Flight tests of a powerful US military scramjet prototype able to exceed Mach 4 while burning ordinary jet fuel have been scheduled for December, according to reports.
Aviation Week reports today that the X-51 "WaveRider" scramjet will now fly in December. The X-51 will be released from a B-52 bomber mothership operated by NASA above southern California. A modified missile booster rocket will accelerate the test stack past Mach 4, after which the 25-foot-long X-51 will ignite using ethylene lighter fluid, easier to get burning in a very fast airstream.
More: http://www.theregister.co.uk/2009/08/05/x_51_tests_for_december/