Sunday, August 2, 2009

Hypersonic civil aviation: Sydney to Brussels in four hours

Imagine long-distance air-travel that could get you to the other side of the globe in less than a quarter of the time it presently takes? Well, this may soon become a reality, and a commercially viable mode of passenger transport. Researchers from Reaction Engines, a company created for design and development of advanced space transport and propulsion systems, are investigating the possibility of hypersonic civil transport in a three year study to examine the feasibility of reducing long-distance flights (e.g. From Brussels to Sydney) to less than 4 hours. The project, called LAPCAT (Long-Term Advanced Propulsion Concepts and Technologies) is aimed at creating a liquid hydrogen fuelled aircraft capable of sustained Mach 5 flight. To put this in perspective, the Concorde cruises at Mach 2.

Reaction Engines was formed in 1989 by well-known rocket developer, Alan Bond, and the two principal engineers from Rolls Royce behind the HOTOL (single stage to orbit space plane) program, John Scott-Scott and Richard Varvill. The LAPCAT project, which is 50 percent EU funded, is aimed achieving a new flight regime for commercial transport with Mach numbers ranging from 4 to 8. The aircraft would also need to attain an exceptional range (approx 20,000 km both subsonic and supersonic). To achieve this, the use of liquid hydrogen fuel is needed because the specific calorific energy of hydrocarbon fuels (i.e. the amount of heat released during combustion) is too low. Accordingly, Reaction Engines have conceived the Scimitar pre-cooled engine concept which exploits the unique thermodynamic properties of liquid hydrogen. The Scimitar engine can reach sustained Mach 5 flight (that's around 1,701.45 ms), whilst achieving an effective exhaust velocity of order 40,900ms. In addition the engine has a second operating mode that features a high bypass airflow permitting efficient subsonic flight and moderate takeoff noise. The Scimitar is based on another concept closed cycle rocket engine conceived by the team at Reaction Engines, called the Sabre Engine. The Sabre is designed to use atmospheric oxygen in the combustion process, thus reducing the quantity of oxidizer that a vehicle is required to carry, and in turn decreasing the weight of an aircraft or rocket. The Sabre evolved from other “Liquid-air cycle engines” (LACE), and is currently being used in the design on the Skylon vehicle, which is an unpiloted, re-useable spaceplane intended to provide inexpensive and reliable access to space. The Skylon will take approximately 10 years to develop and will be capable of transporting 12 tonnes of cargo into space.

The Scimitar engine is derived from the earlier Sabre spaceplane model, however Reaction Engines have improved the design to enhance the life of the engine, making it a more feasible type of engine for long distance commercial travel. The Scimitar is essentially a closed cycle rocket engine with an additional precooled turbo-compressor to provide a high pressure air supply to the combustion chamber. The Scimitar engine is designed around existing gas turbine, rocket and subsonic ramjet technology. However the incorporation of lightweight heat exchangers in the main thermodynamic cycles of these engines is a new feature to aerospace propulsion.

To compliment the Scimitar engine, Reaction Engines has proposed a suitable vehicle configuration (A2) that attains the necessary subsonic and supersonic lift/drag ratio for efficient commercial operation. The A2 airframe is designed to have adequate control authority about all axes to handle engine-out and to achieve pitch trim over the full Mach range. The A2 airframe is designed to withstand prolonged flight at Mach 5 for several hours. This is due to the multi-layered construction with an actively cooled internal screen to intercept the heat leaking from the hot aeroshell.

The LAPCAT’s A2 vehicle is sized to carry 300 passengers - a figure typical of future supersonic transport designs and thought to be the minimum to achieve a competitive seat/mile cost. Analysis of the operating costs of a commercial hypersonic form of transport suggests that the average ticket price would be comparable to an existing Business class ticket. The A2 vehicle could capture all of the current business and first class traffic due to the greatly reduced journey time of 4.6 hours compared to the current 22 hours. This estimate is based on hydrogen fuel that is derived from water electrolysis. However, ticket prices could again be halved if the hydrogen is produced by steam reforming. Also it is likely that the first generation of hydrogen fuelled aircraft would be subsidized to promote the switch to a more environmentally friendly fuel, and therefore, costs may not be astronomical.

