Russia and other developments in Hypersonic Research

lancelot wrote:The West is ahead of Russia in research of rotating detonation engines though. Japan already tested one in space for example.

AFAIK denotation engines deliver enhanced fuel efficiency (up to 25%) but the basic concept is not especially useful for hypersonic systems as they still require subsonic airflow and this puts them into the mach range of ramjets.

Russian research into RDEs seems to be more focused into rocket engines for space applications, but the Chinese seem to be more ambitious and have tested a RDE on a drone in 2023  link.  Looking ahead they are looking at a variable cycle engine that runs as a continuous RDE at air speeds below M7 which then shifts to "oblique detonation" as it transitions into a scramjet for higher mach numbers.

The-thing-next-door wrote:I thought the Sarmat had RDEs.

Sarmat can carry Avangard HGVs (3x apparently) but AFAIK the jury is still out on whether Avangard has propulsion (eg scramjet) or whether its a pure glide vehicle. We don't know, and Russians won't tell

kvs wrote:Nuclear scramjet suggests to me a design where there is no fuel combustion.   Instead air is forced into an aperture which is super-heated by a
nuclear reactor.   This produces a similar effect to the chemical variant without the need to carry any propellants.   I have no idea whether
such a design is feasible.   But certainly some design research team has modeled such a concept.  

Burevestnik is showing that a nuclear powered ramjet is hard to develop, so I hate to think how complex a nuclear scramjet would be. The potential for meltdown in event of an interruption to the air flow would be extreme, you would need to react within milliseconds to cut the heat to the "combustion" chamber.

Burevestnik is showing that a nuclear powered ramjet is hard to develop, so I hate to think how complex a nuclear scramjet would be. The potential for meltdown in event of an interruption to the air flow would be extreme, you would need to react within milliseconds to cut the heat to the "combustion" chamber.

But as KVS pointed out if a nuclear reactor is generating the heat for propulsion (as opposed to burning fossil fuels like in a jet engine) then there is no combustion as such so the airflow through the "engine" does not need to take into consideration combustion because there is none.

It is more about heat transference so a case of airflow into the reactor and super heating the air and allowing it to flow out the back of the engine... it would be a case of transferring the heat from the reactor components or screens to actually heat the airflow without slowing it down and allowing it to rush out the exhaust to be replaced by more fresh air coming in the front... compressing the air in the way in will heat it too so going through the reactor would super heat it, but with this relative airflow absorbing all this heat then the reactor needs to generate a lot of heat quickly on demand.

Metals might not do it... perhaps ceramic material to release heat into the airflow?

But the terms ramjet and scramjet don't apply in the sense that the airflow is not restricted by combustion rate so it could be both with no top speed restriction.

Note even mach 2 or mach 3 at low altitude would be enough... it doesn't need to be mach 10 or anything.

Most conventional turbofan cruise missiles fly at medium altitude for the first two thirds of their flight to maximise flight range... then they drop down to low altitude as they approach enemy airspace to be hard to spot.

With a nuclear powered ramjet it could stay at low level the entire flight, making it hard to spot and hard to deal with.

Fired at low altitude massively reduces the effective range of all AAMs carried by aircraft and no fighter aircraft with weapons can fly faster than about mach 1.3 at low altitudes for very long at all. Their flight range is massively reduced flying low and fast.

Most strike aircraft like F-111 fly at transonic speed at low altitude when loaded with weapons.

Off topic physics stuff moved here.

US Creates Hypersonic Breakthrough With Secret Allies, by Alexander Timokhin for VZGLYAD. 08.13.2024.

Launching massive strikes against the enemy with hypersonic missiles is the goal behind the development of a new type of hypersonic weapon by the United States. What exactly is being discussed, who has become the Pentagon's secret ally in this program, and what threat does it pose to Russia?

The US has been experimenting with developing hypersonic weapons for several years now, but they have generally been unsuccessful.

The most famous US hypersonic missile is the Boeing X-51A Waverider, a small experimental missile with a hypersonic ramjet engine. Work on the programs preceding the X-51A began in the 1990s, and the missile’s actual development began in 2005.

In 2013, the missile reached its set parameters. The product, launched from a strategic bomber over the Pacific Ocean, flew 426 km at a speed of 5.1 times the speed of sound, using atmospheric air as an oxidizer. After that, the program was suspended and nothing has been known about any work on this missile since then.

But another project made a splash for a short time – the AGM-183 ARRW (Air-lauched rapid response weapon). The missile was an American analogue of the Russian Kinzhal, but with the ability to be launched from a subsonic carrier. After the first tests, there was a lot of noise in the press around the missile. But in the end, the project was cancelled; the Americans failed to complete the missile.

A separate topic is the so-called hypersonic gliders. These are gliding warheads for missiles, which with other warheads could be called ballistic. Here, unfortunately, the US is doing well, but these are still not missiles.

It seemed that the US had failed to create hypersonic missiles. However, on August 5, 2024, it became known that the US and Australia have been working on creating hypersonic missiles for tactical aviation for 15 years and that significant progress has already been made.

The agreement on cooperation in the creation of hypersonic weapons between the United States and Australia was concluded in 2007. At the same time, the Hypersonic International Flight Research Experimentation (HIFiRE) program was launched, the full name of which translates as "International Flight Research Experimentation", and the abbreviation sounds like "High Fire". The program was designed to create a scientific and technical reserve for future hypersonic missile projects.

