Propeller question

[BBM]

Don't want to open a can of worms but I have a propeller question

The Skyscout ( Model B powered ) I have is using a Culver 74x48 prop.

Engine compressions are good and it gets 2000rpm on the ground.



In flight the aircraft is quite slow and barley maintaining 55 mph , climb is abysmal.

1930s flying and glider manual says use a 74x48 prop but it sure is not giving the airplane the performance. I think it should.

Many people recommend using a 72x42 or 44 standard Cub prop



I know there are lots of opinions in props but I would appreciate hearing what others are using in their Aircampers/Skyscouts

[Richard Roller]

What is your rpm in cruise?

[BBM]

1600-1800

[zippythehog]

BBM,
You might try the Culver prop calculator, here:
https://www.culverprops.com/PropPitchCalculator.html

You know your engine peak power rpm better than I.

[zippythehog]

I don’t know if you have resolved this but I recently spoke to a builder. He said they had installed a tach and the engine produced poor power. They later noticed the tach had a selection on the back for four or six cylinders. After getting the tachometer to the four cylinder selector and running the engine, they ran the engine at the correct rpm and everything was fine. Might this be the problem?