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Str-Mat / Fluids Problem M10/Fxx Spring 2004 Consider two wings with the same span b = 2 m , and average chord cavg = 0.25 m, but
diﬀerent taper ratios:
Constant chord (cr = 0.250 m, ct = 0.250 m, r = 1.0)
Straight taper (cr = 0.333 m, ct = 0.167 m, r = 0.5)
Constant airfoil thickness/chord ratio κ = 0.08 everywhere. Assume local loading q (y ) is proportional to chord c(y ). Total load on half-wing is F = 10 N (15 oz gross weight at 5 g’s). For each wing . . . a) Determine q (y ), S (y ), M (y ) b) Assuming load is carried by top and bottom sparcaps with separation equal to local h(y ) = κ c(y ), determine sparcap load ±P (y ). c) Assuming max p ermissible sparcap stress (1 ksi = 7 MPa for balsa), calculate minimum cap area A(y ). Assuming balsa density of � = 0.125 g/cm3 , estimate sparcap mass. d) Compute b eam curvature at wing center � = M (0)/EI (0), and esimate tip deﬂection � = w (b/2) assuming w �� (y ) = � is constant along span. Balsa modulus: E = 200 ksi = 1.36 GPa.
e) Discuss structural and aerodynamic merits of straight vs tapered wing. Plotting of the
various distributions is suggested to help with interpretation. c(y) b/2
c(y) y ...
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This note was uploaded on 01/28/2012 for the course AERO 16.01 taught by Professor Markdrela during the Fall '05 term at MIT.
- Fall '05