On this electric 50th anniversary of a notable achievement in the aircraft world, Dr. Reinhard Lernbeiss, a fellow in the Royal Aeronautical Society is a pilot on Boeing 777s and Airbus A330s, 350s, and 320s. He recently alerted us on LinkedIn that on October 21, 1973, Heino Brditschka was the first to fly a heavier-than-air craft on electric power. (The Tissandier Brothers had flown an electric airship in 1883, followed by Captains Reynaud and Krebs in 1884.)
His converted HB-3/MB-E1 (his own design) managed a first flight time of nine minutes, fifty-eight seconds and reached an altitude of 985 feet above ground level. Lernbeiss reports that on additional flights, the craft managed 12, 16, and 22 minutes and an altitude of 1,245 feet. These included go-arounds, with each outing “far below the capacity of the battery on each flight.”
Much of the inspiration for the flight came from an aeromodeller, Fred Militky. A 2018 Federation Aéronautique Internationale (FAI) publication, CIAM Flyer, headlines its article on Brditschka and Fred Militky’s accomplishment, “An Aeromodelling Pioneer Led the Way.”
According to an article, ”The history of Electric Flight,” “Fred Militky, Graupner’s design and development engineer, had been researching electric free flight since 1941 but had only begun to have success around 1957 with a ‘special motor’ presumably hand built by himself.”
Fred Militky’s Silentius model was a 30-inch silent flyer. You can build this vintage model.
Militky had designed the electric-powered Silentius model airplane in the late 1950s. He was also a school friend of Brditschka and worked with him to enlist Bosch (propulsion motor) and Varta (nickel cadmium batteries) in creating a flyable, human-carrying aircraft.
Their success marked not only a first in electric aviation, but doubtless inspired others to look at this new mode of propelling small aircraft. Within the decade, Fred To and David Williams in England flew a solar-powered craft, followed by Larry Mauro in California.
The ”Elektroflieger No. 1,” or MB-E1(Militky-Brditschka) had a 12-meter wingspan, a Bosch 80 Volt motor that could generate 8000 Watts of power, and a Varta nickel cadmium battery. These were first-of-a-kind adaptations for aircraft, and set the approach that would be followed for decades.
Varta Batteries and Bosch motor replaced passenger on first electric craft, Elektroflieger No. 1
The HB-3A on which the electric craft was based had a flying weight of 440 kilograms (970 pounds), which considering the low energy density of Ni-Cads then available was an appreciable accomplishment. That the motor drove the propeller at 2,400 rpm helped with propulsive efficiency and netted a static thrust of 28 kp (kilopond, an obscure unit of measure rarely used any more), or about 62 pounds of thrust if your editor is reading the charts correctly. The 33 kilogram (72.6 pound) motor and 120 cell steel battery obviously added to the high weight and short flight durations.
Despite that, Militky was happy with the results and recognized that things might get better for electric aviation. “After his successful first flight on 21st October 1973, Fred Militky wrote: ‘With the accomplishment of the MB-E1 project, it was possible to prove that an aircraft heavier than air can be flown while carrying electric energy. It is up to battery manufacturers whether they will be able to produce even better batteries that are also lighter and will make electric flying accessible to a wider public, at least in the field of amateur flying.’”
Showing a stronger thrust than possible on the first electric craft, a Brditschka Hobbyliner tows a banner over a couple celebrating their vows
The basic aircraft configuration is still a feature of HB aircraft, but with much improved motors and batteries. The company continues with design, construction, maintenance, repair and flight school facilities. A trip to Austria could include a hop in one of the descendants of electric aviation’s first hopeful flights.