Grim Racer 440/3 versus others

[dtacmed]

I'm new to this. I'm currently running a sharpened and balanced Grim Racer 440/3. How does this prop compare to the others I have read some using. Octura 440 etc. I'm running 6 and 7 cell. Thanks

[dtacmed]

Anybody have an opnion on this ?

[Bill-SOCAL]

No opinions here, but some facts.

The GrimRacer prop you are talking about I assume is the 40x52 3-blade. This prop has a total pitch of 52mm = 2.05 inches.

The Octura 440/3 has a total pitch of 2.20 inches.

So I suspect that the Octura 440/3 might be a tad faster and will pull a bit more amps.

The GR 42x55 2-blade prop has a total pitch of 2.17 inches and is not as fast as the Octura 440/3.

GR names their props with the diameter x pitch in mm. Octura names their props using the pitch factor and diameter in mm.

So a Grim Racer 40x52 is 40 mm in diameter and has 52 mm total pitch. You can convert to inches 25.4 mm = 1 inch.

And Octura X440 is a 40 mm diameter prop. Pitch is 1.4x40 mm = 56 mm = 2.20 inches. In GR nomenclature the Octura would be a 40x56 prop.

X series Octura props are "normal"
M series are modified (de-tongued)
"4" = 1.4 pitch factor
"5" = 1.5 PF
"6" = 1.6 PF

Generalizations:

The same prop in 2 versus 3 blade - the 2 blade will be a bit faster in the straights. The 3 blade will load the motor more (pull more amps) and will generally provide better acceleration out of turns.

There may also be differences in how the boats "feels". For instance my Avenger cat will get some bad rear end hop/shimmy with 2-blade props and it is solid with 3 blades.

Does that help?

[ice329]

That clears up how to read his props. I often wanted to try one but never understood how he sized them.

I see he tumbles them to make them shiny but Do they still need to be balanced.

I have been getting into doing props, read lots of articals and tryed to get someone to talk to who really knows what there doing. People are few and far between or no one wants to share the tricks.

[Bill-SOCAL]

I see he tumbles them to make them shiny but Do they still need to be balanced.

Yes. They are unbalanced when new.

[Steven Vaccaro]

Now that's one hell of a detailed explanation. Thanks for that!

[dtacmed]

Thanks that helps alot.

[Ctonez]

Yeah, nice explanation Bill. Thanks for taking the time...

[SJFE]

BIll I even got that & props have been a problem for me since day one.
Thanks Man.
Tom

[Joe Friars]

I like the Octura x440-3 blade on my SV. I also have the Grim Racer 3 blade but haven't run it as much as the Octura prop, however it did seem to cavitate a bit more but that could be because it is still pretty polished. It also seems a bit meatier that the Octura. I am not sure how this would affect performance as I am still pretty new at this.I have yet to try all of the recomended props butI have used a few:
X440
X440-3
GR 40x52
CF 45mm Fast but skittish in the turns, I rolled it couple of times!
I also have but have yet to try:
x640
GR 42x55
And have read that the x642 and the Prather 220 are good props for the SV.
There is no "right" prop but the one that is right for you. So buy some props and have some fun!
JOe