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Author Topic: APC props, my perspective...  (Read 7372 times)

Offline Andrew Hathaway

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APC props, my perspective...
« on: April 13, 2006, 10:58:42 AM »
I think they're a gimmick.  From the Wikipedia...

"A gimmick is a unique or quirky special feature that makes something "stand out" from its contemporaries. Product gimmicks are sometimes considered mere novelties, and not really that relevant to the product's functioning, even earning negative connotations. However, some seemingly trivial gimmicks of the past have evolved into useful, permanent features."

Think about propellers, specifically model propellers, our uses, our needs, etc.  Think of all the varieties that have been available over the years.  Which ones really worked well and which don't?  It seems to me that the old Top Flite wood props, and Rev-Up's have a very strong following.  If you watch what they go for on Ebay it reinforces that people are paying well more for these older discontinued props then list prices on currently available propellers.

The APC prop came out with this ad campaign talking about how they're more efficient, computer designed, durable, etc.  But the question I ask is do we really need these features?  Does an APC work better than a 30+ year old Top Flite? In my own personal experience the APC is just about the worst prop for stunt. 

I don't like them because they're heavy.  Think about this a bit.  A typical APC prop weighs MUCH more than a similar size wood propeller.  That's more weight the engine has to turn, more drag.  The automotive industry would refer to it as reciprocating mass.  To see how important its viewed in that application look at light weight wheels, aluminum brake parts, aluminum driveshafts, light weight crankshafts, etc.  Further, its weight on the crankshaft, which is going to translate into more heat, more friction, etc.  Also if the prop isn't balanced the effects will be more pronounced because of its excessive weight.  Obviously this is more important with a plain bearing engine then ball bearing, but still a concern.

Beyond the weight, there are reports of offset mounting holes.  If the APC propeller is so much more advanced, and computer designed, why is the ball dropped on what should be a fairly simple operation of putting a hole at the center?

Lets talk about the durability.  Obviously for stunt usage, we're not building or planning for a crash, so how important is durability?  I'd say its not.  However if an APC prop touches ground in a hard landing or soft crash it might not shear a blade, but look closely and it will usually display stress cracks that appear as white marks inside the blade.  They have to be examined closely, sometimes they don't show up unless you gently flex the blade.  This makes them dangerous. 

So basically I can only see a couple advantages.  They're cheap, available, and can be had in a multitude of sizes.  Are there better props out there for what we're doing?  Obviously.  So why are they so popular? 

I have used APC props.  The only stunt configuration I still use them on is the FP20.  Otherwise I only use them on small sport planes (.15 size) and carrier planes.  Just about any wood prop seems more tailored to our needs, and of course there are the high dollar carbon fibre props.  For cheap goofing off props, the Master Airscrew props work very well at a significant weight savings over the APC.

I'm tempted to also point out the gimmick nature of the current Top Flite Powerpoint, but since I haven't used them much at all, and I have one plane that seems to like the one on it, I'll give it a bit more time before I come to a conclusion.  However I will say that I've seen some PowerPoints that should have never made it past quality control.

I'm afraid we get roped into buying these gimmick products because the RC crowd buys into them and they're available.  n1

Offline Ironbomb

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Re: APC props, my perspective...
« Reply #1 on: April 13, 2006, 11:39:52 AM »
For a 3 dollar prop, they are pretty good for me. I have tried Top Flights Power Point, Zinger Pros, and Master Airscrews in varing diameters and pitch, and nothing has made my airplanes grab the air and stay there like the APC props do. I thought my Cardinals stunk and I built crap until I tried the APC props after a suggestion, and it has made all the difference. I am pretty sure a $12-$30 prop is superior, but not for me while I am still breaking them on a regular basis. I dig the hell out of the APC propeller.  Just my take on it.

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Offline Bill Little

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Re: APC props, my perspective...
« Reply #2 on: April 13, 2006, 12:05:01 PM »
I think thee are a lot of variables as to "which" prop is best in each usage.  While I use CF 2 & 3 bld. props on my Pipe engines, I use a lot of different props on other engines. 
The FP 20 loves an APC 9-4.  A couple of other "schneurle" engines in the "35-36-37" range like the 10 1/2-4 1/2 APC.
The LA 46 loves a 12 1/4-3 3/4 trimmed a "little".

