Development of F4 Hotshot Windtunnel for High Enthalpy Scramjet Tests

The French hypersonic propulsion program PREPHA led in 90’s and the system studies which were carried out after its termination up to now, clearly show that the interest of high speed airbreathing propulsion is best drawn as soon as the system is able to use the scramjet up to around Mach 12. Existing facilities, mostly developed during the PREPHA, can today be used in France for direct connect tests of dual mode ramjets up to Mach 7.5 conditions. More recently, the S4 hypersonic blowdown windtunnel has been developed in the frame of the MBDA/ONERA led LEA program to enable vehicle at Mach 6 conditions, to contribute to the validation of the experimental vehicle and its propulsion system before the flights which are scheduled in 2014 and 2015. Some extensions of S4 could enable increasing the available total temperature for Mach 7.5 free-jet tests by adding a vitiator to the existing capacitive storage heater. However, when trying to reach Mach 10 or 12 scramjet test capabilities, it still appears mandatory to start using new facilities able to provide adequate temperature and pressure conditions. The F4 hotshot wind-tunnel offers high capabilities to test moderate size scramjets in free jet or semifree jet in the range Mach 8-12, due to its high pressure and total temperature capability, and to a much larger run duration than the ones offered by shock tunnels. The paper will describe the developments made in 2011 at F4 to enable scramjet combustion. The first qualification tests with hydrogen injection were performed on a simple combustion configuration, and were an opportunity to start implementing now optical diagnostics in the facility. Two model combustion chambers will be tested end of 2012, and the LAPCAT 2 small scale flight configuration will be tested in 2013. All of them will have been tested before in HEG, and hence providing data for direct cross-check on facility effects for these two high enthalpy facilities.