Off-The-Shelf-RC-Technology Powers Electric Ultralight

By Gene Yarbrough

While necessity may be the mother of invention, some innovate just because the challenge is there, and converting a hydrocarbon powered flying machine to electric based propulsion with off the shelf R/C airplane technology is no small feat. Enter Dale Kramer, famous designer and inventor of the venerable Lazair Ultralight' circa 1980's.

Electric powered airplanes are all the rage, evidenced by an entire symposium on the subject at this years’ EAA Airventure, however (and despite some mighty fine minds working on the problem) it remains elusive thus far as a largely viable means of flight. Regardless, as many times is the case, as technology comes upon the cusp of feasibility an innovator applies such to a minimal system to realize the most rudimentary demonstration. Dale Kramer has applied off the shelf radio control model airplane battery, motor, and controller technology to a Lazair airframe to create the first electric powered amphibious ultralight conforming to 14CFR Part 103 regulations.

According to Kramer's postings on an RC group message board,  he anticipated achieving flights of up to two hours solely powered by on board battery packs and expects longer flights while soaring and thermaling the Lazair. Real world results have been a bit less than expected with flights of an hour and fifteen minutes without the float gear, but the learning curve is still in play. While recharging is a bit of a hassle, requiring electric service or a generator or two compared to simply refilling a gas tank, the electrics are expectedly more efficient from an energy usage standpoint and will undoubtedly prove to be more advantageous to gasoline engines as battery technology progresses with better power density ratios. Typical "refills" cost about a dollar or so when coming off the power grid or about four dollars per flight hour from the generators as compared to around eight dollars per flight hour at current gas prices. The lithium polymer batteries Kramer is using are completely off the shelf units numbering 96 packs and are the same as those used in typical R/C electric powered model airplanes, along with the motors and motor controllers. Electrics are still a bit pricey, on the order of about twice the cost of the original 2 stroke engines.

Kramer has fitted all these components onto an existing Lazair airframe with longer nacelles and other minimal modifications to offset the CG change from the gas engines. Initial tests have shown the E-Lazair, for lack of a better term, to be quite adequately powered and gives comparable performance to its petrol counterpart. While Kramer has operated the E-Lazair from both land and water with amphibious floats, the success has been co-mingled with setbacks and challenges as is all too often the case in pushing the technological envelope. Thus far, according to Kramer, he has fried motor controllers, two motors, and/or associated parts while discovering that employing electrons to do your bidding comes with caveats. However, true to Kramer and most innovators, perseverance has prevailed. Dale is at Airventure this year already inundated with queries of all sorts reminiscent of the Lazair heydays of the mid eighties.

Electricity may be the future of recreational aviation as gasoline becomes passe’ and environmental sensitivities demand a re-think in propulsive systems. This endeavor has shown that the technology has matured sufficiently to enter the marketplace. Much as the automotive industry has adopted the paradigm shift aviation is set to follow suit with several big name manufacturers eyeballing electric powerplants and several smaller projects coming online.

FMI: www.rcgroups.com/forums/showthread.php?t=1412424&page=1