AAE 334, Fall 2011, Homework 12 SOLUTIONS
Due Wednesday, September 28 at the beginning of class.
1.
The first Boeing 787 is delivered to ANA today.
It has a maximum takeoff weight of
502,500 pounds and a wing span of 197 feet.
If we assume a takeoff speed of 140 knots
and an elliptical lift loading, then what is the value of the vortex strength distribution at
the root of the wing?
Density of the air is 0.0024 slugs per cubic foot.
Ignore the
fuselage.
The elliptic lift distribution is
2
2
1
b
y
V
y
V
y
L
o
o
o
o
.
The area of an ellipse is
the product of pi and the semiaxes:
ab
.
So the total lift is (remember we have just the “upper
half” of an ellipse) is
4
2
1
2
o
o
bV
b
V
L
.
Solving for vortex strength at the root gives us
bV
L
o
4
.
Lift equals weight (just before the
787 leaves the runway), so
bV
W
o
4
.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '09
 COLLICOTT
 Force, Aerodynamics, Wing, Di CL L, CL Induced drag

Click to edit the document details