6.THE WORKING OF A HYPERPLANE (Seminar Hyperplanes)

B-52 Bomber carrying X-43 Hyperplane for experiments

The aircraft is first propelled by jet engines to the required height. Other method is to take the aircraft to required altitude by another plane. Because neither scramjets nor ramjets can operate efficiently when they are traveling below Mach 2 or 3, a third type of propulsion (perhaps turbojet or rocket) is required for takeoff. So-called rocket-based combined-cycle engines, which could be used in a space vehicle, rely on a rocket that is integrated within the scramjet combustor to provide thrust from takeoff through subsonic, low-supersonic and then ramjet speeds. Ramjet operation is then followed by scramjet propulsion to at least Mach 10 or 12, after which the rocket is utilized again to supplement the scramjet thrust. Above Mach 18, the rocket by itself propels the vehicle into orbit and enables it to maneuver in space. NASA is currently testing several variations of such a system.

Any aircraft faster than the speed of sound creates a shock wave, as air "piles up" in front of the vehicle. Faster the aircraft, more severe the shock wave. Most hypersonic designs intend to confine the most of the high pressure airflow from the shock wave beneath the vehicle, so that it appears to be 'riding' the top of the wave. This results in lower drag to lift ratios than other hypersonic designs. In the process also giving them all a characteristic look.

The landing procedures begin by the switching off of the scramjet engines. Then the horizontal flight is done using normal jet engines and lands like a normal aircraft. Unlike a rocket that carries its own oxygen for combustion, the X-43A's scramjet-short for supersonic-combustion ramjet-scoops air from the atmosphere, making the aircraft lighter, which enables it to carry heavier payloads. The hydrogen-fuelled aircraft has a wingspan of approximately five feet, measures 12 feet long and weighs about 2,800 pounds.

THERMAL PROTECTION SYSTEM FOR HYPERPLANES (Seminar Hyperplanes)

New materials offer good insulation at high temperature, but they often sacrifice themselves in the process. Therefore studies often plan on "active cooling", where coolant circulating throughout the vehicle skin prevents it from disintegrating. Often the coolant is the fuel itself, much in the same way that modern rockets use their own fuel and oxidizer as coolant for their engines. All cooling systems add weight and complexity to a launch system and reduce its efficiency. The increased cooling requirements of scramjet engines result in lower efficiency. Heat resistant materials like insulating tiles and materials made of Titanium and its alloys can be used as passive cooling methods. Active cooling methods (by coolants or fuel itself) can also be employed which is widely used in space crafts.A combination of this two methods can also be tried.The real challenge lies in the development of composite materials which are light weight and also a better thermal insulator.

ADVANTAGES AND DISADVANTAGES OF SCRAMJET ENGINES (Seminar Hyperplanes)

Unlike a rocket that quickly passes mostly vertically through the atmosphere or a turbojet or ramjet that flies at much lower speeds, a hypersonic air breathing vehicle optimally flies a "depressed trajectory", staying within the atmosphere at hypersonic speeds. Because scramjets have only mediocre thrust-to-weight ratios, acceleration would be limited. Therefore time in the atmosphere at hypersonic speed would be considerable, possibly 15-30 minutes. Similar to a re-entering space vehicle, heat insulation would be a formidable task. The time in the atmosphere would be greater than that for a typical space capsule, but less than that of the space shuttle.

New materials offer good insulation at high temperature, but they often sacrifice themselves in the process. Therefore studies often plan on "active cooling", where coolant circulating throughout the vehicle skin prevents it from disintegrating. Often the coolant is the fuel itself, much in the same way that modern rockets use their own fuel and oxidizer as coolant for their engines. All cooling systems add weight and complexity to a launch system and reduce its efficiency. The increased cooling requirements of scramjet engines result in lower efficiency.
The efficiency of a launch vehicle depends greatly on its weight. Calculating the efficiency of an engine system is mathematically complex, and involves trade offs between the efficiency of the engine (takeoff fuel weight) and the complexity of the engine (takeoff dry weight)

Scramjets have few to no moving parts. Most of their body consists of continuous surfaces. With simple fuel pumps, reduced total components, and the re-entry system being the craft itself, scramjet development tends to be more of a materials and modeling problem than anything else.

