General Aviation Aircraft Design Snorri Gudmundsson Pdf 🎯 Free Access

Aspect ratio: for GA, AR = 7–9 is typical. Pick AR = 8. Wing span b = sqrt(AR Γ— S) = sqrt(8 Γ— 14) β‰ˆ sqrt(112) β‰ˆ 10.6 m.

CD_cruise = 0.025 + 0.0486 Γ— 0.0966Β² β‰ˆ 0.025 + 0.00045 β‰ˆ 0.02545 Drag D = q S CD = 5,300 Γ—14 Γ—0.02545 β‰ˆ 1,887 N general aviation aircraft design snorri gudmundsson pdf

Power required (shaft) = D Γ— V = 1,887 Γ— 93 β‰ˆ 175,500 W β‰ˆ 235 hp (assuming propulsive eff 0.8, required engine power β‰ˆ 235 / 0.8 β‰ˆ 294 hp). That’s high for a light two-seater. Aspect ratio: for GA, AR = 7–9 is typical

Choose S β‰ˆ 14 mΒ².

At cruise speed V = 180 kt β‰ˆ 93 m/s. Dynamic pressure q = 0.5ρVΒ² β‰ˆ 0.5Γ—1.225Γ—93Β² β‰ˆ 5,300 N/mΒ² Lift = W = q S CL β†’ CL_cruise = W / (q S) = 7,166 / (5,300 Γ—14) β‰ˆ 0.0966 CD_cruise = 0

Trade: reduce cruise speed to 140 kt (72 m/s) to get realistic engine size: Recompute q = 0.5Γ—1.225Γ—72Β² β‰ˆ 3,178 CL = 7,166 / (3,178 Γ—14) β‰ˆ 0.161 CD = 0.025 + 0.0486Γ—0.161Β² β‰ˆ 0.025 + 0.00126 β‰ˆ 0.02626 D = 3,178Γ—14Γ—0.02626 β‰ˆ 1,169 N Power = 1,169Γ—72 β‰ˆ 84,200 W = 113 hp shaft β†’ engine ~130–160 hp (accounting prop eff and climb reserve). This is a practical choice (e.g., Lycoming IO-320/IO-360 class).