Andy Higgs, a Brit who has lived in Japan for the last 32 years, is on a mission to bring a new engine to aviation, in the form of a jet-A-burning “step-piston two-stroke.” The three-year FAA certification testing program will begin late next year.
“We’ve built several engines to validate the technology, and they have all worked outstandingly well. There are no technical show-stoppers, and I signed off on the final design a couple of months ago.”
President, CEO and sole owner of Tokyo-based AC Corp., Higgs says the engine will be offered in various configurations, among them a 1,000-hp V12 weighing 665 pounds/302 kg (including reduction gearbox); a 350-hp four-cylinder weighing 302 pounds/137 kg (again including a gearbox to reduce the crankshaft’s 5300 rpm down to 2300 rpm for the prop); and a 1.5-liter V4 weighing just 103 pounds/47 kg and producing 120 hp. The commercial business model for the V12 centers on “competing with the low-end PT6 market, 580 to 1,200 hp, as a replacement engine for Cessna Caravans. The killer for Caravan operators is the cost of fuel. Like for like, power for power, our engine versus the PT6 will give the operator 40 percent more range.” For grins and some measure of technology demonstration, the 1,000-hp V12 is also destined to power at least one NXT in the Sport class at Reno at some point.
Higgs describes the technology: “It differs from a conventional two-stroke in that we’re able to isolate the crankcases, which have typical four-stroke lubrication. We can use plain bearings, and we do not have to mix oil into the fuel. We can separate the two-stroke concept from the crankshaft and lube mechanism.