PDA

View Full Version : Grimmm.



chirotray
06-28-2008, 06:07 PM
Has anybody used the grim 38x63 lifter prop? I dont know enough about props to know if this hull would benefit from a high lift prop. Its very close to stock in diameter, and just a HAIR less pitch, but its a lifter. Somebody school me.

Ub Hauled
06-29-2008, 12:35 AM
On what hull are you planning in using a lifter?

chirotray
06-29-2008, 12:39 AM
Bj26

Apples1
06-29-2008, 03:35 AM
i cant remember if a lifting prop is used for a cat or a rigger...Anyone? a cat rings a bell, if it hasnt got as much pitch as a 642 or 645 it will propably struggle, i tried a 3 blade V940 and only got it up on the plane once (after about 30secs of cavitation) but when it got up, it went like a rocket, i have never been able to get it on the plane again. i found on my BJ26 the 645 or 642 with a little cup added and thinned out a bit, and balanced and sharpend the best. 645 for top speed and 642 for run time.

Good luck.

chirotray
06-30-2008, 12:16 AM
How much difference you feel between the 645 and 642??

PropNutt43
06-30-2008, 04:42 AM
Lifter props do exactly what the word says. They are designed to lift the back of the boat. There are different degrees of lifter props , low, medium and high lift versions. High lift props are mainly used for Riggers and Hydros to help lift them on plain.

X642 and X645 props are medium lift props. You can use them with Cats but need to raise the strut and put some positive prop angle on it to get rid of some of the lift or your boat will run too wet. I don't run high lift props on my BJ26.

http://www.astecmodels.co.uk/props.htm (Prop Info)

Even though the site link below is for gas boats there is alot of good general information about props and prop mods.

http://www.rcprops.com/TechNotes/rcprop_tech_info.htm (More Info)

Apples1
07-01-2008, 02:01 AM
on my setup, 3 to 4 mph difference between the 2, however the 645 gives me more torque roll. which is fine for oval racing in one direction but not so much on a general pond and multi direction.