Aviation Technology
Faster than the Concorde

Columnist Col (Retd) EAS BOKHARI writes about the development of passenger aircraft faster than the CONCORDE.

Of course planes have been made which fly with muscle power alone - but then the human muscle power has its limitations of endurance and survivability - and some of these limitations are terribly severe and restrictive.

Perhaps the fastest commercial plane presently in operation is the Concorde - and it has come out in the New Scientist of April 15, 2000 - that planes even speedier than the Concorde are in the pipe line - and it is likely that the next generation Concorde supersonic successor could merge both the turbojet and ramjet technologies in one and the same plane to provide it the extra boost and speed.

The credit of experimenting with this new technology goes to Japan and “Japan is marrying two types of jet engines to power an aircraft that could fly from Tokyo to New York in 3 hours” - Incredible isn’t it.

A revolutionary jet engine was recently unveiled at the Tokyo aerospace show with a breathtaking potential and performance capability. It is designed to power a new generation of commercial aircraft that would be able to fly at five times the speed of sound - and would be known as Hypersonic Transport Propulsion System (HYPR) - and is the brainchild of Japan’s New Energy and Industrial Technology Development Organization (NEDO) which is a branch of the Ministry of International Trade and Industry of Japan.

In this revolutionary project - the heavy industry divisions of the Japanese industrial heavyweights i.e. Kawasaki, Mitsubishi, and Ishikawajima-Harima have teamed up to develop this state of the art engine. This engine is made up of two types of jet engines mounted end to end with the turbo jet in the front, and a ram jet in the rear. (See inset for layout).

The operational/functional arrangement is something like this that at speeds under Mach-3 - the aircraft yet not quite designated would be propelled by the turbo jet. And then “to provide the extra thrust needed for higher speeds, the ramjet would kick in and gradually take over. An ingenious network of ducts and valves handles the transition from turbo jet mode to Ramjet mode.

Basically in a turbojet driven engine the fan draws in air, compresses it - and pushes it through into a combustion chamber where fuel is injected and ignited to produce a hot high speed exhaust that creates the thrust. Ramjet on the other hand has no moving parts - and the forward movement of the aircraft is enough to force air into the chamber where fuel is ignited - thus producing the exhaust that creates the thrust.

The design engineers of this new bird have gigantic problems and getting the two engines to work in tandem - and designing materials to cope with very high engine temperatures are the main difficulties for the design engineers.

During initial tests temperatures in the HYPR reached a 1700 deg C when simulating flight at Mach-3. It is to be seen that the engines in subsonic planes do not get hotter than 1500 deg C. And now when flying at the intended speed of Mach-5 - the engines will be required to cope with temperatures around 1900 deg C. This of course is a very great engineering problem and challenge.

This i.e. HYPR ambitious project began some two years ago as a part of a long-term effort to build a commercial passenger jet capable of flying from Tokyo to New York in just three hours, at an altitude of 20,000 meters.

This is what Mitsubishi Heavy Industries engineer Akihiro Tobita confesses...” We don’t know when the plane will be built... It will take a lot of international cooperation....”

As it is, aviation giants like Rolls Royce from Great Britain, General Electric from USA and United Technologies also from USA are already providing technical expertise for the innovative HYPR - project.

A spokesman from Rolls Royce has confirmed that it is taking part in research for the programme, alongside with United Technologies and the famous French engine maker Snecma.

Finally “...NEDO says that the HYPR engine could be quieter and less polluting than conventional jet engines. Its next goal is to further reduce noise and pollution in the engine and increase its energy efficiency, as well as doing the groundwork for the body of the plane itself.”