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The Effects of Nonstationary Aerodynamics on the Rigid-Body Dynamic Stability of an Airplane


Statler, Irving Carl (1956) The Effects of Nonstationary Aerodynamics on the Rigid-Body Dynamic Stability of an Airplane. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1EHQ-B547.


A first order in frequency theory is developed for the aerodynamic loads on a harmonically oscillating thin wing of finite aspect ratio in a subsonic compressible flow. The downwash in the vicinity of a horizontal tail behind such a wing is also evaluated to the same order in frequency. The results are then used to determine the stability derivatives of a conventional-type airplane and to set up the stick-free longitudinal equations of motion including the unsteady flow effects. An important conclusion of this study is that, within the limitations of a "lifting-strip" theory, the airloads on the oscillating finite span wing are linear in frequency in the neighborhood of zero frequency. This is in contrast with the two-dimensional results which show a logarithmic singularity there. As an example of a practical application, calculations are made of the frequency, damping and transient responses of the stick-free longitudinal motion of an F-80A airplane and the results compared with those obtained using quasisteady aerodynamic coefficients. The indications are that, while nonsteady flow considerations show considerable influence upon the control surface motion, they have a negligibly small effect upon the airplane motion.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Aeronautics and Mathematics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Minor Option:Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Stewart, Homer Joseph
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1956
Record Number:CaltechETD:etd-06302004-095128
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2783
Deposited By: Imported from ETD-db
Deposited On:30 Jun 2004
Last Modified:09 Aug 2023 18:21

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