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Modeling of aircraft unsteady aerodynamic characteristics. Part 1: Postulated modelsA short theoretical study of aircraft aerodynamic model equations with unsteady effects is presented. The aerodynamic forces and moments are expressed in terms of indicial functions or internal state variables. The first representation leads to aircraft integro-differential equations of motion; the second preserves the state-space form of the model equations. The formulations of unsteady aerodynamics is applied in two examples. The first example deals with a one-degree-of-freedom harmonic motion about one of the aircraft body axes. In the second example, the equations for longitudinal short-period motion are developed. In these examples, only linear aerodynamic terms are considered. The indicial functions are postulated as simple exponentials and the internal state variables are governed by linear, time-invariant, first-order differential equations. It is shown that both approaches to the modeling of unsteady aerodynamics lead to identical models.
Document ID
19940028445
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Klein, Vladislav
(George Washington Univ. Hampton, VA., United States)
Noderer, Keith D.
(George Washington Univ. Hampton, VA., United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1994
Subject Category
Aircraft Stability And Control
Report/Patent Number
NAS 1.15:109120
NASA-TM-109120
Accession Number
94N32951
Funding Number(s)
PROJECT: RTOP 505-64-52-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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