Efficient Multi-Mach Aircraft
Sizing and Synthesis
Propulsion and Structures
CAD and Cabin Design
The Efficient Multi-Mach Aircraft (EMMA) project was ad honorem work conducted for NASA as a Grand Challenge to evaluate the feasibility of a quiet supersonic passenger transport. The research team created an environment were the decision maker could trade-off mission requirements, design parameters and technology improvements. Additionally the environment included factors that were not under the control of the designers or operators, such as fuel price and load factor to enable stakeholders to capture these uncertainties in their decision making process. A 3D render of the aircraft was provided in the trade-off environment to allow the user to use his or her intuitive knowledge to determine if the geometry chosen was in fact a viable alternative. The EMMV tradeoff environment was named the Parametric Evaluation Tradeoff Environment (PETE), it was developed using Java and OpenGL, and it integrated validated surrogate models of a medium fidelity sizing and synthesis environment.
The design was to be similar to the Concorde, carry between 175 and 250 passengers and fly in excess of 5,000nm. It was to be smaller than the previous High Speed Civil Transport (HSCT) design developed in the late 1990s. The results indicated that considerable advances in aerodynamic and structural technologies were required before the economic and noise constraints set by NASA could be achieved. In total, the environment included 78 control parameters and tracked 18 responses.
The analysis was conducted by integrating NASA's Rapid Aircraft Modeler (RAM), Flight Optimization System (FLOPS) and Aircraft Life Cycle Cost Analysis (ALCCA) program with VORLAX, AERO2S and the Boeing Design and Analysis (BDAP) program, as well as PBOOM, a NASA Langley sonic shock prediction code. The integrated environment was sampled using a space filling Design of Experiments (DoE) to obtain sufficient data to generate the Response Surfaces. The sampling and regression were iterated in order to improve the quality of the fits and maximize their spanning of the design space. The surrogates were then integrated into the visualization environment developed in Java.
The results presented in the figure above included significant technological improvements in terms of structures (including weight reductions of over 20% from the state-of-the-art) and aerodynamics (significant reductions in both zero-lift and induced drag). The range achieved did not satisfy the 5,000nm requirement. The takeoff field length (TOFL) and landing field length (LdgFL) were within the 11,000ft requirement. The quantities of NOx and CO2 per Available Seat Mile (ASM) did not violate the pollution constraints but were not expected to be sufficiently low to pass future regulations. The noise pollution metrics, Figure of Noise (FON) and Sideline Noise (SLN), were deemed acceptable for a supersonic aircraft. The maximum allowable take-off gross weight (TOGW) of 500,000lbs was required to maximize the range. The empty weight (WEmpty) was estimated to be slightly over 40% of the TOGW. This estimate included significant weight reduction technologies and use of advanced materials. The acquisition price was estimated to be 326 million 2003 USD by ALCCA. The research, development, testing and evaluation (RDT&E) costs were estimated at 12.5 billion 2003 USD. The economic viability of the aircraft was evaluated by computing the revenue per passenger mile (RPM), which was estimated at 0.17 2003 USD. This was deemed as a viable figure to charge passengers for supersonic air travel. Nonetheless, the figures presented included what at the time was considered to be conservative estimates for the cost of fuel, but did not approach current fuel prices. The total aircraft return on investment (TAROC) and direct operating cost plus interest (DOC+I) were estimated at 10.6 and 9.1 cents per available seat mile.
- Jiménez, H. and D. N. Mavris, "Conceptual Design of Current Technology and Advanced Concepts for an Efficient Multi-Mach Aircraft," SAE Transactions, 2005-01-3399, 2005, Vol.114; Part 1, Pg. 1343-1353.