Prop question on Cat

[Nikolas Andriop]

Hello.
I have an Apparition with TP3640 2100KV on 4S and i was trying an Octura V942/3 and a V940/3 but i cant run at all.Only bubbles and noisy
The Cavitation was to big.What can i do???
Thanks!!!!

[NativePaul]

Drop the pitch and blade count of the prop to gain diameter, an x445 will have no trouble getting you going and will pull less amps too.

[Nikolas Andriop]

I run it with a M445 and one friend give me those 2 octura V version to try but ....nothing!!!!!! Max speed 2 miles

[NativePaul]

The Apparition isn't a big boat and 4S 2100kv should be fine for it so I am surprised it doesn't go with a M445, do you know anyone that has a KV reader to check you have the right motor? Are you confident that the ESC is giving you full throttle (some ESCs dont play well with some radios and have to fiddle with end points to get full throttle)? What does it weigh ready to run? The X445 has a fair bit more blade area than the M445, and that extra area is of a lower pitch designed for low speed acceleration.

[kfxguy]

You probably have the strut too high. The bottom of the strut needs to be 2mm lower than the bottom of the sponsons with maybe 1 degree positive. The m445 or x445 should move it quite well. Never tried the v series so I'm not sure what they will do. I think they have way too much pitch

[srislash]

You also may need to 'Chuck' the boat in onto plane to get those V series props to go. But theM445 should have no issue. Follow KFX's advice.

[Nikolas Andriop]

With the M445 I have any issue.
At 4S I have 50~52 miles
The strut is already 2 ~ 2.5 mm below the sponsons and flat.
The weight with batteries and hatch is 3660 gram ( 8 lb)
I know that prop has a lot pitch (1.9) but I wanted to try!!!
Thanks!!!!

[NativePaul]

The Apparition isn't a big boat and 4S 2100kv should be fine for it so I am surprised it doesn't go with a M445, do you know anyone that has a KV reader to check you have the right motor? Are you confident that the ESC is giving you full throttle (some ESCs dont play well with some radios and have to fiddle with end points to get full throttle)? What does it weigh ready to run? The X445 has a fair bit more blade area than the M445, and that extra area is of a lower pitch designed for low speed acceleration.

[Nikolas Andriop]

The Apparition isn't a big boat and 4S 2100kv should be fine for it so I am surprised , do you know anyone that has a KV reader to check you have the right motor? Are you confident that the ESC is giving you full throttle (some ESCs dont play well with some radios and have to fiddle with end points to get full throttle)? What does it weigh ready to run? The X445 has a fair bit more blade area than the M445, and that extra area is of a lower pitch designed for low speed acceleration.

I never say that it doesn't go with a M445
With the M445 i have 50-52 miles at 4S
My problem was the V series props
The total weight with batteries and hatch is 3660 gram ( 8 lb)
I want to beleive that the motor it is 2100KV because it is custom made

[Heath M]

It obviously doesn't like the v series prop so stick with the x or m series props. Not all boats like all props.

[kfxguy]

It obviously doesn't like the v series prop so stick with the x or m series props. Not all boats like all props.

This.

[Heath M]

To add a bit more info, V props are high lifting props usually used on riggers where the arse end needs to be lifted out of the water. Cats and monos don't need this so x and m props are best as they are low lift. You could try a Y545 prop or a X645 for a bit more pitch. Also i think the diameter of the props you were trying was to small for the hull.

[NativePaul]

40mm is fine for that size hull, but not at that weight, It is the weight that makes it sit low in the water and hard to get going, are you running 4s2p? I would expect nearer 5-6lb for a 4s boat that size, if so the V series may work for you if you remove a pack, just make sure you reduce your runtime a lot as you will have half the capacity as well as an increased amp draw.

V series props are a low lift design like all Octuras that have a letter preceding the name, despite that fact due to the nature of high pitch props the angle of the blades gives them a medium amount of lift, much more than an M/X4xx, but if you compare one to a non lettered prop which apart from the 12xx are of lifting designs with the same pitch ratio like a 938, the V940 has a lot less lift despite being bigger.

[Nikolas Andriop]

Thanks so much for all that information!!!!

[Alex Prop]

Maybe not the topic I've written, but I have to show you! CNC working (stainless steel!
I myself am shocked by what I did! This is my latest achievement)
The diameter of from 61 to 64 mm

Your Doctorprops

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