ATK,DARPA&ONR Flies First Liq-Hydrocarbon Fueled Scramjet!

[skyone]

So the technology is moving ahead without NASA! I'd like to see NASA push forwards with capsules and genuine exploration. At the same time, it is good to see government (military) push a field that the private sector has difficulty with by itself.<br /><br />http://webwire.com/ViewPressRel.asp?SESSIONID=&aId=6994

 

[henryhallam]

This is pretty impressive and fascinating stuff. It is interesting to get the occasional glimpse at some of the projects that are being worked on "out of the public eye".

 

[mlorrey]

Well, this is hardly a black project, it just isn't something that the popular press understands much of. There is a decent amount of material out there on this project, including some neat pictures.

 

[spacelifejunkie]

With the success of the X-43 and now the FAST program, how soon until we have a working prototype? If a scramjet missile is developed in the next 5 years, will NASA or the rest of the aerospace industry start to see the value in this and start working on a way to get to orbit? There doesn't seem to be a sense of urgency with this technology despite the recent success. I know it's expensive and I know that NASA has bigger fish to fry with the VSE, ISS and STS but this could be a real breakthrough in performance. I'd like to see ATK prove the technology in a real application and have them or Lockmart or Boeing grab this thing by the horns in five years years and make a real spaceplane. Breakthroughs in propulsion, space access, civil transport and the like are necessary for continued US leadership in science and technology as well as economic and political stability.<br /><br />SLJ

 

[mlorrey]

You don't need scramjet, you just need ramjet with MIPCC active cooling. One thing X-43A showed was that mach 10 and up are excessively hot for current materials technology. Therefore, there is no point in using scramjet to air breath above mach 10. You can use MIPCC to use ramjets up to mach 8. The mach 8-10 range is insufficient to justify scram technology. ramjets give enough boost to average Isp to make SSTO on quite conservative mass fractions.

 

[josh_simonson]

A bunch of such ramjet-rockets could be used at strap-on boosters with a throtleable JP-7/LO2 core. The rocket could be throttled back to idle during the regime in which the scramjets would operate to reduce L02 use.

 

[henryhallam]

What is the minimum operating speed of a ramjet? Something reachable by high-altitude magnetic catapult?

 

[JonClarke]

Just under mach 1, I believe. Proper inlet designs can achieve the necessary shock compression. Many long range SAMS are and have been ram jets, using a solid fuel booster to achieve ignition speeds.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mlorrey]

Official numbers claim 450 kt for any appreciable thrust, though they will light up at 200 kt. If you use LOX or Peroxide as your MIPCC coolant, you could easily get it going with significant thrust at lower speed.

 

[spacelifejunkie]

"You don't need scramjet, you just need ramjet with MIPCC active cooling. "<br /><br /><br />I am certainly a lamen on this board so I learn a lot as I go. What is MIPCC active cooling? Who is developing this technology right now?<br /><br /><br />I am extremely open to criticism for the following proposal so feel free to disect...<br /><br />1. Use a large aircraft (White Knight II?) to lift a small lifting body craft (like Dream Chaser?) to 30,000 ft.<br /><br />2. The MIPCC actively cooled ramjets propel the ship to Mach 5+ at 100,000+ ft where they are discarded. A rocket (a SpaceDev hybrid?) boosts it the rest of the way to LEO.<br /><br />3. The lifting body glides back to earth and is reused.<br /><br /><br />Does the addition of these engines create complications and dollars spent that do not warrant their presence?<br /><br />The altitude (10% orbital) and initial speed (20% orbital) that these ramjets provide is attractive when you consider possible savings in rocket fuel mass and payload gain. Compare that to 3% initial altitude and 2% initial speed necessary for a trip to LEO using a rocket directly after the drop from WK2. The restrictions on jets to speeds at Mach 3 have limited their use when trying to achieve orbit. If that speed is doubled it seems that they could become useful in a configuration outlined above.<br /><br />Your thoughts?<br /><br /><br />SLJ

 

[mlorrey]

MIPCC = Mass Injection Pre-Compressor Cooling. It was developed in the late 50's-early 60's to improve the speed and high altitude performance of turbojet engines, particularly for the F-106, and was used by the F-4 to cheat its way to the two-engine speed record (previously the overall record was held by a stock 106 without MIPCC). With the advent of new low bypass turbofans and the turbo-ramjet of the SR-71, MIPCC seemed to die on the vine (Interestingly, the F-12 proposal for the USAF ADC to use the SR-71 in a fighter version went head to head with an MIPCC and canard equipped "F-106X" which was expected to reach MACH 5!!!! The "Six X" beat the F-12 on paper, but McNamara cancelled any new interceptor buy for the ADC, trying to force the F-111 into an interceptor role, then rammed the Navy's F-4 down the throats of the TAC).<br /><br />MIPCC technology was revived by DARPA for the RASCAL program, to develop a fighter-sized small payload launcher. RASCAL was cancelled last year for budget reasons. <br /><br />MIPCC works by injecting its coolant in the airstream ahead of the compressor. This cools the stream, which causes it to become more dense at a lower temperature. This decreases heating of the compressor, increases thrust, and generally makes the jet engine believe it is operating at a lower altitude and lower speed than it actually is.