A scramjet cannot produce efficient thrust unless boosted to high speed, around Mach 5, depending on design, although, as mentioned earlier, it could act as a ramjet at low speeds. A horizontal take-off aircraft would need conventional turbofan or rocket engines to take off, sufficiently large to move a heavy craft. Also needed would be fuel for those engines, plus all engine associated mounting structure and control systems. Turbofan engines are heavy and cannot easily exceed about Mach 2-3, so another propulsion method would be needed to reach scramjet operating speed. That could be ramjets or rockets. Those would also need their own separate fuel supply, structure, and systems. Many proposals instead call for a first stage of droppable solid rocket boosters, which greatly simplifies the design.

Unlike jet or rocket propulsion systems facilities which can be tested on the ground, testing scramjet designs use extremely expensive hypersonic test chambers or expensive launch vehicles, both of which lead to high instrumentation costs. Launched test vehicles very typically end with destruction of the test item and instrumentation.

There is no published way to make a scramjet powered vehicle (or any other hypersonic vehicle) stealthy- since the vehicle would be very hot due to its high speed within the atmosphere it should be easy to detect with infrared sensors. However, any aggressive act against a scramjet vehicle would be difficult because of its high speed.

DIFFERENCE BETWEEN SCRAMJET AND JET ENGINES ( Seminar Hyperplanes)

Difference between scramjet and jet engine.

The main difference is that the scramjet does not contain any moving parts like compressor blades, turbine blades etc. Also in scramjet there is no compression to subsonic velocities.In a jet engine compression and combustion process occurs at subsonic velocities.Thus combustion efficiency will be better in jet engines.In a jet engine a compressor for compression,combustion chambers for compression and turbines to run the compressors.The main difference is that in a scramjet engine all the processes like compression,combustion and exhaust takes place at supersonic velocities.But there are no moving parts in a scramjet engine.A scramjet engine consisted of only a constricted tube.Thus chances for mechanical failures due to moving parts are avoided.The differences are clearly shown in the diagram released by NASA.

WORKING OF A SCRAMJET ENGINE (Seminar Hyperplanes)

Scramjet engine working

Scramjet operation simple diagram

Like a ramjet, a scramjet essentially consists of a constricted tube through which inlet air is compressed by the high speed of the vehicle, a combustion chamber where fuel is combusted, and a nozzle through which the exhaust jet leaves at higher speed than the inlet air. Also like a ramjet, there are few or no moving parts. In particular, there is no high-speed turbine, as in a turbofan or turbojet engine, that is expensive to produce and can be a major point of failure.Also there is no compressor for air compression.Thus it compress air by shock or by the shape of the inlet and fuel is injected and combustion occurs and air is expanded at higher velocities and is exhausted through the nozzle. Inlet, combustion and exit are at supersonic velocities.Thus scramjet is supersonic combustion ramjet engines.

5. BASIC REQUIREMENTS FOR A HYPERPLANE(Seminar Hyperplane)

The hyperplanes have lot of differences in its design and working, therefore some basic requirements have to be met .They are,

JET ENGINES
Jet engines are required if horizontal take off is needed ( take off like other planes). Normal jet engines can be used for this purpose which will power the air craft to the height required for the working of ramjet engines and rocket engines. The main need for this arises since a scramjet engine cannot be started from zero velocity.

BOOSTER ROCKET ENGINE
rocket-based combined-cycle engines, which could be used in a space vehicle, rely on a rocket that is integrated within the scramjet combustor to provide thrust from takeoff through subsonic, low-supersonic and then ramjet speeds. Ramjet operation is then followed by scramjet propulsion to at least Mach 10 or 12, after which the rocket is utilized again to supplement the scramjet thrust. Above Mach 18, the rocket by itself propels the vehicle into orbit and enables it to maneuver in space. NASA is currently testing several variations of such a system. Hyper-X uses only the first stage of Orbital's Pegasus rocket . For a typical space launch, the Pegasus features three stages. The Pegasus stage has some alterations just for X-43 launches, but it is basically the same booster used to deliver small satellite payloads into Earth orbit.

