Aerospace Engineering 3521: Flight Dynamics
Prof. Eric Feron
Homework 3
due September 15, 2014
1
Problem 1: Please match the following wing/tail or wing/canard configurations with the provided Cm vs. αF RL , the angle of attack of the fuselage
reference line. Explain your reasoning.
(a)
F.R.L.
c.g.
(b)
F.R.L.
c.g.
(c)
c.g.
F.R.L.
c.g.
F.R.L.
(d)
(e)
F.R.L.
c.g.
(f)
F.R.L.
c.g.
Direction of aircraft motion
Cm
Cm
Cm
(3)
(2)
(1)
αFRL
αFRL
Cm
αFRL
Cm
(4)
Cm
(5)
(6)
αFRL
αFRL
αFRL
Figure 1: Airfoil configurations and moment curves
2
Problem 2:[10pt] Develop an expression for the wing dihedral effect, Clβ
for a wing planform that uses dihedral only for the outboard portion of the
wing as shown in Figure 2. Please state your assumptions.
Γ
d
b/2
Figure 2: Wing planform
3
Problem 3: In class on friday, Sep 5, we have derived a formula for the
computation of trim angle of attack and elevator deflection as
αtrim =
Cmα CLδe
−Cm0 CLδe
.
− CLα Cmδe − CT0 CMδe
Nelson’s book page 65, section 2.4.2 gives the different formula
αtrim =
−Cmδe CLtrim − Cm0 CLδe
Cmα CLδe − CLα Cmδe
Is any of the two formulas wrong? Are they both true? Please explain
your reasoning.
4

PowerPoint

Problem 1