Hi to all rc boaters Q:- i have a X467,X470 & X472 prop which i have cut /de tounge all 3. I also have a stock X467 the thing i would like to know is about making or should i go ahead on making a ''cut'' into the ''bar'' into these props that are modifed? and rule of thumb the diameter of the cut for the bar ? This is for a cat (r42).
Thanks for any input
i do have a prather mod 275 & 280 the stock 270 works good

The Barr cut is named after Stew Barr which is a half-circle cut. You want it just a hair off the hub to prevent the blades from cracking off.

While those older style props are doing a good job, you may want to upgrade at some point to a more modern design. Bob English ( G Force Hydros on JRCBD ) modifies an ABC 2814 prop specially for R42s. He does beautiful work at a reasonable cost.

A Barr cut at the hub will unload the blades at launch and slower speeds to help get the boat going. !/4" diameter is all you will need.

I was running a 2814 on my F-41 but was having problems getting on the pipe no matter what I did. Chris "Dasboata" Hoffmann did me up a 7414 prop and it made a world of difference! It wastes no time in hitting the pipe plus a gain in speed. The 74 is not the diameter in millimeters and I haven't found out yet where the numbers come from as it is smaller than the 2814.