Brushless conversion of a Musculus toy boat

[seehuusen]

I re-checked my COG, and the numbers would add up to me needing to adjust the stinger and trim tabs...

Boat is 520mm long

• No Battery 140mm COG from transom - 26.9%
• 2.2A 3S 130mm COG - 25%
• 2.65A 3S 125mm COG - 24%
• 2.65 4S 115mm COG - 22%

So my COG is way back on the boat, there's no other reason to my mind why it would have to be change... If anything, my understanding is that it needs to be moved forward, in an ideal world?

Cheers,
Martin

Edit: Make-A-Wake: didn't see your post suggesting to check COG, thanks for the input, really appreciated mate :) So the above numbers is very close to what I got when I started out with the rebuild, hence why I talked about the stinger/tabs... What do you reckon mate?

[785boats]

I was thinking about coming down 11th or 12th, so that might coincide perfectly :)
I do wonder, I don't have the safety power cut-off lanyard on the outside of my hull, well I don't have any on the inside either LOL What are the rules surrounding that?
What time do you run in the afternoon?

Martin.
On the 11th we will be at Boondall all day, from about 8:00am till around 4:30pm. Come & have some fun.
The safety loop isn't necessary at Boondall. Only at our race club at Petrie. So don't sweat on that.

I should have the Dolphin running by then so we can run them together.
I've just fitted a pair of small turn fins. Not much room on the transom so I had to use the outside trim tab mounting screw for one of the turnfin mounting screws too.
Here's a pic of the fins added. All the other hardware came with the boat.
And a pic of the little 1500kv motor that comes with it. Interested to see how that little motor runs. I feel it will be a bit under powered as this boat of mine is made of some pretty heavy glass, for its size.

[Make-a-Wake]

Shouldn't be running wet with those cog's. Paul can help you with it when you go visit him I guess.............til then maybe move it forward a bit just to test.

[785boats]

I agree.
With the COG that far back boats usually get very flighty.
If there is negative angle in the stinger, that could be causing the boat to run wet.
Check the angle of the stinger with a straight edge along the keel & adjust the centerline of the stinger to have a bit of positive angle, ie prop end up a bit. About one degree or so to start. It may need more. But test that first.
Same with the trimtabs. Place the straight edge along the hull under them & make sure they are not angled down. Actually I would angle them up as far as possible until you get the setting of the stinger right & the bow is not running wet. Then bring the tabs down if needed.

[seehuusen]

Thanks for your input guys

I've got the stinger sitting at pretty much zero degrees, and that is at it's max up position... I've re-adjusted the trim tabs, and will take the boat out again in an hour or two (waiting on a couple more batteries to finish up)
I'll report back :)

[seehuusen]

ohhhh yeah! now we're talking :)
On 4S it screams for that little boat, stability is right there on the edge, prop/motor twists the boat on too much punch on the throttle :D
Gotta trim the trim tabs down a touch to see what that does for stability, but it is looking much better!

Thanks for your help guys :)

Paul, I'll certainly get your input on it when I pop down next Saturday.


Vid to come...

[785boats]

No worries Mate.
Sounds like all you need now is some small turn fins for the corners.

[Make-a-Wake]

You need to possibly lower the port side trim tab 1-2mm as that is the side that drops...............not both tabs

[seehuusen]

thanks for that suggestion Make-a-Wake, I'll try that out on my next outing :)