SCRAMJET AIR BREATHING ENGINE
A scramjet (supersonic combustion ramjet) is a variation of a ramjet with the distinction being that some or all of the combustion process takes place supersonically. At higher speeds, it is necessary to combust supersonically to maximize the efficiency of the combustion process. Projections for the top speed of a scramjet engine (without additional oxidiser input) vary between Mach 12 and Mach 24 (orbital velocity). A scramjet is a type of jet engine designed to operate at the high speeds typically associated with rockets. Its main difference from a rocket is that it collects air from the atmosphere to burn its fuel, rather than carrying an oxidizing substance on board. More conventional jets (turbojets, turbofans and ramjets) share this characteristic but are unsuitable for the high speeds at which scramjets can operate.

4. HISTORY ( Seminar Hyperplane )

A Comparison SuT-4(USSR) and XB-70 Valkyre(USA)
X-15 Three views.
Bell X-1.(USAF)
Chuck Yeager(who took record in Bell X-1)
XB-70 Valkyre (USA)
SuT-4(USSR)

The history of hyperplanes begins with the development of X planes. The rocket powered Bell X1 flown in 1947 by Chuck Yeager was the first plane to fly faster than sound. This was the beginning of supersonic era of flights.

In 1960’s during cold war America developed XB-7O Valkyrie(Mach-3.08) to be used instead of ICBM’s . It was conceived in the 1960s as a strategic bomber that could deliver nuclear weapons. It holds the record for being the largest Experimental plane ever. It could fly at Mach 3.08 and achieve an altitude of 74,000 ft. Ultimately; it was only put to use as a research aircraft. It was simply too impractical when compared to an Inter-Continental ballistic Missile ( ICBM ).

At the same time during cold war time Soviets developed a plane similar to XB-70 , it is Su T4. The T-4, also called S100 (indicating that it was a prototype) first flew in 1972 and easily achieved Mach 1.28 at 12,000m. The aircraft completed a number of successful flight tests and showed a real promise of reaching its design requirements. The T-4 featured world's most advanced electrohydraulic, quadruple redundancy fly-by-wire system. When the nose of the aircraft was up and locked, the pilots had no forward visibility and all flying was on instruments.


The North American X-15 rocket-powered aircraft was part of the X-series of experimental aircraft, initiated with the Bell X-1, that were made for the USAF, the NASA, and the USN. The X-15 set speed and altitude records in the early 1960s, reaching the edge of outer space and returning with valuable data used in aircraft and spacecraft design. The record of Mach-6.7 was set by Pete Knight in the rocket powered X-15 in 1967.

3. BASIC TECHNICAL CHALLENGES ( Seminar Hyperplanes )

The basic technical challenge is to develop a non rocket engine which can attain hypersonic speeds. So far rocket engines are the ones which have attained hypersonic speeds. But they lack maneuverability which is required for a plane. Such powerful non rocket engines could be a great aeronautical challenge. Such engines have not been fully developed. The scramjet engine is the most widely accepted solution, but it is still in design and experimental stages of its development. The scramjets are air breathing engines which have great advantages.


The second technical challenge is the development of advanced materials including Titanium and its alloys and other composite materials that can handle the heat associated with hypervelocity flight. Great amount of heat is developed when planes fly above hypersonic speeds in the atmosphere and also during the re-entry time. The thermal protection shields used today are bulky and thus increases fuel consumption rates. Thus Titanium and its alloys have to be developed along with other composite materials. But the problem lies in the fact that main researches are conducted in defence laboratories which does not have much metalurgical experience.


The development of new cryogenic fuels and the new methods of handling them is a major challenge. Huge cryogenic tanks cannot be accommodated, therefore high calorific value fuels are needed which could burn completely at hypersonic combustion. Development in this area is also difficult.

