Hypersonic missiles. Most Lethal Weapon in the 21st Century?
Before focusing on hypersonic missiles let me set the background for you guys. Starting with flying speeds in aeronautical science Mach number is a dimensionless quantity representing the ratio between flow velocity and the speed of sound in the particular medium that the flow velocity is encountered or in other words, in the medium where the aircraft flies. The medium can be a gas or a liquid. The boundary can be traveling in the medium, or it can be stationary while the medium flows along with it, or they can both be moving, with different velocities. What matters is their relative velocity with respect to each other. With the development of aerodynamic studies engineers were capable of building air crafts that could fly exceeding the speed of sound, hence the Mach number came into use.
The craft speeds were categorized according to the regime of Mach numbers that the craft was capable of flying. The following table brings the ranges and the regime of Mach numbers in technical language as used by NASA and the people in the aeronautical field.
Mach number classification.
Transonic aircraft nearly always have swept wings which are wings that angle backward or occasionally forward from their roots rather than in a straight sideways direction.
Observe that when the aircraft moves in the regime of a transonic range certain airflow speeds upon different areas of the craft can be in the range of subsonic and supersonic regimes. Why would it be so? This can be understood clearly through the following diagram,
Airflow speed above wings increases due to aerodynamic shape.
The supersonic speed range is the range of speeds within which all of the airflows over an aircraft is supersonic (more than Mach 1). Aircraft designed to fly at supersonic speeds show large differences in their aerodynamic design because of the radical differences in the behavior of flows above Mach 1. Supersonic designs include the F-104 Starfighter, SR-71 Blackbird, and the Concorde.
Just a glimpse of the speed we are dealing with here.
With the background set up, we’ll now turn our way back on our path, “Hypersonic missiles”. Anything that flies beyond Mach 5 or above is hyper-sonic. We do have space shuttles that go hypersonically at speeds of Mach 20 or 24. However, it's flying hypersonically for a short period of time because of the extreme conditions that arose due to the hypersonic speeds. However, technology has evolved its guts to the extremes by entering a new era of sustained hypersonic flights. Here we mainly come across three hurdles to overcome when dealing with hypersonic flight.
—Aerodynamics and flight control
— Material Science
— Propulsion system
Aerodynamics and flight control interfere with a serious challenge at these extreme speeds. Temperature and pressure rise exponentially at these flight velocities which bring out the major challenge in material engineering. Materials that can withstand severe temperatures for a long period of time should be used in hypersonic flight/missiles. The third barrier comes from selecting a propulsion system that would power up the whole process of flight. Once you reach Mach 5 or above you can’t use your traditional jet propulsion engines (ramjet propulsion) and make them go faster which is the biggest technological jump that we have to be enrolled with before even thinking of sustained hypersonic missiles. Hypersonic missiles need scramjet-type propulsion systems which I would like to describe in another article just to keep this short and sweet and get you guys to the ending less bored.
Scramjet propulsion system theory
In conventional jet engines which operates up to Mach 3 or Mach 5 fans are used to compress air before combustion takes place but in SCRAMJET (Supersonic Combustion Ramjet) which operates between Mach 5 and Mach 15, a series of shock-waves compress the air and slow it into supersonic speeds As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully before combustion, but whereas a ramjet decelerates the air to subsonic velocities before combustion, the airflow in a scramjet is supersonic throughout the entire engine. That allows the scramjet to operate efficiently at extremely high speeds.
It has been said that this propulsion is so hard to achieve that it's similar to lighting a match in a 2000 miles/hour wind. And combining all these criteria to a weapon system in itself is a challenge. The Russians, the Chinese, and the US is leading in research and probably will hold the glory of possessing this kind of weapon system soon within their territories. They spend billions of dollars in research which the other countries won’t have the urge of doing just to try up researching stuff which leads only the world giants US, China, and Russia to hold the beacon soon in hypersonic weapon systems.
Furthermore hypersonic technology branches down to two main sub-divisions as Hypersonic Cruise Missiles (HCM) and Hypersonic Glide Vehicles (HGV).HCMs are capable of sustained, powered, and maneuvering hypersonic flight . Engine operations, pressure, and temperature constraints limit flight altitudes to 70000 and 100000 feet. Hypersonic glide vehicles are just gliders that glide at speeds above Mach 5 which itself is the beauty of aerodynamics coming into play. These can be flown above altitudes of 100000 feet. Hypersonic glide vehicles are of no innocence regarded along with HCMs. The mass of the vehicle and the speed that it strikes just can cause tremendous damage to the target because of the momentum it's carrying. These are launched using rockets that re-enters the atmosphere whenever it wants and then maneuvered along the atmosphere just like a plane without an engine, hence known as a glider. It uses pure aerodynamic forces to maneuver along towards its target, this maneuverability heightens the level of danger of these types of missiles since the target can be kept a secret until the last moment it strikes. Scramjets are used to power up the hypersonic cruise missiles to their targets which will literally reach their targets in less than 6 minutes which is a terrifying fact for the enemy dealing with it.
The current missile defense system is feathered away with this type of technology since the missile cannot be predicted as a simple ballistic object and no outfielder can predict its path whatsoever. This leaves the hypersonic missile system a great masterpiece of aeronautical science but yet a danger to all humans out there willing for peace. The defense system mechanisms, propulsion systems used here and the OODA loop mechanism followed by most countries to defense against a threat will be discussed later through my blogs. So keep in touch guys.
