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My Feedback: (1)

With the advent of and increasing popularity of the Bobcat-Style pusher-prop jets []AND[] the lack of available 3 and 4 blade pusher props, is the following a 'solution' or a disaster in waiting? I want a, say, 12X10 3 blade pusher for my OS 91FX, but I can only buy a 16X10. Can I cut off the extra 4 inches blade length to make it a 12X10 as long as I re-balance the prop? I have trimmed down 2 blade props to max power out-puts, so this would be an extention of that approach in my mind.

Wayne22

My Feedback: (2)

I wouldn't recommend it...you've got a...what... 3 hp engine spinning the amputated prop at 10 -15 thou........It might work...or it might shake your plane to pieces...or it might even throw a blade, Is it worth the risk?

Take a look at these:

http://www.zingerpropeller.com/3_bladed_Propeller.htm

rjbob

My Feedback: (8)

To cut down a 16" diameter prop to 12" you would only have to lop off 2 inches from each blade; not 4. But balancing a 3 blade propeller is not the easiest thing to do.

If you can, it would probably be better to take Wayne's suggestion and go the Zinger route.

Eddie P

My Feedback: (4)

Also consider that when you trim blade length you are incresing the effective "pitch" of the prop becasue the natural spanwise wash out of the prop is not the same with the outer section missing. That may alter your starting prop pitch selection a bit. If you are a pylon guy you know what I'm talking about but typically an excessive cut in length really starts to kill the efficiency of the propeller.

Widget

My Feedback: (1)

Eddie P! THAT was the answer I was looking for! I'm not a Pylon Racer, but the prop's airfoil and change in AOA from root to tip looks different. As far as balancing goes, it would be balanced the same way one would balance a brand new prop. I use 3 blade pretty much exclusively due to their lack of noise. (I have my own runway/+ 2 acre pond on 10 rural acres and my neighbors are still facinated with my planes- I want to keep it that way...[8D]) Oh! And RJBOB is right on![X(] 2 inches from each side is 4... Duh.... Thanks! I didn't see the Zinger prop(s) I could try out until I looked harder, or rather, after my morning latte... Good advice ya'll. Thanks!

jcarl

My Feedback: (3)

On the other thread abouyt Nitro Models bobcat someone said that they had used a Byron impellor without a shroud or ductting and it worked very well. It does have a lot of pitch to it but is only six inches in diameter. Any one have any thoughts on this? Will it produce enough thrust to fly the plane with authority? Work better with a .61 or a .91 size engine?

Carl Chilton
Borger, Texas