Laurent Serre

French Flight Testing Program LEA Status in 2009

French R&T effort for hypersonic airbreathing propulsion is focusing on needed technologies for the propulsion system and acquisition of aero-propulsive balance prediction capability. A large part of technology development effort can be led on ground and is currently dedicated to combustion chamber to ensure its performance and thermomechanical strength. On the contrary, it is mandatory to flight demonstrate capability to predict the aero-propulsive balance. In that view, MBDA and ONERA are leading the flight testing LEA program. Started in January 2003, the program will end in 2015 after 4 autonomous flight tests of an experimental vehicle in Mach number range 4 to 8. Guidelines for LEA vehicle and its propulsion system design have been validated in 2006 by a Preliminary Design Review. The running Phase 2 aims at getting a detailed design while validating the aero-propulsive configuration by a first free jet test series to be performed early in 2011. It led to a Critical Design Review performed in June/July 2009.

LEA Flight Test Program - Status in 2004

During the 10 last years, a large Research and Technology effort has been led by MBDA and ONERA to develop knowledge on high-speed airbreathing propulsion and master associated technologies. Development of operational, civilian or military, application of the hypersonic airbreathing propulsion depends of two key points : development of needed technologies for the fuel-cooled structure of the propulsion system, capability to predict with a reasonnable accuracy and to optimise the aeropropulsive balance (or generalized thrust-minus-drag balance). The most part of the technology development effort can be led with available ground test facilities and classical numerical simulation (thermics, mechanics

Lapcat II : towards a Mach 8 civil aircraft concept , using advanced Rocket/Dual-mode ramjet propulsion system

As a partner of EU-funded LAPCAT-II project, devoted to high-speed propulsion technologies, Onera is involved in a concurrent system study that aims at designing a Mach 8 civil aircraft concept on the Brussels-Sydney route. The proposed Onera concept, based on a previous high speed propulsion French program (PREPHA), resulted in a 100 m / 900 tons concept, using a rocket/DMR propulsion system. After introducing the frame of this study, design process, trade studies, trajectory results and CAD views of shape and layout are presented in this paper, as well as the on-going work aiming at designing a TBCC PREPHAbased concept, in cooperation with other LAPCAT-II partners (Universite Libre de Bruxelles and University of Rome).

LAPCAT-II : conceptual design of a Mach 8 TBCC civil aircraft, enforced by full Navier-Stokes 3D nose-to -tail computation

Within the frame of the LAPCAT II project (Long-term Advanced Propulsion Concepts and Technologies, funded by the European Commission as part of the 7 th Frame Program and involving 16 European research labs and industries), four concurrent system studies have be en carried out to design a Mach 8 vehicle able to c arry passengers on the Brussels-Sydney route. The required range is above 18000 km, and the defined number of passengers is 300, which correspond to a 60 tons / 1400 m 3 payload.

Reducing the Size of Air-breathing Space Launchers to Enlarge Their Perspectives: How It Works

Application of air-breathing propulsion to space launchers has been the frame of several studies, especially in the USA (NASP) and in Europe (Sanger, Hotol, and French technological program PREPHA). Most of them took the hypothesis of SSTO missions and/or heavy payloads, which led to large vehicles and propulsion systems difficult to be robustly and cost-efficiently developed. The paper presents a parametric system study performed by ONERA under a CNES contract, which emphasizes on small payloads (from 10kg to 150kg) and aims at evaluating the main characteristics (GTOW, empty weight, size, capture area) of a launch system comprising at least an air-breathing stage (that could use combined propulsion such as rockets + scramjet) and a low-cost kick-off stage. The parametric approach is described, whose main entries were the payload weight, the staging mach numbers and the way to provide initial acceleration (boosters, rockets integrated in the airbreathing stage, conventional plane, UAV,...). The credibility of the results is enforced by re-using and extrapolating data and models from the PREPHA program, and validating their applicability to smaller vehicles towards a comparison with experimental vehicle studies previously performed in France. Four interesting families of systems are put forward: boosted horizontal take-off three-stage-to-orbit (for which a more detailed design process was performed, using preliminary MDO tools and trajectory studies) , autonomous vertical take-off TSTO, TSTO launched from a subsonic airplane or UAV, TSTO launched from a supersonic military plane. The optimal staging Mach number between air-breathing and kick-off stage is analyzed. A link is made with other similar studies led in France on this topic.

