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Old 06-22-2005, 11:01 PM
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Jugmaker
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Hi, I have a Cub J3 with a saito 65. It lifts off and flies great but can't seem to get landing speed slow enough. The engine idles as low as I can get it and not die.I understand prop pitch has a lot to do with speed but do not have a clue as how to select the right prop. Saito recommends a 12-6 to 13-6,have tried both. What prop should I use for slow landings and good flight?
Dave
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Old 06-23-2005, 05:37 AM
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Dr1Driver
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Default RE: Prop Choice

Pitch equals speed. Go to a 13-4 or a 14-4.

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Old 06-23-2005, 05:04 PM
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Jugmaker
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Thanks
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Old 06-23-2005, 09:36 PM
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Default RE: Prop Choice

You didn't say which scale or who made it (Cub); not that it matters, except for wing loading and weight, which with the engine choice adds up to the power loading. I have a 1/5 scale Cub, 84-1/2 inch wing, weighed 9 pounds when first built, up to ten pounds now. I also have a Saito .65 in mine and have always used a 14-6 Master Airscrew K series prop. I haven't had any problems getting mine to land, as a matter of fact, I am usually carrying a couple of clicks of throttle all the way to touchdown. It may be due to the weight, which is a couple pounds more than the kit was "supposed" to weigh, according to the plans. I agree that a 14-4 may work, or a 14-5. 14 is scale diameter for a 1/5 scale, and the lower pitch will allow a higher throttle setting for flying. I like the higher pitch, I can tool around at 1/4-1/3 throttle. Play around with the lower pitch; I'd try the 14-5 and if you're still carrying too much speed and can't slow the engine any more, then try the 4 pitch, but I think it will be too low. What does your engine tach at its lowest reliable idle speed? I also have an on-board glow system, and it allows me to get down to about 2100 rpm. At that speed, you can almost see the blades turning.

If by chance you have a smaller, or substantially lighter, Cub, you might just be overpowered. You could downsize to a .56, still have that great 4-stroke sound.
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Old 06-24-2005, 12:19 AM
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Default RE: Prop Choice

I would also put something with a larger diameter and smaller pitch.

In case you didn't know, Pitch is how many inches the prop would move forward in one rotation.
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Old 06-24-2005, 01:50 PM
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It is Great Planes Cub J3, 82-83 in. wing. One of my problems is a short runway,only about 325 ft. with low trees on the end.
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