Although Light Sport Aircraft and Very Light Jets got most of the publicity at EAA’s AirVenture this year, anyone with an interest in engines might have seen it differently.
Six engine manufacturers and developers made what they considered to be major announcements at AirVenture, and most others at least held news conferences, if only to say that big announcements will come later.
Most interesting, to this writer, was the announcement by Powerplant Developments, Ltd. of a three cylinder (but six piston) opposed-piston engine designed to run on kerosene-type fuels. Significantly lighter and with some 40% fewer parts than contemporary diesel-cycle engines, the two-stroke Gemini 100 initially will be offered to the Light Sport market, said Tim Archer, the British company’s new president and CEO. “Right now it is the only diesel meeting LSA specifications,” he said.
“We have been in contact with a number of LSA manufacturers and dealers, and they are all extremely interested in the lower operating costs, reduced installed weight and performance advancements offered by this engine,” Archer continued.
Archer, former head of Superior Air Parts, and Derek Graham, founder and chairman of Powerplant Developments, both stressed the relatively light weight and simplicity of the opposed-piston design.
“The typical installed weight of the 100 hp Gemini 100 is less than 166 pounds,” Graham said. “That includes the heat exchanger and accessories, and is about 34 pounds less than that of a 100 hp Continental O-200.”
The opposed-piston concept is far from new. Many World War II U.S. submarines were powered by Fairbanks-Morse opposed-piston diesel engines and, starting in 1932, German aircraft manufacturer Junkers built six-cylinder, 12-piston, 867 hp engines that were used extensively on large German airplanes right through World War II.
Even so, “The Gemini engine introduces a number of uncommon, yet proven, features to the aviation industry,” Archer said. “For example, it has a unique two-crankshaft, two pistons per cylinder design, which is why the ‘Gemini’ name. This design eliminates the need for a camshaft, valve gear and cylinder head joints – three main causes of unreliability and high maintenance costs in older-generation piston engines.”
The first-generation Gemini engine uses a supercharger to provide forced induction and positive displacement, both of which are necessary on large two-stroke engines. Later, a turbocharger will supplement the supercharger, increasing horsepower and significantly reducing fuel consumption, Graham said.
Prototype engines will be flying around the end of September, Graham stated in July. ASTM certification for Light Sport Aircraft is planned for November 2008, he said, but deliveries for the Experimental market will start sooner.
While “the initial focus will be on the Light Sport market,” Powerplant Developments will explore STCs for the “several certified aircraft with engines in the 90 to 120 hp range” which will be “ideal candidates” for upgrade to the planned Gemini 125, when it is available and certified, Graham said.
Current projections show that, at 75% power at 5,000 feet, the prototype Gemini engine should deliver fuel consumption of 4.75 gallons per hour of Jet-A, compared to the 6.6 gph of avgas consumed by a Rotax 912 engine, Archer said. The Gemini 100 also is designed for a 2,000 hour TBO compared to 1,200 hours for the Rotax 912, he said. “That means that the Gemini 100’s direct operating cost is projected to be better than half that of the Rotax 912.”
The anticipated price is right, too: around $18,000, according to Graham.
Graham characterized the Gemini engine as “game changing.” He may be right. It certainly will be worth watching.
For more information: JadeAir.co.uk.
Sonex Aircraft, well known for its sleek kitplanes, unveiled its E-Flight Initiative electric aircraft motor at AirVenture. E-Flight is “a push to explore viable alternative energies for powering sport aircraft,” said Sonex founder and president John Monnett.
While E-Flight is working on both electric power and ethanol fuel for airplanes, it was the compact prototype electric motor that was introduced at AirVenture. The tiny prototype included a brushless motor, its proprietary controller, a battery pack and on-board charging system “with the goal of determining the feasibility of a marketable line of products,” Monnett said.
The prototype electric power system is installed in a Sonex-built Waiex airframe, which will be flown in a single-pilot, proof-of-concept configuration. It is expected to reach airspeeds of around 130 mph with an endurance of 25 to 45 minutes, utilizing currently available batteries, according to Monnett.
The prototype’s motor is “the most powerful, lightest weight and efficient unit of this type ever produced,” he stated. It is a three-phase, 270 volt, 200 amp motor which, he claimed, “will be over 90% efficient.” Slightly larger than a 35-ounce coffee can, it weighs around 50 pounds, he said. It is modular and scalable, with core sections that can be added for higher horsepower or removed for less output, he pointed out. Its controller is proprietary because an off-the-shelf controller for the high voltage, high current motor is not available.
