BBCLiberator

iTrader: (2)

I am running a 1.43 Ratio KC Drive on my 221 Liberator and 14 3/8 x 21 Ballistic Propeller. The numbers don't make sense.

GPS between 70.5 and 71 on a dead smooth day, I get a hair more rpm and speed with a little chop. Tach reads 5000rpm so I checked it with a digital snap-on gauge, reads ~5250. I punch that into a calculator and I get 3.6% slip, and I'm relatively certain that is not correct. I've now used two digital tachs, check the GPS on my iphone, my garmin etc etc etc. I've verified the drive ratio (1.43 is as low as it goes for the cone cluth king cobra).

I bought this prop used and have always said it acts more like a 22" prop. Is this typical of this prop? Is there any use doing any work to this prop since the blades are pretty thin? Maybe a balance? etc. Also this prop has a rubber hub and i figure I'm on borrowed time with that (well over 500 horse), do you guys have a solution for that?

The prop doesn't look like it's had any work done to it and is in like new condition.

thoughts/insights??

Trash

Get some pitch blocks on the prop and measure it. I'd bet your closer to a 23" pitch than 21".

BBCLiberator

iTrader: (2)

I agree, which would be ironic since the first prop I bought during the build was a 23" ballistic and never used it, I started my break in on the stock 20" Raker then moved to the 21" Ballistic after a few hours and never needed to go any further. The stock prop was a 20" Raker and I could way over rev it afte the build, but with the stock motor it ran about 62 with it. I put this 21" Ballistic on after the ugrade and the revs are good and I see good speed. I should have tried the 23" but if figured what's the use, the 21 is good. Maybe these props are just that far off??? I mean that's a lot, right??? I did try a 22" Raker and the revs are down ~50rpm, so not much, and the speed is also down just a bit. That's why I've always said it acts more like a 22" prop at least that gets the slip numbers into "reality land" though still quite low, probably too low to be realistic.

BBCLiberator

iTrader: (2)

Nothing?

bbladesprops

Ballistic props can be a touch high on pitch. Also, depending on the manufacture day and the technition that day the cup heights could be off.
If you desire we can measure the prp for you.
Also, Labbing doesn't typically do much for those props (+75-150 rpm). Balancing is a good idea though.

22P makes the slip 8.5%. Still better the usual.

Brett

BBCLiberator

iTrader: (2)

Thanks for the info, can you PM me a price for balancing/measuring?

Also, do you have a solution for the rubber hub? Is there some ype of kit to convert o a solid tha is compatible with OMC?

Mayers89

Balancing is a good idea

bbladesprops

I apologize for the delay.
I have been dealing with some family issues as well as other involvements.

If you could, please call us at your leasure and we can explain the options completely rather than typing back and forth. Depending on your desires, the prices vary slightly.

Thanks for your patience.

Brett