2. THE NEED TO TRAVEL AT HYPERSONIC SPEEDS ( Seminar Hyperplanes )

There are many reasons why we should travel at hypersonic speeds.

Faster intercontinental travel is one major need. For this hyperplane X-3O was proposed which was expected to cover New York-Tokyo in around 1 hour.


Another major need is to allow seamless entry to space. To exit the atmosphere and park in LEO, a spacecraft must attain a speed of Mach 26(ouch), where it can either deliver payload which can be a satellite or even another vehicle that will travel further.


Other major uses are in defence fields. Here hyperplanes can be used for invincible spy planes and strategic bombers. USAF projects like the Hypersoar are hypersonic craft (Mach 10).


The major reason for the usefulness of the technology is because they can be used as reusable satellite launchers which could replace costly rocket missions.

They can thus be used as reusable missile launchers which could reduce cost and improve accuracy.


Our desire to constantly push the limits is also a reason for their development.

1. INTRODUCTION ( Hyperplane Seminar )

Hyperplane X-43 ( USA )

Speeds greater than Mach 5 are called hypersonic, equivalent to about one mile per second or approximately 3,600 miles per hour at sea level. A regular passenger plane flies at 0.8 Mach while fast military jets fly at Mach 2. SR-71 Blackbird, the fastest jet flies at Mach 3.2. The fastest rocket plane, X-15 flied once at Mach 6.6 way back in 1960. Russian jets (unmanned) have flown at Mach 6.4. Pretty evident as it is, flying at hypersonic speeds is difficult. According to NASA it is "one of the greatest aeronautical research challenges”. The main technical challenges are the development of non rocket engines and also the development of composite materials which can withstand the heat produced at this speeds .There is a wide range of application and scope for this technology. Many countries have started developing this technology, but it is still in a nascent stage. Most successful of the hyper planes developed so far is X-43.Thus we can analyze the working and technology of X-43 to learn more about hyperplanes .Also the key technological requirement is a scramjet engine which is more essential to sustain hypersonic speeds. Due to its wider applications in defense and in space transport India is also developing a hyperplane called Avatar, which is mainly for defense uses. Thus once fully developed this technology could bring a revolution in space transport.

ABSTRACT ( Hyperplane Seminar )

Abstract

Hyperplanes are multipurpose, fully reusable aerospace vehicles. These vehicles are using air-breathing engines and can take-off from any conventional airport. They are multipurpose vehicles in the sense that they be used for passenger or freight transport as well as satellite launching. The key enabling technology for hyper planes is scramjet engines which uses air breathing engine technology. The hyperplanes requires a booster rocket which will give it the supersonic velocity required for scramjet operation. Thus the hyperplanes require normal jet engines for horizontal take off, then a rocket to boost the velocity and a scramjet to sustain the hypersonic speed. Once operational it can even launch satellites at lesser costs compared to rockets. Many nations are working on hyperplane technology, which include USA, Russia, India etc.The only successful hypersonic flight was shown by X-43 of USA.The hyperplane Avatar which is developed by India is expected to be used as a reusable missile launcher. This would be the most modern technology which will revolutionize the modern day’s travel.Here we will discus about the working ,advantages ,disadvantages and various examples of hyperplanes.

SEMINAR ON HYPERPLANES (for MECHANICAL ENGINEERING)

Dear readers I would start posting a seminar topic on Hyperplanes ( planes traveling at hypersonic speeds).Don't confuse it with Hyperplanes in mathematics.This topic will be useful to many engineering students mainly mechanical and aeronautical.

I have prepared this seminar for my sixth semester mechanical engineering studies.Now I have completed my engineering degree.I am really happy to share this seminar topic.But it is a difficult topic for seminar since the technologies for hyperplanes are still in a nascent stage and research is mainly conducted by defense laboratories ,it is difficult to get more details.If you plan to take this seminar,you should update with the improvements that have been made at that time as it is a fastest evolving technology.

Hope it will provide some information to my dear readers.I will publish the abstract in my next post.