Whatever Became of Neptco's Carbon Rod

Whatever Became of Neptco's Carbon Rod?

By Jim Marske

(Sailplane Builder September - October 1998)

Here was a spectacular product that held so much promise. We had thoroughly tested the material in static and dynamic endurance tests. We were so pleased with the results that we made production molds to use it in the Genesis's wing spars. We static loaded a completed Genesis wing panel to +12 g's where ihe supporting fixture failed. I really got excited over this stuff - and it takes a lot to get me excited. Now NEPTCO told us that they are not going to make the rod anymore. I was shocked!

I made many calls to NEPTCO encouraging them not to abandon their GRAPHLITE carbon rod. They said this rod was a very small part of their business and didn't need the hassle to make it. They had problems running carbon rovings through their machines.

After much begging on my part, they decided to give it another 90 day try. Then the fateful telephone call came. I have some good news and some bad news. The bad news was that NEPTCO dropped anv further efforts to make the carbon rod. The good new~s was that someone else makes carbon rod using the same process. It was a small factory in North Carolina. I immediately called them and arranged for a visit.

The company's name is AVIA SPORT COMPOSITES. It is most interesting that this new company was started by the same man that developed the carbon rod at NEPTCO. I drove down to North Carolina to look at the factory and meet the people. I was very impressed with what I saw and the quality of the rod. Better than NEPTCO's. They have been so successful with their carbon rod that they make many sizes and shapes. I saw tubes, rectangles and even "T" shaped sections. AVlA SPORT is so comfortable with their process that they· want to try more difficult shapes.

Just one look at ihe following charts and yov can easily see that AVIA SPORT's carbon rod is far superior to any current aircraft construction material. However, you must be careful to look at the resulting beam deflection before finalizing the spar design. The deflection may be surprisingly high despite the car bon's high modulus especially in high aspect ratu wings.

To make a long story short, I got so excited over this rod and what AVIA SPORT is doing that I wanted to be part of their organization. So I am now an engineering sales representative for them. I can of fer you not only an outstanding product at factory prices but also assist you in designing wing spars for your aircraft. If you w-ant to know more about AVIA SPORT carbon rod write or give me a call at (740) 389-3776.

AVIA SPORT "Micro" Carbon Rod

Standard Properties

Fiber Volume 65%-67%

Tensile Strength 320,000 psi (2,207 mpa)

Tensile Modulus 19-5 msi (134 gpa)

Compressive Strength 275,000 psi (1,896 mpa)

Compressive Modulus 19.0 msi (130,986 mpa)

Ultimate Tensile Strain 1.3%

Diameter Tolerance +/- 5%

Glass Transition Temp 212 deg F (100 deg C)

Special Request 320 deg F (160 deg C)

Matrix Material Epoxy

Carbon Fiber 32 msi (221 gpa)

Standard Carbon/Epoxy Shapes

Rounds:

Lbs/1000 ft (grams/meter)

O19" (0.48 mm) 0.2 0.3

027" (0-69 mm) 0.4 0.6

037" (0.94 mm) 0.8 1.1

052" (1.32mm) 1.5 2.2

060" (1.52 mm) 1.9 2.8

070" (1.78 mm) 2.6 3.9

079" (2.01 mm) 3.4 5.1

098" (2.49 mm) 5.3 7.9

110" (2.79 mm) 6.9 10.2

125" (3.18 mm) 8.8 13.1

.156" (3.96 mm) 13.5 20.0

.188" (4.77 mm) 19.6 29.0

Rectangels:

Lbs/1000ft grams/meter

.034x.121" 0.9x3.lmm 2.6 3.9

.057x.177" 1.5x4.5mm 6.9 10.2

.032x.317" 1.1x1l.2mm 7.2 10.8

.092x.22D" 2.3x5.59mm 13.5 20.0

TYPICAL MATERIALS USED IN AIRCRAFT CONSTRUCTION

Item Material Tensile Compression Moduls Density

(psi) (psi) (psi x 10/6) (Psf)

1.Carbon/Epoxy (A.S.C.) 320,000 275,000 19.5 95

2.Carbon Roving/Epoxy 20,000 50,000 18.5 94

3.Kevlar 49/Epoxy 200,000 40,000 12.0 86

4.Fiberglass Roving/Epoxy 100,000 50,000 5.5 120

5.4130 Steel 95,000 75,000 30.0 490

6.2024.T3AIuminum 70,000 50.000 10.4 162

7.6061-T6Aluminum 45,000 40,000 10.4 162

8.Sitka Spruce 10,000 5,000 1.4 27

TYPICAL MATERIALS USED IN AIRCRAFT CONSTRUCTION PROPERTIES ON A STRENGTH TO WEIGHT RELATIONSHIP

Tensile Compressive

Strength Strength Stiffness

Item Material per pound per pound per pound

(T/lb) (C/lb) (E/Ib)

1. Carbon Rod (A.S.C.) 3,368 2,895 205,2631

2. Carbon Roving 1,330 531 196,809

3. Kevlar 49 2,326 465 139,535

4. Fiberglass Roving/Epoxy 833 416 45,833

5. 4130 Steel 194 153 61,224

6. 2024-T3 Aluminum 432 309 64,198

7. 6061-T6 Aluminum 278 247 64,198

8. Sitka Spruce 370 185 51,852