Title

Low Frequency Instabilities of Free Systems

Date

1963

Index Abstract

Coming Soon

Photo Quality

Not Needed

Report Number

ASD TDR 63-655

Creator

Schwendler, Robert G.

Hill, Jack H.

Corporate Author

Computer Engineering Associates

Laboratory

AF Flight Dynamics Laboratory

Extent

127

Identifier

AD0426543

Access Rights

OTS

Distribution Classification

1

Contract

AF 33(657)-8293

DoD Project

8219

DoD Task

821901

DTIC Record Exists

Yes

Distribution Change Authority Correspondence

None

Distribution Conflict

No

Abstract

This report contains an investigation of "mode interaction" instabilities of aircraft. "Mode interaction" refers to coupling between an elastic mode and a rigid body mode of the free system. Three rather general airframe configurations are analyzed in detail. It is shown that systems which tend toward steady state divergence are particularly susceptible to mode interaction. Also, that aerodynamic damping terms can have a destabilizing effect upon a free system. The analyses show that aeroelastic systems which possess no finite frequency elastic mode can be susceptible to a finite frequency instability. Computer studies of several different airframe configurations are discussed. An appendix to the report contains stability charts for an aircraft having two rigid body modes and one elastic mode.

Report Availability

Full text available

Date Issued

1963-11

Provenance

Lockheed Martin Missiles & Fire Control

Type

report

Format

1 online resource