This AVL Tutorial - Part 4 - is all about calculating in AVL. We will cover static (longitudinal) stability, talk about the optimum center of gravity, the lift-distribution and how you can foresee, where stall occurs and finally we will calculate three trimmed flight conditions (Landing, Turn and Looping flight).
The Athena Vortex Lattice (AVL) Code is very useful for quick and reliable Aerodynamic Analysis, Trim Calculation and Dynamic Stability Calculation. I used this program extensively in my Bachelor Thesis and further works on the battery-electric touring motorglider FVA 30 (www.fva.rwth-aa..., as a research assistant at the Flight Systems Dynamics Institute of RWTH university (www.fsd.rwth-a...) and for personal UAV and model aircraft design.
This is the list of contents covered in this video
Topic: Stability, Lift distribution, Stall, Trim Calculation
Static Stability
* What is static stability?
- Derivative Cma, Moment coefficient curve
- Zero Lift Moment Cm0
* How can I calculate that (in AVL)?
- no-trim run case
- output stability derivatives
* Estimating the correct Center of Gravity (CoG)
- Rule of Thumb - 1/3 of x_MAC
- Aircraft Neutral Point
* Outputs, Stability Derivatives
Lift distribution, Treffz-plane
* Elliptical lift distribution
* Stall prediction, Taper
* Oswald Factor
Trim Calculations - control surface deflection
1. Landing configuration, Flaps down
2. Turn, banked flight
3. Looping flight
AVL was written by Mark Drela and Harold Youngren (Massachusetts Institute of Technology).
"AVL is a program for the aerodynamic and flight-dynamic analysis of rigid aircraft
of arbitrary configuration. It employs an extended vortex lattice model for
the lifting surfaces, together with a slender-body model for fuselages and nacelles.
General nonlinear flight states can be specified. The flight dynamic analysis
combines a full linearization of the aerodynamic model about any flight state,
together with specified mass properties."
More information on web.mit.edu/dre...
26 авг 2024
