EV Aircraft ELEKTRA ONE performs first 30 min flight [video]

The Elektra One EV aircraft performed the first flight on 19 Mar. 2011 at the Augsburg Airport in Germany. Jon Karkow, an well known test pilot and aircraft engineer performed the first flight. Flight characteristics and engne parameter were tested.

The ultra lightweight aircraft weighs just 220 pounds, plus an additional 220 pound battery pack. With a 660 pound weight capacity, there is ample room for a more than just the pilot.

The test pilot was very satisfied with the results. Three flights were performed. The climbing rate was 400 ft/min. A new 30 min. flight was performed on 23 Mar. Only about 3kW from the total on board of 6kWh energy was used.

Over the next two weeks a new variable pitch propeller and retractable landing gear will be installed for further testing.

Solar UAV QinetiQ Zephyr records ratified

The flight in July over the US army Yuma proving ground by the Qinetiq ‘Zephyr’ has been ratified by the Federation Aeronautique Internationale (FAI) as a world record for the longest unbroken time spent in the air by an Unmanned Aerial Vehicle (UAV). The flight lasted 10 times longer than the previous duration record held by the RQ 4A Global Hawk.

• the absolute duration record for an Unmanned Air Vehicle – being filed at 336 hrs / 22 minutes
• the duration record for a UAV (in the U/1.c / 50-500Kg category) – time as above
• the absolute altitude record for a UAV (in the above category) – being filed at 70,740ft (21,561m)

Launched by hand, the aircraft flies by day on solar power delivered by amorphous silicon solar arrays that cover the aircraft’s wings and are no thicker than sheets of paper. These are supplied by Uni-Solar, the world’s largest producer of flexible solar panels. The solar arrays are also used to recharge the lithium-sulfur batteries that are used to power the aircraft by night and supplied by Sion Power Inc, a leading developer of the next high energy rechargeable battery technology. Together they provide an extremely high power to weight ratio on a continuous day/night cycle, thereby delivering persistent on station capabilities.

Around 50% larger than the previous version, Zephyr incorporates an entirely new wing design with a total wingspan of 22.5m to accommodate more batteries that are combined with a totally new integrated power management system. The entirely new aerodynamic shape also helps to reduce drag and improve performance. Zephyr’s ultra-lightweight carbon fibre design means it weighs in at just over 50Kg.

Previous records beaten include:

• Surpassing the previous world record for the longest flight for an unmanned air system (set at 30 hours 24 minutes by Northrop Grumman’s RQ-4A Global Hawk on 22 March 2001).
• Surpassing the Rutan Voyager milestone of 9 days (216hours) 3 minutes and 44 seconds airborne – previously the longest flight by an aeroplane without refuelling and set in Dec 1986. Quadrupling its own unofficial duration record of 82 hours, 37 minutes set in 2008

NASA Looking at Electric Railgun / Scramjet Launcher to replace Shuttle

Last week saw Navy researchers set a new world record with a test firing of a new 33 Megajoule railgun. Turns out NASA are also seriously considering a railgun to replace conventional rockets but in their case it would be 5x more powerful and two miles long.

An early proposal has emerged that calls for a wedge-shaped aircraft with scramjets to be launched horizontally on an electrified track. The aircraft would fly up to Mach 10, using the scramjets and wings to lift it to the upper reaches of the atmosphere where a small payload canister or capsule similar to a rocket's second stage would fire off the back of the aircraft and into orbit. The aircraft would come back and land on a runway by the launch site.

How To Fly Into Orbit:


Rev Up The Rail Gun
A 240,000-horsepower linear motor converts 180 megawatts into an electromagnetic force that propels a scramjet carrying a spacecraft down a two-mile-long track. The craft accelerates from 0 to 1,100 mph (Mach 1.5) in under 60 seconds- fast, but at less than 3 Gs, safe for manned flight.

Fire The Scramjet
The pilot fires a high-speed turbojet and launches from the track. Once the craft hits Mach 4, the air flowing through the jet intake is fast enough that it compresses, heats to 3,000ºF, and ignites hydrogen in the combustion chamber, producing tens of thousands of pounds of thrust.

Get Into Orbit

At an altitude of 200,000 feet, there isn't enough air for the scramjet, now traveling at Mach 10, to generate thrust. Here spaceflight begins. The two craft separate, and the scramjet pitches downward to get out of the way as the upper spacecraft fires tail rockets that shoot it into orbit.

Stick The Landing
The scramjet slows and uses its turbojets to fly back to Earth for a runway landing. Once the spacecraft delivers its payload into orbit, it reenters the atmosphere and glides back to the launch site. The two craft can be ready for another mission within 24 hours of landing.

"All of these are technology components that have already been developed or studied," NASA says. "We're just proposing to mature these technologies to a useful level, well past the level they've already been taken."

For example, electric tracks catapult rollercoaster riders daily at theme parks. But those tracks call for speeds of a relatively modest 60 mph -- enough to thrill riders, but not nearly fast enough to launch something into space. The launcher would need to reach at least 10 times that speed over the course of two miles in Starr's proposal.

The good news is that NASA and universities already have done significant research in the field, including small-scale tracks at NASA's Marshall Space Flight Center in Huntsville, Ala., and at Kennedy.

The Navy also has designed a similar catapult system for its aircraft carriers. The EMALS Electromagnetic Aircraft Launch System, which uses a linear electromagnetic accelerator motor, will replace the current C-13 steam catapults in the new USS Gerald R. Ford (CVN-78) currently under construction.

