Tune pipe and prop size for kougar
 

Just bought Macs tune pipe for the Kougar. It will be on a OS 46 AX. What do you think the best prop would be. It has an 11x7 on it now. I heard that if you use this size prop that the header does not need to be cut.

RE: Tune pipe and prop size for kougar
 

I would try the 10x6 or 9x8. 11" diameter is too big. You want the motor in the 15-16k range on the ground. I know the 10x6 will get there.

On our unpiped T-34s we run a 10x5 or 9.5x6 at ~16.8k on the ground. Believe it or not they run pretty well at those RPMs. With a piped AX you need to load it so that it just reaches 17k in the air.

RE: Tune pipe and prop size for kougar
 

I use a 9x7 on my .46 fx and it works very well.[8D]

RE: Tune pipe and prop size for kougar
 

why would anyone trying to make cougar go faster with a 11x7 on a 46 size engine,is beyond me, 16k on a 10x6 prop with a mac's pipe is gonna make it move , cutting the header isnt any big deal, i am sure some here has a os 46 running a pipe, but no one is running a 11x7, i am running 4" header length on a 46 os , but i am spinning a 10x8 at 14 plus on a much lighter airframe

RE: Tune pipe and prop size for kougar
 

Chris , what about the bearings on the AX at those RPM , do they last ????

RE: Tune pipe and prop size for kougar
 

First set lasted over a season of racing. I just changed them at the end of the season out of habit. I haven't heard of anyone losing a bearing or rod at these rpms. Matter of fact, most of the engines in our series have been through a crash or two and they still run strong.

RE: Tune pipe and prop size for kougar
 

OK , good to know it , just as a reference how many racings complete a season there ???

RE: Tune pipe and prop size for kougar
 

I practiced a couple times a week plus raced 4 races. I'd say the motor had 120+ flights on it.

RE: Tune pipe and prop size for kougar
 

Thank you Chris . ;)