In 2020, due to the success of the research program, a practical one was launched on its basis, with the incredibly pretentious name of Southern Cross integrated flight research experiment (SCIFiRE), which translates as “Integrated flight research of the Southern Cross (a constellation visible in the Southern Hemisphere), and the abbreviation can be understood by ear as “Scientific Fire”.

The result of this program should already be the creation of a new missile, a ready-made weapon system. What will it be like?

The Americans have announced the following characteristics. Speed ​​– five “sonic speeds”. Carriers – tactical aviation, that is, fighters and, for some reason, anti-submarine (patrol) aircraft. The Americans claim that the missile is supposed to be cheap.

In a joyous move, the US Air Force has begun integrating joint programs with Australia and its only hypersonic weapons program still underway, the Hypersonic Attack Cruise Missile (HACM). Deliveries of production missiles are expected to begin in 2027.

What is interesting is how secretively the US did it all. Australia has huge uninhabited areas, and this was an important factor for the Americans, who needed a lot of free air space above the ground for experiments.

But it is also easier to ensure the secrecy of all actions in Australia. In fact, apart from satellite reconnaissance, neither we nor the Chinese have any means of collecting information about what is happening on this remote continent. And who would have guessed to monitor Australia from space?

So, one day you might get an unpleasant surprise. The US successfully cooperates with Australia not only in the field of missiles, and it is worth wondering about the intelligence capabilities on this continent.

The second problem is more acute. Of all the hypersonic missiles, the Americans "got" the X-51A, and, coincidentally, the new missiles repeat its "ideology" - they are "five-speed" and use atmospheric air as an oxidizer. "Pure" hypersonic.

Since the Waverider flew back in 2013, and then the program "disappeared from the radar", it is worth proceeding from the fact that the Australians and Americans will succeed in the same way in the new program. Perhaps even using the backlog from the supposedly stopped X-51A program.

And then any American aircraft will be able to hit a target outside the air defense zone in 40-60 seconds from the moment the missile is launched. That is how much time the air defense calculations will have to hit a super-fast and small-sized target.

And what if there are dozens of targets in a salvo? After all, they plan to make the missile cheap. And therefore, in the realities of the USA – mass. And that means – massive strikes with such missiles are ahead.

We don't know for sure whether the Americans will succeed this time, but for our own safety we should assume that this threat will become real. No modern air defense is ready to combat such targets yet.

It would also be good to intensify work on such weapons in our country. While the Navy has received the Zircon, the Air Force does not yet have its own hypersonic guided missile. But in a number of aspects of hypersonic weapons development, we are still ahead of the US. The enemy's activity in the hypersonic direction is a good reason to increase our activity.

https://vz.ru/world/2024/8/13/1281928.html

The second problem is more acute. Of all the hypersonic missiles, the Americans "got" the X-51A, and, coincidentally, the new missiles repeat its "ideology" - they are "five-speed" and use atmospheric air as an oxidizer. "Pure" hypersonic.

Air breather so it is a ramjet or scramjet, but only mach 5... that is about the top speed you will get from a ramjet powered missile and is a little slow for a scramjet.

The Kh-31 is a 600-700kg tactical mach 3.5 missile in its current form with a range of about 250km.

Just swapping its ramjet propulsion with scramjet would likely improve flight speeds by two to three times and therefore also range by two to three times without increasing weight by very much at all.

Sounds more like a MA-31 copy to me... which they got in the early 2000s from Russia.

Not Russian but still worth a mention (or gloat... )

Reaction Engines to close as cutting-edge SABRE fails to advance

https://www.flightglobal.com/aerospace/reaction-engines-to-close-as-cutting-edge-sabre-fails-to-advance/160565.article

Hilarious! Arrogant UK tossers have been yabbering about how they would build engines for a hypersonic orbital transport, and their 35 year effort has collapsed into a pile of sht. Promise the world and deliver nothing. Laughingly they try to pass of their technical failure as a "lack of funding", but I guess thats to be expected from Perfidious Albion where the regime monkeys do cartwheels rather than openly admit their failures and imperial collapse...

Chinese engineers combine technologies to create new type of hypersonic engine, reveals media, 11.08.2024.

A team of engineers from China is developing an innovative new hypersonic jet engine design that should be one of the existing fastest, reports the South China Morning Post newspaper.

By mounting a ramjet, a jet engine with no moving parts, on a rotary detonation engine, scientists want to achieve "better continuous thrust, lower starting speeds and improved performance".

The very concept of a rotary detonation engine is a developing engine that uses one or several detonation waves that propagate continuously through an annular channel.
During detonation, combustion products expand at supersonic speed, which, theoretically, is 25% more efficient than traditional combustion.

Nowadays, various countries are developing different types of this engine, but most projects have traditional limitations:

pulse detonation engines do not have continuous thrust;

oblique detonation engines require very high starting speeds;

rotary detonation engines do not achieve optimal full pressure gains.

The invention of Chinese scientists, who combined ramjet-based rotor compressor with a blasting motor, has a rotating rotor with blades installed in a stationary housing.

The engine works by compressing the combustible mixture, initiating combustion by detonation and the expansion of the gas in the various channels between the blades.

"By adjusting the rotor speed, the detonation wave is held in a relatively fixed position inside the engine, approaching the optimal total pressure gain and thermodynamic efficiency of a detonation cycle," the article explains

Yandex Translate from Portuguese.

https://noticiabrasil.net.br/20241108/engenheiros-chineses-combinam-tecnologias-para-criar-novo-tipo-de-motor-hipersonico-revela-midia-37270396.html

Murhkans will claim that China "stole" the technology from them... just like how Russia stole hypersonics missiles from them.