Brushless Motor kv Question

[Steve]

Hey Guys!
I have a small RC boat, the FT009, [17 inches] was having a blast wave jumping in the Gulf, then the ESC died.
The power plant is a brushed 540 motor and corresponding ESC.
I figured, being addicted to upgrading and all, I'd promote this boat to brushless.
So, here's the question:

On a boat, with self-righting, which would be optimal?

• Lower kv's, like 3900-4800 range, to get outta the hole
• Higher kv's, like 5200 and up, for their faster spinning and top end?

While this should prob be posted in the Electronics section, this might get more views in General Chaos.
As always, thanks AF Members!

-Steve

 

[Rdub]

Hey Guys!
I have a small RC boat, the FT009, [17 inches] was having a blast wave jumping in the Gulf, then the ESC died.
The power plant is a brushed 540 motor and corresponding ESC.
I figured, being addicted to upgrading and all, I'd promote this boat to brushless.
So, here's the question:

On a boat, with self-righting, which would be optimal?

• Lower kv's, like 3900-4800 range, to get outta the hole
• Higher kv's, like 5200 and up, for their faster spinning and top end?

While this should prob be posted in the Electronics section, this might get more views in General Chaos.
As always, thanks AF Members!

-Steve

Good luck with your upgrade, Steve!!! I'm tuning in to hopefully learn a thing or two. I've always been interested in the RC boats, just felt I'd never get enough use out of it. Maybe this will spark some interest.

 

[Steve]

Good luck with your upgrade, Steve!!! I'm tuning in to hopefully learn a thing or two. I've always been interested in the RC boats, just felt I'd never get enough use out of it. Maybe this will spark some interest.

Thx @Rdub !
I'll have to post some pics of the FT009.
I picked it up pretty cheap on Amazon, was running $80 on my watch list, then got notice it dropped to $30 so I pulled the trigger.

 

[Rdub]

Thx @Rdub !
I'll have to post some pics of the FT009.
I picked it up pretty cheap on Amazon, was running $80 on my watch list, then got notice it dropped to $30 so I pulled the trigger.

Wow that's a great deal! The closest I've ever had were the cheap toys r us ones for the pool, which aren't even close to hobby grade (and we're probably 29.99).

 

[MSgt]

I haven't messed with RC boats, but deciding on a motor is going to depend on the prop diameter and pitch, similar to gearing and tires on a car... I have no clue what to do to tune the boat though.

 

[Rdub]

I was surfin around the web and any boats that called out the kv on the motors were all in the 1800 - 2200 range.

 

[Steve]

I was surfin around the web and any boats that called out the kv on the motors were all in the 1800 - 2200 range.

I noticed the entry-level brushless boats at Horizon Hobby were 2900kv - Recoil and 2000kv - Blackjack.
The self-righting system brings the boat up using the torque of the sudden direction change of the prop shaft, so for more torque to accomplish the self-righting, the lower kv range makes sense.
Thx @Rdub for your search!