Size: 0.75 inch radius fillet
¾” radius fillets and bigger, the fin breaks before fillet
Epoxy: systems 3000
higher temperature epoxy, better structural properties than alternatives
Risks: air bubbles weaken fillet (mitigation: 9% cabosil, vacuum epoxy for 45 minutes)
Later Testing: Make fillets with radii ¾” and under
INSTRON test fins, identify breaking points
Identify smallest radius feasible → reduce drag
EPOXY | TENSILE STRENGTH | ELONGATION AT BREAK | COMPRESSIVE STRENGTH | GLASS TRANSITION TEMP (K) |
|---|---|---|---|---|
Systems 3000 | >36,500 PSI | 1.7-1.9% | >15,000 PSI | 427 |
Proline | 9,500 PSI | 15,000 PSI | 408 | |
Aeropoxy | 8,000 PSI | 7% | 11,500 PSI | 443 |
MATERIAL | Service Temp (K) | Density (g/in^3) | Weight (g) | Therm. Conductivity (W/mK) | Machinability (%) | Cost ($/lb) | CTE (µm/mK) |
|---|---|---|---|---|---|---|---|
Stainless Steel | 1143 | 127.819 | 63.143 | 16-24 | 40-55 | $0.65 | 16 |
Aluminum | 623 | 44.2451 | 21.86 | 205 | 75-450 | $0.33 | 23 |
