Jugmaker

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

Dr1Driver

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

Dr.1

Jugmaker

Thanks

khodges

My Feedback: (1)

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.

Pilot Chad

My Feedback: (4)

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.

Jugmaker

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.
Dave