jrp124

I'm going to cut a apc 11/12 down to a 9/12, will it still have the same 12 pitch after I cut it??

w8ye

My Feedback: (16)

yes but some of the aerodynamic effect will be gone if you examine the prop before it is cut.


What you will likely notice is more noise than a prop intended to be that size

airbusdrvr

If you have the time to order or find one locally, why not use a prop similar to this, http://www3.towerhobbies.com/cgi-bin...&I=LX1538&P=SM . This way you won't have to worry about the aerodynamic changes that may occur with an inch and a half cut from each tip.

Ram Jet

I would think that if you cut a prop's diameter down you would reduce tip speed and would have to compensate with additional pitch.

Bill

dhal22

the guys on the extreme speed prop planes forum will have good info on this idea.

Stickbuilder

I routinely cut props down to suit my needs. Example, I will cut a 20X6 Zinger down to an 18X6 to use on one of my scale Wacos, since the 20" diameter prop has a wider blade than the 18X6 that they sell. I like the way the model performs on the cut prop. The main thing is how you cut it, and that you did not introduce any splintering to the blades. Then carefully balance the prop, both tip and hub. I have some cut props that are over 10 years old, and still perform well.

There is no reason not to cut a prop down, if you know what you are doing. I would reccomend having someone who knows something about doing this prior to running an engine with the cut prop installed. We even used to make our own props, since you couldn't just run down to the hobby shop and buy what you needed.

I don't think that I would reccomend cutting down a plastic, nylon or composite prop though. The carbon fiber props would probably cut down well.

Bill, AMA 4720
WACO Brother #1

aerowoof

back in the old days when prop selection was not up to par with today it was common to cut props down to size.specially in racing you would pick the pitch for speed then trim the prop to get the engine to run at the rpm desired.

Jester241

Why not these kind?

Semi Retired Aviator

If you cut a prop down, you will change the pitch. You won't change the actual pitch, i.e., angle of the blade, but there won't be as much prop to act on the airflow, so there will be less diameter and less pitch.

Better to find exactly what you're looking for.

w8ye

My Feedback: (16)

Cut the prop down if you like. A lot of people do it.

Just make sure the prop is balanced when you are done

LuftwaffeOberst

I whole heartedly agree. ^


I've curved the tips with a sanding stick a few times to give it that " Scale look." Make sure you put the prop on tha balancer after your cut... it's very critical that you do.

It's even good to re-balance the prop... even if you just paint the tips.

w8ye

My Feedback: (16)

Often when balancing a prop, as you get the blades close to the same weight, you will discover that you need to remove some material from the side of the hub.

jaka

Hi!
No!
If you cut down a prop (reduce diameter) you only reduce diameter... The pitch is the same!
Filing a prop, custom making a prop is no big deal! It's easy! Could be done with both wooden and plastic (APC type) props, but see to that you thin it down at the tips and balance it properly.

w8ye

My Feedback: (16)

Before APC made the "Wide" series of props, I would take a larger prop and cut it down to made a wide bladed prop.