In theory, the LAPCAT vehicle would possess exceptional range and therefore would be able to service a large number of routes whilst simultaneously avoiding supersonic overflight of populated areas. Its good subsonic performance enables it to service conventional subsonic overland routes thereby increasing its sales potential to airlines. The possibilities of long-distance air flight at sustained Mach 5 speed, might still be some time away, however the three year study being undertaken by Reaction Engines is very exciting for the future of hypersonic transportation.

Solar-powered Zephyr smashes record for the longest unmanned flight

Using new solar array technology and a tailor-built autopilot system, QinetiQ’s Zephyr High Altitude Long Endurance Unmanned Aerial Vehicle has nearly doubled the official world record time for the longest duration unmanned flight with a 54 hour flight achieved during trials at the US Military's White Sands Missile Range in New Mexico.

The duration of the flight exceeded the current official FAI world record for unmanned flight which stands at 30 hours 24 minutes set by Northrop Grumman's RQ-4A Global Hawk on 22 March 2001. However because there was no FAI official present at White Sands it may not stand as an official world record.

Launched by hand, Zephyr is an ultra-lightweight carbon-fibre aircraft with a wingspan of up to 18 metres but weighing just 30 kg. By day it flies on solar power generated by amorphous silicon arrays no thicker than sheets of paper that cover the aircraft's wings. By night it is powered by rechargeable lithium-sulphur batteries that are recharged during the day using solar power.

The trials validated recent modifications that have improved the efficiency of Zephyr's power system. These have included new solar arrays supplied by United Solar Ovonic, a full flight-set of Sion Power batteries as well as a novel solar-charger and bespoke autopilot developed by QinetiQ, all of which were being flown for the first time. During the trials the same aircraft was flown twice while carrying a surveillance payload – first for 54 hours to a maximum altitude of 58,355 feet, and then for 33 hours 43 minutes to a maximum altitude of 52,247 feet.

Paul Davey, Zephyr business development director at QinetiQ, said: “The possibilities suggested by unmanned flight are truly exciting and with these trials Zephyr has secured its place in the history of UAV development. Both flights were achieved in the face of thunderstorms and debilitating heat in the hostile environment of the New Mexico high desert in the summertime. They have proved that an autonomous UAV can be operated on solar-electric power for the duration required to support persistent military operations.”

Potential applications for Zephyr include earth observation and communications relay in support of a range of defence, security and civil requirements.

Zephyr has demonstrated consistent progress during a series of flight trials at White Sands Missile Range. In December 2005 two aircraft achieved a maximum duration of 6 hours and an altitude above 26,000 feet. The maximum flight duration was trebled to 18 hours and the maximum altitude increased to 36,000 feet at subsequent trials at the missile range in July 2006.

Micro-UAV distance record smashed

A hydrogen fuel-cell powered Micro-Unmanned Aerial Vehicle (UAV) has set a new distance record for craft of its type while only using a quarter of its available fuel. The “Pterosoar” flew 78 miles (120 km) - beating the previous record of 50 miles set in Estonia last year – consuming only 16 of the 64 grams grams of Hydrogen stored on board in a pressurized hydrogen tank, giving the aircraft a potential flight range of 310 miles (500 km).

Horizon Fuel Cell Technologies (the company known for the H-Racer RC car and its involvement in the propulsion system for the 200 km/h Hyfish jet-wing UAV) provided the fuel cell system for the joint project supported by NASA, the Dryden Flight Research Center, the U.S. Air Force Office of Scientific Research and the National Science Foundation and led by Principal Investigators Dr. Maj Mirmirani, Dean of the Mechanical Engineering Department at California State University of Los Angeles (fuel cell system testing and integration); Dr Andy Arena of Oklahoma State University Aerospace Engineering Laboratory (fuel cell aircraft development); and Temasek Polytechnic of Singapore (system control electronics).

Fuel cells are an attractive proposition for micro-UAVs because they have the potential to deliver longer flight times, quieter operation, less heat signature, and higher reliability than batteries or other methods of propulsion. The ultra‐compact propulsion system used in project Pterosoar reacts hydrogen and oxygen from the air without combustion. The fuel-cell creates electrical power at 480 Watt hours per kilogram - 2.6 times the energy density of the best available batteries according to Horizon Fuel Cell.