My "Old engines" do not seem to tolerate them well, or I just haven't found th eright PAC for them.  Some guys do have great success with the APCs on Fox 35s and such.

The "one" brand that I could never seem to make work is the black glass (??) Master Airscrew props.
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Offline Louis Rankin

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Re: APC props, my perspective...
« Reply #3 on: April 13, 2006, 12:27:42 PM »
If you have an OS 35 or 40 FP the APC 10.5X4.5 will make these engines come alive.  APCs are great props!!!!!!!!!!!!!
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Offline Ron Hofacker

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Re: APC props, my perspective...
« Reply #4 on: April 13, 2006, 12:43:58 PM »
Maybe I missed one of your points, but I don't see how the weight of the prop contributes to "drag". It would certainly contribute to gyroscopic effects. There are many variables in matching a prop to an engine/airframe combination. Load on the engine, installed net thrust, mass properties, twist distribution, blade area. blade planform, blade airfoil, etc., etc. The APC props do have a thinner airfoil than wood props which may or may not be a good thing depending on your specific needs. The Top Flite Power point has a notoriously thick airfoil. My diesel loves 'em. The "pros" for the APC include availability, low cost, very wide selection. The "cons" include weight and sometimes poor QC. Because of the weight (rotating mass) factors I usually start experimenting with wood props. But I still include APC props in my search for the best performing prop I can find. I don't generally have the funds needed to experiment with a bunch of CF props.

Offline Andrew Hathaway

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Re: APC props, my perspective...
« Reply #5 on: April 13, 2006, 01:28:14 PM »
I want to make it perfectly clear, I'm not trying to ruffle any feathers.  So far it doesn't look like I've angered anyone with my comments, which is good. 

I see drag entering the equation when dealing with a heavier prop because gravity will pull the crankshaft against the bushing or bearing surfaces, accounting for drag.  While it probably doesn't make a huge difference, every little bit counts.

From my experience the APC and the Fox 35 is a serious no-no.  On the 35-40 FP's all the problems got worse with the APC's.  In fact I think the FP's worked better for us before we started trying all the fixes.  Back when we were running Rev-Up 10x6EW's and 11x4's the FP's worked really well. 

On the 20FP I've run somewhat extensively the 9x4 or 9x5 APC works well, but I had better luck with a Zinger 9x4.6.  I found equal performance from the Master Airscrew black plastic 9x4 as with the APC, but continue to run the APC for compliance with the popular tune up. 


Offline Jim Thomerson

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Re: APC props, my perspective...
« Reply #6 on: April 13, 2006, 02:50:06 PM »
I'm a considerable fan of APC's.  In my search for the best prop for a particular engine/airplane, I usually start out with APC's and usually end up with APC's.  I have been surprised a time or two, so I am more open minded than I used to be.

Offline Scott Jenkins

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Re: APC props, my perspective...
« Reply #7 on: April 13, 2006, 03:37:10 PM »
APC props do have a place in our hobby most of the racers I know like them due to the assortment of pitches available. I think it is quite a bit better to be able to spot a problem with a prop by the change in color of an affected area that to miss a hairline crack in a wood prop only to find out it is a problem when the prop, engine and plane exploded  midair. I use to use Zingers almost exclusively for combat and racing due to the range of pitches available. Then APC came on the market and you could write or call them and say you would like to see a prop with a half pitch difference in a given size and if they got enough calls. They would make a new mold and you got your prop, that's good marketing on their part. If you are running old engines or the venerable Fox 35 yes stick with props of that era if you are running new engines for sport or combat and racing events then an APC may give you the satisfaction you want.

