Which prop? 12s mono

[Mattwarner]

Hi guys

Building a 46" deep v mono, running a Leo 5692 740kv on 12s with a 300a 16s esc and 1/4 drives, but what prop should I be spinning? I am after a sport setup and want things reliable, was thinking of something like an X452/3? But really have no idea

Also there doesn't seem much selection for props for the 1/4 drive, should I go for a stepped down flex to 3/16?

[Old Sloppy]

Go with a stepped down flexcable. Your motor is a 10s, not a 12s, prop needs to be less diameter, around x646/3 or x447/3.
In fact, with the proper prop you might settle on 9s.

[Rumdog]

Go with a x457 minimum. Any smaller is useless, and won't efficiently push your hull

[martin]

I agree 100%, you want a larger diam prop on that size boat. Larger the diam the more efficient the prop will be to push a large boat like that. Obviously as Rumdog says you need to go down to a 2 blader to be able to turn larger props.

[Mattwarner]

Thanks, quite a few people are suggesting the x457 as a good starting off point

[Old Sloppy]

Thanks, quite a few people are suggesting the x457 as a good starting off point

Are these people suggesting a x457 with 12s and 740 KV ?

Harry

[Mattwarner]

Yep that's te one everyone so far has recommended to me, what's your thought? although I am going to start off on 9s and see how it goes.

[Old Sloppy]

what's your thought? although I am going to start off on 9s and see how it goes.

I am thinking about post #2

Harry

[cugino]

Go with a stepped down flexcable. Your motor is a 10s, not a 12s, prop needs to be less diameter, around x646/3 or x447/3.
In fact, with the proper prop you might settle on 9s.

Hi How do you know, 5692 740KV is 10S motor? With 12S it spins about 32000rpm and it seems still good for me? And higher Voltage means lower Amp draw with proper KV motor. So can anyone explain me, why 5692 740KV is 10S motor? Thanks.

[Make-a-Wake]

In order to spin a "larger" prop..........457 or better, 10s seems to be the max to me as well. The 5692, as good as it is, is no Castle 2028. It will have trouble spinning a 457 on 12s. I recommend 10s and an x457, if 12s is settled on then the prop will be smallish for that hull...........55mm or less.

[cugino]

Thank you for your reply.

If i understand, it means that 5692 740KV is too hot spinning X457 prop, right? Ok, then, what is max safe temperature for Leopard 5692 motors and where to measure (bearing, cooling jacket, front of motor?).

Sorry for offtopic, but does anyoune know?

THX.

[Make-a-Wake]

I'd try to keep the temps below 140* on the endbell.

[Old Sloppy]

higher Voltage means lower Amp draw with proper KV motor. So can anyone explain me, why 5692 740KV is 10S motor? Thanks.

2 items here:

"proper KV motor" take your chosen lipo cell count (12s) times 3.7 (volts) times Kv = RPM's
so 12*3.7*740= 32,856 RPM'S (TOO HIGH OF RPM'S FOR LONG LIFE OF THE MOTOR)
My 14s Lehner 2280/15 motor has 471 KV so 14*3.7*471= 24,397 rpm's ( this motor will last a long time)
and 10s 10*3.7*740= 27,380 rpm's ( long term performance without total destruction)
So the Proper cell count for your motor is 10s.

next item "higher voltage means lower amp draw"
the only way this happens is if you decrease (one or both) KV of the motor or less load (smaller prop + smaller hull too )
In theory .......6s with 3KW = 3,000/22.2= 135 amps
12s with 3KW= 3,000/44.4= 67.5 amps
Normaly ....... Higher volts = higher heat generated .