The Future of Flight: Hybrid-Electric VTOL Aircraft

nasa-greased-lightning-10-foot-drone-640x480It may look like something a dedicated hobbyist built, and sound like something cheekily named, but NASA’s new electrical vertical take-off and landing (VTOL) machine is a very serious venture. Known as the GL-10 Greased Lightning, this unmanned hybrid-electric aircraft is the agency’s proposal for a vehicle that one day replace the reigning champion of VTOL – the helicopter.

 

The G-10 is in part the result of the recent strides made in electric propulsion, which is made possible thanks to the growing power and energy density of batteries allows for some very efficient hybrid-electric aircraft designs. With eight prop engines mounted on the two main wings and another two mounted on the tail, the vehicle swivels them into vertical position for takeoff and landing, and then horizontal for conventional flight.

nasa-greased-lightning-prototype1While it’s not particularly hard to create an aircraft capable of VTOL, it has so far proven to be very tough to create an aircraft that can also efficiently cruise through the air after taking off vertically. The helicopter is the only common example of a VTOL aircraft that can also cruise acceptably, but at a cost. Compared to other aircraft, an everyday helicopter has a much lower-lift-drag ratio, which means it burns more fuel, has less range and can carry less weight.

However, electric propulsion allows for much more efficient designs, since vehicles no longer have to accommodate large fossil fuel-powered engines or manage the mechanical stress across the airframe. Instead, they can rely on smaller, more efficient, optimally placed electric motors, and without the mechanical complexity of big jet engines, it suddenly becomes a lot easier to have wings and propellers that can swivel between horizontal and vertical.

https://i2.wp.com/www.extremetech.com/wp-content/uploads/2014/08/nasa-greased-lightning-ground.jpgWhile pure-electric aircraft do exist – in the form of quadcopters – hybrid-electric designs with longer range are generally of more interest to military and commercial groups. In the case of NASA’s Greased Lightning, there are two small diesel engines in the body of the aircraft that turn electric alternators that constantly recharge the lithium batteries. This theoretically gives the GL-10 the same range and duration as a modern plane alongside its VTOL capability.

Interestingly, NASA also says that such a hybrid-electric design is “scale free” — meaning the same principles could be used to revolutionize everything from helicopters, to military UAVs, to massive jetliners. Much like hybrid-electric cars, the concept is set to revolutionize an entire fleet of aircraft designs that could be far more efficient than they currently are. One party who is sure to be interested in the possibilities is the US military, with its ever growing fleet of UAVs.

For now, Greased Lightning only has a wingspan of 3 meters (10 feet), and on its first test flight  – which took place on National Aviation Day, August 19 – it was tethered. Untethered flights are planned for later in the year, an event which is sure to be a media sensation and produce some viral videos!

 

 

Source: extremetech.com

The Future of Transit: The Solar-Powered Jetliner

skywhale1Solar-powered airplanes have already proven feasible, but only in the sense of single-seat, turboprop powered plane.s When it comes to a long-range, commercial jet aircraft, the field remains pretty sparse so far. But thanks to a Spanish designer, and some unconventional thinking, “whale planes” that are eco-friendly and combine the convenience of air travel with the luxury of a cruise ship might soon be a reality.

Oscar Viñals, from Barcelona, envisioned the “AWWA Sky Whale” concept plane as a mixture of today’s current designs and future concepts that don’t yet exist. The end result is like an Airbus A380, but with considerable expansion and designed to be powered by micro solar panels and four large hybrid electric engines that would rotate to ease takeoff and landing.

skywhale_specsIn addition to reducing noise and pollutants, it would also significantly reduce fuel burned during what is currently one of the least green modes of getting to a destination. Despite the introduction of more fuel-efficient and less polluting turbofan and turboprop engines, the rapid growth of air travel in recent years has contributed to increasing CO2 emissions in the upper atmosphere.

In fact, in the European Union alone, greenhouse gas emissions from aviation increased by a total of 87% between 1990 and 2006. In 2005, global aviation contributed roughly 5% to the overall “radiative forcing” effect that our annual emissions of CO2 have on Global Warning, but the added effects of water vapor and the disruption to cirrus cloud formations also enhances this role to a varying degree.

skywhale4One of the reasons aviation’s role in Climate Change is overlooked is because the focus tends to be on urban infrastructure and automobiles, which account for the vast majority of carbon emissions. But given the current trend of increasing travel, international economic development, and growth in tourist industries, aviation is likely to get a bigger slice of that pie down the road and clearer methods need to be devised.

Hence the concept for the Sky Whale, which Viñals imagines would come with other futuristic components . These include a self-healing skin with adaptable opacity, active wings that change shape as needed, and ceramic and fiber composite materials. He even has a plan for the plane to break apart on an emergency landing, with the wings separating from the fuselage to limit damage to the passenger compartment.

skywhale3The three-story aircraft, which could accomodate 755 passengers, would have a wingspan and height greater than any of today’s biggest carriers – 88 meters in comparison to the 80 meters on an Airbus A380-900 – making it the largest commercial aircraft in existence. However, the combination of active wings (which would also reduce drag) and the hybrid-electric systems would render it the most fuel efficient.

Another thing that Viñals imagines would make it into the design is virtual reality windows – aka. display glass that allows people to go online, watch movies, and experience in-flight entertainment simply by looking outside. Can’t imagine why this would be necessary, as the range of personal devices people are likely to have by this time ought to be entertainment enough. And failing that, the view should be enough to inspire!

skywhale5Naturally, much of this technology – particularly the healing smartskin – is still many years away. But judging by the reaction to his designs, there is definitely some hunger for innovation in how we fly. Given the range of ideas for mass transit (like the Hyperloop, podcars, etc.) and personal transit (robot cars, robotaxis), it’s only a matter of time before the way we fly becomes smarter, sleeker, and cleaner.

Sources: fastcoexist.com, cnn.com, gov.uk, europa.eu