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.
The benefits of this design approach are many. The engine will burn less fuel for a variety of reasons. At times of high pilot workload, especially on departure and initial climb, the system monitors fuel consumption. The pilot simply sets the desired level of power. This procedure will vary from airplane to airplane, but in many applications, it will require the pilot simply to set the throttle to a detent and then return to the matter of aviating. Especially with a high-powered turbocharged engine, the difference in fuel flow between maximum mixture (which in most cases is just how pilots set the fuel flow initially) and the right mixture can be measured in several gallons per hour of wasted fuel. On extended climbs, that can mean expending many extra gallons of fuel, which can make the difference between having enough fuel to reach the destination comfortably, or not.
Because the engine monitors cylinders individually, it doesn’t need to throw gas at every cylinder in an effort to stop detonation in its tracks. Moreover, you save fuel and money in every phase of flight (while adding range, I might add) by not having to adjust mixture based on the hottest cylinder. The ECU does the job by simply tuning that one cylinder.
The safety advantages of electronic engine control are many and real. Instead of spending heads-down time fiddling with knobs and waiting for data indications, pilots can set the desired percentage of power and just fly.
Evolution Test Bed
Lancair, which has been in the kitplane business for more than 20 years, is working with Lycoming on the development of the iE2 partly for selfish reasons. While its big, pressurized, carbon fiber four-place Evolution is built to be powered by a turboprop engine — and has the tall landing gear to prove it — Lancair has a good number of customers who are interested in a more economical piston power plant for their airplane, and the new Lycoming fits the bill nicely. In its final iteration, it will likely be rated for a time-limited takeoff power of up to some figure in excess of its nominal 350 hp rating, perhaps as much as 400 hp.
I flew a couple of other Lancairs, the IV and pressurized IVP, years ago, and I came away unimpressed by the airplanes’ handling and by the high book speeds. The Evolution is in every regard a better flying airplane. In fact, it handles very conventionally — which was one of the prime goals of the program — and its approach, stall and glide speeds are in keeping with what a single-engine airplane’s speeds should be and, in fact, are required to be.
I was reminded in many ways of a product the company began developing many years ago, which eventually became the Columbia and, later, the Cessna Corvalis. The Evolution is much bigger, it handles like the heavier airplane it is, and it is not intended for certification, but, with the exception of too-heavy aileron forces, it is a good flying airplane.
It’s also an excellent test bed for the iE2 technology.
I flew with High Performance Aircraft Training’s David Robinson in the right seat and Lancair’s Doug Meyer in the back. The startup sequence is a push-button affair, literally. You simply turn on the power, push a button and let the brains of the system do the rest. In fact, the system starts the engine using much less fuel and much less wasted motion than a manual start does, getting the engine turning and continuing to turn at much lower power than I’ve ever been able to manage with any large-bore aviation piston engine. It runs through the electronics check, and when it’s done, it gives you the green light to go.
Setting the power for takeoff was as easy as pushing the power control in and, again, letting the computers optimize the power. Taking off for the first time in an airplane I’d never been in before, I really appreciated the fact that I could concentrate on flying and not on setting the power while we accelerated down the runway.
As it turned out, the Evolution was the opposite of a handful. I rotated at 70 knots, almost exactly the same as in my Cirrus SR22, selected 120 knots on the flight director, pointed the nose skyward and watched the airplane climb. The maximum rate of climb, by the way, is 2,000 feet per minute, though we didn’t see that, but only because we wanted to keep the nose down for better visibility in the busy Sun ’n Fun traffic area. Even at our higher climb speeds, we were seeing around 1,500 fpm well up into the teens at around 43 inches and 2,500 rpm burning 34 gph. The temperatures stayed in the green with CHTs (cylinder head temps) in the low 400s. The differential between the hottest and coolest EGT (exhaust gas temperature) was just 27 degrees.
We were VFR, and the plan for our short hop was to stop at 17,500 feet and check out the cruise numbers at that altitude. They were impressive — 235 knots at a cruise power setting of 36 inches and 2,500 rpm burning 22 gph. At slightly higher power, we were seeing 242 knots true. With 168 gallons of fuel capacity — remember, this airframe was designed to accommodate a PT6 — there’s huge range and little need other than financial to worry excessively about the fuel flow. At higher altitudes, and the Evolution’s ceiling is 28,000 feet, you can cut fuel flow substantially while maintaining true airspeed or burn the same amount of fuel and go a lot faster.
We didn’t go to the mid-20s, but Lancair says the airplane can do 270 knots true at a high cruise power setting and 250 knots at less than 20 gph. And with a nearly 800-pound full fuel payload, the Evolution can take four regulation grownups plus around 100 pounds of bags.
The range of the airplane, thanks to its huge fuel capacity and high speed, is spectacular, though it’s hard to imagine anybody making use of that full range on a regular basis. But trips of 1,500nm or greater (no wind) at speeds of around 240 knots with a fuel flow of around 17.5 gph in the mid-20s will be routine for the Evolution. The engine is truly a remarkable fit for the airplane.
Just what the future holds for fadec engines remains to be seen. Teledyne Continental Motors’ PowerLink fadec engines have been certified for a few years now, though their clear advantages over the old technology has not been enough to motivate either manufacturers or owners to adopt them in any great number.
The coming need for us all to use what we now can still refer to as “alternative” fuels will change the market for good, and electronic ignition engines will become more than a novelty. When that happens, Lycoming, with its iE2 lineup, will doubtless be exactly where it wants to be.
For more information about the Lycoming iE2 series of engines, visit lycoming.com. To learn more about the Evolution, including the turboprop-powered version, visit lancair.com.