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Offline john e. holliday

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Re: APC props, my perspective...
« Reply #8 on: April 13, 2006, 08:46:51 PM »
Well I say APC props have their place.  A 10-6 APC made the Dragon a different airplane.  The OS 35S in the Falcon 35 loves the Zinger 11-5.  The RO-Jett 40 is working like a champ with the prop I got from Richard.  the little LA 25 is happy with a Power Point 10-4 on the Primary Force.  The ARF Nobler loves the Power Point 10-6 on it.  Each and every plane is different and works different.  Got to go to work.  DOC Holliday
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Offline Kreth

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Re: APC props, my perspective...
« Reply #9 on: April 14, 2006, 06:08:58 AM »
I'm sure there are a lot of us that wish we had loads of the old revups.  There are also plenty of us that realize that APCs are a quantum leap past Master Airscrews.  If you cannot see and feel the difference in performance between these two - give up.

Kreth
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Offline Bob Kruger

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Re: APC props, my perspective...
« Reply #10 on: April 14, 2006, 07:35:26 AM »
I don't like them because they're heavy.  Think about this a bit.  A typical APC prop weighs MUCH more than a similar size wood propeller.  That's more weight the engine has to turn, more drag.  The automotive industry would refer to it as reciprocating mass.  To see how important its viewed in that application look at light weight wheels, aluminum brake parts, aluminum driveshafts, light weight crankshafts, etc.  Further, its weight on the crankshaft, which is going to translate into more heat, more friction, etc.  Also if the prop isn't balanced the effects will be more pronounced because of its excessive weight.  Obviously this is more important

Andrew;

As for APC props, yes, there is greater reciprocating mass, and yes, APCs sometimes need a little work in terms of balancing.  And that greater mass is probably harder on the conrods and the case bushings.  But when someone like Marvin Denny, who knows how to make a Fox do things most of use just imagine, goes with an APC 10-5 for his Stunt 35 setup, I tend to take notice.

At the same time, I do wish someone would come up with a CNC wooden propeller cutting/shaping device that could be easilly programmed for different diameters and pitches and make some nice props the quality of which we have not seen since Clarence Bull left us.

V/r

Bob

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Offline Andrew Hathaway

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Re: APC props, my perspective...
« Reply #11 on: April 14, 2006, 11:08:51 AM »
I'm sure there are a lot of us that wish we had loads of the old revups.  There are also plenty of us that realize that APCs are a quantum leap past Master Airscrews.  If you cannot see and feel the difference in performance between these two - give up.

Kreth

For resale? or flying?  I can't see any substantial difference between the Master Airscrew and the APC.  Well, except that when I use an APC on a Fox 35 they burp, lines go slack in maneuvers, and the plane generally flies like a wreck.  Guess that's why I've given up on the APC in that application. ;)  On the other hand, my Fox 35's run great with the Master Airscrew 10x6, Zinger 10x5, 10x6, 10x6W, Rev-Up 10x5, 10x6EW, etc.  Maybe it's just a placebo effect, but they really don't work for me.

Marvin's Fox 35's run great, I can't debate that.  Mine don't run the same way.  I wouldn't attempt to emulate his performance or setup because it's unlikely that most parts of it would carry over to my own engines. 

If a 10" APC prop didn't weigh as much as a 2x4 I'd probably be more inclined to run them, however on a profile with a Fox 35 I feel its too much weight for the platform to handle.

Again I'm not saying anyone else is wrong, just providing a less popular opinion.  I realize my opinion is outnumbered but nothing should ever go unchallenged.

Offline Marvin Denny

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Re: APC props, my perspective...
« Reply #12 on: April 14, 2006, 11:44:22 AM »
  Andrew is correct in that the APCs are heavy.  Too heavy for the Fox35???  I don't think so as far as causing a failure of the crankshaft or main bearing when used as most of our stunt planes are used.  You put one on a Bi-Slob, and wring it out a couple of years, and you can expect a "one-piece" crankshaft to become a "two piece" shaft.  The same thing goes for putting either a Prather  weight or Higley Heavy Hub on one and wring it out. The spinning weight out front DOES put a serious load on the shaft.
  Every time I hear of the APCs (or ANY props) having either a pitch or off center hole problem, if the problem is in the sizes that I use, I go out to the three hobby shops in my area and buy several of every size that I use and check them for the problem.  I have NEVER found any APCs with the High/low pitch nor the off center shaft hole.  That is not to imply that it doesn't exist, but that it is possibly not as widespread as some might think.
  I cannot fathom why Andrew's engine would burp on an APC and not on a Master Airscrew???  When I have a Fox 35 that burps,  IT BURPS ON ANY PROP!!! Also, I do not do much to my Fox 35s to get them to run well, contrary to a lot of nasty rumous.