As far as the aircraft that would launch on the rail, there already are real-world tests for designers to draw on. The X-43A, or Hyper-X program, and X-51 have shown that scramjets will work and can achieve remarkable speeds.

Silent flight: Sikorsky's electric helicopter

A team at Sikorsky Innovation, the technology development arm of Sikorsky Aircraft, is attempting to develop the world’s first all-electric, near-silent helicopter in a programme known as ’Project Firefly’. The team’s plan is to validate the benefits of the electric rotorcraft in flight while addressing some of the challenges of making an environmentally friendly helicopter both commercially and technically viable.

’We’ve had electric cars, electric buses and electric street sweepers for a while now, but we really want to understand the unique difficulties associated with integrating electric propulsion into rotorcraft,’ said Jonathan Hartman, a programme manager for Project Firefly. ’In an ideal world, we would want an electric helicopter to compete on a one-to-one basis with your internal combustion aircraft today.’

Despite advances in electric powertrains for automotive applications, progress in aviation has been slow. The industry faces a very different set of challenges due to its high power requirements and Hartman believes that technology development has to begin now

’You can either wait until your technology is fully commercially ready and then just integrate it into your product, or you can get out there ahead of time and start learning about all these issues that will come up during construction. That’s what we’re doing.’

The Firefly team has retrofitted a 50-year-old military S-300C design with an electric motor and digital controller, together weighing in at 180lb. Much of the S-300C’s original design has remained the same to keep costs down, with the main difference being the addition of an interactive LCD monitor in the cockpit. Two battery packs, each made up of 150 individual 45amp-hour (Ah) lithium-ion cells, are the backbone of the energy-storage system. They sit outside the aircraft much like an agricultural spraying kit, and run at 370V to provide enough power for a continuous 15-minute flight.

’That’s obviously not a lot of time,’ said Hartman. ’There is one technology that needs to mature to make this a commercial reality and that is energy-storage distribution. There are projects out there that we are watching. If some of the technologies that are on the bench now can come out and provide the energy-surge capacity they are claiming, we could well see helicopter endurances in the half hour to the hour range instead of just 15 minutes, which is exciting.’

Sikorsky claims it has increased the propulsion efficiency of the helicopter by around 300 per cent from baseline. The use of an electric motor reduces the complexity of the helicopter, cutting down on the number of components and reducing maintenance costs. There is also a reduction in vibrations and associated acoustics with electric propulsion, which could one day lead to a new series of low-observable, optionally manned aircraft for both military and civil applications.

The benefits, however, sit against a long list of challenges. The motor must be air cooled rather than liquid cooled, and has to remain at operating temperature while sitting on the ground. Sikorsky presented this problem to US Hybrid, which came up with an adaptation of a motor it uses for surface-vehicle programmes, such as the electric-powered Humvee for the US Marine Corps. The group provided 40 per cent more power and added a number of control laws to allow the motor to run at a constant high rpm.

While a conventional motor requires time to engage and build up torque, an electric motor can do this straight away so further control laws were added to prevent pilots from taking off and landing too quickly. Feedback from pilots also showed that the lack of noise could affect handling. ’Our toughest challenge was on the human factor side,’ said Hartman.’We have this electric helicopter that produces substantially less noise than a traditional helicopter. All of the pilot cueing is basically gone and that presents some unique difficulties that a pilot never had to worry about before.’

To address this, integrated sensors were added that feed real-time aircraft health information to the pilot through an interactive LCD monitor. Monitoring of health data is done automatically through the flight-control computer and any potentially hazardous conditions are avoided with automatic system re-routing or electric shutdown. As well as providing information to the pilot, the system tracks critical stages of flight in real time allowing the team to rapidly prototype new ideas as it goes through the development programme.

The issue that poses the greatest challenge, however, is weight. ’The helicopter itself weighs empty several hundred pounds more than it did in its legacy configuration,’ said Hartman. ’What we did in the project was take the maximum weight of the aircraft, subtract out the motor, the weight of the cockpit, control and the pilot and fill the rest of it up with batteries. They are not the most weight-efficient batteries that are on the market today, but we went for reliability over weight and selected safe components that we knew would work… If a bus loses charge that’s one thing, but if a helicopter suddenly loses charge then you have a problem.’

Hartman is confident that with improvements in battery technology, weight will be reduced and reliability improved significantly allowing electric helicopters to compete with conventional aircraft. Hartman added that in the shorter term electric helicopters could have some interesting applications using endurances of between half-an-hour and an hour. ’My director has a fantastic vision. He would love to see a helicopter fly on a two-seat tour of the Grand Canyon. You and the pilot, no shaking, you don’t even have to wear headphones - you just enjoy the view. You can imagine something similar for applications in urban transportation.’

The Firefly project is undergoing component bench testing and is scheduled to move to ground testing and first flight early next year. It seems inevitable that at some point full-scale electric rotorcraft will be seen in our skies, but just when that will happen is anyone’s guess. ’I would need a crystal ball to tell you,’ said Hartman. ’But if the trajectory continues as it is, the next five to 10 years are going to be very interesting.’

The specs

Airframe: converted S-300C
System efficiency: 89 per cent during cruise, 91 per cent maximum power efficiency
Power: 190hp permanent magnet electric motor
Endurance: 15min
Lithium-ion battery: 150, 45Ah lithium-ion cells
Maximum velocity: 79knots