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NASA/TP—2015–218751 NDARC NASA Design and Analysis of Rotorcraft Wayne Johnson Ames Research Center Moffett Field, California National Aeronautics and Space Administration Ames Research Center Moffett Field, CA 94035-1000 April 2015 Available from: NASA Center for AeroSpace Information National Technical Information Service 7115 Standard Drive 5301 Shawnee Road Hanover, MD 21076-1320 Alexandria, VA 22312 443-757-5802 703-605-6000 This report is also available in electronic form at http:/ntrs.nasa.gov iii Contents 1. Introduction ................................................................................ 1 2. Nomenclature .............................................................................. 9 3. Tasks ...................................................................................... 17 4. Operation .................................................................................. 23 5. Solution Procedures ........................................................................ 43 6. Cost ....................................................................................... 55 7. Aircraft .................................................................................... 63 8. Systems .................................................................................... 81 9. Fuselage ................................................................................... 85 10. Landing Gear ............................................................................. 89 11. Rotor ..................................................................................... 91 12. Wing ..................................................................................... 123 13. Empennage ............................................................................... 131 14. Propulsion System ........................................................................ 135 15. Fuel Tank ................................................................................. 141 16. Propulsion Group ......................................................................... 147 17. Engine Group ............................................................................. 153 18. Jet Group ................................................................................. 163 19. Charge Group ............................................................................. 169 20. Referred Parameter Turboshaft Engine Model ............................................. 173 21. Compressor Model ........................................................................ 187 22. Motor Model .............................................................................. 191 23. Referred Parameter Jet Engine Model ..................................................... 199 iv Contents 24. Fuel Cell Model ........................................................................... 205 25. Solar Cell Model .......................................................................... 207 26. Battery Model ............................................................................ 209 27. AFDD Weight Models .................................................................... 223 Chapter 1 Introduction The NASA Design and Analysis of Rotorcraft (NDARC) software is an aircraft system analysis tool that supports both conceptual design efforts and technology impact assessments. The principal tasks are to design (or size) a rotorcraft to meet specified requirements, including vertical takeoff and landing (VTOL) operation, and then analyze the performance of the aircraft for a set of conditions. For broad and lasting utility, it is important that the code have the capability to model general rotorcraft configurations, and estimate the performance and weights of advanced rotor concepts. The architecture of the NDARC code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis, and optimization. Initially the software is implemented with low-fidelity models, typically appropriate for the conceptual design environment. An NDARC job consists of one or more cases, each case optionally performing design and analysis tasks. The design task involves sizing the rotorcraft to satisfy specified design conditions and missions. The analysis tasks can include off-design mission performance calculation, flight performance calcula- tion for point operating conditions, and generation of subsystem or component performance maps. For analysis tasks, the aircraft description can come from the sizing task, from a previous case or a previous NDARC job, or be independently generated (typically the description of an existing aircraft). The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated; and the aircraft attributes are obtained from the sum of the component attributes. Description and analysis of conven- tional rotorcraft configurations is facilitated, while retaining the capability to model novel and advanced concepts. Specific rotorcraft configurations considered are single-main-rotor and tail-rotor helicopter, tandem helicopter, coaxial helicopter, and tiltrotor. The architecture of the code accommodates addition of new or higher-fidelity attribute models for a component, as well as addition of new components. 1–1 Background The definition and development of NDARC requirements benefited substantially from the ex- periences and computer codes of the preliminary design team of the U.S. Army Aeroflightdynamics Directorate (AFDD) at Ames Research Center. In the early 1970s, the codes SSP-1 and SSP-2 were developed by the Systems Research Integration Office (SRIO, in St. Louis) of the U.S. Army Air Mobility Research and Development Laboratory. SSP-1 performed preliminary design to meet specified mission requirements, and SSP-2 estimated the performance for known geometry and engine characteristics, both for single-main-rotor helicopters (ref. 1). Although similar tools were in use in the rotorcraft community, these computer programs were independently developed, to meet the requirements of government analysis. The Advanced Systems Research Office (ASRO, at Ames Research Center) of USAAMRDL produced in 1974 two Preliminary 2 Introduction Systems Design Engineering (PSDE) studies (refs. 2 and 3) using SSP-1 and SSP-2. These two codes were combined into one code called PSDE by Ronald Shinn. The MIT Flight Transportation Laboratory created design programs for helicopters (ref. 4) and tiltrotors (ref. 5). Michael Scully, who wrote the helicopter design program and was significantly involved in the development of the tiltrotor design program, joined