Phil Thomas PT Stealth Build

[Rumdog]

Why did you go with a starboard side rudder?

[longballlumber]

sailr - Not a bad idea. I'll let Steven know. Maybe he could have a large qty machined up and start selling them. Seems to work pretty well.

No to take away from the machining, but you can achive the same thing by using 3/16 rod for the collet and then lengths of brass tubing telescoped to the correct ID for the stuffing tube. I use a little CA or Locktite to keep the brass tubing moving off of the 3/16 rod.

I can't wait to see it run tomorrow. I've been working on mine too..

Later
Mike

[detox]

Shooter, Great job on the build.

[v-spec]

Looks really nice and the puretech straps are great! I use them in my all my boats, a little pricey but nice.

[Shooter]

Rum - No specific reason. I've seen a lot of boats built like this lately and just figured I'd try it. It makes sense weight wise (rudder, rod, servo, etc...) for oval running.

Mike - You can work hard or work smart. Apparently I was working hard!!! Good call with the telescoping tube! Much more practical. As for seeing it run, me too! It may be the first and last run....especially running in tandem with FF.

[Shooter]

Thanks for the kind words guys. Here is a final shot with the graphics...

Phil makes a pretty mean looking boat. Almost looks like it wants to pounce on something. Very cool stance.

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[Shooter]

Maiden voyage last night. What a boat!!!! I love it. Definitely needs some weight in the front and probably a little strut lowering, but she will be a nice stable running boat. Probably no surprise to anyone here. The wide stance helps. Mine is a bit jerky in the turns though. I don't think the fin is thick enough (it actually came back bent after a run!). Also, some of the club guys thought the rudder linkage was a bit on the flexible side. I've got some work to do.

I noticed right out of the gate that the steering wasn't nearly as effective as any of my other boats, regardless of the 'jerky' behavior. The rudder clearly has enough throw. I suppose it could also be tied to the turn fin and linkage mentioned above (I'll address that first). Is there any way it is due to the rudder being on the right side? Anyone?

[Boaterguy]

It might be that, maybe a little back angle or less front angle on the rudder if you have any will get the nose out of the water in the turns.

[marko500]

Which turn fin are you using? I used the black "upgraded" UL-1 one. It's the thickest one and I've had no problems with flex or it bending. If the fin your using is a hooked one I wonder if the fin flexing or bending might be part of your problem.
I have the Speedmaster rudder mounted on the left side.

Mark

[Shooter]

Thanks for the help guys.

I'm suffering from a little bit of turn fin envy after seeing Terry's. I've made them from scratch before years ago for my tunnels, so I figured I'd give it a shot. Started with 0.088" Al. I've never added a curve though. How do you guys usually do this? Round stock and vice??

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[Boaterguy]

hacksaw, tinsnips. akthough pretty inaccurate
Jigsaw with metal blade works better
in the tips/ info area there is an article on making hardware, under misc.

[Shooter]

Did you read the last post ? I already finished the fin (see photo), I just need to add a bend to it.

[marko500]

I made one and for the curve I used a piece of pipe and a vise. Clamped the fin and pipe in the vise and gently rolled and worked the fin over the curve of the pipe. Depending on the thickness you may have to tap it with a hammer to get the bend even. Came out OK.

Mark

[Fluid]

Is there any way it is due to the rudder being on the right side? Anyone?

Probably not. I've seen PT boats with right-mounted rudders run fine, but they all had hooked fins. Both the rudder and fin have to be "matched" in size, too little fin area and the boat will have a tendency to hook. Too little rudder and you can't make the turn.

The fact that your fin bent in use tells me it is at least part of the problem. As was mentioned above the black Grim UL-1 fin is a good one for hulls this size. Both the fin and the bracket need to be strong with no bending! It's usually cheaper to buy a proven fin, the one you made is very thick. Thin and stiff is better, if you can put a bend in it easily then it really isn't very stiff.

The rudder linkage needs to be strong too, especially as long as your linkage is. No wimpy 2-20 rod, used 4-40 rod I hope. A brace half way along the rod wouldn't hurt. No wimpy servo either, use one with at least 70 oz in of torque (more is better). The boat is fast and heavy for its size (as you have set it up) and will have problems with weak servos. You'd be surprised how having too-little servo will limit turning. A 5-cell receiver pack will give more servo power and if put up forward will give you some functional balast.

That is a gorgeous boat, well built and with a lot of potential. Have fun with it!


.

[AlanN]

The type of aluminum you should use is either 6061 T6 or 7075 T6. I make mine from .062 or .074 thickness for that size of a boat. Curvature bends are best for turns but can be tricky to set up correctly for the straights. I prefer to sharply form 1-2 angles for a total of around 25-30 degress of total bend. The higher temper aluminum is not easy to form. I use a real V form punch and die in a press to set mine.