Which prop?

[JohnZ]

Decided to run my 21" Oval master on 3S, leo 3650/2930 KV but unsure about prop and current draw.
I have several props a couple I believe are too big but will throw them in anyway: Octura X632, 1732, X445-too big?
Grim Racer 42X55- too big?
Not going to be racing but looking for good speed anyway. I decide using a 2S pack was not really going to be any advantage.
The one thing is there are no current ratings provided for the Leopard motors so I'm guessing somewhere around 40-50 A. for that motor.

[CraigP]

You should be able to find the current ratings on the Leopard web site...

[Meniscus]

I would venture to guess that on a 2930kv motor on 3s, your loaded RPM may be around 20,700 for a mono. Taking that into consideration, as-well-as adding slip to the equation, the X632 would be about 39MPH. I would guess that as-long-as the boat doesn't run too wet, amp draw would be close to 60A in the turns, when fully on plane, maybe a little less. Again, this is just a guess.

The real question is the overall weight of the boat. Many years ago, I ran some different 36x50 2-pole motors at much higher RPM on 3s, but only saw 80A. What is the overall weight of your boat, RTR?

The other props mentioned sound like a lot from that motor. I would imagine it tops out at around 1200 watts or so, but I don't know which motor version you have and haven't tested with them on a setup like this.

[Speed3]

A x632 or x435 I can imagine being good props for that setup.

Unloaded rpm would be over 36000 rpm.

I would definitely true x632 or x435 if it was me.

[JohnZ]

I would venture to guess that on a 2930kv motor on 3s, your loaded RPM may be around 20,700 for a mono. Taking that into consideration, as-well-as adding slip to the equation, the X632 would be about 39MPH. I would guess that as-long-as the boat doesn't run too wet, amp draw would be close to 60A in the turns, when fully on plane, maybe a little less. Again, this is just a guess.

The real question is the overall weight of the boat. Many years ago, I ran some different 36x50 2-pole motors at much higher RPM on 3s, but only saw 80A. What is the overall weight of your boat, RTR?

The other props mentioned sound like a lot from that motor. I would imagine it tops out at around 1200 watts or so, but I don't know which motor version you have and haven't tested with them on a setup like this.

It is not the X2 version. Just the 3650/2930KV

[JohnZ]

I figured the others would probably be too big . I remember buying those larger ones to use with a lower KV motor ie: 2200KV. Looks like I'll have to get an X435.

[Meniscus]

Speed3 has made a good suggestion with the X435. You'll want to detongue for sure, but I run that prop in several of my 3s boats.

JohnZ, I don't know that I referenced the X2 version, so I am confused about your post. I was calculating purely off of the 2930kv and the motor size.

I looked in my prop box again last night and have a few other suggestions. Sometimes, the Y535 can be used, if the model likes that prop. However, you have to be sure your setup is fairly light or it can create issues. Here are a few other props to consider:

• Grim 36x55 - does pretty well with monos sometimes. This would be a prop-up, so be careful to monitor amp draw. This is not a 1st choice for testing.
• Tenshock props, if you can get them:
  • 32x36 (32mm with a 1.42 average pitch)
  • TSJ-K4834 (34mm with a 1.41 average pitch)
  • TSJ-K5036 (36mm with a 1.39 average pitch)
  
  
• Octura 1.25 (31.75mm with a 1.8 average pitch) - this can sometimes be used if the model is light.
• Propshop 3214 (32mm with a pitch of 1.4, but it is progressive) - may be too little blade area, but it works with models that get on plane well.

Hope this helps.

If you find that you are not seeing a lot of heat or amps, I believe you have a Wye wind and you could advance the timing on a smaller prop that the hull likes. You just won't have as much acceleration in most cases, when compared to a larger diameter, especially on smaller boats.

[JohnZ]

Leopard makes an X2 version of their inrunner motors: https://www.offshoreelectrics.com/pr...od=leo-3650-X2
The answer I'm looking for is the current rating for this motor and no one seems to know. I can't find it on Leopard 's website either but I would hazard a guess it's around 45-50 A. The motor is a 2.5 Wye.
Like I said, I won't be racing this boat. There are no clubs in my area so I don't need to get all out maximum performance either if it's going to fry a motor.

[Speed3]

http://www.leopardhobby.com/html/en/pro/Car/LBP36xilie/20150916/47.html

I think this link should give the ball park rating for the motor.

The v1 leopard should have the same specs as the x2.

[Meniscus]

Excellent find Speed3! Steven should be able to tell us what updates they made to this motor. It could just be an update to the bearings.

[NativePaul]

2930kv is a bit of a poor compromise if you want to use Octura props, there is a huge difference in amp draw between an x435 which is the big end of 1/8"drive, and x437 which is the small end of 3/16" drive. With a motor that size you should be able to use an x437, but it will be pretty amp hungry.

For a 21" boat I would use a smaller 28mm motor and either drop the kv to 2800 is to run 3/16" props, or raise the kv to 3400 to use 1/8" props.