looks like torque roll causing this?

[JPriami]

The other day I thought I had the boat nearly dialed in.and ran the 58.9MPH with little chine walk issue. though a little lift on the starboard side was the trick.

I ran the thing again yesterday and it was chine walking and I think that was also keeping me from reaching max speed because it only pulled 56mph.

Only difference I can tell is the water conditions are playing a roll. The day it ran 58.9mph the water had a little chop to it. and yesterday at 56mph the water was pretty smooth. Im thinking is it possible that the water conditions helped it with not chine walking?
I tried adjusting the right starboard trim tab and it helped but didn't take it out.

After I got home and watched the videos it seems to be when the boat is spooling up rpms that it leans a little to the right starboard side. Then comes up on plane and then the chine walking starts. I cant seem to trim that out with the tabs. So I am thinking I will try shifting the weight a little more inside the hull. I already have been making it about 5oz heavier on the left port side placing my gps there. Now I had the idea to shift the batteries over just slightly but still in their trays. Just on their sides. I checked this in the bath tub to see if the weight does in fact make the boat a little heavier on the left port and it does. I just hope it helps counter the boat wanting to lean right.
any ideas or thoughts, something maybe I haven't thought of yet is welcome to be brought to the table. thanks,
justin

Pic of what I just thought of trying.

[Brushless55]

I dig how you keep chopping at the block on this!!
and yeah, having some chop on the waters gets some air under the hull to loosen it up and so does the speed

I love to run my UL-1 in chop vs glass

[JPriami]

Lol yeah. I can't seem to quit something till i figure it out. I'd have to put the boat back stock and start another project b4 I quit if I can't get it to do right.

I've read all kinds of other things to do. Like the rudder has to be a certain size. To the propshaft can be offset out the hull. And a bunch of other possible solutions.

I kinda feel obligated too. Since there are others out there trying to do similar and running into the same problems. I want to be able to contribute. I feel just as bad as they do about having this and getting the burnt feeling from traxxas and things not doing what they should.

[Make-a-Wake]

I shift my batteries over in most of my boats..................

[Brushless55]

tell me again what prop your using

[JPriami]

Make a wake,
Thanks. Glad to know this thing hasn't drove me loco to the point I'm coming up with crappy ideas lol

[JPriami]

tell me again what prop your using

M645 S&B from ose

[dag-nabit]

Is there room for two batteries on each side? Either one in front of the other, or make a brick by putting them in side by side (on their sides).

I'm wondering what more weight would do for the chine walking, and also wondering if there is room to do a parallel set up for longer run times.

I know the extra weight will make top end speeds more of a challenge, but can't help wondering what it might do for stability.

Kevin

[JPriami]

im not sure if you could squeeze 2 packs on one tray or not. I cant fit both may packs on one side i dont think. I'll try it after i finish my soup for you :D.

[JPriami]

Kevin,
I was able to get both packs side by side in there. But it was tight and the strap might need to be longer. You could propbally stack them too.

[shctexas]

"J" you're not only contributing but leading the charge! I'm rebuilding mine based on your success. By the way, I now own 3 boats in my brief exposure to FE boating. THANK YOU VERY MUCH!

[Fluid]

Chine walk can be helped in several ways. One is to lower the outside trim tabs, this sometimes helps. Rounding the bottom of the rudder can help lessen chine walking. But the real problem is that boat is too far out of the water now that it's traveling fast. Traxxas mounted the strut low to lift the boat up at the stock 30 mph, now it is too low and is lifting the hull too much. The boat is trying to balance on that narrow keel and any disruption will start it wobbling and chine walking.

The solution is to raise the strut 1/8" or so and see how that helps. It may need to be raised a bit more, only trial and error will tell you. This isn't easy and requires moving the stuffing tube, but it IS the solution to chine walking on most all deep vee monos.


.

[JPriami]

Thanks Fluid. That was something else similar to one of the things I had read. If the shifting of weight dosent do it. I may try remounting the strut.

This thing is about as quirky as the old Alfa Romeos I maintain and drive.

