Help With Prop Picks

[Russell Bear]

Should have replaced the old flex shaft instead of using the old one. It broke at the weld today and I lost my prop, well I didn't loose it, I know where it is, just don't want to go swimming. If anyone can give me some suggestions of props that I can try I would appreciate it. BTW, I was using a Prather 245 and it would scoot, just wanted to see what others are using.

45 Youngblood Mono

7-8 lbs

OPS 45 stock

Muffled pipe @ 10.5"

50 / 18 Fuel

McCoy #9

Thanks.........

 

[Ian Inverarity]

Octura X447/3 works pretty well on that setup, possibly even an X450/3.

Ian.

 

[Russell Bear]

Thanks Ian, I was wondering though. The Prather 245 has a diameter of 2.25" and a pitch of 3.50". The X447/3 and the X450/3 are considerably smaller on both pitch and diameter. Are these props preferred for getting the engine into a higher RPM band?

 

[Russell Bear]

So far I've seen that the Prather 245 is a 11cc prop. Maybe that's one reason I am running the pipe at 10.5".

 

[Ian Inverarity]

Russel,

I will ask one of the club memebers this Sunday what pipe length they run with those props, but I do know that 2 blade props are not favoured for that combo!

Ian.

 

[Russell Bear]

Cool, Thanks Ian, I'll be standing by.

 

[ernie lafleur]

russel dont be so concerned with diameter , its blade area ratio . a 2 blade prather has about a .5 blade area ratio and a 3blade octura has about .75 blade area ratio . to better explain this , its like a 4inch wide tire versus a 6inch wide tire . the 6inch wide tire is going to grip better therefore applying more load to the motor . and also the three blade props tend to give you more hole shot out of the corners which will result in lower lap times .

 

[westoz]

:unsure: :huh:

 

[Russell Bear]

Thanks Ernie........

 

[Ian Inverarity]

Russel,

I talked to one of the guys here who ran that combo, he used the OPS 60 pipe, but ran it full length which is about 11 inches! I guess if you can run shorter you should go quicker!

Ian.