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Analysis of Advanced Rotorcraft Configurations
| Content Provider | Semantic Scholar |
|---|---|
| Author | Johnson, Wayne |
| Copyright Year | 2000 |
| Abstract | Advanced rotorcraft configurations are being investigated with the objectives of identifying vehicles that are larger, quieter, and faster than current-generation rotorcraft. A large rotorcraft, carrying perhaps 150 passengers, could do much to alleviate airport capacity limitations, and a quiet rotorcraft is essential for community acceptance of the benefits of VTOL operations. A fast, long-range, long-endurance rotorcraft, notably the tilt-rotor configuration, will improve rotorcraft economics through productivity increases. A major part of the investigation of advanced rotorcraft configurations consists of conducting comprehensive analyses of vehicle behavior for the purpose of assessing vehicle potential and feasibility, as well as to establish the analytical models required to support the vehicle development. The analytical work of FY99 included applications to tilt-rotor aircraft. Tilt Rotor Aeroacoustic Model (TRAM) wind tunnel measurements are being compared with calculations performed by using the comprehensive analysis tool (Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD 11)). The objective is to establish the wing and wake aerodynamic models that are required for tilt-rotor analysis and design. The TRAM test in the CermanDutch Wind Tunnel (DNW) produced extensive measurements. This is the first test to encompass air loads, performance, and structural load measurements on tilt rotors, as well as acoustic and flowvisualization data. The correlation of measurements and calculations includes helicopter-mode operation (performance, air loads, and blade structural loads), hover (performance and air loads), and airplanemode operation (performance). Figure 1 shows an example of the comparison of TRAM-measured performance with calculations. The figure shows the difference in calculated rotor power obtained by using an aerodynamic model (wing and wake) appropriate for helicopter rotors, instead of a tilt-rotor aerodynamic model. The span loading and wake formation are very different on tilt rotors and helicopters, so it i s essential to use model features specific to tilt rotors in order to adequately predict the behavior. Future analyses wil l be concerned with TRAM tests in the Ames 40by 80-Foot Wind Tunnel, which will produce data over a much larger operating envelope for two rotors and the airframe, including advanced flow-visualization results, and with XV-15 rotor tests in the Ames 80by 120-Foot Tunnel in order to obtain tilt-rotor data at a larger scale (although no air loads data) with different blade planform and twist. The quad tilt-rotor configuration has been proposed in order to meet the objective of a large rotorcraft; it is hoped there will be fewer difficulties |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040077149.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
