Hypersonia: The Propulsion

The resources and technologies for making horizontal takeoff and landing hypersonic flights a reality are available. And making is happening in different places, but the development of the engines are mostly in the US and UK. 

The focus is airbreathing hypersonic engines. These are advanced jets, ramjets, scramjets and airbreathing liquid fuelled rockets. The development of propulsion technologies happening in military sphere and by companies. The latter coming out with their business roadmaps for innovation. 

To start with, the main challenge precluding using a normal jet engine for hypersonic propulsion, is the inability to produce much kinetic energy. Energy as a measure of physics — is the amount of power required for work within a specific period of time.  The challenge  is due to the nature of the engine and the fuel being used. 

Jet engines are designed to burn fuel at a slower rate, and the low density of the fuel itself is an issue. Continuous firing requires a ready made supply of oxygen igniting a high density fuel. Thus, the configuration, nature and type of the engine matter. Capable examples have been shared on this platform. 

The main benefit of a jet engine is the use of atmospheric air. And it is its main limitation. Oxygen makes up a small proportion of air, nitrogen denser than oxygen makes up most of the air. It is, however, a less suitable combustor, even though its density offers the front section of the airframe and engine a surface area to push against. Acting as an outside propellant. 

A waverider airframe design, for instance,  maximises such power of the air. Riding on it as a cushion for lift and gulping loads of it into the combustor chamber of a scramjet for generating enough thrust. 

Overcoming such limitation in a turbine jet engine requires an innovation. An on-board propellant is typically used for generating thrust for a rocket engine. Such is energy dense, with the ability and design to burn at a faster rate, thus producing the rapid acceleration required for speed. The configuration of a rocket engine, makes it to burn at such high rate. A turbomachinery or a high pressure tank pushes the propellant mixed with an oxidant into the combustor chamber.

The same advantage, is also its main limitation. The high burn rate typically prones a rocket engine to either be discardable or requiring a long turnaround time before it can be reused. Notwithstanding, the various advances being made by various companies, it is still an issue. 

The innovation is making a jet engine in various configurations and designs to burn a dense propellant, enriched with a certain amount of an oxidant as the onboard fuel. Onboard gaseous or liquid hydrogen mixed with oxygen in similar states, is one. Another suitable candidate is hydrogen peroxide. A monopropellant being used for powering a missile or a spacecraft is another choice. 

Such an advanced jet engine is still airbreathing. Using atmospheric oxygen together with the on-board one. It’s design requiring the controlling high temperature and pressure. Using a diffuser for slowing down the incoming high speed air.  And a heat exchanger or precooler, for reducing the temperature of the incoming  air. 

The use of advanced materials and metals being used in making advanced jet and rocket engines, contributing to making the  innovation possible. The aim is preventing unnecessary explosion or fire. And depending on the configuration, prolonging the life of the engine and its compressor, chamber, combustor and fan. The use of a dense propellant for powering, making a typical turbine jet engine with the suitable high bypass configuration, dimension and nozzle size & shape capable of hypersonic outputs. 

A turbo -ramjet or -scramjet with such features even goes better and further. As previously presented on this platform, with an Air Chemical Engine System (ACES) design, atmospheric hydrogen, nitrogen and oxygen can be made in-flight. Or for making, for instance, ammonia or hydrogen peroxide. 

Such reducing the takeoff weight by carrying less fuel to start with, using the in-flight made fuel for the return flight. Negating the need for worldwide fuelling infrastructure. A problem currently associated with hydrogen at the moment. The implement — the engine is the locus of innovation. With the possibility of reducing the cost of building widespread infrastructure.

An airbreathing turboscramjet-powered spaceplane possible with such design. The propellant powering the in-built thruster, using ionisation of the fuel for moving around in space. Such configuration already elaborated on on this platform. Such not requiring a rocket in any forms. 

The innovation requiring due attention from entrepreneurs and companies. This is a design that is possible now. It is a boundary-pushing one, capable of transforming not only the aerospace industry, but its associated and supplying ones. Notwithstanding its enormous benefits and possibilities, the challenge is making the industry to rise up to it. 

The Mach 5 barrier still prevalent in the jet engine industry. For instance, Pratt & Whitney (P&W) in its roadmap envisioning a hypersonic design process, using the J58 that powered the SR 71 as a platform to innovate on. The 1950s engine proving its worth for Mach 3-5 flight, with the use of advanced configuration, materials and techniques.

The advanced jet engine is a quasi-turboramjet, using high bypass and suitable inlet design. It is capable of beyond Mach 5 flight, but the intentionality of the company of not making a true turboramjet out of it or using a heat exchanger in the engine, the reasons offered. Such advancement, as previously presented on this platform, will make the F135 engine powering F35 and F119 engine powering F22, capable of near hypersonic flights. 

The military is the sole customer for these engines. It’s preference for advanced jetry, and not Scramjetry can contribute to frustrating an early arrival of Hypersonia. As will be shared down the line, this is not the whole story. 

However, for P&W, it is paradoxical that such an innovative company is playing to the limit set by its parent company — Raytheon. Having ATK Orbital a rocketmaker and a GASL a scramjet inventor as part of the larger company, relegating the former to not going beyond Mach 5. Much about having the independence to innovate even when located within a parent company. Whichever, the pathway towards hyper speed flight is ever expanding. 

