Pretty new to this stuff, advice on prop needed

[Assocracer]

I'm working on building a shallow v hull 42" boat. Right now I've got the option of running 2-6S for batteries, with a 2000KV 42mm motor. Not quite sure where to start with what prop to use. It's going to use a 3/16" shaft. Any help would be great. Just let me know what else you guys need to know.

[Fluid]

First off, ditch the motor. The Kv is way too high for a hull that size and you will burn it and/or the ESC up. How long is the motor? It should be a minimum of 92mm long for that boat...

What are you performance expectations? You will want at a minimum a 40 x 92 mm inrunner with a Kv around 1000. On 6S2P you will have a good running sport boat assuming it is reasonably light and well designed.


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[Assocracer]

To be honest I'm not really sure yet. The motor is a 40mmx74mm. I'll look into getting a different motor as this motor wasn't all that expensive to begin with. I'm not sure how much I'm going to be into this so I don't wanna spend a whole lot of money right away. If I like it then I will probably drop some cash on it. At some point maybe some kind of racing but for not just putting around, so I'd like to get a bit of speed out of it.

Edit: Motor case is 74mm, motor length with shaft is 91mm. Am I looking for a 92mm case length or full length with shaft?

[Assocracer]

Oh, and if you can, if it wouldn't take too long, educate me on selecting a motor. Why a 4092 and not a 4074? Why not the 2000KV with a 2S setup? That would be the equivalent of of a 1000KV with a 4S setup wouldn't it?

[Assocracer]

This is the boat btw.



Not sure what it is. I've had the hull for about 15 years or so. Someone told me it was a Dumas but don't remember the model.

[martin]

92mm case length, the 4092 motor will produce more power & more torque allowing larger props than a 4074 motor.

[Fluid]

Okay, what matters most here is voltage and you seem confused about that (no problem with that, no one is born knowing this stuff). Your 6S packs will each produce 22.2 volts nominal. Wired 2P gives the same voltage but twice the capacity/runtime. A 2000 Kv motor on 6S will spin over 40,000 rpm, way to high for a sport boat that size. You will want to be closer to 22,000 rpm, with a larger motor for more torque to spin a larger, more efficient prop for that big boat. A Leopard 4092/1050 motor like OSE sells is relatively inexpensive, of decent quality and will give good performance.

It looks to me like your boat could be an older Dumas deep vee, these were tough hulls but on the heavy side. You will need to build a hatch which you can seal VERY WELL, preferably with the seam taped. FE boats do not like water in the hulls, the hull must be sealed. This is one of the hardest things for new FE boaters to understand. Too, I am amazed at the number of relatively experienced boaters who tolerate water inside their boats. I have taught my fellow club members how to build a dry boat, and water problems are rare for them.

[dasboata]

don't think dumas,?? looks like a youngblood ,,I think spartan ? realy shallow vee ,,, turns like poo but fast in the straights

[Assocracer]

Yeah, I know I need to build a cover for it. I will silicit help doing that once I get the electronics and hardware all installed. I was looking at the Leopard motor you mentioned. I wasn't planning on buying a new motor so this project is going to have to wait a few weeks as I just dropped some money on my quad. It's definitely not a deep vee, the hull is pretty shallow. Luckily though I have an old Kyosho catamaran nitro boat that I'm planning on converting to electric that isn't as big as this boat so hopefully the motor I have will work for that one.



The Kyosho boat. Can't remember what the name of it was. Picked it up BRAND NEW for like $75 about 5 years ago. I don't like the nitro motor. It's really finiky and hard to get to stay running once you toss it in the water, even if I toss it forward with some good forward motion. Figured it'd be a good platform for an electric conversion once I'm done with this one.

[Assocracer]

And I'm a dumb ass, it's a Kyosho Heatwave :)

[Assocracer]

I think the Kyosho hull is 30"? It's quite a bit shorter than the other hull I have and lighter. Will that 4074 motor work? Maybe run it on a 2S setup to keep the rpms down?