Rio EP brushless conversion HELP??????? plz

[aminoacid]

Some pics. Center of gravity is about 7.5 inches from transom. 25 inches from back to front. pushing batteries back as far as I can get them gives me a 7.75 cg , close.
I like the turn fin ideas, those would be fine tuning I assume. Notice proximity of rudders to prop, literally will hit the prop if the rudder turns far enough. I had the prop pushed inwards towards the transom when videos were taken. Could the prop wash be hitting the rudders too much contributing to the roll? I will pull it out maybe 1/8 inch or a hair more? What u think?


I have a spartan stock, it screams an a bit unstable wobbly at full speed. This rio is more exciting to me and more fun because we try things out and build, creativity is wonderful.

[aminoacid]

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[Make-a-Wake]

Some pics. Center of gravity is about 7.5 inches from transom. 25 inches from back to front. pushing batteries back as far as I can get them gives me a 7.75 cg , close.
I like the turn fin ideas, those would be fine tuning I assume. Notice proximity of rudders to prop, literally will hit the prop if the rudder turns far enough. I had the prop pushed inwards towards the transom when videos were taken. Could the prop wash be hitting the rudders too much contributing to the roll? I will pull it out maybe 1/8 inch or a hair more? What u think?


I have a spartan stock, it screams an a bit unstable wobbly at full speed. This rio is more exciting to me and more fun because we try things out and build, creativity is wonderful.

So pushing the batts all the way back puts the cg at 7.75" from the transom? If so you are at 31%...............where was it before?

Im with you on the creativity..............i have just as much fun with my brushless Villains that i built from the ground up.

[aminoacid]

I didnt check what the cg was before i moved batteries back, but i moved them back at least 2 inches.

wondering if i can shave down the prop I have to shrink it a little and give it a whirl, water here is freezing and i doubt i have a week for props to arrive in the mail.
If I shave the entire blade edge equally, will that work for a temp fix?

[Make-a-Wake]

I didnt check what the cg was before i moved batteries back, but i moved them back at least 2 inches.

wondering if i can shave down the prop I have to shrink it a little and give it a whirl, water here is freezing and i doubt i have a week for props to arrive in the mail.
If I shave the entire blade edge equally, will that work for a temp fix?

Yeah, just for a temp job................i've done that before, wouldnt recommend a whole summer of running that way, but on a cheapy plastic prop i'd do it............try to get it as close as you can to equal. Then with the new cg and smaller prop it should run better.

[aminoacid]

I actually found a 32mm prop from traxxas blast that I modified a bit the shaft hole and got it to work for now.ill give it a run tomorrow. Quick question about lipos I have 5000mah and a complete charge is showing about 2100 mah on the charger which is onyx 235. I have the charger set to 5000 mah capacity. Both batteries are showing up like this. Showing about 4.2 volts each cell. Charger has built in balancer. Ideas? Batterie are bran new turnigy 2s.

[Make-a-Wake]

4.2v per cell is fully charged, brand new turnigy's come in storage mode at 3.85-3.90v per cell so they wouldnt take a full charge.

Looking forward to hearing/seeing how it runs now...................one more thing, you may need to move the batts up slightly if it porpoises bad on the first short run.................just play with em.

[lenny]

You could remove the left rudder to, And it may help some with the roll and drag.
Your prop dog should be out from stuffing tube no more than 1/8 " and should not hit the rudder with the stock 42mm prop.
If it does, Adjust your steering trim on your tx so the rudder will not hit the prop.
Where are the lipos setting at in the hull ?
I think you could rotate the esc for better cg to,
May be with a bridge across the cells with velcro strapping to hold in place for easy in and out,
With the cells to.

Need some picture with lipos in the hull.

[JoeOvercoat]

Lenny ~ how might offsetting the left battery aft/right battery forward mitgate torque roll?
Is the idea to put the counterweight closer to the plane of the prop, to reduce lever arm length from counterweight to torque/walking force?

[JoeOvercoat]

Possibly the batteries are fully charged, given the 4.2V voltage each cell (balanced, to boot), and it was just that they only needed 2100mah of juice to get to their 'full' 5000 mah capacity (more or less: I've read that new lipos need some cycles to get up to snuff, then I expect they drop off as they age). You might be able to get some advice from Turnigy directly via [email protected].

[aminoacid]

UPDATE

32mm prop
batteries moved back as much as possible
pulled the prop/shaft out little less than 1/4 inch
a little snow falling towards the end of video. time is running out!!!

Results: I can now get somewhat of a plane on the boat. 32mm is too small/slow with too much cavitation. never had porpoising either way.
Still leaving to the right, but much less, so turning right will make it 360. often i couldn't get it to go straight, it'll go left to right, im thinking prop wash.
V I D E O with improvements.
I might try using 1 battery placed on left side, going to 35mm prop and see what happens. have to wait for the prop to come in. Good plan? should I keep the 32mm prop and use another brushless i have rated at 2600kv?
I seen a youtube vid of this, he said he's using 2600kv motor, 3s lipo, 38x55 metal prop..... but WHERE should the battery be placed?

[aminoacid]

that might be correct, not sure if thats what the charger means that it only gave it that much mah. on 2x2s 5000mah ...i only got about 12 minutes of run time in this last video. ... doesn't seem right does it?

another note, i took out the spartan too and one battery swelled up like a damn sausage. turnigy said take a pic, we need to see volts of each cell and send the email. wtf?

[Make-a-Wake]

OK.................gettin somewhere now!! Thats really not much cavatation at all............a bad case is when it just sits still and stirs the water, it only takes a couple seconds for you to get on plane. I bet the x435 will be the sweet spot for propping. You may have your steering rate up too high, either that or the rudder throw is set up to far..........thats mainly why its spinning out, basically turning the rudders too far at speed, plus FE boats hate to turn left.

The x435 should get you the bite and speed you want without the bad torque roll the 42mm was giving you.

You hit full throttle in the vid a couple times?

[aminoacid]

Also, Now you have a lot more power,
So you will need longer turn fins to.
I made my turn fins 1/2"longer and trim tabs 1/4 longer then stock the ones.

so the width of the trim tabs is ok, just need to extend them away from transom a bit?

[aminoacid]

You hit full throttle in the vid a couple times?

actually most of that video was full throttle except turns and when it's starting to act crazy on me