Miss Geico setup issues

[miguelflores0928]

I have a dual motor Miss Geico 36? and I?m struggling to keep the front of the boat from bobbing up and down at speed. I clocked 57mph around half throttle and I can?t seem to go any faster because I fear the bobbing will get so bad that it?ll flip and crash

I?m using stock props and stock transom hardware and struts. They are adjusted all the way down. I?m running dual spektrum 160 amp ESCs each capable of 8S using dual parallel 6S 5000mah packs and a pair of Traxxas 2400kv motors. Sometimes I even use extra batteries as ballast to help keep the front down.

I can?t seem to figure out how to remove the bobbing. If I bring the struts up, the bobbing gets worse. Adding weight doesn?t seem to affect anything.

Thoughts?

[Xrayted]

I'm assuming your batteries are placed in the middle of the boat on the factory battery plate? Ive always had the same issue with my MG as well doing it like that, until I found a 6S lipo that would barely fit under the deck, so I have two 6S packs pushed all the way forward under the deck as far as they will go. Even with all the weight forward, I still need to be gentle on throttle and slowly get the model up to speed or else it will try and do a wheelie or start bobbing. I can get up to full speed without blowing over with proper throttle control.

I'm getting 90MPH with custom props on the factory motors. You are running 2400 KV motors which is quite high for 6S and even more than the already high factory 1900KV motors, and is likely going to cause heating issues with the electronics if run for more than a minute or two constantly. Make sure to keep a check on things once you finally get it to the point of running, otherwise you might overheat the electronics and start to desolder connections. Even the factory setup runs hot on 6S, so you are going to have a challenge keeping things cool

Just an FYI in case you are unaware, but the factory prop is a clone of the ABC 1716 prop, so 1.7 (43mm) inches diameter with 1.6 inches (41mm) pitch for a total pitch of 2.72 inches. Anything with more diameter or more pitch is going to load things up even more for you, so keep this in mind if playing around with different props

Good Luck!

[miguelflores0928]

I don?t have any heat issues with my setup, runs very well! I?ll actually sit at full throttle for drag style pulls up to about 50 then let off. It?s very durable and stays cool so I don?t think I have any issues there. The reason I run this setup is because I found the Traxxas motor to do surprisingly well in boats and the 160 amp ESC is a powerhouse. If it can power a blackjack 42 up to 60 with an enormous prop with no issues then it?ll power this smaller motor too, and it does! I run the same setup in my hydro, just with one ESC/motor instead of two.

Anyway yeah my batteries are shoved way forward under the deck. You can barely see them. I?ll also put in another set of batteries between the main batteries and ESCs just as ballast, not connected in any way. Still bobbing. Even if I roll on the power slowly on glass water, it?s like flipping a switch it goes from butter smooth to choppy instantly at 50mph

Here are some photos of my setup with a video at the end

https://imgur.com/a/pKav0sI

[Xrayted]

It's possible that your boat hull isnt properly flat on the ride plates which will cause the water to flow from them improperly, sort of sucking the boat down onto the water instead of letting it ride free likes its supposed to. The additional drag can cause the nose to lift, then you let off and it drops and then the process keeps repeating when back on the throttle again.

Many will do something to correct this if its the case called blueprinting the hull. Do a Google search for RC boat hull blueprinting and you will find lots of post and videos of how this works with before and after runs on some of them. One of the symptoms of unlevel/uneven hull ride pads is porpoising that doesnt change no matter how you adjust the boat hardware.

Yes, running your 2400KV setup on 6S for short burst like you are doing will work out just fine. The problem will occur when you try and run it for long periods like you would in a heat race, and by long I mean 2 minutes constant

[miguelflores0928]

Yeah I know what blueprinting is. I guess I have a new project! Thanks

[fweasel]

I ran my four 3S packs straight across, two up on the stock mount halfway under the deck and one down in each sponson under the foam blocks. I did run my drives with a negative trim angle, but not full negative. Once you get your ride attitude sorted, that setting will certainly cost you speed.

[miguelflores0928]

So I should be figuring out my ride first, eliminate the bouncing, then adjust the struts accordingly?

[fweasel]

Not necessarily, as both weight distribution and trim angle directly affect ride attitude. Once you get more battery weight forward, I would adjust your drives up a little, still down a few mm from neutral, so they're not forcing the hull down into the water as much and scrubbing speed.

[Racingjake]

Anyway yeah my batteries are shoved way forward under the deck. You can barely see them. I?ll also put in another set of batteries between the main batteries and ESCs just as ballast, not connected in any way.

Those rear batteries are just dead weight now, remove them and put them in the sponson to move your C/B forward and see if that helps.

[dasboata]

I do a modified set of 447 that help keep the bow down !

[miguelflores0928]

Thanks for the advice everyone! It?s raining today so I?ll set up the boat how you guys recommend on the next sunny day

[leski379]

What are the wind conditions like where you are running? I just ran my MG36 and I had 5-10mph winds blowing one direction. I could only get about 1/3 throttle running into the wind before she's hopping/proppin wheelies and just one trigger pull away from blowing over. When I drive with the wind, full throttle no problem. This is with 4 3s packs in the factory trays (4x 6900's she's heavy). Stock props, struts down, but not all the way down. Sponsons/ride pads have not been modified, and when the boat sits on a flat surface, you can rock the boat left to right a little. My hull really needs some work and could be much better but it works.

[miguelflores0928]

I don?t run on windy days so there is no wind in my area when I?m running