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Engine basics => Engine set up tips => Topic started by: frank mccune on October 17, 2020, 11:11:40 AM
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I often hear that one brand, shape or material is far better for our ic engines than other types. Any comments or thoughts concerning this matter.
Tia,
Frank
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Just like brands of beer, people tend to have favorites. But the favorite of "A", may not work for "B". I always watch for what others are using on a particular engine. If there is a majority favoring a certain engine/prop, that's what I try. Saves me a lot of work.
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Define "better".
FWIW APCs are very efficient and repeatable.
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As the Hoffmeister has pointed out, "better" may take on performance characteristics you may not be considering.
As an example, I would only use a lightweight (ie. wood) prop on a Fox .35 stunt. Those cranks are notoriously underdesigned therefore subjecting the crank to the higher oscillating torsional stress from a heavier prop is not a "superior" way to go.
The Divot
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My first thought is find someone else to listen to about props. There is no one prop that is superior for everyone.
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The superior prop for any given engine on any given airplane is the one that works best when you try it. I have had props work very well on one engine/airplane combination, and then not so well on another. I am assuming that we are talking about off the shelf commonly available props, correct? Not all of us have the financial where withall to be able to buy 30 dollar or more Bolly and such, so you spend the money on regular, common production props and what doesn't fill the bill, you stash away for the next adventure. Then when you settle on a good prop, you buy 6 more so you have them in case of an accident. That is how you build an inventory for the next adventure. In sizes ranging from 4 inch to 14 inch, I probably have accumulated close to 1000 props in my inventory, but I have never counted them. They just fill several large plastic tubs on the shelves in my garage. Through experience, I usually know about where to start with a new engine/airplane combination and proceed from there. Like anything else in this hobby, you have to work at it.
Type at you later,
Dan McEntee
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APC are good albeit a little heavy. I’ve had good success with Xoar wooden props too, nice and light and perfectly balanced out of the factory.
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Among commonly available commercial props, APC is far and away the most promising. Props to avoid are Zinger/Zingali, the injection-molded Master Airscrew.
Among the cottage industry types, I have made almost all of my full competition flights with either Bolly or Brian Eather props.
You *do* need to experiment for particular combinations, but learning how to evaluate it takes some sort of stable starting point. One of the advantages of graphite props is that you can adjust them for pitch and pitch distribution without changing anything else. Comparing a Zinger 10-6 and a Rev-Up 10-5, or something like that, tells you absolutely nothing useful aside from which one works better in a particular case.
Brett
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AND you can need differant props for differant weather . Wind & calm .Heat Cold & dampness . Just as well theyre removeable ! .
PLUS , one may have advantages , or disadvantages , in comparison to others , say across the top , or uphill , or downhill .
Centuries ago , people ( in N.Z. ) said the Tornados pulled harder , but the Top Flight went better uphill / vertical . in comparison . the ' round ' blade top flites . Wood . Still a good prop .
(https://i.pinimg.com/564x/c2/f3/da/c2f3da9f264de2f5804b2d12d97c5d68.jpg)
Some the wood is a bit soft .
The Tornado Plasticote were THE Team Race prop , in the 1960s . ( The Nylon ones are copys , if ya wanna do F'glass copies . )
(https://www.picclickimg.com/d/l400/pict/153895003025_/8-Vintage-Tornado-Plasticote-5-2-Wood-Props.jpg)
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I've had WAY better results with APC props than any other LHS-type plastic prop, or even BY&O and Rev-Up wood props. Graupner plastic props (FG/nylon) are also good IF they offer the size you need. A 9-4, 12-6 or 11-6 Graupner is a good choice for a 4-2-4 run IF that size suits your engine. I think they've gone "Tango Utah" since SIG bought them. y1 Steve
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This is where I really like this forum. I have often searched what props people are using with certain engines. With the 20 FP, 25 FP and 25 LA, many start with an APC 9/4. However recently, one person found that and APC 9.625x3.75 was giving him the best performance on an ARF Nobler powered by an LA-26. I had never even heard of that prop. Many use the APC 10.5 x 4.5 on a Brodak 40. I personally have found that to be the best prop for my uses of that engine. I also use it on an LA 40. Others are using different ll inch props and larger on both those engines for their best performance.
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one year at the nats we were each given a couple of the new narrow 9/6 APC.test flying was over so no one tried them i was in the next to the last heat and knew my set up was not going to put me in the top 6 so i tried the new prop and ended up 3rd .a month later in Dayton it was the slowest prop in my box