LAPCAT (Long-Term Advanced Propulsion Concepts and Technologies) was a 36-month European

FP6 The Framework Programmes for Research and Technological Development, also called Framework Programmes or abbreviated FP1 to FP9, are funding programmes created by the European Union/European Commission to support and foster research in the Europea ...

study to examine ways to produce engines for a

Mach number Mach number (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Moravian physicist and philosopher Ernst Mach. : \mathrm = \ ...

4-8

hypersonic flight Hypersonic flight is flight through the atmosphere below altitudes of about 90 km at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds of Mach 25+ have been achie ...

aircraft. The project ended in April 2008. It was funded by the

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...

research and development fund (rather than

ESA , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (1 ...

), and cost 7 million euros. LAPCAT II, a 10 million euro, four-year, follow on project, started in October 2008. The study aims to 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, 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 being researched as part of this project is the A2 by

Reaction Engines Limited Reaction Engines Limited is a British aerospace manufacturer based in Oxfordshire, England. History and personnel In , Reaction Engines was founded by Alan Bond (lead engineer on the British Interplanetary Society's Project Daedalus) and Ric ...

. The researchers are looking at an aircraft capable of flying from

Brussels Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...

(Belgium) to Sydney (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 is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of t ...

properties of

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...

. The engine is theoretically capable of powering the A2 to a sustained Mach 5 throughout flight with an effective exhaust velocity of 40,900 m/s or

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine (a rocket using propellant or a jet engine using fuel) creates thrust. For engines whose reaction mass is only the fuel they carry, specific impulse is ...

of 4170 s, SFC . "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 A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forceful ...

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..

Notes

References