formandfunction wrote:100 low lead! That is the problem facing the 80% of the ga industry that doesn't require high octane fuel. Maybe more than 80%. I don't know,just what I've read.
Reality is a small low compression engine requires high power settings just to initiate the reaction that removes lead from internal engine parts. There is a chemical in the fuel to aid in this process but it takes a decent amount of heat to work. They shouldn't even make the stuff or for that matter force us to use it by making it our only airport option.
Think about it for a minute,2018 and we are still using ww2 fuel.

In all fairness, most of the stuff on our engines is WW2 tech...

And good stuff. Given such low demand, vs cars or farm equipment, we are lucky to have it.

billjesstaylor wrote:........Aero101 ran a fixed pitch 1a200DFA 80X44 on his Maule 180A. Made by McCaully I think? If I got into a 180B I’d try to put that prop on...Unless there is something better performing?? ....

Bigger is usually better when it comes to props and out of the hole pulling power.
An 80" prop isn't all that big for 180hp IMHO.
FWIW I was at the NW Supercub fly-in a few years back, and a guy there was running a 90" fixed prop on his 180hp Supercub.

The "borer" prop for a 150/160hp Supercub is an 82" Mac,
I'm not sure and can't seem to google it up right now but I want to say that the borer for a 180hp SC is an 84".
Dunno about approval for a Maule though.

Catto seems to be the go-to prop for STOL guys now, but I'm not sure where he's at on getting them STC'd.
You might wanna look into one of those.

Billjesstaylor, The MX7-180A is a fixed pitch whilst the MX7-180B and C are constant speed, so Aero101 prop won't work on the latter.
A 180hp and 235hp flying at same speed together, with same drag factors (tyres, antennae, vgs etc) will use about the same amount of fuel.
The difference is in engine set aside cost of $10.50 O360, $15 O540, $17 IO540. The IO540 is more efficient by a gal or two per hour than the O540. However the IO W and O J engines at max 2400 rpm last a long time . Think pieces of metal sliding or rotating past each other at 2400 times per minute versus 2700 times per minute.

The O is also STC'able for Mogas and the I is not, IIRC.

Given that Mogas will go away someday I factor that into purchace decisions.

maules.com wrote:Billjesstaylor, The MX7-180A is a fixed pitch whilst the MX7-180B and C are constant speed, so Aero101 prop won't work on the latter.

Thanks for the info Jeremy.

Are there any other big props that guys/gals are putting on their 180B c/s engine???

billjesstaylor wrote:

maules.com wrote:Billjesstaylor, The MX7-180A is a fixed pitch whilst the MX7-180B and C are constant speed, so Aero101 prop won't work on the latter.

Thanks for the info Jeremy.

Are there any other big props that guys/gals are putting on their 180B c/s engine???

MT has a 83" and 80" Ultra for the 0-360. They also drop about 20 lbs off the nose from a 76" Hartzell and don't have the 2000-2250 RPM limitation like the Hartzell. They are spendy, I put an 80" Ultra on a 180hp Cessna 172, it was worth every penny after it was on.

I have had all the MT props on my 2 Husky's over the years, great props! Stick with the 2 blade for better all around performance. The MT Ultra is an incredible prop and would be my choice on a 180hp Maule.

I run low power settings in my Husky, all settings are over square, I never run under square. I run in the 50-55 percent power range according to my MVP-50 engine monitor. I normally use 1850-1950 RPM and 21 to 24 inches, these power settings yield amazingly low fuel burns at good cruise speeds for amazing miles per gallon figures that will rival a Mooney! At the power settings I am seeing 5.0 to 7.0 gallons per hour and 105 to 120mph speeds in a 180hp Husky. All temps are in the green and I regulate my oil temps at 180-195 degrees with my oil cooler shutter I control in the cockpit. My EGT's and CHT's are always within limits. I have had no issues with fowling plugs (fine wire tempest, NO Champions) or any other issues, I lean aggressively, I am a believer. I have hundreds of hours running this way.

As for longer props and more blades, they may pull harder (and sometimes not) but the extra length or extra blade is more drag at cruise and you will sacrifice speed for possibly increasing lower end pull. Its best to have a good prop that is matched for your mission, the MT Ultra is fantastic in this regard.

Hope this helps

Kurt

With this thread in mind, I flew the M7-235C a couple days ago along the beach outside Huatulco.

The bottom of the green arc for this Lycoming O-540 B4B5 is 15 inches and 2200 RPMs. This burned about 8.3GPH according to the totalizer.

rw2 wrote:With this thread in mind, I flew the M7-235C a couple days ago along the beach outside Huatulco.

The bottom of the green arc for this Lycoming O-540 B4B5 is 15 inches and 2200 RPMs. This burned about 8.3GPH according to the totalizer.

And what kind of speed were you getting at that power setting?

Kurt

G44 wrote:

rw2 wrote:With this thread in mind, I flew the M7-235C a couple days ago along the beach outside Huatulco.

The bottom of the green arc for this Lycoming O-540 B4B5 is 15 inches and 2200 RPMs. This burned about 8.3GPH according to the totalizer.

And what kind of speed were you getting at that power setting?

Grr! I knew I was forgetting something when I wrote that! Bad pilot, no cookie!

Very slow. Somewhere in the 80-85kts range.

What’s a Knot? I thought that was a unit of measure requiring a rope and a log[emoji16]

The Bearhawk designer (and engine builder) is quite fugal and flies around at 19sqrd in his 540 Bearhawk. He has no concerns about engine harm at those low settings. Claims 7.5gph and 120mph.

Wow! A lot of you guys are getting really good good fuel burns. I didn’t realize you could get it down that low and still moving at around 95mph.

Like I said, for me, I prefer low and slow. It’s nice to enjoy the views and look where I’m going, rather than have to look back to see where I’ve been.

rw2 wrote:

G44 wrote:

rw2 wrote:With this thread in mind, I flew the M7-235C a couple days ago along the beach outside Huatulco.
The bottom of the green arc for this Lycoming O-540 B4B5 is 15 inches and 2200 RPMs. This burned about 8.3GPH according to the totalizer.

And what kind of speed were you getting at that power setting?

Grr! I knew I was forgetting something when I wrote that! Bad pilot, no cookie! Very slow. Somewhere in the 80-85kts range.

I thought Maules didnt fly in knots....