Wednesday, April 13, 2016

The 18-Rotor Volocopter: The World’s Safest Helicopter?

Its aerodynamic design was said to be inspired by the inherent aerodynamic stability of quad copter drones, is the 18-rotor Volocopter VC200 the world’s safest helicopter? 

By: Ringo Bones 

Ever since Igor Sikorsky “perfected” the main rotor and small tail-rotor type helicopter near the end of the 1930s, it has since become the favored configuration of helicopters in military and civilian use since. And despite its inherent safe record, accidents still happen, but is there a better aeronautical engineering design out there that’s much safer than the “Sikorsky Configuration”? Fortunately, a bunch of Germans got inspired by the inherent stability of quadcopter drones and believe that a safer helicopter design should involve increasing the number of rotors, so they designed and built a helicopter with 18 different blades.   

It’s called the Volocopter VC200 and the German engineers have been working on it since 2010. They’ve done manned flights before, operating the craft like a gigantic 18-rotor man-carrying drone, but this time, E-Volo Managing Director Alexander Zosel got behind the controls and flew the craft himself. 

One of the biggest problems with helicopters is that they’re extremely difficult to fly in comparison with conventional fixed-wing aircraft. Helicopter configuration that’s in widespread use – the Sikorsky Configuration – only has one main source of lift and when it fails the results are usually disastrous. Multi-rotor flying craft like the popular quadcopter drones are more stable in the air, and more importantly, much easier to handle aerodynamically for inexperienced pilots. The Volocopter team wants their flying craft to bridge the skill gap between everyday transportation like cars and human flight. The Volocopter’s controls are incredibly simple – a single joystick with a few buttons – and a giant canopy of independent rotors mean it can hover almost perfectly with very little effort or skill required.  

Using current battery technology, the battery powered Volocopter VC200 only has a flight endurance of 25 minutes but if its batter runs out in flight, the Volocopter can automatically lands itself safely even with a student pilot at the helm. Currently the Volocopter VC200 costs around UK£200,000 each but E-Volo Managing Director Alex Zosel hopes that demand from interested affluent buyers and flight schools could generate enough funds for additional research and development funding for a Volocopter version with an increased flight time and greater payload. With its inherent safety and low carbon footprint are multi-rotor battery powered helicopters the future of helicopters? 

Sunday, April 3, 2016

Steam Powered Aircraft: An Aeronautical Engineering Impossibility?

Even though mid 19th Century accounts of their flight attempts are notable for their “comical failure” are those steam powered aircraft still an aeronautical engineering impossibility in the 21st Century?

By: Ringo Bones 

Maybe we should be “blaming” the Mythbusters for doing those proof of concept experiments in their shows – especially ones pertaining to “aeronautical engineering impossibilities” – like the lead balloon and the concrete glider, which more or less, they managed to successfully flew on their shows and confirming them that they are not an aeronautical engineering impossibility after all. But has the Mythbusters ever tried to build and fly a steam powered aircraft? After all, if one managed to successfully fly back around 1850, the Wright brothers would probably have given up designing and building their first successful gasoline-powered aircraft. 

The steam powered aircraft gained legendary status probably because the press-at-large became very intrigued by William Samuel Henson’s publication of the design of his “Aerial Steam Carriage” back in 1843 after it was patented in 1842. Although a full-sized model was never built, illustrations of this “remarkable aircraft” were given world wide publicity and did more than anything else to establish the modern airplane configuration of fixed monoplane wings, a fuselage, a tail unit, and propulsive airscrews – features that became standard in many airplanes some 65 years later. 

Another intriguing possibility that a steam powered aircraft – like William Samuel Henson’s Aerial Steam Carriage and those like it – could have successfully flown back in the middle of the 19th Century is that Henson hired a very skilled mechanic named John Stringfellow to design and build an extremely light steam engine that could have flown the first ever steam powered airplane. Stringfrllow’s steam engine achieved a power-to-weight ratio of around 20 pounds of engine weight per horsepower produced – which was comparable to the power-to-weight ratio of the engine used by the Wright brothers during their first ever successful flight. Sadly, neither Henson nor Stringfellow managed to design a propeller that is as efficient as the one designed by the Wright brothers in converting mechanical rotation into forward thrust – i.e. the Wright brothers’ propeller has a 66-percent efficiency rating. Given that today’s modern propeller designs can now achieve 90-percent efficiency, will the Mythbusters or any other daring aeronautical engineer be building their own flyable steam powered aircraft anytime soon?