fishjunky

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What's the difference in these types of props Sport, Pattern, and Pylon? I'm about to buy a new prop for my airboat and curious about my options.

Thanks,

pro27

In a simplistic way...........

As an example...a 10-6 prop...........

A pylon prop will have blades that are very narrow in width. This allows for the engine to run up to it's designed rpm's easier. It will genarally also have sharp/pointed blade tips.

A Pattern prop will have blades that are very wide. This allows the torque produces by the engine to be more useful. Engines used in pattern aircraft generally run at lower rpm's and can take advantage of using a wide blade prop. The tips are usually also wide and squared off.

A Sport prop has blades that are in-between the two described above.

Unless you have an engine like a Nelson or Jett, stay away from pylon props. You won't see much if any difference in performance.

If you have a real torqy engine, a pattern prop would be helpful. Also, if you choose to always run your engine on a good rich setting, you can take advantage of a wider blade prop due to the lower rpm's.

fishjunky

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Thanks Pro for simplifying it for me. As I've been looking all the "Pattern" props I've found on APC's website are for .60 engines [&o] I'm runnin' a .40. I had on a "sport" 10x9 but it uhh.... became un-balanced after my mishap. I read somewhere in the forum's about using pattern props. Do you think I could swing an 11x10 or 11x11 pattern prop with my .40?

pro27

That is a lot of pitch for a .40. A 46 MAY be able to handle that much, but it would have to be a strong engine.

If you want to use an 11" prop, start out with an APC (best in my mind) 11-5 or 11-6. With the added blade area of the pattern prop, that should increase the performance.

Remember though, with a larger prop, the engine will turn less rpms than it will with a 10" prop, but it should have greater pull. You should see the performance increase more at the top end of the rpm range of the engine with a larger prop as the engine unloads ansd is running wide open.

One other thing to keep in mind, a lower pitch prop will give you faster acceleration. A higher pitch prop will give you more top speed, but will take longer to accelerate.

pro27

One other thing to remember about pylon props, ......

they are usually run with less diameter than a sport prop.

If a 10" prop is average for a .40 engine, pylon racers will use a 9" prop for the rpm gain, as well as high pitches like 10-12 or higher. The load upon the engine is about the same as running a 10-6 prop, but with the reduced diameter, more pitch can be added and still run at higher rpm's.

Sport engines though, are not designed to run at the rpm's as pylon engines, so a small diameter-high pitch prop would be of little benefit.

fishjunky

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Thank you Pro for the information. I have finally made it to the LHS to see what selection they had of APC props. I bought an 11x5 which they classify as a sport prop. I was looking and even their pattern props have a sharper end than the MA props do. I'll give this one a good trial on my upcoming camping trip. I think the quicker response on the low end will do me more good than the faster top end. Most of the places I run aren't big enough to get up to top speed before I have to turn.

pro27

IMO.........and this is not intended as a slam........but ANY APC prop is better than a MA prop.

MA props ARE good props and serve extremely well in most cases. But the design of APC is more superior and better performing. And as far as price goes, they are not that much more expensive.
Also, due to the blade design, it is my opinion that you can run a little more pitch than if using a MA. If a 10-6 MA prop works well for you, in most cases, an APC 10-7 or 10-8 will work also with a little better performance and not put any more strain on the engine than the MA 10-6 does.