Reasonable performance update with McCauley Scout prop

[Chris in Milwaukee]

So, looking back on aero101's post about a Scout prop as a nice performance upgrade for us fixed-pitch solid-crank 180 guys, I embarked on a mission to see what data supported this update.

It seems as though Burl's Aircraft has a 180hp STC for the Aeronca Sedan that calls out the McCauley 1A-200-DFA-8244 prop as suggested. However, none of the O-360-Cs are on the list.

http://www.burlac.com/hp_conversion.html

But because I'm a Googling idiot, I led myself down this rabbit hole:

https://www.lycoming.com/sites/default/ ... ngines.pdf

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O-360-C4F : 180 2700 100/100LL 8.50:1 : Same as –C1F except has solid crankshaft and no provision for prop. governor

O-360-C1F : 180 2700 100/100LL 8.50:1 : Same as –A1G with conical mounts and Slick Magnetos

O-360-A1G : 180 2700 100/100LL 8.50:1 : Similar to –A1F but has horizontal carburetor and induction housing

O-360-A1F : 180 2700 100/100LL 8.50:1 : Same as –A1A with -1200 series Magnetos

O-360-A1A : 180 2700 100/100LL 8.50:1 : Dynafocal mounts

So with that family tree happening, is the -C4F a similar enough configuration of innards to the -A1A, and will technically accept this prop? Oversimplification, but hopefully the question makes sense. Just out here looking for the technical justification versus the "well, this guy on MaulePilots.org did it".

[Andy Young]

My Scout had a C2E from the factory, with the fixed pitch Mac, if that. Helps you get the genealogy closer.

[Chris in Milwaukee]

It certainly does. Aside from aero's installation, I've not heard of anyone else doing it (at least here). But at ~$6000 for a new prop, it sure beats the heck out swapping to a C/S setup.

I presume that one would have to reference an STC/337 running a similar setup before it would be considered by the man. So I was looking for something published that would get a fella close.

[Andy Young]

The type certificate is A21CE. Under the Scout section, it lists the O-360-C2A, C2E, C1A, C1E, and C1G

It lists the 1A200HFA80 propeller.

Should be able to find the type certificate on the FAA site, though I found it quickly here:

http://www.luscombeassoc.org/tc/Aeronca ... 08KCAB.pdf

[Chris in Milwaukee]

Hmmmm, it does, doesn't it. Not the same prop that was referenced above. The mystery thickens...

[Andy Young]

My understanding was that there was only ever one fixed-pitch prop certified on the 8GCBC Scout. If memory serves, it was an 80", 42 pitch.

[Chris in Milwaukee]

That’s what I’m gathering too. Maybe I can get that STC for the Sedan to work as reference data...

[Andy Young]

For what it’s worth, on the Scout I had to have the throttle back to about the 2/3 position in cruise just to keep the RPMs down to 2600 (redline of 2700). That gave me about 120 mph. A constant-speed Scout will go 140 mph. Great climb prop, but not a great cruise prop.

[Chris in Milwaukee]

Thanks for that bit of insight. Always a trade off, isn’t it?

The reason for this line of thought is to see if floats are an option with a 180 here in the flatlands. Lots of folks have said they’re marginal, and a 540 is the way to go. But if a prop can make enough difference, then I’m all ears.

[DeltaRomeo]

I would think that if your goal is floats, you won't have any cruise to speak of anyway with all that hardware dangling in the breeze below you. As such, a good climb pitched prop would fit your mission without the expense of replacing the engine and prop to get C/S.

I haven't seen any applications of MT's composite fixed pitch prop on a Maule, and outside of the factory combo's, there's really not a lot of options since our fleet is so small and the process for certification for anything "new" or different is so archaic. But I digress...

[Chris in Milwaukee]

I agree. On a good day, I’m lucky to get 115mph as it is!