Prop hits rudder

[russbolt]

My Sonicwake somehow is getting the prop hitting the rudder.
I replaced the stock rudder with a dual pickup and the prop, and it still is hitting. In fact, it broke the ends off of the new prop, see the pics.
Anyone else seen this?

[Panther6834]

You indicated you swapped to a different prop...but, you forgot to say what prop your actually running.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[1coopgt]

My Sonicwake somehow is getting the prop hitting the rudder.
I replaced the stock rudder with a dual pickup and the prop, and it still is hitting. In fact, it broke the ends off of the new prop, see the pics.
Anyone else seen this?

I'm guessing that prop is a bit bigger than the stock one. If you're going to run a bigger prop you're going to need to move your rudder back farther. You don't show us much unfortunately like the rear of the boat and the rudder mounting bracket with the prop and rudder on the boat to see where the interference is/was.

Instead of close ups how about moving the camera back a little bit so we can see the whole back of the boat.

[russbolt]

The stock prop was hitting the stock rudder before any changes.
The new prop was 42mm, SMALLER than stock at 44mm

[Panther6834]

The stock prop was hitting the stock rudder before any changes.
The new prop was 42mm, SMALLER than stock at 44mm

That's strange. Neither my stock prop, not the stock props on two other SonicWakes I've seen, were hitting the rudder. I've even installed larger props, which also do not hit the rudder.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[russbolt]

When I look at the stern of the boat, there seems to be no way possible for them to make contact. This is why I am so confused.
I am using a rudder, drive shaft and prop all bought here at OSE. The stock prop/rudder were hitting, that was the motivation to upgrade.

[leonard feeback]

Maybe you have too much rudder throw to the left, moving the blade in front of the prop.

[russbolt]

Can't see how, I cannot get them anywhere near each other.20201124_183502.jpg20201124_183510.jpg

[1coopgt]

Something tells me your rudder arm is flexing or the transom is. Turn the radio and boat on and turn the steering all the way to the left and see what it does.

[russbolt]

Is it possible the drive shaft "extends" a little when under power? or in reverse? It is a spring (sort of).

[785boats]

It is definitely the rudder arm flexing.
Quite a few people have reported the same thing over on R/C groups in the Sonic Wake thread.

[plinse]

Do not rely on the ruder position maintaining its limits when the boat runs at high speed, jumps or flips.

The maximum ruder position, which is mechanically feasible with the servo switched of should not touch the propeller and still you should have some gap left then for the hull flexing.
When the boat flips and hits the water many servos can not keep the position and when you change the propeller to a bigger one or one with more rake you will have to check this topic.

The ruder in the picture is pretty thin material - cheap stuff - all this will bend under load. You have pushed the limits too far.

[Johnc]

One thing I ran into, was the bolts/nuts that hold the rudder bracket to the hull was loose and getting to much play. Actually, on mine the nuts on the inside were both gone (must have vibrated off, silly me for not using loc-tite) Everything looked A-OK (but did the same thing what your showing) Found out the servo was holding the rudder in place when just sitting on stand and looked like it was locked down to the transom.

[MarkF]

Also turn down the amount of throw. These aren't meant to turn on a dime.

[russbolt]

Thanks for all the help. I ordered a new rudder and mount and a new servo. Hoping this will finally solve the issue.

[fweasel]

If you ordered the same rudder, it will not solve your problem. This has been an issue since the same design was used on the original Voracity hull. It's a combination of transom flex, too much rudder travel, an interference position of the rudder blade with the prop, and sometimes loose mounting hardware.

The solution is a transom doubler to stiffen the hull at the mounting point and or a rudder mount with a longer setback to eliminate the possibility of the prop and rudder blade from contacting one another to begin with. I did both.