Successful recent ground tests of jet-fueled, ramjet/scramjet demonstrator engines by Pratt & Whitney Rocketdyne and Aerojet represent important progress toward flight-testing of three separate hypersonic-vehicle programs.
Using JP-7 jet fuel, PWR ran the combustor successfully at a variety of Mach numbers from Mach 2.5 to Mach 6.0, demonstrating "desired operability and performance" at each speed, the company said.
PWR's approach is to use a closed-loop or "heat sink" system, whereby the fuel is pumped as a coolant throughout the engine casing to remove heat and pressure from the combustor. This 3,000-degree heat also prepares the jet fuel for combustion by cracking it into smaller molecules that burn very quickly when they enter the combustor.
A full-sized version of PWR's combustor will form the heart of the FaCET program, sponsored by the U.S. Defense Advanced Research Projects Agency (DARPA) and the U.S. Air Force. Lockheed Martin is FaCET prime contractor.
FaCET aims to develop a hypersonic test vehicle -- which could fly in 2012 -- that would take off and land by itself, use an advanced turbojet to get up to a speed of at least Mach 4 and then use a liquid hydrogen-powered scramjet to get to Mach 10 and beyond. Jet fuel can't be used as a scramjet fuel at speeds as high as Mach 10.
FaCET isn't linked to the DARPA/U.S. Air Force/NASA X-51A hypersonic aircraft that is due to fly in 2009. But PWR, which is making the JP-7-powered X-1 scramjet engine for the Boeing-built X-51A, uses what it learns from each program to improve both engines.
"The engines are not the same shape or configuration but, technology-wise, the FaCET engine incorporates much of what we've learned through the X-51 engine," said McKeon. "The flip side is that we also have learned stuff with this (FaCET) engine regarding different configurations that could also be used in future X-51 activity."
There are also tests planned for the airframe to make sure it can survive the speed and temperatures The Falcon was to fly Sept 2007 but has been delayed.
Hypersonics rockets for space launches could have an ISP (rocket fuel efficiency) of about 2800 (with good designs) which is over 6 times better than the best chemical rockets (450 ISP)
I think there are better technology that we can develop for far cheaper access to space and that any manned hypersonic plane system will take 15-30 years. However, if they can get this working that would be great.
Skylon space plane concept