Author Topic: Cutting down props...od or bad idea? (Read 1475 times)

frank mccune · « **on:** June 16, 2014, 12:40:08 PM »

Hi All:

Are there any problems with cutting props down to a smaller diameter?

I have a supply of newwooden Power Props that are all 12 and 13 inches in diameter. I need to cut them down to 9 and 10 inches to enable me to take off from a grass field. These range from 4" to 6" in pitch.

Suggestions?

Tia,

Frank

Frank

RandySmith · « **Reply #1 on:** June 16, 2014, 03:40:49 PM »

Quote from: frank mccune on June 16, 2014, 12:40:08 PM

Hi All:

Are there any problems with cutting props down to a smaller diameter?

I have a supply of newwooden Power Props that are all 12 and 13 inches in diameter. I need to cut them down to 9 and 10 inches to enable me to take off from a grass field. These range from 4" to 6" in pitch.

Suggestions?

Tia,

Frank

Frank

Your first consideration should be how the prop works for the airplane, at least consider using larger wheels or ?? If the plane flies OK with a 9 inch prop then by all means cut it to that.

Randy

Phil Krankowski · « **Reply #2 on:** June 18, 2014, 10:29:13 AM »

Might want to check on a pitch gauge, often the tip pitch is more flat the the hub pitch, and the indicated pitch is somewhere in between.

Second check the blade dimensions against a prop made to the desired dimensions. The cut down blade might be too stout and heavy.

Mechanically and safety cutting props down has been done, and will continue to be done. Trim carefully and cleanly, seal, and re-balance.

Removing 3+ inches is a lot of material to remove though. It may still make sense for your setup.

Phil

Paul Smith · « **Reply #3 on:** June 18, 2014, 05:09:00 PM »

I scribe the prop with a 6" dial caliper, saw if off with a Zona saw and balance it.

They don't make props in every diameter. You usually need to cut to get to the RPM you need. Engines are not happy at the wrong RPM. A 10x6 cut to 9" is a whole 'nother prop than store bought 9x6.

phil c · « **Reply #4 on:** June 19, 2014, 06:53:02 PM »

Cutting from 11-12 down to 9-10 is a lot, especially from 12 down to 9 in. That kind of prop makes a good bench test prop but won't fly a plane very well. Even trimming down from 11 to 10 requires a lot of other rework to thin the tips and reshape the outline and airfoil. Otherwise the prop will waste most of its energy stiriing air instead of producing thrust.

Author Topic: Cutting down props...od or bad idea? (Read 1475 times)

frank mccune

Cutting down props...od or bad idea?

RandySmith

Re: Cutting down props...od or bad idea?

Phil Krankowski

Re: Cutting down props...od or bad idea?

Paul Smith

Re: Cutting down props...od or bad idea?

phil c

Re: Cutting down props...od or bad idea?