Posted: 8/14/2012 6:08:55 AM EDT
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Just heard on radio. Mach 6???
Anyone know more? |
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Well Crap, from today's Boring News Now:
3rd X-51A test flight ends prematurely The third X-51A Waverider test vehicle was successfully launched from an Air Force B-52 bomber over Point Mugu Naval Air Warfare Center Sea Range Tuesday at approximately 11:36 a.m. Pacific time. According to U.S. Air Force officials, the X-51A safely separated from the B-52 and the rocket booster fired as planned. However after 16 seconds of flight, a fault was identified with one of the cruiser control fins. The X-51A separated from the rocket booster as planned, but approximately 15 seconds later the vehicle could not maintain control due to the faulty control fin and was lost. "It is unfortunate that a problem with this subsystem caused a termination before we could light the Scramjet engine," said Charlie Brink, X-51A program manager for Air Force Research Laboratory. "All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives." This particular control subsystem had proved reliable in the previous two flights of the X-51A including the historic May 2010 flight when the Waverider flew for more than three minutes at Mach 4.88 under scramjet power –– nearly five times the speed of sound. Program officials are now evaluating the flight data to determine what occurred to cause the fault. One of the four X-51A test vehicles remains. Air Force Research Laboratory officials have not yet decided when or if that vehicle will fly. |
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Quoted: So what's the top speed of an SR71? Still classified? So how fast does the SR-71 really go.......? The fastest published speed of the SR is Mach 3.5. There are several factors that limit the speed of the SR, one is the shock waves generated by various parts of the plane, at around Mach 3.6- 3.8 the shock wave off the nose of the aircraft narrows enough to go into the engine, while there is the inlet spike (which slows the air to subsonic before it enters the engine), the shock wave bypasses the spike and causes the engine to unstart. Second is the heat generated by the plane moving through the atmosphere, even titanium has it's limits, and the heat generated by the SR brings the fuselage to the brink. Just recently I found out that during a Lockheed Skunk Works study to see how much money and development it would take to get the SR to go faster than it's designed top speed 3.2- 3.5, the designers discovered (among other things) that the metal divider between the windshield was heating up so much above mach 3.5 that it was affecting the integrity of the windshield, and at that point they had stretched the glass technology to the max! So Mach 3.2 to a max of 3.5. Now according to Richard Graham: "The design Mach number of the SR-71 is 3.2 Mach. When authorized by the Commander, speeds up to Mach 3.3 may be flown if the CIT limit of 427 degrees C. is not exceeded. I have heard of crews reaching 3.5 Mach inadvertently, but that is the absolute maximum I am aware of." |
