NACA 8-H-12 AIRFOIL

1.00000 0.00000

0.94990 0.00120

0.90020 0.00340

0.80110 0.01890

0.70250 0.03840

0.60360 0.05850

0.50390 0.07670

0.40290 0.09030

0.29970 0.09530

0.24750 0.09240

0.19610 0.08600

0.14500 0.07630

0.09430 0.06260

0.06910 0.05380

0.04420 0.04310

0.01980 0.02940

0.00800 0.02010

0.00360 0.01520

0.00000 0.00000

0.01140 -0.00950

0.01690 -0.01120

0.03020 -0.01410

0.05580 -0.01740

0.08090 -0.01920

0.10570 -0.02060

0.15500 -0.02240

0.20390 -0.02350

0.25250 -0.02420

0.30030 -0.02450

0.39710 -0.02490

0.49610 -0.02440

0.59640 -0.02290

0.79880 -0.01640

0.89980 -0.01050

0.95000 -0.00630

1.00000 0.00000

From Posting: The important thing to know is that 6063 has a very poor fatigue life. Parts made of 6063 will crack and break due to vibration. This is very unsafe for any aircraft part. I recommend that you never use 6063 on a gryo! 

Take the nose weight of a Vortech extruded blade and mill out a lot of it while still retaining its structural strength. Then add a lead weight at the leading edge for the outer 50% of the blade length. This weight and milled nose weight will be less than the original, un-milled nose weight. It will also reduce the amount of tip weight required.

We could go one step further and replace the nose weight completely with a composite one.

John Uptigrove thinks that strength that was removed by milling must be replaced.

Vortech supplied a solid brass bar that filled the front cavity in the airfoil. Eagle's Perch milled out a 1/4" by 1/4" slot in the back to obtain the correct balance. The bar required quite a bit of sanding so as to fit into the cavity. They would then force the epoxy down this slot under pressure. They now fill the cavity with approximately 25 3/32" diameter brass rods that are surrounded in epoxy.

Some thoughts of my own. What is the difference between the 2 coefficients of thermal expansion? Could a heavier metal be used in front of an aluminum bar?