As a platform, an engine increases in scale and size as the airframe is. The scaling is a direct proportionality between the thrust produced by the engine and the gross weight of the aircraft. As such, the handful turboramjet makers, are making engines suitable for powering a private jet or a jet fighter, not a large commercial airliner. 

The military in the US and UK are preparing for making the 6th generation aircrafts. This will rely more on speed and less on stealth for evading attackers and defences. The US Navy is setting to replace its  carrier based F 18 with one. To be powered by a dual-mode turbine-based combined cycle engine (TBCC). Such a turbo-ramjet-scramjet is capable of Mach 6 and beyond. This is even as the Navy has cancelled a hypersonic missile to be powered by such engine. 

The reason for such not given. However, it is that such an engine is better for powering an aircraft than an air-launched missile. A liquid fuelled rocket, preferably an airbreather is more suitable. Moreover, the Pentagon has different joint service pure rocket- and scramjet-powered hypersonic platform-programmes, that the Navy is partaking in. 

Ship- and submarine-launched hypersonic missiles are in the pipeline. And in an increasingly networked organisational structure, the Navy can rely on the Airforce for air-launched, or the Army for ground-launched, hypersonic missiles as required. 

The development of suitable propulsion technologies for different use-cases, rising, nonetheless. Overall, there is limited investment going into airbreathing hypersonic propulsion. The gap can be filled with innovative private financial mechanisms. Public investment can kickstart, especially for military purpose, as it is being done in some countries. 

Such governmental input is not interventionism. Hypersonics is a new technology, in which there is no available fully developed one. As such, the government as a customer is seeking answers to a strategic question of fighting contemporary warfare. Therefore, financing the companies to innovate and create the novel. Such has being the origin of many groundbreaking innovations.

The funding of the invention is kickstarting, not procuring.  The latter is usually customising extant technologies to public requirements. Notwithstanding, private investment is the preferred source of finance. 

The engine as a platform requires multiple inputs and results in similar outputs. And innovations and improvements generated in each stage, step or sequence of the development and commercial programme. The making by companies is located within a nation for strategic or national security reasons, and for protecting sensitive commercial secrets. And co-making with other like-minded companies in friendly nations. The assemblers, makers and suppliers of the components linking up together on the platform. 

The global supply chain in the aerospace industry is not as widely distributed or stretched as others, even though certain chips or electronics can be procured from other countries. The danger associated with such was raised with the F35 a few years back. Software for planes are usually written by suppliers located within a trusted country. 

Software is bundled with hardware i.e. the aircraft, and perfecting its integration and use as a unit requiring overcoming teething problems. Such business, organisational and process innovations are necessary for making the experience and functions better. The F35, for instance, as transformative as it is, is still being perfected. And making it communicating directly with F22 in-flight is one of those issues, for instance. 

Both hardware and software require investment. A hypersonic engine requires investing into both for full, maximum and proper performance. 3D printing is another technology that requires both as well. The making of such machines, requiring integrating components from various sources, even as the technology itself can easily be used for making the components and the whole. 

The making of hypersonic airframes and engines is by crafting using machining and by 3D printing. Even as increasingly the latter is being used in the aerospace industry, it will reinforce the localisation of making in the home nations, even pulling component-making from the friendly nations. And such can happen in similar industries. 

The making of the 3D machines, will still be global. The components going into the making, sourced by companies from others in various countries. The duration and level of dispersion will be determined by how quickly the machines are increasingly being made in-country with 3D printing by companies. 

The development of airbreathing engines using the suitable high dense propellant, will contribute to actualising widespread hypersonic flights. The innovations going into the making coming by entrepreneurs and inventors. The outcome is transformative technologies changing economies and nations. 

The Covid pandemic is still on. The UK government is taking actions. The vaccination going apace. The making of the vaccines in the UK and US, for instance, is an example of the government making the necessary investment for kickstarting certain previously immature bio-innovations. The companies carrying out and doing the innovations. 

The making of the propulsion technologies for powering hyper speed flights is happening. Innovation is about pushing the boundaries that are necessary for breakthroughs. It is overcoming limitations posed by extant infrastructure, systems and technologies. 

P&W’s technology roadmap is limited by the capability of the extant airframes. It’s willingness to stay within Mach 5, is explained by both the civilian and military aircrafts only capable of making supersonic flights, albeit even near hypersonic speed. The challenge for moving forward is not making the necessary investments into building airframes and engines capable of sustaining hypersonic flights. 

The crossing of the boundary to Mach 5 speed and beyond changes everything. A plane capable of making supersonic flights, cannot withstand the turbulence created by the dynamics of the air around the aircraft. Therefore, innovation is going over the extant.

The UK 6th generation fighter will be powered by durable SABRE engines. It is of UK’s long-term benefits that Rolls Royce’s ongoing efforts to using Reaction Engines’ heat exchanger technology for advanced jetry, produces a beyond Mach 5 engine. So that it’s working relationship with the airframers, can contribute to making aircrafts that are capable of durably withstanding hypersonic flights. 

Crossing the boundary is breakthrough. The use of mRNA for making vaccines is a breakthrough. A fully functional hypersonic aircraft and engine is one as well. 

God Bless. Jesus Heals.

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