Right , just like Boeing reputation as passenger airliner are so well established that B737 Max 8 tragic can happened. Now nobody want to get Max 8. Nobody trust Boeing new product.
It is also this mentality that tragic of CVN Gerald Ford happened too. American brag about their past glory and forget about hardwork needed to put into new product.
Let us take a look at China's latest prototype weapon...
The ICBM is boost-dive method. China's just tested the boost-glide method. Are there any conceptual advancement here? None.
A conceptual advancement is one that irrevocably changed warfare, meaning if you do not have said weapon, you will most likely lose the war. Not guaranteed, just most likely you will lose. Guerrilla warfare is in a different type of warfare, so we do not consider that here.
The horse changed warfare. The horse enabled the soldier to be faster, stronger, more mobile, and with greater combat range. The bow and arrow gave greater lethal distance. Gunpowder, the rifle, the machine gun, aviation, and many other too long to list, all changed warfare past the point of no return.
There is a difference between a conceptual advancement vs a process/engineering advancement. The water cooled machine gun was a P/E advancement. The water jacket compensated for a problem of overheating gun barrel but did not alter the repeating cycling method itself.
China's latest prototype missile used the rocket boost method. Nothing spectacular there. Then the vehicle used gravity assist to gain Mach 5+ or hypersonic speed. NASA lifting body designs back in the 1960s-70s done that and the Space Shuttle reentry speed was almost Mach 25. So this Chinese prototype did not even expand any current knowledge with its gliding body. The tactical advantage here is that by traveling in a horizontal path and making at least one orbit, the weapon rendered its final destination unknown to current external estimation methods, aka 'guesses'.
On the other hand, DARPA's Hypersonic Air-breathing Weapon Concept (HAWC) vehicle...
The Hypersonic Air-breathing Weapon Concept vehicle made a free flight at hypersonic speed as the Air Force and DARPA look to develop a hypersonic missile.
www.airforcemag.com
Sept. 27, 2021
The engine “kicked on” seconds after being released from an aircraft, which DARPA and the Air Force declined to identify, although DARPA expressed appreciation to “Navy flight test personnel.” The Navy has been conducting hypersonic missile research with F/A-18 aircraft.
The engine “compressed incoming air mixed with its hydrocarbon fuel and began igniting that fast-moving airflow mixture, propelling the cruiser at a speed greater than Mach 5,” DARPA said. In order for the scramjet engine to ignite, the vehicle must be moving at hypersonic speed, so a booster is used for that portion of the flight.
All of the “primary” goals of the test flight were achieved, including “vehicle integration and release sequence, safe separation from the launch aircraft, booster ignition and boost, booster separation and engine ignition, and cruise.”
The HAWC is exploring air-breathing hypersonic flight in parallel with the Air Force’s AGM-183A Air-launched Rapid-Response Weapon (ARRW), which is accelerated to hypersonic speed by a rocket before being released and gliding toward its target.
...Is a true conceptual advancement of the hypersonic vehicle.
The US version eliminated the ballistic rocket boost method and instead rely on a parent launch aircraft, which immediately made the weapon more tactically responsive to varying needs. It also rendered the weapon essentially undetectable by current satellite reconnaissance, unlike ballistic missiles that will be detected upon launch from surface.
The propulsion method is a P/E advancement. The SR-71 J58 engine is essentially a turbojet mated to a ramjet. The HAWC engine replaced turbojet with a rocket booster to push the vehicle to Mach 5+ speed then the scramjet takes over and sustain that speed. So unlike China's hypersonic missle that uses gravity, the HAWC vehicle have a true engine.
Now, with the US version of the hypersonic weapon, there are
POTENTIAL variations that cannot exist in the Chinese version.
The ramjet have been known to operate subsonic speed, at airliner altitude, and even lower. But in order to sustain operation, inlet airspeed must be constant or the engine dies. Lower altitude means higher air density which produces higher drag which mean lower inlet airspeed which would kill the engine. That mean a scramjet design is pretty much restricted to a certain range of altitude.
en.wikipedia.org
This optimal climb/descent profile is called a "constant dynamic pressure path".
So how low of altitude can a scramjet maintain Mach 5+ ? Unknown at this time. But it does raise an interesting possibility with using an air breathing hypersonic vehicle where there could be custom hypersonic missiles designed for specific altitude to avoid air defense radars. The Chinese hypersonic missile do not glide in full atmosphere but in sub-orbital altitude where it will be detected. An air breathing hypersonic missile design for a specific altitude and being air launched will be far less vulnerable.
