About the American hypersonic vehicle X-43
The X-43: The speed record broken by an unmanned aircraft
**April 7, 2004 - completed on April 8, 2004 **- **added on July 18, 2007 **
All the press has picked up the news. The Americans have just broken a speed record with an unmanned machine, carried to altitude under the wing of a B-52 and then launched at Mach 7 by a large solid-fuel booster, at which speed (8,000 km/h) the machine would have maintained for a few seconds, propelled by its "scramjet," a ramjet operating at supersonic speeds.
Everyone believes in it. Thus, "the Americans are planning to take hold, in a distant future, of the hypersonic world. The numbers are announced: 10,000 km/h, a machine capable of circling the Earth at 60-80 km altitude.
Still, I have a question. The SR-71, the famous American spy plane flying at Mach 3 and some, at 3,500 km/h, has been in the Seattle museum since 1991. That's thirteen years. What do the Americans have to replace it?
Generally, when something is retired, it's because we have something better. Nothing replaces the airplane. The satellite only makes a ballistic flight. It is costly to launch. The rocket is not reusable. You can't say "could you not make a detour here, fly over there." The satellite is on a circular trajectory. We are forced to make choices. Moreover, it cannot descend below a certain altitude, otherwise the air slows it down. According to the Americans, they no longer have a spy plane. If they had one, it would have taken over from the Blackbird SR-71. How does the latter work? With turbojets. It has air intakes with conical tips on which the shock waves attach, through which the air is not only recompressed but also heated. Recompression is desired. Combustion could not take place in air that is too rarefied. That is why at the inlet of a turbojet there is an axial compressor, with blades, which then directs this recompressed air into combustion chambers.
But beyond Mach three, the shock wave produces air that is too hot to be sent to the turbine blades. Those would be vaporized. Between Mach 3 and Mach 5 is the ramjet. It is sufficient to remove the turbine. The shock wave then provides the recompression. It is possible to arrange for the flow downstream of the shock wave to be subsonic. But for higher Mach numbers, this becomes problematic again. We then enter the world of the scramjet, a ramjet where combustion takes place in supersonic flow. Very difficult to make work. Not at all flexible. But it can work between Mach 5 and Mach 7. There are Franco-Russian studies where vehicles with rotational symmetry are tested, brought to these high speeds by Sam 7 ground-to-air rockets, I believe. In this configuration, the fuel is liquid hydrogen, which is first circulated through the leading edges of the vehicle.
Beyond Mach 7 lies the "heat barrier."
Let's take stock. If the Americans are really at the alleged stage, testing a 2.5 meter model for ten seconds, then the manned vehicle will appear in 10 to 20 years. For 15-20 years, while children play with the Blackbird at the Seattle museum, the Americans will remain "without anything." Like us with our military nuclear monitoring, without tests since 1996. That's already eight years. It seems that we will manage this with a supercomputer and a laser simulator.
Ah, if you read this month's Air et Cosmos, you will see that the Americans are planning to use MHD to facilitate atmospheric reentries and even to steer warheads. We live in a fantastic era. We are kept informed of progress on a daily basis. Secrecy is outdated. We are shown the systems under consideration at the preliminary study stage. Before, we were kept in the dark about the existence of the U2 (until Gary Powers was shot down over the Soviet Union), the F-117 A, and the Blackbird. But today, everything is known. We are informed. It's nice.
I wrote a book where I expressed my thoughts on all this. There has been no debate, anywhere. Except for scientifically incompetent ufologists like Gildas Bourdais, my writings have been ignored. I even read, regarding the famous photo taken more than 20 years ago at Groom Lake, showing a dotted trail, that an "ONERA expert" (National Office for Aeronautical Research and Studies) concluded it was a pulsed combustion, specifying that this regime would be very uncomfortable for any potential passengers or pilots. I believe I remember that I gave another explanation for this phenomenon in my book: that the semi-guided nozzle of the vehicle was not working "at its adapted altitude," which created, as is classic, a succession of "nodes" and "antinodes" in the exhaust jet, with shock waves.
Well, I said what I thought. I published files on my website on the curiosities of the B2. In fact, I'm completely off the mark. In terms of long-range bombing, subsonic with multiple in-flight refuelings is the future. For surveillance and stealth, I predict a strong return of the balloon. On the naval level, the ideal is the sail-powered ship. It's obvious; wood is completely stealthy. We don't go fast, but we are completely invisible to radar.
It is useless to fight against the dominant idea. Besides, I don't fight, I no longer fight. In astrophysics, long live dark matter, dark energy, inflation, and the pre-Big Bang. It seems that in labs, people are equipping themselves with extremely fine and short needles (the Planck length: 10-33 cm), to knit branes for winter, of course with superstrings. Since the future seems so problematic, I said to myself, "let's try to turn to the past." Hence this interest in the ships of the Old Egyptian Empire, the drifting rafts of the ancient Peruvians, and some other things not worth mentioning. In a month, I think, we will be able to proceed, with Yan Souriau and the rest of the group, with the tests of the "Coelacanth," of course subsonic. It was supposed to happen in February, but we had minus ten and a meter of snow. Now, the lake is dry. We will find another one.
A reader sent me these few photos taken on an American site, showing the X-43 from different angles. The comments are his.
**Note the two blinking lights on the top of the stainless steel plate, used to signal turns. **
**In this close-up view, the headlights or turn signals, port and starboard, are more clearly visible. **
In fact, when you look for other images, you see that these large light alloy nipples are not the turn signals of the aircraft. They have at least one function. The flats they bear (and which are clearly in different directions for both) show that they allow these parts to be screwed onto the structure. These parts also have conical machining which allows (there is the same device below) to clamp the vehicle in a frame to be able to handle and transport it.
Below, a close-up showing technicians handling the vehicle, firmly fixed in a frame.
It is clearly visible that there are two "nipples," upper and lower, which allow the vehicle to be secured using two large nuts...