VS-1 Randomly hooking to the right - what's going on?

[Stinger9D9]

Hey all, has anyone seen this?

I put together an electric VS1 late last summer with a REK lower on a dubro mount, AQ 60 amp ESC and UL-1 motor. To try and keep the CoG about 8" from the transom, I configured it with the steering servo in the stock location, running a pull-pull cable, the ESC in the back and the batteries just ahead of them.

I've used a number of props, from an X642 detongued, a 42x55 and a 40x52/3.

Here's the problem...under full power on any given straight, the boat will randomly pull to the right. It starts slowly, then builds until the motor is almost full lock to the right (with no steering input).

The only thing I can do is immediately let off the throttle - which I generally always can before she flips, but as you can imagine, it's no fun at all.

I first thought it was the servo (I was using one of those all metal Hobby King servos that claims 166 oz/in) so I went and bought a Hitec HS5645MG. That didn't help. I then machined my own mount out of delrin to ensure the steering pivot is not behind the transom at all (the centerline is about dead even with the transom) - didn't help. I then thought it may be caused by slack in the pull-pull cable (allowed by the flexible plastic housing) so I ran the housing it inside rigid brass tubing from the stock servo box all the way to the outboard - that didn't help, but it did introduce quite a bit of friction into the steering system.

This past weekend, I spent all my spare hours ripping all the wood out, rebuilt the whole radio/battery box and completely reconfigured it to have the servo at the rear. There are now 2 rigid 2-56 rods no longer than 2" long from the servo arm directly to the motor. No rubbing, no interference. I managed to keep the CoG no farther forward than 8.4" from the transom when it was all back together.

I just got back from the pond. I took it easy in the corners (I didn't have a really great retrieval method...fishing rod). The first few straights were crazy fast (mid 40s est) and straight but then (about 2-3 straights into the first set of packs) the hooking to the right came back.

I'm at a loss to what is causing this. I've tried 2 different receivers (Tactic 2.4ghz), 2 servos, a bunch of batteries, AQ 1800 and 2030 motors, a total rebuild, steering linkage/configurations and all. I just can't get a consistent straight full throttle pull. You just never know when she'll decide to turn the corner.

Between the Top Speed 2 I had (and gave up on) before this hull (which was a disaster from a handling standpoint - I went through a few rebuilds with that one too) and now the VS-1, I'm starting to wonder if all this work is worth it.

Any ideas?

[siberianhusky]

Is the hull steady when you put it on a glass table or does it rock? I had to do a bit of sanding to get mine to sit solid.
I'm running a K&B for now x442 prop UL-1 motor and controller, no issues, tracks straight. I did the bottom before I ran it so I have no before and after comparison.
A twist in the hull will cause tracking problems that can appear and disappear at certain speeds.
I run a 140 OZ Spektrum MG digital servo so I can't see servo strength being your issue. Pull Pull but running through nylon pushrod sheath for its full length.
CG about the same as yours.
I did do my own pivot on mine as well to get it a bit farther back.
They sound almost identicle with the possible exception of blueprinting the bottom.

[Stinger9D9]

You know, it seemed fine out of the box when I checked it, but I didn't give blueprinting the hull the attention it deserved. I'll go over it and see what I can find.

[detox]

Sounds like a radio/receiver glitching problem. My Tactic would glitch around fencing and powerlines. Move to a different location well away then try again.

[Stinger9D9]

Sounds like a radio/receiver glitching problem. My Tactic would glitch around fencing and powerlines. Move to a different location well away then try again.

That's what I originally thought too. Sorry I should have mentioned that I've also tried 2 different ponds (about 25 miles apart) along with 2 different Tactic transmitters and receivers (at each). I've had good luck with my UL-1 and Motley Crew at both of these ponds too.

I put the hull on my granite layout plate (it's overkill, but I know this thing's flat), no twisting or rocking at all, both sponsons looked pretty good at first, the right side is flat for about 12" ahead of the transom, the left side was flat about 11.75" ahead of the transom. I kept looking for something wrong, then I found that at the transom, the left side sponson curves upward slightly (about 0.015") for the last inch or so.

I'd start the sanding, but after all the other work I've put into this boat this weekend (but mostly because it's 96F outside right now and the garage isn't air conditioned) I think I'll start the sanding/sealing/testing a bit later.

I know it seems small, but since the problem area is at the transom, does it sound reasonable that this (having the trailing edge of the left side sponson being just a bit high) could cause the right side to dig in at a given speed and cause this hooking issue?