Electric power comes from 80 Lithium Polymer cells housed in “safe boxes” intended to thwart the volatility of Li-Poly batteries. The boxes utilize heat sinks and “cooling foam” padding and are designed to contain and “safely direct” fire or explosion within the boxes, Monnett said. Future generations of Li-Poly batteries are expected to be safer and more powerful, he pointed out.
For more information: SonexAircraft.com.
GE HONDA AERO ENGINES
GE Honda Aero Engines president Bill Dwyer noted that the joint venture’s HF-120 turbofan engine is completing hot section tests and that the first full engine tests will come later this summer. The engine is expected to be available to power business jets in 2010, he said, following certification in 2009. It is scheduled to power both the HondaJet and Spectrum Aeronautical’s Freedom. More than 200 of the engines are on order, Dwyer said. Production is expected to reach 140 engines a year eventually, based on “the promising outlook for new-generation light business jets,” he said.
The HF-120, rated at 2,095 pounds of thrust, was developed from Honda’s HF-118 prototype. That engine has accumulated more than 4,000 hours of ground and in-flight testing, according to Dwyer. GE and Honda redesigned the engine for more thrust but better fuel efficiency, durability, noise footprint and emissions, he explained. The HF-120 is expected to run for 5,000 hours between overhauls, he said, “with no need to open the engine for interim hot-section inspections.” That durability will make it “ideally suited for high-utilization aircraft such as the emerging air taxi segment,” he said.
For more information: GEHonda.com.
MUNRO & ASSOCIATES
Standing out among the rows of kit airplanes and experimental powerplants was the tough-looking, automotive-based propulsion system developed by Munro & Associates. Sandy Munro proudly demonstrated the quiet, powerful engine built for a Corvette and linked to a ducted fan propulsion system in a mockup fuselage. It was a crowd-pleaser.
Munro’s ideas didn’t stop with the power train. His exhibit included scale models and large drawings of a proposed four- to five-seat airplane utilizing the engine technology. His vision is for a point-to-point airplane capable of cruising at 200 mph – four times highway speed – at a price substantially lower than that for existing airplanes of comparable performance. He intends to reach that goal using automotive manufacturing technologies and methodologies he has developed as a Lean Manufacturing consultant to the world’s largest airframe and automobile makers.
Munro’s nifty propulsion package currently is undergoing field tests in partnership with NASA, seeking “a quick start toward prototype demonstrations and FAA certification,” Munro said, foreseeing “a huge global market potential.”
For more information: LeanDesign.com.
Germany’s Thielert Group, which builds certified diesel-cycle Centurion engines in Germany for general aviation and unmanned aircraft, and owns Superior Air Parts in Texas, announced extensions of its “TBR” (Time Between Replacement) up to 2,400 hours from its current 1,000 hour engine exchange time.
President Frank Thielert said that no new engine models are planned for the near future, but that production of certified 2.1 and 4 liter Jet-A engines is increasing to match the “trend away from avgas” around the world. Currently there are STCs for Thielert engines for several Cessna models.
Thielert will not develop STCs in the future, he said, leaving that up to airframe manufacturers. Instead, the company is offering firewall forward kits.
Thielert provides the engines for Diamond’s DA-40 twin, one of which recently suffered a complete engine failure due to electrical power loss. How could that affect a diesel? It had no direct effect on the engines, Thielert explained, but killed Diamond’s FADEC control systems which, at that time, had no backup batteries. An airframe AD now requires the backup batteries, he said.
For more information: Thielert.com.
SMA, a division of the much larger Safran Group based in France, admitted that it is moving slowly into diesel-cycle power compared to its obvious competition, but has 51 engines flying with some 10,000 hours total flight time accumulated, worldwide.
SMA’s strategy is to control all aspects of development as it improves its engines and specifications to meet customer expectations, said Luc Pelon, the company’s chairman and CEO. SMA engines are “mainly for professional uses such as training and cargo,” he said, although the most prominent U.S. OEM using the engines is Maule.
The SMA diesel is “quieter than any gasoline engine,” running at 2,200 rpm without gearing. It is “not a car engine,” he commented, taking a swipe at Thielert’s Mercedes-Benz-based products.
Pelon said that SMA is “working on a more powerful engine” but – like rival Thielert – would no longer develop STCs.
For more information: SMAengines.com.