Sunseeker Duo Goes Dual

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 1 Comment

Irena Raymond became the first passenger of a solar-powered airplane recently, even taking over control of the Sunseeker Duo she and husband Eric built over the last several years.  Her thoughts provoke awe and envy. “Flying the Duo, skimming the white fluffy clouds from above and playing on the sky, I feel like a bird. No limitations, a pure freedom. It’s so quiet! Compared to a normal airplane, it’s like night and day. You need a very good headset in every other powered airplane, but in this airplane you can speak normally even when the motor is running full power, no headset needed. It is unbelievable.” Eric provides some hard data to complement Irena’s understandably poetic words.  “I am expanding the flight envelope, so far up to 13,000 feet and 85 mph.  My heaviest passenger… is 85 kilograms (187 pounds), and we were able to climb up to 12,500 feet.  80 percent of the solar cells are hooked up.” Responding to …

Quiet May Be the New Black

Dean Sigler Diesel Powerplants, Electric Powerplants, Sustainable Aviation 1 Comment

Noisy airplanes are the bane of modern living.  (Well, that and the myriad other intrusive sounds with which we are surrounded.)  People can create and easily get signatures on petitions to close 70-year-old airports surrounded by 20-year-old housing developments, so General Aviation’s survival will at least partly depend on hushing our aircraft. We’ve been privileged to see and hear the passage of e-Genius, Pipistrel’s G4, and Chip Yates’ Long-EAS with a Craig Catto propeller, which emitted a barely discernible howl when it pushed the airplane at full power to a new time-to-climb Guinness record at the California State Airshow in early October 2013, reaching 500 meters (1,640 feet) in one minute, four seconds. This quest for quiet presses on the big airplane producers, too, anxious to be good neighbors and give passengers a less raucous flight.  One engine make, Snecma, has been working on the problem since before 2009, when this report appeared in the blog Envirofuel. “Volvo Aero will …

Green Speed Cup Day Two – A Clear Winner

Dean Sigler Diesel Powerplants, Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

Robert Adam, one of the organizers of the Green Speed Cup in Germany and pilot of the Flight Design CTLS that ended the competition in seventh place, shared some information on the challenges faced by pilots in this year’s event. “We had 12-15 knots crosswind today (only a little less yesterday) and Tim-Peter (-Voss) managed this demanding taildragger (the SPACEK s.r.o. SD-1 microlight) calmly!”  This very light and short-coupled airplane flies with a variety of two- and four-stroke engines, but Voss’ had a Verner JVC-360 four-stroke unit of 38 horsepower.  It averaged a little over four liters per hour fuel consumption per 100 kilometers (59 mpg) over the practice day and two contest days.  In the Green Flight Challenge, it would have been penalized for being a single-seater and thus having a lower passenger-mile-per-gallon figure than the two, and even four-seat entrants. The TDI turbo-diesel DA-40, for instance, would have had a 4X passenger mile per gallon figure if that had …

Green Speed Cup – Training Day is Over and Day One Establishes a Record

Dean Sigler Diesel Powerplants, Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

Happily for those of us who champion the idea of electric aircraft, the practice day and day one of the Green Speed Cup in Strausberg, Germany fetched a world electric aircraft distance record for e-Genius and an outstanding showing for all concerned.  This beginning for the third running of the Cup sets a high standard for the coming days. The Green Speed Cup has elements of soaring flight through the use of thermals, careful speed flying that emphasizes fuel economy, and precise flight planning with attention to the planned route, winds aloft, and power settings. Green Speed Cup organizers map out a series of triangular routes to test the limits of piloting skills and airplane efficiency.  As the organizers explain, it’s all pretty simple: “To fly ‘green’ you have to know how fast to fly and which power setting to use. This depends on the current wind-profile, on the current lift and on several other parameters like the aerodynamical properties.”  …

Avoiding Propeller Strikes on Electric Aircraft

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

At last year’s Electric Aircraft Symposium, Ron Gremban, developer of the Prius plug-in hybrid, shared several questions about promoting safety in electric aircraft.  One aspect that provoked deep thought was that of safety for those working around an electric airplane, whose propeller could start quietly and possibly strike an unaware bystander.  During the Green Flight Challenge, it was noteworthy that unlike their gasoline-powered counterparts which idled while awaiting takeoff, the Pipistrel G4 and e-Genius awaited their turn to launch with propellers at rest, only spinning when commanded – and very quietly at that. The question of avoiding prop strikes found at least one answer at EAS VII.  Karl Kaser demonstrated, in model form, his ePropeller Safety Device (eSD), noting “the risk to people, animals or objects in the propeller disk area and that they can be injured or damaged accidentally during the run-up of the propeller.”  He first noted that issue in the case of e-Genius, on which he was …

