Octura M or X

[jetskier]

What's the difference between M445 and X445 all the spec seems the same.
Thanks,

[785boats]

In the link below, if you look at the X series at the top of the page & compare them with the M series lower down you will see that the tongues have been removed on the M series. That's basically the difference.
This unloads the prop a bit & therefore the motor can rev a bit faster & therefore the boat runs a bit faster, & should have a slightly less amp draw as a byproduct.

http://www.offshoreelectrics.com/cat...ura+Propellers

[J.W. Pepper]

What's the difference between M445 and X445 all the spec seems the same.
Thanks,

Found this explanation while searching for props for my IM-31... add's a little more detail to 785boats' post.

An Octura M series prop is basically a de-tongued (de-eared) X series. The M series gives you higher top RPM, but less torque or off the line grunt. They also produce less lift, less prop walk & less prop torque than the same size X series prop. It's known as a cleaver style propeller.

Found that info here... http://www.funrcboats.com/ProductInf...oductid=OCM440

Hey 785boats... What the heck is prop walk?? And what do they mean by a "cleaver style prop"?? -- Lotta people on this forum recommend a M445 for the PB IM-31's, so needless to say I have reason for wanting to learn why.

Also, I attached a prop diagram, think I found it here... http://www.offshoreelectrics.com/inf...s_Tips_&_Info_ - tons of great info, highly recommend you spend some time there. The "ears" 785 referred to are at the bottom of the tongue / very beginning of the leading edge.

[TheShaughnessy]

Prop walk is when the thrust cone inherently steers the boat to one direction. This usually happens when using large props. How large depends on the size of the hull. A cleaver style prop refers to the shape of the blade

[wayne middlemiss]

the idea behind the de tounged m series or x series is to remove an area of the prop that acts as a govenor and basicly increase the leading edge pitch so it allows more water on the prop to give you more positives with the prop= better boat performance.

[J.W. Pepper]

Prop walk is when the thrust cone inherently steers the boat to one direction. This usually happens when using large props. How large depends on the size of the hull. A cleaver style prop refers to the shape of the blade

Is the thrust cone part of / inside the concave part of the prop??

How does one determine what is considered a large prop for a given hull size?? Also, does it matter if the hull is a mono or a cat??

[TheShaughnessy]

The thrust cone isn't a part of the prop more a function of it. 47mm would be considered on the large size for a 27-30 inch hull. Yes different hull types react differently. Have a look at sweet accords gallery, should be a pic illustrating a thrust cone.

[TheShaughnessy]

http://rcraceboats.webnode.gr/news/gas-prop-essentials/

Check out the pic at the bottom. Should give you the jist of prop wash/ thrust cone

[jetskier]

great info guys. thanks again

[J.W. Pepper]

http://rcraceboats.webnode.gr/news/gas-prop-essentials/

Check out the pic at the bottom. Should give you the jist of prop wash/ thrust cone

Well, I just got one of my questions answered... http://rcraceboats.webnode.gr/news/propwalk/

Then discovered that I have one hella-va lot to learn Example I heard the term chine walking and thought to myself... great, wt* does that mean?? Still don't know, but at least now I know what the hell the chine is, that's a good place to start.

Thank you so much for the link, wish more people would do that, I love to learn, point me in the right direction and I'll take of the rest. Trust me, I will be spending quite a bit of time there the next couple / three / four days, a ton of info to absorb.

[wayne middlemiss]

the prop info has been used from marty davis site www.rcboat.com nothing new there.

corection guy's that site is no longer but go to this www engine analysys software.com and look in the old tech files and other info.

[Randy Rapedius]

One thing to remember is that the M series might give you a little extra top end speed however, it could cause cornering handling issues especially in a mono.

[hydro_pyro]

"Prop walking" is the effect of a surfacing prop exerting a slightly "sideways" thrust torque due to the prop being half-submerged, causing the back of the boat to skate sideways or strafe across the water. The "taller" the prop's pitch and the higher it's run, the worse the effect can be. Also called "paddle-wheeling."

"Chine walking" is what mono Vee hulls sometimes do at high speeds when there's a small area of the hull in the water. It pitches side-to-side, or "chine-to-chine", trying to find balance. On a 1:1 performance boat, the driver uses steering input to keep it balanced on the keel or pad.

[jetskier]

"Prop walking" is the effect of a surfacing prop exerting a slightly "sideways" thrust torque due to the prop being half-submerged, causing the back of the boat to skate sideways or strafe across the water. The "taller" the prop's pitch and the higher it's run, the worse the effect can be. Also called "paddle-wheeling."

"Chine walking" is what mono Vee hulls sometimes do at high speeds when there's a small area of the hull in the water. It pitches side-to-side, or "chine-to-chine", trying to find balance. On a 1:1 performance boat, the driver uses steering input to keep it balanced on the keel or pad.

good inputs.
my Kawi SXR 800 chine walks like crazy on glass, give it a little chop it handles like a dream, choppier the better till it gets too crazy then your hanging on for dear life.

[Brushless55]

Great info in here!