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Engine basics => Engine set up tips => Topic started by: Jim Nohsey on November 30, 2014, 02:24:47 PM
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Looking at running a fox 35 on a ringmaster, trying to figure out what props to use. In the early 70's I used TF super m 10x6 and some nylon 10x6 Tf and was wondering what to use now??
Will be using either a 25% or 29% castor fuel with 5% nitro.
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10-6 props still work good on Fox 35's for me on profiles. On full fuselage planes I sometimes like 10-5 APC's. 10-6 props help to keep the revs under control and by doing that they also help with vibration issues on profiles. Just my 2 cents though cause others may say different.
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Jim, what brands? apc?
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If you're feeling retro enough to run a Fox 35 on it, run a 10-6 wood.
If you want it to perform way better than a Ringmaster ought to, put an OS 20 FP or 25 LA on it, running a 9-4 or (on the 25 LA) a 10-4.
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Jim, the Master Airscrew 9.5 x 6 is an excellent choice for the Ringmaster. Let it wind up and don't look back. Ken
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I'm running an APC 10x5 on my Ringmaster/Fox 35. It's happier with this prop than many others I tried.
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Here's a whole bunch of Fox prop tests. It makes interesting reading. http://www.tulsacl.com/PropTest1.html
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Here's a whole bunch of Fox prop tests. It makes interesting reading. http://www.tulsacl.com/PropTest1.html
This may make it easier: http://www.tulsacl.com/PropTest1.html (http://www.tulsacl.com/PropTest1.html).
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One of mine liked a 10x6W Zinger with the blades thinned with a touch of undercamber sanded into the blades, the other was very happy with the APC 10x5. Try a handful of 9.5-10" 5-6 pitch props and go with the one you or the engine likes best.
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The prop testing at the Tulsa Glue Gluedobbers site matches my experience from 35-ish years ago for the props that existed at the time. Not too surprising since nothing consequential has changed about air since then and even less has changed about the engine. I would just go with what it says there.
Note that in the "top tier" you get a very wide range of performance, which would allow you to tweak the results for the airplane and conditions. My experience was that the Top Flight 10-6 was the best I found, overall, mostly because it has a bit more pitch than the Rev-Up (which keeps the engine slow enough to be happy) and less blade area than the 10-6EW (which helps control the wild whip-ups the EW was absolutely notorious for). The EW always worked great in hot, dead air. So you get a decent range of performance with the 'top tier" list.
I never had much luck with anything that was marked 5" or less. The Rev-Up 10-6 actually measures around 5.25 and that sometimes got a bit thin - which is why you wanted the W of EW to make up for it. In this case, a lot like 4-strokes, I think the RPM required puts the engine too close to the edge. Even though the prop is probably better/less efficient, you lose more engine performance than you gain with the prop. Maybe when it is really windy, but then you trade whip-up for "penetration" and vertical performance.
This might all change if you are willing to pump the engine up on lots of nitro. I didn't know to do that, or was afraid to do that, back in the day.
All this sort of fiddling (which went on endlessly in the 4-2 break era) reminds me why I don't want to do it any more. Enjoy the Fox in Classic and OTS, but don't expect miracles.
Brett
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I kind of view a plane with a Fox 35 in it the same way I'd view a Model A with a spiffed-up flathead V-8: you do it because it was the cool thing to do in 1954, not because it was the cheapest, fastest ride in 1960.
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Very interesting article, it picks up what the CLW article started by adding some of the newer props. One question - did they run a muffler on the Fox35 or open face?
Best, DennisT
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Open Face (No Muffler)
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This may make it easier: http://www.tulsacl.com/PropTest1.html (http://www.tulsacl.com/PropTest1.html).
thanks for the link.
that was good reading there.
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If you're feeling retro enough to run a Fox 35 on it, run a 10-6 wood.
If you want it to perform way better than a Ringmaster ought to, put an OS 20 FP or 25 LA on it, running a 9-4 or (on the 25 LA) a 10-4.
Tim, I have an OS 25FP that I may try. I have some apc and master airscrew 10x4 props that I can try.
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Try the APC 10-4 first.
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Another vote for a 10x6 prop. I'm running an old Fox 35 in a Miss BJ profile stunter, spinning a Top Flite super M 10x6 wood. Have also used a Zinger 10x6 wood. Both work very well on the old Fox.
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Since the test was done "open face" it would be interesting to do a few test with the muffler. My experience with the Fox running a muffler has been that you need to reduce the diameter between 1/2" and 1". The muffler holds extra heat in the engine and can cause it to pre-ignite and go over into runaway. If you richen to the point that you stop the runaway you are off on rpm to fly the needed lap time. I started running 9x6 old Top Flites and it cured the problem. Maybe an extra head gasket would help with the bigger 10" diameter.
Best, DennisT