Accession Number : AD0861958


Title :   A Survey of Reverse Flow Problems with High Speed Rotary Wing Aircraft


Descriptive Note : Special project


Corporate Author : NAVAL AIR SYSTEMS COMMAND WASHINGTON DC PROFESSIONAL DEVELOPMENT CENTER


Personal Author(s) : Perkins, Jr, R G


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/861958.pdf


Report Date : 01 May 1969


Pagination or Media Count : 47


Abstract : A survey of the problems and concepts (design solutions) related to the reverse flow region on high speed rotary wing aircraft has been made. For each design solution, the performance benefits and engineering problems are discussed. Since the technical approach is non-analytical and uses results from many sources, the recommendations are made as a best-judgement on the basis of the data presented herein. A chart of ten problem areas common to all the design solutions which has been developed indicates the following. Resources should be allocated to the design and testing of a high stiffness rotor blade capable of operating at low rotational speeds and advance ratios greater than one, and an investigation of the cyclic-collective blade pitch control interchange which begins as the advance ratio approaches one. The information obtained and the experience gained will be applicable to the largest number of design solutions. The offset-shaft rotor has the least number of problems and may be the most feasible design solution.


Descriptors :   *ROTOR BLADES(ROTARY WINGS) , ROTARY WINGS , PERFORMANCE(ENGINEERING) , AERODYNAMIC CHARACTERISTICS , FLUTTER , FOLDING HELICOPTER ROTORS , SECONDARY FLOW , DRIVE SHAFTS , JET HELICOPTER ROTORS , TWIST(AERODYNAMICS) , BLADE AIRFOILS , AERODYNAMIC CONFIGURATIONS , AERODYNAMIC CONTROL SURFACES


Subject Categories : Helicopters
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE