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Anticipation of the landing shock phenomenon in flight simulationAn aircraft landing may be described as a controlled crash because a runway surface is intercepted. In a simulation model the transition from aerodynamic flight to weight on wheels involves a single computational cycle during which stiff differential equations are activated; with a significant probability these initial conditions are unrealistic. This occurs because of the finite cycle time, during which large restorative forces will accompany unrealistic initial oleo compressions. This problem was recognized a few years ago at Ames Research Center during simulation studies of a supersonic transport. The mathematical model of this vehicle severely taxed computational resources, and required a large cycle time. The ground strike problem was solved by a described technique called anticipation equations. This extensively used technique has not been previously reported. The technique of anticipating a significant event is a useful tool in the general field of discrete flight simulation. For the differential equations representing a landing gear model stiffness, rate of interception and cycle time may combine to produce an unrealistic simulation of the continuum.
Document ID
19870020058
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Mcfarland, Richard E.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 5, 2013
Publication Date
September 1, 1987
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
NASA-TM-89465
NAS 1.15:89465
A-87237
Accession Number
87N29491
Funding Number(s)
PROJECT: RTOP 505-67-51
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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