A Hybrid Motorized Ultralight Sailplane

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Dr. Paul Robertson of the University of Cambridge has been sorting out the necessary components and relationships to make hybrid-electric-gasoline aircraft a practical reality for the last several years.  His Photonics and Sensors group at the University researches many areas of optics and electronics, including holography and “nano-photonic structures,” with hybrid flight last on the long list of studies.  The blog has been reporting on his aeronautical activities since 2009, including what turned out to be the second and third electric aircraft flights in England, and the first flight of an electric-gas hybrid in a modified Alatus motorglider. The current aircraft uses larger power components and is a bit more sophisticated.  In fact, an external view would not give away the uniqueness of what nests inside.  Its operation has a unique flavor, too – it’s the first ever, according to reports, that can recharge its batteries in flight. The parallel hybrid system, built by Cambridge technicians, can pull power from …

Launching on a Leaf Blower and a Hacker

Dean Sigler Electric Powerplants, Sustainable Aviation 4 Comments

Paul Dewhurst and Dr. Paul Robertson, chronicled in an earlier entry about their simultaneous electric ultralight flights last year, have created another first, a parallel hybrid motorglider launch. The truncated flight of their Alatus took place on September 9, 2010 at Sywell Aerodrome, between Coventry and Cambridge north of London. Dewhurst notes, “Flight was quite short though (around 1.5 minutes) after the controller suffered a bit of tantrum complete with sparks! Rework [is] in process and we hope to have a rather longer flight soon.” Replacing the Lynch unit normally used in the Alatus’s motorized version with an unspecified 76cc, 2.8 kilowatt (3.75 horsepower) internal combustion four-stroke leaf blower unit paralleled with a Hacker A200 12 kilowatt (16 horsepower) large model airplane motor approximates the Lynch motor’s output.  Despite that, the airplane seems reluctant to leave the ground in the video. Dewhurst explains, “Ground roll is quite long on the film, not entirely due to low thrust – it was uphill slightly …

A Tale of Three Pauls

Dean Sigler Uncategorized 3 Comments

Dr. Paul Robertson lectures at Cambridge University’s Engineering Department, and Paul Dewhurst serves as Director and Chief Flying Instructor at Flylight Airsports, Ltd.  The two Pauls made simultaneous takeoffs March 1, 2009 in Britain’s first two electric aircraft.   A third Paul, Welsh by name, acted as certification engineer for the effort. Dr. Robertson took to the skies in a Dragonfly hang glider powered by a Geiger/Eck 10kW motor/controller/propeller combination, while Dewhurst became skyborne in a Lazair ultralight propelled by a pair of Plettenberg Predator 12 kW (peak output) model airplane motors.  This testbed in particular reflects Dr. Roberton’s studies toward the constuction of a sub-115 kg electric twin called Hummingbird.  His PowerPoint presentation shows the mathematics of powering such a craft on model aircraft motors, the batteries required, and the anticipated and tested thrust for successful performance. The fact that practical outcomes matched mathematical projections attests to the care involved in his analysis. The presentation provides a good model for others who …