Winning the LEAP and Berblinger Prize Writing for Plane & Pilot magazine, Jim Lawrence opined, “As an industry, electric flight is still in toddler mode. Batteries provide, pound for pound, a mere fraction of the energy density of gasoline. Therein, as the Bard said, lies the rub: The culprit is weight, simply because one pound of avgas has roughly 40 times the energy delivery of a pound of battery. For electric aircraft (and other vehicles) to become common, battery efficiency will need to double, then double again, and double again. “To spur recognition and development, several major awards and competitions now offer substantial money prizes. On the last day of this year’s Aero e-flight-expo in Germany, the Berblinger Flight Competition divided |100,000 ($142,604) among three proven aircraft, each with a unique application of electric power: the elegant, single-seat Lange Antares 20E self-launcher sailplane (the world’s first certified electric); Eric Raymond’s record-setting, solar-powered Sunseeker; and Manfred Ruhmer’s Elektro-Swift, an ultralight flying wing with streamlined pod and folding pusher prop.

Composite Fuselage as “Batteries?” A June 6, 2011, article in the New York Times reported that researchers at Imperial College London, the Swedish Institute of Composites, and Volvo are looking to build auto bodies with carbon composites that can serve as capacitors (devices that hold an electrical charge) that could store more electrical energy than batteries. The dual-function materials could also make electric vehicles and hybrid vehicles lighter. To enable the composite materials to store electricity, the resin that binds the carbon fibers is laced with lithium ions; the fibers serve as conductive electrodes for this type of charge-holding capacitor. At present, the research teams have a distance to go to gain such efficiencies. The work continues and funding appears secure. If future composite structures could store energy as efficiently as lithium-ion batteries, an electric vehicle would require only the roof, hood, and trunk lid to be made of such materials to achieve an 80-mile range, researchers said.

Energy Density Primer Perhaps it is helpful to understand the significant technical challenge electric flight still faces by comparing the energy densities of gasoline and batteries. Jim Lawrence (also see “Winning the Berblinger Prize and LEAP” sidebar) wrote, “Lead-acid batteries like those in boats and cars have been around for 150 years. They’re cheap and relatively environmentally friendly to fabricate and recycle, compared to lithium-based (Li-Ion-lithium-ion, and LiPo – lithium-polymer) batteries. Lead-acids store around 6% the energy density of gasoline. Running the numbers tells us it takes 167 pounds of batteries to hold the same energy as a single pound of gas. “Lithium batteries as typically used in cameras, cell phones and radio-control models store around four times as much energy as a lead-acid battery, but cost several times more per watt-hour. That still means an airplane needs to carry more than 40 pounds of batteries for the equivalent energy of a single pound of gas.

The Technical Work of F37 Light sport aircraft industry stakeholders engaged in the ASTM standards initiative include manufacturers of airplanes (conventional fixed wing aircraft), powered parachutes, weight shift controlled aircraft, gliders, gyroplanes, and lighter-than-air. In addition, F37 volunteers come from the flight instructor community, recreational pilots, parts manufacturers, and the regulatory community. Committee F37’s work embraces: Minimum safety, performance and flight proficiency requirements. Quality assurance to install manufacturing controls confirming that aircraft meet design criteria. Completed aircraft production acceptance tests and procedures assuring that completed aircraft meet reported performance as demonstrated in the prototype aircraft, including design limits such as empty weight; center of gravity; performance specifications; controllability and maneuverability; longitudinal, lateral, and yaw stability; stall speeds; handling characteristics; engine cooling and operating characteristics; propeller limits; systems function; and folding or removable lifting surfaces. A plan for continued airworthiness, including methods for monitoring and maintaining continued operational safety, and processes for identifying, reporting and remedying safety-of-flight issues.

Many aircraft manufactured in European and Eastern European countries are poised to enter the United States light-sport aircraft market as special light-sport aircraft (S-LSA) because the European microlight standards have, for years, allowed the manufacture of ready-to-fly aircraft that closely match the definition of an LSA. Like all LSA manufactured in the United States, these aircraft must meet the consensus standards established for LSA. In addition, the aviation authority in the aircraft’s country of origin must have a bilateral agreement with FAA, and the aircraft must be eligible for certification in that country. The manufacturer must also test fly the aircraft prior to shipping it to the U.S. Lastly, before the aircraft is offered for sale in the U.S., the dealer/distributor should already have certificated the aircraft as an S-LSA. (This applies to domestic aircraft as well.) As with all aircraft purchases, wise buyers will adopt a “buyer beware” attitude to make sure that the dealer/distributor will be able to provide after-the-sale services, including timely parts replacement.