Prop lift for cats

[BHChieftain]

Got a general question for Cats. Do cats prefer lifting X props or lower lift M props? Or does not matter that much?

I'm running X series on my monos. For my OPC Tunnel, it really likes the M prop which makes sense to me as outboards don't need any lift. On my shovelnose hydro, I'm also running a large X prop for lift to get the back up in the air.


Chief

[Fluid]

First, X-props are not lifting props, they have less lift than almost any other model prop. M-props usually exhibit slightly less lift than the X-props, but often I can't see much difference switching between X and M on the same boat - cats, monos or hydros. True lifting props include the Octura 1600 series along with the ABC H props and their 'Cleaver' designs. Try these and see some real lift. :wink:

To your question - most casts do not need a lifting prop, so the X and M work great. If you have a cat which is too flighty you can help reduce blow offs by running a prop with more lift. But too much prop lift and the cat won't run well without adjustments in the strut and CG.


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[egneg]

If you want less lift you can always cup the last 1/3 of the leading edge and slightly round the tips to narrow the thrust cone.

http://forums.offshoreelectrics.com/converse.php?u=2610&u2=786

[lenny]

Is the cat a Geico or Mystic ?
I just pick up a modded Mystic and ran it with a x642,
But I am trying to set it up better than what I see out there running.
I was thinking of trying some of the M and prather props,
To see if they help any with the up and down of the rpm that I hear all the time on a lot of these boats,
It is like they air out or something like that and the motor sound go's up and then down.

[egneg]

You are running a surface prop and unless the water is perfectly smooth it will "air out".

[lenny]

Hey Chuck,
Do you know what I mean about how most of them run with bounce and sound ?

Like this one sounds steady and run nice and steady.


http://www.youtube.com/watch?feature=player_embedded&v=Poz3OC9cSlM

[Fluid]

I was thinking of trying some of the M and prather props.These props are different in their lifting characteristics. The Prathers lift more than the M props, but less than the ABCs.



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[BHChieftain]

Thanks for the feedback everybody.

Chief

[Heaving Earth]

i generally prefer m props on my cat and x on my monos

[Heaving Earth]

Hey Chuck,
Do you know what I mean about how most of them run with bounce and sound ?

Like this one sounds steady and run nice and steady.


http://www.youtube.com/watch?feature=player_embedded&v=Poz3OC9cSlM
i think alot of people run their struts to low on cats. for whatever reason theyre afraid to raise that sucker up, which in most cases make cats run much better. im not saying its true for all cats, but the majority do. im talking 3/16 above sponsons. maybe people think the boat wont move with the prop so high, but mostly i see boats with major handling issues i believe strut height has alot to do with it.

[lenny]

So what props do you think would help with this hull ?
Running in very lite chop and glass.

The setup in mine is sw-180,keda 4074 2364kv, 4s -150 flex.
CG at about 30,
I ran two sets of pack on it so far, 2 - 4s packs and 2- 2s packs on a x642.
It ran pretty good with strut at 1/16 above the sponson and +2 on angle of the strut,
But it was loose and had a little bit of bounce or seasawing to it.

[lenny]

Hey Chief,
How is your sons new geico running for him ?

[Heaving Earth]

i would go for a m440 or x442 to start

[iamandrew]

I think the issue here, is that we have to remember that RC boats, are not Scale toys.
Ive found that if your running large single drive props, you just get a poor handling boat. but it sure will have a lot of kick thats for sure.
Ive found, even with the advice offered here, the best thing is to get the equipment and try it yourself.
E.g. I picked up some crappy props for like $10 inc shipping, found my genesis runs so stable with a 3 blade prop

[BHChieftain]

Hey Chief,
How is your sons new geico running for him ?

Runs well on x442, have not tried x642 yet. But the x442 is actually too much speed for my son, and when I try to slow her down with an x440, the boat starts to bounce. Moving packs forward did not help. But I have not tried cranking up the strut yet.

I suspect the x440 will just be to slow to air her out, and I'll probably keep him back up on the faster props and have him practice his handling skills.

(I call this a high class problem!)

Chief

[oscarel]

i think alot of people run their struts to low on cats. for whatever reason theyre afraid to raise that sucker up, which in most cases make cats run much better. im not saying its true for all cats, but the majority do. im talking 3/16 above sponsons. maybe people think the boat wont move with the prop so high, but mostly i see boats with major handling issues i believe strut height has alot to do with it.

I agree. Was doing the same w/ gas boat until a member told me to raise it. Worlds difference.