ZEHST: environmental challenges for hypersonic passenger transport

The ZEHST hypersonic transport airplane, derived from Astrium Space Plane concept, and having roots in a French-Japanese cooperation, was unveiled by EADS at Paris Air Show 2011. In the frame of a DGAC (French Civil Aviation Authority) sponsoring, EADS Innovation Works together with MBDA, Astrium and Onera launched a feasibility and system study to set up the detailed requirements, assess the technologies envisioned and perform a first design loop, based on shortterm availability of technologies. The 3-propulsion-system concept comprises turbofans for subsonic operations, rocket engines to cross the transonic regime and ramjet engines for efficient high-speed cruise. ZEHST stands for Zero Emission High Speed Technologies, thus emphasizing the will to take into account environmental footprint while designing the vehicle and its trajectory. The aim of the activities on environmental impact within the ZEHST program, for which Onera is responsible, is to set up a methodology highlighting the phenomenology to be taken into account, selecting the appropriate models to compute significant metrics, and conducting trade studies and assessments to provide design guidelines to the conceptual design team. This paper will illustrate this methodology with selected examples among sonic boom, rocket noise and particle emissions assessments.

French Contribution to Hypersonic Airbreathing Propulsion Technology Development - Status in 2006

The development of operational, civilian or military, application of the hypersonic airbreathing propulsion depends of two key points : • development of needed technologies for the propulsion system as a low weight, highly robust fuel-cooled structure for the combustor, • capability to predict with a reasonnable accuracy, and to optimise, the aero-propulsive balance (or generalized thrust-minus-drag).

Design and full 3D nose-to-tail computation of a turbofan+ scramjet Mach 8 civil aircraft

ithin the frame of the LAPCAT II project (Long-term Advanced Propulsion Concepts and Technologies, funded by the European Commission as part of the 7th Frame Program and involving 16 European research labs and industries), four concurrent system studies have been carried out to design a Mach 8 vehicle able to carry passengers on the Brussels-Sydney route. The required range is above 18000 km, and the defined number of passengers is 300, which correspond to a 60 tons / 1400 m3 payload. Inspired by the previous analysis led by Onera on PREPHA-based concepts, by the University of Rome on TBCC hypersonic performances and by Universite Libre de Bruxelles on precooled turbofan performances, a deeper analysis on a LH2 turbofan/ramjet/scramjet concept was performed, including a parametric sizing of the vehicle, a more detailed internal layout and especially a step-by-step numerical analysis of the aeropropulsive performances on the Mach 8 cruise point, using a nose-to-tail approach. The preliminary steps of the design process have been described in a previous paper. This new paper will focus on the progress made to enforce the consistency of the vehicle, especially regarding its 2-flowpaths propulsion system. Conceptual design of the low supersonic intake feeding the turbofans will be presented, as well as a final evaluation of its performance on the Mach 8 cruise point using a single-domain nose-to-tail computation where the combustion chamber is precisely modelled, including injection and bleeding systems. A new layout will then be presented, taking into account several options for the hydrogen tanks arrangement. 1 Research engineer, Long-term Design and System Department, Sebastien.Defoort@onera.fr. 2 Research engineer, Fundamental and Applied Energetics Department, Marc.Ferrier@onera.fr. 3 Head of advanced aeropropulsion systems, Long-term Design and System Department, Laurent.Serre@onera.fr. 4 Engineering student cyril.daghrir@ulb.ac.be 5 Professor – patrick.hendrick@ulb.ac.be W

LEA flight test program - Status in 2004

MBDA and ONERA are leading a specific scientific program, called LEA, aiming at demonstrating their ability to predict the aeropropulsive balance of a hypersonic vehicle, ensuring sufficient margins to undertake a costly full scale development program, by : • Defining a methodology for the development of a hypersonic vehicle using ground tests and numerical simulation • Developing the required tools (experimental or numerical) for this purpose • Applying this methodology to the development of a simplified, low cost experimental vehicle • Validating this methodology through a series of flight tests. Started in January 2003, this program is planned to end in 2012 after 6 autonomous flights of the experimental vehicle in the Mach number range from 4 to 8.