Consumers have become accustomed to electric or hybrid automobiles over the past decade, as major manufacturers like Toyota and Honda have turned out electric cars and upstarts like Tesla have also made waves in the industry. The new vehicles help buffer buyers from roller-coaster fuel prices and have some impact on reducing greenhouse gas emissions, which contribute to global warming trends.
But we’re still used to our aircraft burning buckets of hydrocarbon-rich aviation fuel to jet around the globe, putting even the most environmentally-friendly passenger into massive carbon debt on every trip.
A new motor developed by Siemens might help change that status quo. The lightweight motor, weighing in at just over 100 pounds, puts out 260 kilowatts of energy output on a continuous basis. That makes it five times more powerful than any comparable motor, as well as delivering it all in a record-setting five-to-one power-to-weight ratio.
The company claims that this will allow aircraft weighing up to two tons to make use of the electric motor instead of the traditional gas-guzzling aviation engines.
Part of the key to the innovation is the rotational speed range used by the new engine. Spinning at 2500 revolutions per minute (RPM), the motor can drive a propeller directly instead of requiring the use of a heavy transmission unit.
The motor of a Tesla Model S operating at the same energy output, by contrast, is spinning at more than 4000 RPM — a rate that would be unsafe for most propellers, as the velocity at the tips would be approaching the speed of sound, creating buffeting and instability.
The weight reduction is another important factor for aircraft, where every extra pound of structure or equipment reduces the payload capacity. Most electric-powered aircraft to date have been variants of glider designs, extremely lightweight but without broad practical application.
A combination of computer simulation and analysis of existing electric aircraft engines provided the impetus for the new motor. In-flight testing is due to begin by the end of 2015.