I think most people swear that the APC props are the best, but now Master Airscrew has a Scimitar based propeller as well...what do people think

Probably APC will come out on top, ther are two reasons (IMHO) for this.. first few people had used the Scimitar series of props, second most advanced fliers uses APC or wood.
In my experience, smaller engines .91 and lower benefit from the Scimitar style over the APC for quicker acceleration and top rpm's the APC weights almost double so spool times are 'a bit' slower also for small displacement the less weight may result in longer life due to the lighter load.
Bigger engines whose torque far outweights the prop's weight are happy with the more stiff and heavier APC's.
At our field we have find that Scimitars (an regular) MA props survive better the day to day wear caused by nose-overs, rough landings, etc, etc while APC nick and break more easily.

Could you guide me to a source that explains the differences?

Thanks

This should be a good thread....

....it's kinda like....what kind of underwear do you prefer....

....Hanes, BVD's, or Fruit of the Loom....
....do you like Fords, Chevy's, or Chryslers...
....what kind of fuel do you prefer....
...what's your favorite brand of engine....ect....

APC's will probably win the poll....they seem to be accepted
by many....mainly, I think, because they are "modern looking".
I'm a bit old fashioned, I guess....and prefer the conventional
style props. I've been using MAS since they first came out,
as well as Top Flight "Power Point's", and Zinger wood props.

I just got some of the scimitar type props today from Tower,
just to give them a try...10-7, 10-8, 11-8, 12-8, and 14-8.
I tend to use smaller props than most....with the most
pitch the engine will pull, and I think that my elevation at
3,000 ft., and the dry desert air....makes things a bit different.

For instance....I run 12-9's on .90 four strokes. Some of
the guys are using 14, and 16" props. The 12-9's don't
even unload fully in the air. (thin as it is) Another example,
I use 14-8 on an OS 1.08 FSR.....which probably makes
twice the power of a .90 4-stroke....YS's excepted....
some guys run 16 and 18" props on them.

So, don't ask me....I prefer the conventional type props....
I've used the APC's as well....and haven't found any advantage
with them.

Dave.

Hey what about Graupner props? I seem to get great results with those on my YS 4-strokes.

Shouldn't the small tips on APC props be a concern since they push very little air volume? So a 15x8 APC is almost equivalent to a 14x8 Graupner or MA since the tips on an APC do little work. Maybe this is why APC props generally spin at higher RPM than the others because in effect, APC props have "smaller" effective diameter.

Richard L. ....

....<Flame suit on>....

....I always "heard" that most of the thrust from a prop
comes from the tips....yet the pitch at the tips of an APC
is almost non-existant, I don't get it.... The "meat"
of the APC's seems to be near the hub, but....unfortunatly
the "hub" was mostly covered by my spinners.

Although others will disagree.....I've never seen an increase
in RPM, speed, acceleration, or climb with the APC's....

Dave.

My favorite sport props are the Bolly Clubman series.

They offer more static and dynamic thrust than the other makes.
Compared to comparable props from APC and MA, they produce better performance, despite the lower RPM, from their +1/2" diameter.

They survive minor ground contact without adversely affecting their performance.
In addition, they are only marginally more expensive than MA.

The APC props are efficient and produce good top speed, but ANY ground contact can spell a new prop and they cost more.

MA standard (up to 11") props produce less thrust, but withstand minor ground contact. But despite being minor, the slight tip damage has a profound effect and reduces thrust very significantly; much more than in Bolly props, where it isn't noticeable.

...Yes Dave, the tip produces most of the thrust in MA props. In Bolly, it is probably the 70-80% station.

I'm in agreement with Dave and Richard, I have several APCs but have only used them on the bench, most of my flying is done with Graupners, and most of them are three blades.

Hanes...
International Harvester....
15% Cool Power (20% oil)
O.S. (so far)



I usually try the MA, APC and wood Top Flite props in varying sizes on each engine/airframe combination. I've found that, for instance, my Advance 40 with an OS FS52S likes a 12-7 APC. This same engine on one of my SPAD DPS's prefers a 12-6 MA (standard one, not the K series). I'll be maidening[:-] this same engine on an Eindecker this weekend and I wouldn't be a bit surprised if it wants something different.

I think it boils down to each engine and airframe combination as to which is best. Try several and see what you like.

Disclaimer: The above results are from a purely un-scientific testing session and the results posted are based on the testing un-scientist's "gut" reaction. This test should carry a lot of weight in the RC community because of the testing un-scientist's enlarged gut.[X(] You're mileage may vary....

Have fun!

i see an increase in speed climb and rpm when i use APC.......i like them......they are heavy but they are sharper.......if apc made there prop in carbon fiber then it would probly be the best but then they would be way too expenaive.