July 2010 — For the past few years piston-engine giant Lycoming has been developing a new engine, the TEO-540-A1A. The designation is meaningful: It is a “turbocharged,” “electronic ignition” and “opposed” — nothing new there — version of the venerable 540-series Lycoming engine that has been a mainstay of the general aviation fleet for decades. Versions of the 540 power dozens of airplanes, from the Piper Saratoga to the Britten-Norman Islander, from the Cessna Turbo 206 to the Robinson R44 helicopter. The 540 is a tremendously durable and versatile engine.
It’s also the basis of the TEO-540-A1A, the first in a coming lineup of iE2 engines from Lycoming that takes the basic recipe for success of Lycoming engines — the 540 is, after all, essentially a six-cylinder version of the even more prolific four-cylinder 360-series Lyc — and transports that technology into the future by integrating electronic ignition and engine control into the design. The “iE2” brand name means “integrated electronic dual channel,” and an additional two channels are available and will doubtless be used in most production engines in certified applications.
This is Lycoming’s electronic engine of the future. And it will be here soon. Lycoming plans to have it certified by the end of the year. Lancair is already offering it as an option for builders of its Evolution kitplane. Price of the experimental version of the engine from Lancair is $115,000.
I flew the engine in the Lancair Evolution kitplane at the Sun ’n Fun fly-in this year and was very impressed by how remarkably smoothly the engine performed. If it’s not ready for prime time now, it surely is not far from that point.
Lycoming introduced the iE2 series engines to the aviation world at last year’s EAA AirVenture, where it also announced its strategic teaming with Lancair International on the testing of the power plant. While it seemed like an odd couple, a maker of certified engines (and sister company to Cessna) with an experimental amateur-built kit manufacturer, there are huge benefits to Lycoming. The engine, which first flew last year, can be installed in the kitplane and, after its FAA-required 40 hours of local flying are flown off, it can be operated like any other amateur-built airplane. So flight test engineers can collect a great deal of data in a much shorter time than it normally takes.
Lycoming’s commitment to the technology — and to new technology in general — seems genuine. Last year the company announced that it was teaming with the FAA and Swift Enterprises to research 100SF, an alternative, renewable fuel being developed by Swift as a possible replacement for 100LL that wouldn’t require modifying existing engines. For lower-horsepower engines, this is not a particularly difficult target. Since 1995, Lycoming has been approving some of its lower-horsepower engines for use with auto fuels. For higher-powered engines, the problem is to avoid detonation without 100LL’s key ingredient, lead, which is being more aggressively targeted by the Environmental Protection Agency, which issued a notice of proposed rulemaking on the subject just a few months ago. No one doubts that leaded avgas will be banned; the only question is when.
Lycoming senior vice president and general manager Michael Kraft, who formerly headed the company’s R&D program (a good indication of just how important R&D is to the company), said at last year’s AirVenture that “synthetic renewable fuels hold great promise to achieve high octane ratings without the tetraethyl lead additives required by crude oil derived fuels,” while stopping short of endorsing 100SF specifically. It’s clear that Lycoming wants to foster research while remaining agnostic on the subject of which fuel, or fuels, will win out in the end as the replacement to 100LL.
Regardless of the fuel that wins out, Lycoming clearly sees its iE2-series engines as its pathway to compatibility, and there’s good reason.
Technology Gains
Lycoming says that the TEO-540-A1A, which produces 350 hp as installed in the Lancair Evolution, is not merely “bolted on” to an existing “mechanical engine,” and it truly does look to be a thorough integration of electronic control.
You’ll note that Lycoming does not call its engine a fadec model. That’s because it isn’t one, at least not technically, though pilots won’t be able to tell the difference. For an engine to be fadec, it has to have “full” electronic control, and the iE2’s throttle is mechanical. With true fadec engines, power is attained through throttle-by-wire, with the lever essentially being an electronic adjustment with no cables required. That said, the iE2 does sense throttle position, just as a fadec does, so the end result to the pilot is the same.
The engine has single-lever power, one of the big selling points of the technology. In the Evolution test bed, there are mixture and prop controls installed to allow test pilots to make power setting changes that the electronic system won’t let them make, in order to be able to collect more data. The production configuration will give the pilot just a single power throttle lever.
The fuel distribution system makes use of a common-rail system with individual electronic fuel injectors. Single or optional-double dual-channel computerized ECUs (electronic control units) monitor the status of each cylinder and regulate the health of that specific cylinder based on its conditions. The engine also incorporates “knock detection” with each cylinder having its very own “knock sensor,” a prime defense against the dangers of detonation. When the potential for detonation, so-called “incipient knock,” is detected, the ECU will adjust the tuning and fuel flow to that one cylinder in response. The process is completely transparent to the pilot.
