Multi-year technical support was provided to the U.S. Army Aviation and Technology Command, St. Louis, for the structural dynamics and vibration analysis of the RAH-66 Comanche. The RAH-66 Comanche helicopter is the U. S. Army's attack helicopter for the 21st Century. During 1995, the Comanche began a program of ground vibration and flight tests, intended to validate structural dynamic performance of the airframe and to demonstrate the helicopter's performance characteristics. These tests typically uncover dynamics problems with rotor-fuselage coupling and forced response. In order to ensure the survival of the Comanche program, these problems, when discovered, must be quickly resolved. This effort provides rapid technical support to the Comanche Program , to resolve structural dynamics problems.
A specific focus of this work was the examination of the torsional stiffness of the empennage. Due to the low observability requirements, achieving acceptable empennage torsional stiffness was constrained by material requirements. The project designed and analyzed a suite of structural changes to be made to the tailcone and empennage which were demonstrated to provide an 18% increase in torsional stiffness with no appreciable change in mass. In addition to the work in structural dynamic design, work included the identification of random airloads on empennage control surfaces using NASTRAN-calculated transfer functions and measured flight test data.
Sponsor: Comanche Program Manager's Office
Wood, E. R., Danielson, D. A., and Gordis, J. H., "Research
in the Structural Dynamic Response of the RAH-66 Comanche Helicopter,
Report Submitted to Comanche Program Manager's Office. Reports
on work carried out from Jan. 1, 1997 to Dec. 31, 1997.
The following Master's theses are available on this topic:
William F. Beaver, Jr.
NASTRAN Dynamic Analysis of the RAH-66 Comanche Helicopter
Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate
School - September, 1996
Tobin, V., Analysis of Potential Structural Design Modifications
for the Tail Section of the RAH-66 Comanche Helicopter.
Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School,
June, 1997. Abstract
Shoop, B., Structural Design Analysis of the Tail Landing
Gear Bay and the Vertical/Horizontal Stabilizers of the RAH-66
Comanche Helicopter.
Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School,
September, 1997. Abstract
Mason, Patrick H. Identification of random loads impinging
on the RAH-66 Comanche Helicopter empennage using spectral analysis.
Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate
School, June 1998. Abstract
