Is it okay to cut down props? I have a 9x7 3 blade Master Airscrew glass filled nylon prop and I want to cut it down to 8". Will this cause and safety issues with the prop?

I have done it many times without any problems. Inorder to get the blades identical lengths I put a dowel in a wood block and clamp this to my table saw or band saw. I put the prop on the dowel and rotate the prop through the saw blade.

Balance afterwards and there won't be any major problems. Make the cuts accurately and there won't be any minor ones.

I've got a number of planes flying today with prop diameters of N-and-a-half inches. I want as much fan area as possible and that's one way to insure it's possible with every engine/plane combination. Since they only sell props with diameters in inches, doing your own lengths gives you infinite choice.

We used to carve our own props for special use. Working the diameter accurately isn't even close to the hardest part.

You want the blade lengths to be equal, but main thing is balance.

The filled nylon used today won't cause any strength problems at all. Laid up props won't either if you cut them shorter with sharp tools.

Thanks for the replies, will cut it down and balance.

Hi!
Not only can you cut them down...you can rework them whatever you want. But start with a good prop like the APC not with a MA.

Eureka. I can do this! Buy large props and if they overload the engine, trim them down.

That may alleviate another trip and $ to the LHS.

I like that dowel idea!!

If you're planning to shorten a prop that wasn't turning what you considered as adequate rpms, don't lop off too much right away. Try about 1/4" and see what that does. Also, taking more than 1/2" won't usually do much for you as the aspect ratio has an effect on performance and it's going in the wrong direction... fast.

For Apilot I just use the drill I used to drill out the hub to fit the shaft .