  Bigiron
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Offline RandySmith

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Re: APC props, my perspective...
« Reply #13 on: April 14, 2006, 12:36:37 PM »
Hi All

I will add this I have seen over many years, several Foxes that ran 100s of flights with wood props, then a heavy plastic prop was tried and  , you guess it, the  crank broke. Matter of  fact if you want a  great recipe for breaking FOX shaft, just use 15% fuel and a heavy plastic prop.

REgards
Randy

Offline Scott Jenkins

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Re: APC props, my perspective...
« Reply #14 on: April 15, 2006, 09:46:19 PM »
On a side note I have been shaving with a 7.8x7 since 2001 ;D

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m) During the refuelling and the restart of the motor, and until the time when he releases the model aircraft, the mechanic must keep the model aircraft in contact with the ground by at least one point and with the centre line outside the flight circle. During that time the pilot must be crouching or sitting inside the centre circle. He keeps one hand on the ground and his handle and his lines as close to the ground as defined by the F2C panel of judges until the model aircraft starts again.

Offline Jim Thomerson

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Re: APC props, my perspective...
« Reply #15 on: April 16, 2006, 05:54:01 AM »
Back when I ran Foxes, before there were APC's, I think, I found an 11 x 5 W Zinger to be a good prop for larger airplanes, and the  10 x 6 of the times to be better on small airplanes.   I always ran heavy hubs on my Foxes without any problem (I build tail-heavy airplanes).  I have seen two Fox stunt 35's break; one the rod, and one the crank, so they can break, although I have not experienced it personally.

Offline dirty dan

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Re: APC props, my perspective...
« Reply #16 on: April 16, 2006, 03:26:07 PM »
I must admit that I am a bit taken aback by the premise put forth in opening this thread.

By and large, APC props are terrific!

Is there an APC prop which is the best for every application? Clearly not. But just like the situation with glow plugs--if you had only one to choose from it would the O.S. #8--and with props if one had to limit his selection to one manufacturer, clearly it would be APC.

This deal about the holes being off-center in some APC props--mostly small-diameter props in my experience--has been hugely overplayed.

Yes, this is a (minor) problem with 9-4 APC props, a problem easily resolved by making a drill guide. I am pretty sure that if one were to chase down this problem it would turn out that Landing Products makes large runs of props at a time, they got a final op wrong one time, but the stock level is high and/or they simply don't know about the problem.

Remember, this is a company known for high-quality, exceedingly consistent props which actually work. I can readily forgive them a couple mistakes. (There is a certain size of AMA Combat prop which has the off-center problem.)

When it comes to wood props, I like 'em, especially on Classic models powered by Fox 35s. But even when Clarence was making the B-Y&O line, if you were serious at all you didn't just bolt on one prop and go flying. Ideally, you took a whole bag and flew each one of them...

Wood is not dimensionally stable, you know. Even Clarence couldn't overcome that physical fact of life.

However, with the APC props--and other lines, granted--if you like that APC 10-5 on your Fox 35, ideally an engine fitted with Randy's High-Zoot crankshaft, and it gets buzzed-down on takeoff, merely bolt on another new prop.

Amazing consistency.

With what "really" worked so many years ago...I wonder.

I have nothing more than anecdotal evidence to offer, but then I am refuting other anecdotal evidence, so it's all fair...

Mike Conner is a good friend, a serious trader of modeling goods, and he has a very fine eye when it comes to trim. We were at the NW Regionals a couple years ago and Mike give me a double handful of three different sizes and styles of props to try on the 20FP w/BB T-U. I cannot remember the sizes, but do remember Top Flite "Power Props," "Super-M" and (I think) some standard Top Flite props.

