New thrusters with ducted fan unit

[nomore]

Hi!

I'm working on a new ROV very similar to The Seafox design. For thrusters I want to use brushless outrunner DC motors with electronic speed controller. And I think I've found a working combo, but want to chech with you experienced ROV builders before I order

The motor: Turnigy Park300 Brushless Outrunner 1080kv http://www.hobbyking.com/hobbyking/stor ... 080kv.html


The ducted fan unit: http://www.hobbyking.com/hobbyking/stor ... 6inch.html


The ESC: Turnigy Brushless ESC 18A w/ Reverse http://www.hobbyking.com/hobbyking/stor ... ramm_.html

On the motor specs it says that the motor pulls maximum 9A. Running in water, with the above ducted fan, I expect it to be a bit higher. And at the same time, I'm not going to run these on full power(which would be around 12,000 RPMs(!) if my numbers are correct). So I think 18Amp ESC would do. Either way, it's the only ESC I can find on HobbyKing which is air cooled, and a working reverse program.

The ESC's should be controlled by a Arduino uC, so I can limit the controll signal for speed(and perhaps build in a "power" mode for short runs where extra speed is needed).

Any inputs? Should I forget about the ducted fan and go with simple propellers instead?

[nomore]

A new combo

This motor: NTM Prop Drive 28-36 750KV / 265W http://hobbyking.com/hobbyking/store/uh ... duct=19611


And this ducted fan unit: http://hobbyking.com/hobbyking/store/__ ... _70mm.html


The reason why I changed was that the ducted fan in my first post had the wrong shaft diameter. These two should fit nicely. And in addition the motor has less RPM's pr volt, and higher amps. Which might suggest higher torque?

I'm also pondering on ordering normal boat propellers at the same time. If the ducted fan proves unfit I can still use the casing and just mount the propeller directly on the motor.

[bikerbones1968]

Hi nomore, Hobby King also has these...



http://www.hobbyking.com/hobbyking/stor ... duct=11742

These are the ones I just purchased for my 750kv brushless outrunners. $14.99 ea and 10 in stock.

I am using 52mm boat props.

[nomore]

Thanks for the reply. The reason why I kind of skipped that ESC is the lack of reverse programming information. If if goes straight into reverse or if you need to brake first, then go back to neutral, and then reverse. Like some car ESC's works.

But when I check the comments I see that this question has been asked and answered, but perhaps you could confirm this as well?

[bikerbones1968]

I should know more later this week. They havent arrived yet. If you look at the hobbyking link again below the image there is a "discussion tab", "reviews tab", "videos tab" and the "FILES" tab. You can download two manuals.

[MaPe]

Also this one has reverse. http://www.hobbyking.com/hobbyking/stor ... _ESC_.html. Already tested.

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[bikerbones1968]

Thanks for the reply. The reason why I kind of skipped that ESC is the lack of reverse programming information. If if goes straight into reverse or if you need to brake first, then go back to neutral, and then reverse. Like some car ESC's works.

But when I check the comments I see that this question has been asked and answered, but perhaps you could confirm this as well?

Nomore, the esc's arrived today. They are completely programable and only a quick pause from full forward to full reverse. I had to change the default reverse setting to 100% it was 50% by default and I reduced the brake force also. It was easy to program with the "key" button from the manual I downloaded.

[nomore]

Thanks for the feedback. I'll order some this weekend

[bikerbones1968]

Nomore, when you get the ESC's also program the running mode to the mode "two" It comes default mode "two 2" and requires a brake, full stop, then neutral, before reverse. In mode "two" it quickly goes from forward to reverse witha milisec pause.