The Pterosoar aircraft (the name comes from a class of dinosaur that the aircraft resembles due to the shape of the fuel cell cooling scoops in its nose) will attempt a new world endurance record for small‐size unmanned planes in the next few weeks, aiming to exceed 15.5 hours of flight.

Sky-high designs for a flying car

Nearly eight years into the 21st century and we still don't have flying cars… frankly, it's disgraceful. No point complaining about it though - while Dr. Paul Moller continues development of the intriguing and exciting M400 Skycar, others around the world are also working to turn the cogs that will set the personal flight revolution in motion. One of them is Italian Gino d'Ignazio Gizio, a helicopter pilot and designer whose Cell Craft designs are reminiscent of the Skycar with a few touches of his own.

The evolving stable of Cell Craft designs - including the G416ef designed specifically for civilian commuter use, the G420 "flying-sportscar" and the Search and Rescue focussed G500e - have culminated in the G440 - a new design which aims to become the key concept design to showcase the technology and function as the primary example of what a CellCraft represents.

The G440 design uses a seven seat format (including the pilot) and is based on the quad-turbine Vertical Take Off and Landing (VTOL) design shown in the G416ef. The turbines force air through and push it out the back, either straight through for horizontal flight, or at a directed downward angle (to allow vertical takeoff, landing and hovering) through a tilting exhaust tube at the rear of each turbine.

Gizio's intention with the Cell Craft series is to capitalize on the easy access, take-off, landing and hovering abilities of a helicopter, and combine them with the high speed potential, relative safety and stability of regular airplane designs. It also has to be easy and intuitive enough for the average car driver to operate.

The control system features twin joysticks mounted to the armrests of the sportscar-like pilot's seat. The left joystick handles power level control and the right handles tilt and direction. Press it forward, and the Cell Craft tilts forward from a stable hover and beings moving forward, gradually tilting the thrust tubes until the vehicle is moving forward at a rapid rate. Similarly, it is possible to tilt the vehicle sideways for lateral movement from a hover, or to steer while in horizontal flight.

A trigger-style lever on the left control allows the pilot to rotate the Cell Craft from a stable hover, in much the same way as a helicopter pilot's foot pedals allow rotation around the central axis - except with this vehicle the rotation is attained by slight adjustments of the directional thrust tubes.

The history of the different Gizio G series designs can be viewed at his personal website, which also details his exploits in music, photography and next-generation cell phone design. He's yet to make a prototype, needing significant investment, but ready to drop what he's doing at a moment's notice to bring his Cell Craft dream to reality.

Sportcopter Super Sport Gyroplane set to launch – bridging the gap between plane and helicopter

Simple to build, easy to fly, faster than helicopters and arguably safer than anything else in the sky: gyroplanes are a long-overlooked segment of the personal aviation industry, but as innovators like Sportcopter bring the entry price down to family car levels, these fun little aircraft are finally starting to get some of the popularity they deserve. Sportcopter's highly anticipated Super Sport 2-seater is currently undergoing flight testing - and with its 2.5 litre Subaru engine producing 190hp and propelling the agile little gyroplane to well over 100mph, it should be a real winner.

Gyroplanes, although they’ve been around since the early 1920s, are some of the best kept secrets in the affordable aviation game. These fun little devices use an unpowered, free-spinning top rotor and a simple thrust propeller to deliver a flying experience that's somewhere in between a plane and a helicopter.

Powering the gyroplane forward using the front or rear-mounted thrust propeller causes air to flow over the top rotor, which begins spinning and develops enough lift to get the vehicle airborne. This doesn't take a long runway - as little as 40 feet is needed to develop enough upward lift to get off the ground, and it's possible using aftermarket kits to perform jump-style takeoffs with no ground roll at all.

Gyroplanes can cruise at roughly the speed of a helicopter, or float along so slowly you'd nearly call it hovering. The powered top rotors of helicopters cause a torque reaction that necessitates the use of a sideways-mounted tail rotor to control rotation – which makes them mechanically complicated, expensive and quite tricky to fly. The gyroplane's design is so simple that you can buy one for less than the cost of a touring motorcycle, build it and maintain it yourself.

