Accession Number : ADA306235

Title :   Expendable Main Rotor Blade Study. Phase 1.

Descriptive Note : Final rept.,

Corporate Author : UNITED TECHNOLOGIES CORP STRATFORD CT SIKORSKY AIRCRAFT DIV

Personal Author(s) : Longobardi, John A. ; Fournier, Everett ; D'Onofrio, Mario J. ; Olson, John R. ; Reinfelder, William C.

PDF Url : ADA306235

Report Date : APR 1973

Pagination or Media Count : 309

Abstract : The report presents results of a design study of expendable main rotor blades for the UH-1H helicopter. The objective of the study was to design blades which could eventually be thrown away after extensive damage rather than be sent back to depot for major overhaul. Unit cost, field repairability, resistance to corrosion and erosion, fatigue strength, and damage tolerance were factors considered for maximum cost effectiveness or lowest life-cycle cost. The study was limited to the UH-1 blade, which requires a structural skin for edgewise rigidity. For an articulated rotor blade, some of the conclusions regarding skin construction and material could be different. The study included development of reliability, maintainability, and cost- effectiveness models. In addition, the United Aircraft Normal Modes Computer Program was modified to include two-bladed teetering rotor dynamics. The cost model was based upon the present LJH-lH aircraft to provide life-cycle cost comparisons with the new blades designed in this study. More than fifteen blade designs were generated. They included aluminum, steel, and composite blade designs. The study covered two time frames: 1972 and 1980. The results showed that a low-cost aluminum extrusion with a fiberglass composite skin is the most cost effective blade for the 1972 time frame. This blade, which has 30% fewer parts, was estimated to be 20% cheaper and 75% more repairable than the Bell blade. It is estimated that this blade could save $12 million for a base-line fleet of 1,000 aircraft. For the 1980 time frame, the Sikorsky 'twin beam' all-composite blade has the potential of being twice as repairable as the Bell blade and could save $26 million for a baseline fleet of 1,000 aircraft. (MM)

Descriptors :   *FIBERGLASS, *COMPOSITE MATERIALS, *HELICOPTER ROTORS, *ALUMINUM, *TOLERANCES(MECHANICS), *ROTOR BLADES, VIBRATION, COST EFFECTIVENESS, CORROSION, DAMAGE, STIFFNESS, CRACKING(FRACTURING), COMPOSITE STRUCTURES, STRENGTH(MECHANICS), EROSION, MAINTAINABILITY, RELIABILITY, REPAIR, BASE LINES, COST MODELS, AERODYNAMIC CHARACTERISTICS, LIFE CYCLE COSTS, FATIGUE(MECHANICS), LEADING EDGES, SKIN(STRUCTURAL), DELAMINATION, EXPENDABLE, HONEYCOMB CORES, TRAILING EDGES, ABRASION, PULTRUSION.

Subject Categories : Helicopters
      Refractory Fibers
      Laminates and Composite Materials
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE