I am wondering what the difference in performance is between APC and MAS props of the same dimensions.

For example, I am moving to a 10X6 prop from an 11X5 for my 40LA on an LT-40.

Would an APC 10X6 be different from an MAS 10X6 in terms of performance?

Just curious, thanks in advance.

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An APC propeller will out perform a MAS propeller.

Yep APC over MAS any day but i prefer Bolly over both of them, not only that the Bolly are cheaper as well (at least in AUS they are)

Lucky you, until you qualified where you lived, I was going to ask you where you shopped!

Master Airscrew props outperform APC in only ONE area: they are STURDY. APCs are noticeably quieter and, I believe, more efficient. But a Newbie should not be worried as much about anything more than getting more flight time. You can bounce the MA off the runway a few times and still fly it-but the APC will lose a tip.

ALSO, the MAs are sold with the mold parting line not fully removed. They are SHARP. Scrape off the parting line with a sharp knife on the leading AND trailing edge. APCs are sharp at the tip because they are thin for efficiency, but they are molded more carefully than MAs.

I use a lot of both. As stated, APCs tend to spin up better. I find myself using them a lot more than MAs any more. The shorter prop you are switching to will give you more RPMs no matter which you use.

Hmm, I've always found that moveing from MAS to APC causes a REDUCTION in RPM, but an INCREASE in thrust most of the time.

RPM wise, I find an APC prop is about equal to a MAS of one higher pitch, so I'd expect a MAS 10x7 to rev about the same as an APC 10x6. But the APC will pull harder in most kinds of flying. The APC is certainly more efficient and quieter. So, most of the time, for best performance, try the APC. The MAS is a lot stonger though.

I have found that APC propellers run at a higher RPM than MAS but I am using 20x8 and 20x10 propellers.

I have tried APC props on 32 and 40 size engines and lose too much rpm to be usable because the APC props don't flex when the rpms go up. They simply try to move more air increasing the load on the engine. Based on my experience I won't use APC props on any engine smaller than a 46.

Yeah, the size ranges I've compared APC props in is 7" up to 12", though not all sizes in that range, and not all in what I would call "consistant" conditions. I've no clue about props in the 20" range, things could easily change quite a lot in different size ranges.

Flexing of the prop tips is a bad thing, not a feature. It causes noise and burns off energy in movement and noise instead of moving air. I agree that the smaller APC props do load the engine more, so, if you want to unload it, go to a slightly smaller prop.

It's also worthwhile to keep in mind that RPM does not equal power output. I've found that turning an APC prop at a lower RPM usually results in better all around performance than a screaming MAS.

There are, however, exceptions. I run MAS 9x4s on all my .25 and .28 combat engines. An APC 9x4 is too much load, an APC 9x3 isn't quite enough. But combat flying pushes the envelope in different ways than some other types of flying. And then there is the durability issue. Combat flying has some unique prop durability "issues" that other flying doesn't have to deal with

So you really should pick a prop based on your specifc uses. Buy one of each, fly em, and see. That's the ONLY way to know for sure.

My OS .32F engines on a Macs pipe or mousse can just LOVE the APC 10x5. more thrust than you know what to do with, and plenty of speed.

YMMV of course.

at 13000, you would gain .29 lbs of thrust by switching to apc. a .40 la will crank that. However, you would only be getting .942 hp.

Where are you getting those numbers?

In my experience, bhp is pretty useless as a measure of how an engine actually pulls your plane. Way back in the day, engine makers and reviews would hook up engines to dynometers to get real HP numbers. But they discovered along the way that it wasn't really all that helpful when picking an engine anyway, so no one bothers with that anymore.

Also, most thrust calculators I've seen are "best guess" or have built in assumptions that might or might match your personal reality. For example, all engines "unload" a bit in the air, and pick up some RPM once off the ground. However, not all engines unload the same, not all props unload the same, and the weather conditions and air density at the moment can really affect things as well.

I'm not saying the numbers are wrong, I just want to know the source.

It is thrust hp. you can edit the air density. It is a static thrust measurement, not how much it will pull in the air, compared to a plane.

You're kidding right?

If your RPMs are too low, don't go to a cheap flexible prop. Go to a better size. You want a prop that will move more air, not just flail around and give you more RPMs. APCs are all I run on my smaller engines (less than 1.2) because they give the best performance. The bigger sizes are a little heavy IMO so I use wood or composite on my larger engines.

What other propellers do you guys use?