LAPCAT
Encyclopedia

LAPCAT was a 36 month European FP6 study to examine ways to produce engines for a Mach 4-8 hypersonic
Hypersonic
In aerodynamics, a hypersonic speed is one that is highly supersonic. Since the 1970s, the term has generally been assumed to refer to speeds of Mach 5 and above...

 aircraft. The project ended in April 2008. It was funded by the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....

 research and development fund (rather than ESA), and cost 7 million euros.

LAPCAT II, a 10 million euro four-year follow on project was due to start in October 2008. The study will refine some of the results of the first study "allowing the definition of a detailed development roadmap" of a Mach five vehicle.

Objectives

Two major technologies were to be considered:
  • ram-compression
    Scramjet
    A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow...

    , which needs an additional propulsion system to achieve its minimum working speed.
  • active compression, which has an upper Mach number limitation but can accelerate a vehicle up to its cruise speed.


Key objectives were the definition and evaluation of:
  • different propulsion cycles and concepts for high-speed flight at Mach 4 to 8 such as turbine-based and rocket-based combined cycles
  • critical technologies for:
    • integrated engine/aircraft performance
    • mass-efficient turbines and heat-exchangers
    • high-pressure and supersonic combustion experiments
    • modelling


Intended results were:
  • definition of requirements and operational conditions for high-speed flight at system level
  • dedicated experimental data-base specific to high-speed aerodynamics for supersonic and high-pressure combustion and flow phenomena.
  • setting-up and validating physical models supported by numerical simulation tools to address supersonic and high-pressure combustion, turbulence and transition phenomena.
  • feasibility study of weight performance turbine and heat exchanger components

Results

Among the several vehicles studied, only two novel concepts were retained for LAPCAT II: a Mach five vehicle and a Mach eight vehicle.

Mach five vehicle

One possible supersonic transport aircraft
Supersonic transport
A supersonic transport is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. The only SSTs to see regular service to date have been Concorde and the Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 with its last ever...

 being researched as part of this project is the A2
Reaction Engines A2
|-See also:-External links:* *...

 by Reaction Engines Limited
Reaction Engines Limited
Reaction Engines Limited is a British aerospace company based in Oxfordshire, England.- History & personnel :Reaction Engines was founded in 1989 by Alan Bond and Richard Varvill and John Scott-Scott...

. The researchers are looking at an aircraft capable of flying from Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

 (Belgium) to Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

 (Australia) in 2-4 hours, significantly reducing journey times across the globe.

To attain and maintain such high speeds, Reaction Engines Limited would need to develop its newly designed concept engine called the Scimitar, which exploits the thermodynamic
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

 properties of liquid hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

. The engine is theoretically capable of powering the A2 to a sustained Mach 5
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...

 throughout flight with an effective exhaust velocity of 40,900 m/s or specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

 of 4170 s, (SFC 0.86 lb/lbf h).

"Results so far show [the Mach 5 vehicle from Reaction Engines] can avoid later [technology] pitfalls and could travel from Brussels to Sydney," says ESA's LAPCAT project coordinator Johan Steelant.

Mach eight vehicle

Although the cruise flight of the scramjet
Scramjet
A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow...

 based Mach eight vehicle seems feasible, the fuel consumption during acceleration requires a large fuel fraction, severely affecting gross take-off weight. Initial studies of a first stage rocket ejector concept gave poor range with large take-off mass.

A conceptual design of a Dorsal-Type Mach 8 vehicle produced by the study can be seen here.

See also

  • Precooled jet engine/Reaction Engines SABRE/Reaction Engines Scimitar
    Reaction Engines Scimitar
    The Reaction Engines Scimitar is a derivative of the SABRE engine technology, but intended for airliners , rather than space launch applications. Consequently, most of the Scimitar engine technology is similar to Sabre but designed for much longer life...

  • Reaction Engines A2
    Reaction Engines A2
    |-See also:-External links:* *...

  • Liquid air cycle engine
    Liquid air cycle engine
    A Liquid Air Cycle Engine is a type of spacecraft propulsion engine that attempts to increase its efficiency by gathering part of its oxidizer from the atmosphere...

  • HOTOL
    HOTOL
    HOTOL, for Horizontal Take-Off and Landing, was a British air-breathing space shuttle effort by Rolls Royce and British Aerospace.Designed as a single-stage-to-orbit reusable winged launch vehicle, it was to be fitted with a unique air-breathing engine, the RB545 called the Swallow, to be...

    (1986-88 design for single-stage-to-orbit reusable winged launch vehicle to use an air-breathing engine)
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