[JPriami]

I just got back a while ago from testing the weight being shifted. It was a little better. When I was at low to 75 maybe 80% throttle the boat wasnt rolling over to the right & no chine. But soon as I go WOT it leans over a little and then starts the chine walking.
the water was pretty smooth and GPS recorded 56.6 Mph

So what Fluid mentioned seems to make sense. And goes along with much of what I am witnessing first hand experience and in video reviews. The boat is trying to balance on the tip of the Vee at WOT. Moving the strut up will allow more of the Vee/Keel to be in the water and help keep it stable. But will it make it slower too?

I guess I'll start some more modifications soon.

pics of the stock strut and hull alignment

[JPriami]

I was just talking to brushless55 and said this to him about the pic above.
"you know the more i look at that pic it begins to look like the boat was supposed to have a slight offset to the right with the strut and slightly higher and they had to re drill the holes when they glued the transom plate thats inside in because they glued it in wrong."

[JPriami]

Screw it, Im going to slightly relocate the strut up a hair and towards the starboard side near 1/8". This should help both the torque roll and chinewalk issues from all the setups I have been reading about.


primed & cleaned

2 part epoxy that bonds to plastics really well PC-7 laid out

drilled out the stock stinger bracket holes so I could fill them in with no air trapped because they will need to be moved over as well.

[Make-a-Wake]

Man................this is major renovation to this boat................hope it works out..........

[JPriami]

yeah me too.
Its hard for me to give up on something after already investing so much time into it.
I can get to that point once I feel like I have extinguished all my ideas. But in the mean time I dont have any other hobby projects so it gives me a creative outlet to do things in my spare time.

[Brushless55]

Keep it up bro, I'm really looking forward to this..

[martin]

The Spartan also has a deeper v than most of the good v hulls that we all know & use. Its around 3 degrees different + theirs no ride pad, Any thoughts on this re chine walk. Thanks Martin.

[JPriami]

My other idea I had was to take the tip of the vee off the hull and make it about 1/4 wide flat. Starting about mid ways up the hull towards the transom. That would help wouldn't it by giving a ride pad?

[dag-nabit]

I'm guessing here, I'm no hull design engineer, but....

If you create a flat pad on the vee to run on, wouldn't that increase the tendency to slip out in the corners and/or increase the opportunity for prop walk?

Kevin

[JPriami]

I'm no hull doc either lol. Just brain storming. Scrutiny welcome.

[JPriami]

This article is what gave me the idea.

"A sharp keel cuts through the water and will limit lift. Even sharp keels have limitations. Ride pads integrated into the hull bottom have to be used once you hit speeds in the upper 50-60 MPH range. At this kind of speed even a sharp strake less keel can provide enough lift to cause chine walking. Trim tabs can help but your really fighting against the physics involved and mother nature will win this one! "

Bellow, a picture of a ride pad on Ron Frank's boat"

[JPriami]

I have also read that most all good fast running deep vees the strakes stop before the transom a ways. This boat dosent do that with the outter ones. They go right into the trim tabs. But if the boat isn't riding there i guess that's ok?

This is what I read off the same article above mentioned.
""The strakes are flat riding surfaces that limit the water from spilling off to the sides. As a result they act like ski's. They tend to make the hull ride on top of the water opposed to cutting through it. The further back toward the transom the strakes extend then the bigger the ski (surface area for this to occur). All high speed hulls eliminate the strakes several inches ahead of the transom or eliminate them completely. This allows the hull to lift up to the point where the strakes end. The rounded keel doesn't help much either. As Don says - it's like a rounded ride pad."

[JPriami]

This is how it's looking so far. I'm probably going to leave the stuffing tube hole the size of the tube and seal it temporarily for testing. If it works good I'll make the hole bigger to put the rubber gromet back in so the tray can be removed easier.

[Brushless55]

Oh yeah!

[JPriami]

Hope it works, Ive heard mixed up things about moving the strut over off center of the hull vee.
I guess if it dosent work I can make the hole bigger with a file back towards the center of the hull and put the rubber grommet back in, but the strut will still be slightly higher overall.
Ive also heard that moving it up will cause problems because not as much water will be getting to the prop. im getting wore out with this thing

[dag-nabit]

Looking good

As usual we wait anxiously to hear the results.

Kevin

PS Judging by the diagram of the ride pad, it looks as though the Spartan might benefit from another set of trim tabs on the inside mounts.

[chummer]

Subscribed...

I am interested to see how this works out for you. It's threads like this that make OSE such a great forum!