To keep a decent rate of climb at that speed requires 2400 RPM. The only time I'm at 2200 or less cruising is if I'm just tooling around wasting time. Yes you do burn less fuel at lower RPM, but if you have a fuel flow meter, you'll find your MPG isn't much changed. You'll get almost identical MPG by reducing manifold pressure to the same airspeed. As far as I can tell, airspeed is the biggest factor in fuel burn or MPG.

[Flyin'Dutch']

Why would you want to reduce to 2200 in the climb?

Noise!

We generally operate at 65% or 75% the extra fuel one uses by running at 75% gives only a few knots extra in speed.

[TomD]

It was hammered into my head to keep the noise to a minimum when I was flying floats out of Lake Washington.

As a result once I get to an altitude that looks like I can make a safe emergency landing, I pull back the RPM to keep the noise down then back off the power to about 75% or 80% if I don't need to climb rapidly.

Not as big an issue w/ three blade but two blade 80" props make a huge racket at full RPM.

We of course now have new neighbors who just noticed that an airport was next to the house they just bought and the noise from our planes are infringing on their rights right along with the smells from the dairy barn that has been there about as long as the airport.

[Wayne]

Drop them a few COW pies to make them feel more welcome to the neighborhood.

[a64pilot]

Yeh, noise, I guess. But anybody that has heard a C-185 with a seaplane prop turning 2750 RPM or more realises that nothing I can do at 2400 RPM is noise with my three blade scimitar.
I had never thought of a Maule as noisy, but I guess the low compression O-540 does turn guite a lot higher RPM doesn't it.

[TomD]

Huge noise difference between a big two blade and a three blade.

A C185 at full throttle will rattle your fillings at about a mile. The Kenmore phone lines light up like a Xmas tree when some 185 jock hammers it out of the lake at full throttle max RPM on an early take off.

I was on Isabelle one afternoon when a C185 made multiple attempts to take off. Followed by a M7 w/ a three blade. The difference was amazing.

TD

[Flyin'Dutch']

I was on Isabelle one afternoon when a C185 made multiple attempts to take off. Followed by a M7 w/ a three blade. The difference was amazing.
TD

Not just in noise!

[a64pilot]

Now if you want to hear loud, we are building the old 1340 Thrush again. The P&W 1340 with the 12D40 prop turning at 2250 RPM takes the tips transonic, I believe the 185 does also.