Help with 1/8 scale Miller

[poolschool]

Guys,

I have been building a 1/8 scale U-31 Miller Highlife - I think it is the 1988 model since the dawn of time - anyhow, somewhere between now and then - probably when I put the canard spar in I've managed to somehow "twist" the front sponsons.

I've measured the front tips of the sponsons and noticed the left sponson is about a bit less than 1/4 inch higher than the right sponson. This model has the 2 different sponson bottoms. How critical is the 3 degree angle of the sponsons as per the Newton plans?

Do any of you guys see this as a major problem? If so is there anything to correct this problem without throwing the hull to the lions? The rest of the hull seems quite straight on the building jig.

Any help would be greatly appreciated.

Gino

 

[P THOMAS]

Gino, Your hull may have a twist to it, you can chek this by setting it on a flat table the rear corners and the front sponson pads should sit on the table with out a lot of rocking more than an 1/8th inch would be a worry.

Another check you can do is block up the rear so the flat airtrap is parrallel with the table, use a 1/4 thick stick slid under the front sponson pads, this stick should stop at the same point on the pad for the left and the right. this tell you if the angle of attack is the same on both sides.

If you havnt painted the boat yet you can add to or tear off the pads to fix it.

you say

"I've measured the front tips of the sponsons and noticed the left sponson is about a bit less than 1/4 inch higher than the right sponson. "

It would be nice to have the sponsons measure the same at the tips but the sponson pad angle is the more important thing to get right.

It will run much better if you get it straight.

 

[poolschool]

Thanks Phil,

I did what you suggested and found that it had no rock at all and when I measured the angle with the method you describe - it was approximately 1/8 difference between the 2 sponsons - strange :blink:

Gino

 

[P THOMAS]

Thanks Phil,
I did what you suggested and found that it had no rock at all and when I measured the angle with the method you describe - it was approximately 1/8 difference between the 2 sponsons  - strange :blink:

Gino

86787[/snapback]

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OK you know more about your boat.

All surfaces are not as flat as you think, find another surface and try to set it up the same agian and check it to see if the result is the same.

You can add to the high pad or remove the low pad and cut the frames down to get both the same.

If you have a long 1/4 thick stick place it under the ride pads and slide it back to touching the left and right bottoms, if you get the pads even the stick will stop 90 degrees to the center line, if one end is farther back you still have work to do.

If you make the afterplane level, (the bottom of the air trap or the flat part where the strut comes out) The 1/4 stick should stop about 5 inches from the rear of your pads to get a 3 degree angle of attack.

3 3/4 about 4dg

4 1/4------- 3.5dg

5-------------3.0dg

6-------------2.5dg

 

[poolschool]

Phil,

did what you suggested and sat it on a plane of 3/8" glass. No rock

Measured with the afterplane level, and found the 1/4 stick touching the pads at 5 3/8" from the rear of the pads - even on both sides. So this should be around 2.5 to 3 degrees as you have suggested.

What do you think?

I appreciate your assistance and am learning a great deal about this hull that I did not know

Thanks

Gino

 

[P THOMAS]

Phil,
did what you suggested and sat it on a plane of 3/8" glass. No rock

Measured with the afterplane level, and found the 1/4 stick touching the pads at 5 3/8" from the rear of the pads - even on both sides. So this should be around 2.5 to 3 degrees as you have suggested.

What do you think?

I appreciate your assistance and am learning a great deal about this hull that I did not know

Thanks

Gino

86988[/snapback]

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Ok you are in the ball park depending on how deep you run your strut the angle you have should work, just have to test it on the water to find the right strut setup.