Leopard 4092 motor

[sport hydro]

I am looking at putting the motor into a 1/8th scale hull per IMPBA rules. The motor comes in 7 versions:
700 Kv/rpm per volt 4Y
930 Kv/rpm per volt 3Y
1050 Kv/rpm per volt 5D
1390 Kv/rpm per volt 2Y
1480 Kv/rpm per volt 3.5D
1730 Kv/rpm per volt 3D
2080 Kv/rpm per volt 2.5D
which one is best suited for the scale?

 

[Chris Thomas]

Are you planning on running it locally or against other clubs. I guess for fun or competitive. Most guys are going 8S or 10S in this size hull. So 8S @ 3.7 v per cell = 29.6 V pack
29.6V x 930Kv/rpm = 27,528 rpm not including slip (efficiency). That pretty good R's if you were running Nitro scale. Not really an apples to apples comparison. But, I am experimenting with this combo myself this year. Let me know what you come up with...

 

[RaceMechaniX]

Perhaps Don will chime in, but rules allow either 8 or 10 cells fro what I see online.
You will want the 700kv motor for 10S and likely the 930kv motor for 8S.
Any higher KV and you will be running very small props to keep the load on the motor and ESC reasonable.

In my experience I would shoot for a loaded RPM no higher than 10% above a competitive nitro scale.
I use 3.7-3.8V for my battery voltage under sag. you can assume 15% efficiency loss for the motor and controller combined.

 

[sport hydro]

It will be running at the local pond for now. I will be running with 2- 4S 5000mah batteries through a ZTX 200a ESC.