Hi!

A while ago, I put brushless motor and ESC in my daughter's Zig Zag Racer, and It has run very good and stable with 3-cell li-po. My daughter really enjoyed much faster speed.

Recently, there was lots of water-coming in through the prop shaft tube, even though I thoroughly lubricated with high quality marine grease. Thus, I have replaced the stuffing tube with a little bit bigger diameter tube and a teflon liner in it. Now water does not come in, but I got a problem.

The boat hardly goes straight, even though I keep trimming the streering trim. And when turning, the boat seems to tilt to the turning direction, turning too sharp.

Also when advancing throttle, the boat begins to badly wobble and then spins out at high speed.

Before replacing the stuffing tube, it used to run so stable and nicely, but now all of sudden it goes crazy. My little daughter and I are so frustrated

What causes this issue? If anyone can help my daughter and me, it will be greatly appreciated! Thank you for your attention!

James

Hello James

In the future you may want to consider using a piece of nitro fuel tubing on the driveshaft. The tubing fits over the stuffing tube and rests half on the prop shaft. This acts like a seal.

Do you have photos of what it looks like now. My initial thoughts are the prop shaft height or positioning has changed.

Ryan

Hi, Ryan!

Thank you very much for your response! My 6-years-old daughter really enjoys RC cars and boats with me, but at this moment, she is very disappointed with this issue. I hope you and other boaters can hlep us. Here are some pictures. Thank you again!

Since posting the pictires, for 24 hours, there has been no response here!

If anyone can help me out, it will be greatly appreciated! Thank you!

James,

I don't always quite make it back to every thread I have replied to in 24h

It appears and sounds to me as if the shaft angle is not identical to how it was setup up previously.

The only way I see you moving forward with this is to try shifting the CofG around. Battery placement may help here. Try moving weight towards the rear.

If this does not completely work I would look in to adjusting the shaft output angle. However this will require you to re-position it using trial and error. Less angle relative to the hull may be a good start. Unfortunately, the only option here is trial and error. Both on CofG and shaft output angle.

Ryan

Hi, Ryan!

Thank you for your answer! My duaghter has been asking if I got a solution.

One more question, could you tell me what makes you think that the stuffing tube angle is slightly different from before, please?

What about the slightly different distance between the prop and the rudder?

Once again, your help will be greatly appreciated! (I really want to make my little daufhter happy again with fixing this issue! Thank you!

Any differences in the prop shaft distance or angle may contribute.

I'd first start at moving around your CofG. If this can't relieve it to a tolerable level you may have to move the shaft around

Ryan

Thank you Ryan!

Does CofG means the center of gravity or somthing different?

You got it.

Ryan