1. A model of the AeroVironment Pathfinder
(a 100 ft span solar-powered flying wing) is to be flown at sea level. It is designed to be able to fly at CL's
ranging from 0.5 to 1.0 with +/- 5 degrees of elevator travel. ( This model has trailing edge elevators over the
entire trailing edge of the wing.) The model will weigh 20 lbs, have a wing area of 40 sq ft, and an aspect ratio
of 12.5. It has a moment of inertia in pitch of only 0.2 sl ft^2. From experiments we estimate the following:
dCm_a.c./dde = -0.01 per deg
dCL/dde = .045 per deg
Cmq = -0.8
CLq = -2.0
CLa = 0.1 per deg
Ignore alpha-dot and speed derivatives.
The problem is to find the static margin or c.g. position to permit trim over the desired CL range and
then (so that we could order suitable actuators) compute the characteristic short period frequency and damping.
For extra credit see if you can verify the reasonableness of the derivative values given here using simple theory.
2. Explore some of the relationships between airplane trim, stability, and performance using the ModelAirplane program. Build a glider, test it, and bring it to class on Thursday 4/25.