Anyway, these props are known to be good 'uns. Because that is the way they are remembered. And in Mike's specialty, Nostalgia FF, these same props are regarded as the best for grabbing altitude.

To be honest, I didn't do much with these props. Finally Mike and I were together at Arlington (WA) and I owed him some tests.

We bolted on one of these props of legend. The Pukey Profile went 20 feet and I knew the prop was a dog. Mike claimed that he had the same sort of insight after the model had traveled a mere 10 feet. And I believe him.

We tried the other props. Truly, it was amazing how badly these apparently similar props performed. Not even close...

Gimmick, APC props are a gimmick?

C'mon...

Dan


 
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Offline john e. holliday

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Re: APC props, my perspective...
« Reply #17 on: April 16, 2006, 03:46:00 PM »
Randy & Jim;  If you were at VSC this year on Saturday you seen Jim Lee doing his thing with a Bi-Slob.  I do not know how many flights Jim has on that Fox 35 Stunt.  But, the shaft broke at an angle acroos the port hole.  I have never seen Jim use anything but wood on those planes.  Maybe if Jim sees this he might give more history on the combination.    Later,  DOC Holliday
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Offline Steve Scott

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Re: APC props, my perspective...
« Reply #18 on: April 16, 2006, 08:04:58 PM »
I've converted over to the APC props 'cuz everyone told me they were loads better than the Master Airscrews I had been using.

There is a local guy here in the Twin Cities tooling up to release a batch of RevUp clones done in carbon fibre.  Should be available later this summer.  He already has an impressive line of composite props in a wide variety of diameters and pitches.

Goes by the trade name Eliminator props - swilk@cpinternet.com.


Offline Joey Mathison 9806

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Re: APC props, my perspective...
« Reply #19 on: April 17, 2006, 06:08:37 AM »
those elimanator props are very hi quality. the speed guys use them
200 mph man ama#9806 joey mathison

Offline George

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Re: APC props, my perspective...
« Reply #20 on: April 17, 2006, 07:55:01 AM »
On a side note I have been shaving with a 7.8x7 since 2001 ;D

Scott Jenkins
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Scott,

I think this went over some folks' head.  Good point...

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Offline Jim Thomerson

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Re: APC props, my perspective...
« Reply #21 on: April 17, 2006, 09:16:05 AM »
It is good to have a glove on when flipping an APC.  If you flip bare handed, flip with the tip of your finger on the front of the blade, not curled around the trailing edge.  Trust me!

Offline Andrew Hathaway

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Re: APC props, my perspective...
« Reply #22 on: April 17, 2006, 10:45:34 AM »
Since posting this thread had the probability of going down like a Ford Vs Chevy thread, I'm pretty happy with the results.  I doubt any diehard on either side of the issue is going to give any consideration to either viewpoint, but perhaps the middle of the line folks will get some ideas.

PS:  I broke a APC prop this weekend, and it felt GOOD.  >:D

« Last Edit: April 17, 2006, 11:02:19 AM by Robert Storick »

Offline RC Storick

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Re: APC props, my perspective...
« Reply #23 on: April 17, 2006, 11:02:35 AM »
This is my first post on a subject like this but here is what I think. Use the prop that works best with YOUR airplane. Years ago on Viper 5 APC 11.25X3.75 worked the best for that airplane so I had Dan Winship make me a few CF copys.
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Offline Randy Powell

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Re: APC props, my perspective...
« Reply #24 on: April 17, 2006, 09:54:00 PM »
I agree with Robert. I have a number of APC props. While it has yet to be THE prop for a plane, they usually work pretty well overall. And I like that they are repeatable. One is pretty much like another. That's a good thing. I've had many Bolly props in which one was absolutely spectactular and another of the same size was marginal. One 12x5 APC is pretty much like another 12x5 APC. Repeatability is the ticket.
« Last Edit: April 18, 2006, 11:46:51 AM by Randy »
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