Flying e-Genius for Two Years

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

At this year’s Electric Aircraft Symposium, Rudolf Voit Nitschmann, Len Schumann, and Ingmar Geiss shared their well-documented experiences with e-Genius, second place winner in 2011’s Green Flight Challenge.  Flown by Erik Raymond and Klauss Ohlmann, the airplane managed 397.5 passenger miles per gallon on its 200-mile trek around a closed circuit between Santa Rosa, California and the distant geothermal power plants that provided the electricity for its flight. As Voit Nitschmann, leader of the e-Genius team since 2005 noted, one must design electric aircraft around the beneficial aspects of such vehicles to gain the greatest performance.  Originally slated to be hydrogen powered, e-Genius mounts its 59-pound motor on the leading edge of the vertical rudder, more difficult with a heavier internal-combustion engine.  This permits ample propeller clearance, provides blade protection and allows a short, retractable landing gear that is light and simple. With no turbulent flow over the nose, the cockpit can be streamlined like that of a sailplane and …

Pipistrel,PADA, and “Gus” Raspet

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

Pipistel, the innovative Slovenian company that won the Green Flight Challenge with its G4 electric four-seater, continues to earn plaudits from the aviation industry. At this year’s AirVenture, the Experimental Aircraft Association’s annual gathering at Oshkosh, Wisconsin, the company was honored with the Dr. August Raspet Memorial Award and original and pace-setting design work exemplified in Pipistrel products. The Exerimental Aircraft Association has awarded the “Dr. August Raspet Memorial Award” annually since 1960 “to a person who has made outstanding advancements in the field of light aircraft design and the Experimental Aircraft Association.”  John Thorp, Lockheed engineer and designer, was the first recipient, with those following including Curtiss Pitts, Burt Rutan, Alan and Dale Klapmeier and Gordon Pratt. Taja Boscarol, in the company’s press release, notes that, “This year’s award being given to the Pipistrel Team is definitely proof that Pipistrel’s innovativeness is now fully recognized and appreciated even in the cradle of the aviation industry, the USA.” Michael Coates, …

Vimeo Viewing of First Ever Electric Aircraft Charging Station

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

Dr. Brien Seeley, President of the CAFE Foundation, points us toward a video his son Damon just posted to Vimeo.  It depicts part of the 2011 Green Flight Challenge sponsored by Google, for which the Foundation played host. Dr. Seeley explains, “NASA’s Chief Technologist Joe Parrish refers to the Wright Brothers in the video as Sonoma County Supervisor Mike McGuire and I cut the hose to a gasoline dispenser nozzle.”  The symbolic hose is then proudly replaced by a very real electric charging station for airplanes, capable of providing a continuous 9,600 Watts to each of 12 aircraft and used to charge the Pipistrel G-4, e-Genius and Embry-Riddle’s hybrid Stemme during the contest. The video features great in-flight footage of the two pure-electric competitors from the GFC, and makes one wish for the day when private flight is quiet, pollution-free, and inexpensive. The G-4, according to Pipistrel CEO Ivo Boscarol, made the two 200-mile flights in the contest on about …

A Weighty Matter

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 2 Comments

Several readers have asked for the weights of the Green Flight Challenge competitors.  Here they are, pound for pound, among the most efficient flying machines on the planet. Those who wish can calculate different takes on that efficiency, including overall glide ratios for the course, ton-miles per gallon energy equivalent, or more exotic parameters.   Empty Weight Takeoff Weight in Competition   Pounds Pounds e-Genius 1670.2 2070.2 Pipistrel   G4 2491.0 3294.1 Embry-Riddle 1970.0 2370.0 Phoenix 754.0 1199.7  

Green Flight Challenge Final Results

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 15 Comments

Steve Williams, CAFE Foundation board member and e-totalizer guru, released the final results for the NASA Green Flight Challenge sponsored by Google, held at the Charles M. Schulz Sonoma County Airport from September 25 through October 1, 2011.  Figures show a profound difference between the two electric winners and the two gas-powered and hybrid runners-up. All competitors flew extremely clean motorgliders with demonstrated lift-to-drag ratios between 25:1 and 35:1.  Possible explanations for the large differences in energy use include low cooling drag for electric aircraft and the efficiency of electric motors – but the differences are still surprising. Note that a little over 11 US gallons of gasoline (energy equivalent) were used to fly seven people (Embry Riddle’s Eco-Eagle flew with only one pilot) over a total of 725.5 miles (Embry Riddle flew a shorter total distance on both “runs”).  This is an enormous achievement for all concerned and a significant increase in efficiency over even the best general aviation craft available today. Congratulations are …