Motor suggestions needed

[PaulHeaton]

deep v's draw more current than stepped mono's with hydro's drawing the most.

[stablgr]

What would be an appropriate size prop to start off with if I was to run either a 13L or 8XL on 4S, and what would the maximum current consumptions be for each?

[PaulHeaton]

the best size prop to start with would a graupner 42mm hydro prop. as for amp draw this is hard to say as no one knows the amp draw of the boat.

[astecme]

Paul is an expert so a 42 would be fine but he knows his boats and can set up from the start fairly accurately. I would suggest that you start with a 37 and work up.

[PaulHeaton]

on the subject of props a 42 carbon is not the same as a 42 octura. if you want to aoctura prop run around 4 mm smaller size prop for the same results.

[stablgr]

Thanks guys, I appreciate the help.

[astecme]

on the subject of props a 42 carbon is not the same as a 42 octura

Indeed the carbon props bend and the pitch is reduced - nor are they as efficient as metal props. I would have thought around 2mm smaller for metal though. But it does depend on the starting size.

[stablgr]

The next question I have (sorry there are so many but this is all new to me!) is regarding the placement of the motor. As I see it I have two options. Either mount it as far forward as possible, or as far back as possible.

Mounting it forward would appear to allow me to get the LiPos lower down and closer to the centreline, but restrict how much I can move them forwards/backwards to adjust weight distribution.

Hopefully the two attached sketches will explain my thoughts a bit better

[PaulHeaton]

mount the motor forward with that size hull on 4 cell you will probably need to add lead around 150g

[astecme]

BUT - you need to keep the weight central and allow room to move the c of G a bit - Lay the main components out and rough out their position to give you a cog 30% fwd from the transom as a starting point.