[Derrick Davis]

I agree with detox. Based on what you've described I would do more trouble shooting with your radio set up. I'm experiencing the same issues with one of my boats that I changed the AM rx/tx to digital last season. Full throttle in a straight line and all of the sudden it hooks...HARD. Like you stated "it's no fun at all".
I think my mistake is trying to use a traxxas (surface) radio from my slash and a traxxas surface receiver in my boat. I do not advise using this brand type of set up in a boat. Most of you already know this. I'll be getting another spectrum marine receiver and adding to this boat and simply use my dx3c
I digress.
Please let us know what you find out or how you remedy the issue.
Take care,
Double Deez

[properchopper]

My thinking is, once both sponsons are trued, but the servo actually pulls to one side is that the servo isn't getting enough power. Are you using a built-in BEC or a rcvr pack? I'd look in that direction for an answer.

[Stinger9D9]

My thinking is, once both sponsons are trued, but the servo actually pulls to one side is that the servo isn't getting enough power. Are you using a built-in BEC or a rcvr pack? I'd look in that direction for an answer.

I was considering that too. Can I disable the BEC on the AQ 60amp ESC? Has anyone tried it? With the new layout, I have plenty of room for a separate battery pack.

Again, I can't see it being the radio as I've tried multiple separate transmitters and receivers. I do have a Futaba 3PM FM radio laying around I could try.

It's a bit of an ordeal to get time to make it to the pond. So while I'd love to trying running it in between disabling the BEC, changing the radio and truing the hull, I probably won't be able to make a change, get to the pond, then another change, then pond and so on.

So I'd probably try all three before I got to the pond next...if the problem is corrected I won't know what was the problem.

Also, on disabling the BEC, does anyone know if the Tactic rx can put up with a 7.4v lipo rx pack?

[properchopper]

Disabling the AQ 60A (or any other built-in BEC) is simply achieved by eliminating the red wire from the SC lead that plugs into the Rx. Using a spare servo extension harness with the red wire disabled is one way to do it. Truth is, I've smoked my share of Tactic Rx's by overvolting them so you may want to use an outboard UBEC that's voltage-adjustable but supplies sufficient amperage. A decent Rx pack might be the best bet. Li-Ion battery rx packs might be worth looking into. Insane Boats just got some nifty ones in stock - call Jeff @ 310-351-0744 & tell him I sent you. (these packs power the big gasser servos along with the Rx's)

[siberianhusky]

If you use a pin you can push down the locking tab that holds the wire into the connector, then just fold it back and wrap some tape around it. You can just slide it right back in if you want to go back to using the bec.

[Rumdog]

How deep are you running your prop?

[Stinger9D9]

The centerline of the stub shaft is about 0.2" above the bottom of the sponsons. Pretty much the standard starting point recommended in the manual for the hull.

Looks like I've got some sanding/truing and BEC disabling to do.

I sure would like to sort this out because I really wanted to do a TS3 for my next boat, but I'm not going there until this one's running well.

[Stinger9D9]

So I went to sand the bottom of the sponsons, but I didn't have a sanding bar so I went one better.

I used a trick I learned a few years back while working in a smaller machine shop. I stuck sandpaper to the surface of a granite surface plate (flat within 0.0001" over the 12" x 18" surface) and passed the whole hull back and forth over the paper.

I thought the bottom of the sponsons was reasonably flat, but when sanded this way, every little imperfection shows up and it takes a LOT of sanding to get all the shiny (low) spots to go away. The rear edge of that left sponson took the most work. If you have even a 0.01" low spot, you need to take 0.01" off the entire surrounding area just to get down to it.

I then turned things sideways to sand the inside of the sponsons. I managed to get a sharp edge along the right sponson, but the wood on the inner edge of the left sponson sticks out just a bit too far inward of the inner edge of the ride pad to sand away (without taking a day or two). I got it better, but not super sharp (I'd need to take about 1/32" off the inside face of the sponson to do so).

Anyway, now when the hull sits on the surface plate, NO light shines through anywhere along the bottom edge.

So now, after a few thin coats of polyurethane (with sanding in between of course), that part will be done.

I also pulled the red wire from the ESC plug and that ESC works just fine with the BEC bypassed. I still need to get a proper rx pack (Tony, I'd call Jeff, but getting a pack up here to Canada may take a while - I'll try a 5 nimh cell 6 volt pack for now, just to see if it works before ordering one or two from him).

Hopefully I can get all the pieces in place before this weekend and give her a try again.

Thanks for all the suggestions guys!

[NorCalZ71]

i use these in everything from boats to rock crawlers to airplanes. they work great and are easy to install and waterproof!
large__24_10_2007_05_00_cc-bec.JPG
http://www.offshoreelectrics.com/pro...0004-00&cat=72

[detox]

Here's the problem...under full power on any given straight, the boat will randomly pull to the right. It starts slowly, then builds until the motor is almost full lock to the right (with no steering input).
Any ideas?

Are you sure the motor is full cocked right? Can you see it full cocked right? I wonder if your right sponson is digging in causing to turn right? Can you move COG more rearward?