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.

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/IMG_0124-1.jpg

[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! :wink:

[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
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/f02f8880.jpg
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/0dd0accf.jpg
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/0dc9b67f.jpg

[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."
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/0dc9b67f.jpg

[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.

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/fa888416.jpg
primed & cleaned
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/047f3692.jpg
2 part epoxy that bonds to plastics really well PC-7 laid out
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/229955cc.jpg
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.
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/39206dd5.jpg

[Make-a-Wake]

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

[JPriami]

yeah me too. :Praying:
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"

http://img.photobucket.com/albums/v337/Jpriami/37b6090f.jpg

[JPriami]

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/debacbdd.jpg

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.

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/c09aac20.jpg
http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/d673c1fb.jpg

[Brushless55]

Oh yeah! :thumbup1:

[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 :thumbup1:

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!:buttrock::buttrock:

[JPriami]

This mornings test was a little inconclusive. First few mins of it looked better. The boat wasn't chining as much. I was able to hold WOT and make some decent passes. Then noticed the boat wasnt tracking straight and had to adjust the rudder trim to fix( I'm guessing because the force exserted on the hull isn't in the center line of the hull). After that it seemed to want to torque roll over on it side worse at low/mid speeds. But would still go ok at wot. Then there was a drive line failure. at first i thought it was lvc. But the boat wasn't moving. Then thought I lost a prop because i could still steer the boat. Sent out the rescue boat to get her back. Found out the collet started to slip on the shaft. It was pretty tight in there too odd how it lost the bite.
I think I'm going to move the strut & stuffing tube back over to center of the hull but keep it up a bit from the stock location.
Gps recorded 55.4mph on this run.

[Fluid]

Ive also heard that moving it up will cause problems because not as much water will be getting to the prop.

That statement was made by someone who does not have much experience with surface drive setups and has a poor understanding of them. Right now the hull is riding too high because it is riding largely on the prop. To settle the hull down into the water to reduce chine walk you need to raise the prop. The hull will ride lower but plenty of water will still get to the prop. Heck, the whole idea is to reduce the amount of water going to the prop!

Sorry you are getting wore out by the Spartan, but it is sometimes difficult ot impossible to turn a sow's ear into a silk purse.


.

[JPriami]

That's true Jay about turning it into something it not. I just want it to at least be a better one that how it came. I'm not giving up yet. But I know in the end it won't be a gem. Just better. Btw thanks for the help.

Honestly im ready to start my next project (just want to finish this one up first). Building a cat little larger than the one i have now with twins.

[Greg Schweers]

The next thing I would try - bending the outside corners down on the trim tabs a little bit to see if that helps. For an example: I ran my new Insame mono last week for the first time, and I also ran the stub shaft .400 thousanths above the bottom of the boat. I always backcut the props on my mono. With the first set of batteries I ran, the boat was chime-walking really bad. The next set of batteries, I turned the outside screw on the righthand trim tab down a 1/16" and the boat was perfect. The only time I've ever run the strut level with the bottom of the boat was in N-1 class, because you want the boat to run as loose as possible. All the guys in our club that run the SV-27 bend the trim tabs down in the corners to help limit chime-walking.

[JPriami]

That's a good tip. And trust me I tried that first. No dice. I've also tried various configs on battery and weight placement. I've gotten real close but in the end it will chine at WOT to some degree. I have gotten it to go away but only with the help of water conditions. it was med chop those times. I want it to be versatile and still run all out on smooth water as well as chop.

Okay i just re-read what u said. U bent the outside corners of the trim tabs down? I haven't tried that. Or are you reffering to adjusting them down with the set screw?

[Brushless55]

The next thing I would try - bending the outside corners down on the trim tabs a little bit to see if that helps. For an example: I ran my new Insame mono last week for the first time, and I also ran the stub shaft .400 thousanths above the bottom of the boat. I always backcut the props on my mono. With the first set of batteries I ran, the boat was chime-walking really bad. The next set of batteries, I turned the outside screw on the righthand trim tab down a 1/16" and the boat was perfect. The only time I've ever run the strut level with the bottom of the boat was in N-1 class, because you want the boat to run as loose as possible. All the guys in our club that run the SV-27 bend the trim tabs down in the corners to help limit chime-walking.

can you post a picture?
I'm trying to follow what you did
thanks

[Greg Schweers]

I don't have a picture, but if you pm Darin, I'm sure he has a pic of his SV-27 with this done to it. You just bend the corner of the trim tab on a 45 degree angle, probably about 5/16" in, using a pair of pliers.

