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LSA FAA definition. Max gross takeoff weight = 1320 lbs Max stall speed = 45 knots Maximum speed in level flight = 120 knots. ASTM F 2245-07 guidelines. Limit load factors Ultimate load factor of safety = 1.5 Special ultimate S.F.s for hinges, bearings, pins, control components
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LSA FAA definition • Max gross takeoff weight = 1320 lbs • Max stall speed = 45 knots • Maximum speed in level flight = 120 knots
ASTM F 2245-07 guidelines • Limit load factors • Ultimate load factor of safety = 1.5 • Special ultimate S.F.s for hinges, bearings, pins, control components • Flight conditions • Design speeds
Design speeds • 45 knots = Stall speed (LSA) • 99.6 knots= Minimum maneuvering Speed • 108 knots = Minimum cruise • 120 knots = Maximum cruise (LSA) • 160 knots = Dive speed
Flight envelope VA VC,max VD Vs
Total Loads • Level flight 1320 lbs • Design Limit load = 5280 lbs • Ultimate load = 7920 lbs (for 3 seconds)
XFLR5 • Simulations • Various A.O.A. and Reynolds numbers • Wing panels • Data (spreadsheet) • Aerodynamic coefficients • Lift, drag, and moment forces
Shear and bending • Integrate ultimate load equations • From 0(root) to 8ft (airfoil switch) • F = -5.2139x + 318.37 • From 8ft to tip (15ft) • F = -3.255x2 +54.497x + 42.791
Torsion/control loads • 75% positive maneuvering load, plus torsion from max aileron displacement • Gust loads at VF with flaps extended (7.5 m/s)
Gusts • Symmetric vertical gusts (up and down) • 15 m/s at VC • 7.5 m/s at VD