Some Grim Props are now in stock....

[ReddyWatts]

pitch?

Therefore, the pitch (55mm/2.16") is how far the prop travels in one revolution for a Grim prop. So do the Octura props, like a X447, Y547, X647, have a 40mm, 50mm and 60mm pitch for each revolution?

[Darin Jordan]

Octuras work like this... at least the X and Y series do (I think they all do actually):

The X4__, X5__, Y5__, X6__, etc... describe the pitch ratio... In these cases, X4 = 1.4, X5 = 1.5, X6 = 1.6, etc...

I think the 14__, 17__, etc. series are the same... 14 = 1.4, 17 = 1.7, etc... The V9__ series I think are all 1.9...

The "47" in your examples is the diameter in mm....

The pitch, therefore, is the pitch ratio * Diameter...

So, the X447 has a pitch of 1.4 * 47mm / 25.4 (conversion to inches) = 2.59"

The X547 is 1.5 * 47 / 25.4 = 2.78"

etc...

Hope this helps...

[SJFE]

My head hurts :p

[ReddyWatts]

prop conversion?

So a X447 is the same pitch as a 47 x 66 in a grim racer prop?

The props that Steven has are Grimracer.

Grimracer 40 x 53 = 40 x 1.325 - simular to an Octura X340

Grimracer 42 x 55 = 42 x 1.31 - simular to an Octura X342

[SJFE]

Ehhh..I ordered 3 ofem just for the heck of it:D.

[Darin Jordan]

So a X447 is the same pitch as a 47 x 66 in a grim racer prop?

The props that Steven has are Grimracer.

Grimracer 40 x 53 = 40 x 1.325 - simular to an Octura X340

Grimracer 42 x 55 = 42 x 1.31 - simular to an Octura X342

If Octura made such things... then I think you'd be on the right track...

In my experience, you can't go symply by pitch alone, however... blade area, shape, and style have a LOT to do with it... You'll have to play around a bit to figure out what really works...