[JPriami]

moved back over towards center but still a little higher than stock.

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/8e7b5e1d.jpg

[chummer]

Here is Darrin's pic. This is what Greg is trying to describe. However, I think you will have to move the trim tabs inwards a little to take advantage of this.

[JPriami]

moved it back but up 1/8 from stock location. hope I can test it soon. covered up with work lately

http://img.photobucket.com/albums/v337/Jpriami/Traxxas%20Spartan2/f0509168.jpg

[Brushless55]

Oh man!
I totally forgot about what your trying here.. let us know how it works man!! :thumbup1:

[JPriami]

Ive been busy with work, and in the hospital one day and down over the weekend. now back busy with work.

[Brushless55]

Ive been busy with work, and in the hospital one day and down over the weekend. now back busy with work.

:w00t:
you ok??

[JPriami]

Having kidney stone issues. My first time. Seems to be dragging along too. Might have to go back to see a doc.

[Brushless55]

Having kidney stone issues. My first time. Seems to be dragging along too. Might have to go back to see a doc.

sorry to hear this!
I'll be praying for you

[dag-nabit]

sorry to hear this!
I'll be praying for you

:iagree:

Take care of yourself, health and family first.

Kevin

[JPriami]

Thanks guys.
I might see is I can run at lunch today. Rain coming in tho.

[chummer]

Take care of yourself. I have never had stones but I do know plenty of people that have had them and it sounds very painfull.

Keep this thread updated when you get a chance. I am very interested to see what can be done with this hull.

:beerchug:

[shctexas]

Will wider (2 1/4) trim tabs stabilize the boat?

[JPriami]

Ive been wondering about this with the trim tabs. If someone has them I'd say give it a try just to find out if it helps or hurts. because I hear some say and reading that you need two sets of trim tabs on a vee. the outter set are for cornering & the inner set are for ride attitude and fine tuning. But I also hear some say and read that a good boat doesn't even need trim tabs.
So just to put caution to the wind and find out by trial and error. maybe they will or wont. Lets find out.

[shctexas]

Well, I have a set coming. On mounting them, shouldn't they be flush with the bottom of the hull? The stock spartan tabs are slightly above the bottom of the hull. Should they be centered between the strut drive and turn fins or biased one way or the other?

[JPriami]

It's to my understanding that trim tabs should be just a little above the bottom of the hull. So how they are on the Spartan is correct to my knowledge. I had that same question. But I did a bunch of reading and even reading on real vee hull setups with trim tabs. And even on a real vee hull it's recommended that the trim tabs be about 1/2" or more above the bottom of the hull. So on scale that would just be a little bit on an rc but looks about right on the Spartan. It has something to do with the fact that your just using the back edges of the tabs for correction. I won't go into grave detail.

[martin]

The tabs need to be above the bottom. Thanks.

[dag-nabit]

Ive been wondering about this with the trim tabs. If someone has them I'd say give it a try just to find out if it helps or hurts. because I hear some say and reading that you need two sets of trim tabs on a vee. the outter set are for cornering & the inner set are for ride attitude and fine tuning. But I also hear some say and read that a good boat doesn't even need trim tabs.
So just to put caution to the wind and find out by trial and error. maybe they will or wont. Lets find out.

'nuff said?? :doh:
Kevin



As JP has already pointed out, there are differing opinions on trim tabs.

I read one opinion on the spartan, that because the vee is so deep when it comes onto plane at high speed it will be high enough out of the water the stock trim tabs will be running basically dry.

This individual suggested a second set of tabs closer to the strut would help provided stability when the hull is high out of the water.

If you look inside the hull you will see there are specific moldings in the plastic designed to hold mounting screws coming through the transom. It might be advisable to try to utilize those mounting points if at all possible.

JP had posted a photo of them early.

Kevin

[shctexas]

Yep, i recall the posts and photos. I've identified the tabs and it's going to be a tight fit. I won't know for sure until I have them in my hand. Thanks for the input.