Perhaps the key to the growing popularity of this segment, though, is the fact that gyrocopters are incredibly safe. Because all lift is provided by a top rotor that's completely unpowered, engine failure or running out of fuel simply results in a pretty much normal landing. The free-spinning rotor is far more effective than a parachute in ensuring a slow and safe descent.

The Sportcopter Super Sport is a roomy, weatherproof, fully enclosed twin-seater with space behind the seats for cargo. Each seat has a full set of controls and instrumentation, making it an ideal training craft. As it's significantly heavier than Sportcopter's earlier Vortex and Lightning models, it's been fitted with a long-travel suspension kit for soft and cushy landings, even in rougher fields.

A range of between 300 and 400 miles from a 30 gallon tank full of ordinary 87 octane unleaded makes the Super Sport a good day tripper, and it should be good for thrills as well with a top speed in excess of 100mph.

Future designs in the works at Sportcopter include a larger 4-seat gyroplane with retractable landing gear, and an extra-quick, super sleek speedster dubbed the "velocity" featuring a nose-mounted prop and either two or four seats.

The gyroplane concept is perhaps the best type of simple aircraft to look at converting for a combination of highway and skyway use – like Larry Neal has done with his road-registered flying motorcycle kit. All you need to really do is drive the rear wheels and find some way to keep the main rotor out of the way, and you've got yourself a vehicle you can fly, drive and park in a garage. We'd love to see Sportcopter start experimenting with this angle on future models; quite apart from our obsession with flying cars, a simple version would mean a huge boost in convenience for hobby aviationists, who could drive it slowly to the airstrip and eliminate hangar and transport charges from their cost of ownership.

Sportcopter will release details on pricing and availablility as soon as it comes to hand; meanwhile, they're building up a global distribution network, and are interested in talking to potential dealerships around the U.S. and the world.

BATMAV System with AeroVironment's Wasp III Micro Air Vehicle achieves full rate production

The United States Air Force BATMAV (Battlefield Air Targeting Micro Air Vehicle) program with AeroVironment's Wasp III Micro Air Vehicle has received approval for Full Rate Production. The Wasp is a small, portable, reliable, and rugged unmanned aerial platform designed for front-line day/night reconnaissance and surveillance.

The result of a multi-year joint development effort between AeroVironment and the Defense Advanced Research Projects Agency (DARPA), Wasp is 16 inches (38 cm) long, has a of wingspan of 29 inches (72 cm), weighs just 430 grams (around one pound), can be controlled manually or programmed for GPS-based autonomous navigation and can carry interchangeable targeting payload modules including an infrared camera, along with two integrated color cameras that transmit streaming video directly to the hand-held ground controller.

The hand-launched Wasp III has a 5 km range (Line-of-Sight), operates continuously for approximately 45 minutes at 40-65 km/h and to altitudes of 1,000 ft (300 m). There is also a water landing version in development.

For system interoperability, Wasp uses the same advanced technology found in other AeroVironment small UAS systems, such as Raven RQ11-B, Swift and Puma - which recently set a 7 hour flight record for fuel cell powered MAVs - and is controllable through a common Ground Control Station.

The BATMAV program milestone comes less than a year after the US Air Force selected AV's Wasp III as the MAV for the Program in December 2006.

"Achieving full rate production in just 11 months from contract award reflects our team's efforts, working closely with our customers, to satisfy program requirements quickly and efficiently," said John Grabowsky, executive vice president and general manager, AV Unmanned Aircraft Systems. "The rapid achievement of full rate production means that we can now produce our Wasp III systems in higher volumes so that our customers can deploy them to the front-line units who need them.".

In November 2007 the U.S. Marine Corps awarded AV a $19.3 million contract for Wasp III MAV systems. The Marines plan to deploy Wasp at the Platoon level and use it as a complement to their Raven small UAS systems, which they currently deploy at the company and battalion levels.

Boeing KC-767 refuels an F-15E in night conditions

January 31, 2008 The Boeing KC-767 tanker aircraft has successfully transferred fuel to an F-15E at night – a world first manoeuvre for that model. Transferring fuel through a boom, via the remote vision system, and during night-time conditions, will significantly reduce risk for future tanker customers like the U.S. Air Force