Engines

The two leading contenders to replace 100LL with an unleaded equivalent, Swift Enterprises Swift Fuel and General Aviation Modification Inc.s G100UL, both say their fuel will cost more than 100LL. But how much more? We took our own run at it based on what weve been able to glean about these fuels from patent filings and information from the two companies. According to its patent filings and published FAA test data, Swift is a binary blend of mesitylene (also known as trimethylbenzene) and isopentane. Mesitylene is a bit of an exotic, used for specialized solvents and industrial processes. Its a terrific octane enhancer, but so rare in industy that no commodity prices are available. One supplier we contacted sells it for $53 a gallon, a price thats obviously unsustainable for fuel use.

More than a decade ago, Teledyne Continental bought a fully formed full authority digital engine control system from a startup called Aerosance. It made perfect sense, since at the time, many in the engine business thought the market was overdue for dumping magnetos in favor of electronics, which cars have had since the 1970s. The many turned out to be wrong. TCM got hardly any traction with its FADEC system, even though those who have flown it, installed it and own it say it should have succeeded. Why it did not seems to be due to a combination of bad timing, a hidebound market and conservative OEMs. But with fuel prices rising and 100LL threatened, is there resurgent interest in electronic ignition in general and TCMs PowerLink specifically? It appears so.

Imagine a world in which youre considering an expensive new luxury car, only to be told by the dealer that fuel to run it may be legislated out of existence in five years, but don’t worry, someone will come up with something. This is exactly the conundrum buyers of new aircraft face and, increasingly, so do owners of legacy airplanes considering upgrades such as paint and avionics. We wondered if lack of confidence in future fuel supplies is putting a drag on the market, so we asked. In a survey published on our sister publication, avweb.com, more than 3100 owners and pilots gave us their opinions on the quest for a replacement for 100LL. Among the findings: One in five owners told us theyre definitely delaying any purchases or upgrades and more than half-53 percent-say theyre either on the fence about purchases or definitely not buying until the fuel situation clarifies.

As general aviation moves bumpily along toward a replacement fuel for 100LL, there’s a backlash brewing. Why, ask the owners of low-compression, low-output engines, do we have to settle on a single fuel? Why cant there be two unleaded fuels, a less expensive one for some users and a high-octane version for the rest? And why cant one of those fuels be mogas, which enjoyed wide popularity during the 1980s? Two-fuel systems are in place throughout western Europe, although not every airport has dual fueling. Some-usually smaller grass and club fields-have only one fuel available, while others have a 91/96 (the equivalent of 94UL) and conventional 100LL. A handful even have three fuels, since mogas has a tiny presence in Europe.

Two articles, plus several letters, in the August issue might be summarized as “electrical vs. mechanical.” The description of the Lycoming IE2 system again raises the question of why most of us are still flying behind antiquated mixture, ignition and engine control systems, when even the most economical compact car sports electronic ignition, fuel injection and variable spark advance.

When Continental announced in May that it planned to develop a diesel engine for the light aircraft market, it was boldly going where many have gone before. Unfortunately, the many have had their diesel entries ground to a bloody pulp by a fickle market more interested in speed than economy and unconvinced that diesels supposed longevity is worth the higher purchase price. A historical fact: Depending on how you define commercial success, there has never been a commercially successful diesel engine for aircraft. The Thielert/Centurion line launched in 2005 comes closest, but the company went belly-up and although its building engines again, it remains insolvent

To visit Lycoming and Continental, as we did last month, is to step into a disconnected world that almost qualifies as an alternate reality. And no, were not resurrecting the hackneyed complaint that the engine companies are out of touch with the wants and needs of their customers. Its the other way around. While the world of piston GA drifts along in business-as-usual mode, the engine makers see a looming cliff defined by the extinction of 100LL and no one is tapping the brakes. Panic may be too strong, but if no universal fuel replacement emerges two years from now, it may be too mild.

Some inventions seem to be naturally bad ideas but work anyway, while others are bad ideas that don’t actually work that well. In-tank electric fuel pumps are an example of the first, the Bendix dual mag as a poster child for the second. But not for much longer.Earlier this year, in a terse two-line press release, Teledyne C ontinental announced that its discontinuing manufacture of the D2000 and D3000 Bendix magnetos. No details were offered nor provided by follow-up query, but we can connect the dots. D-mags arent used on any Continental engines, just Lycomings. Litigationally speaking, theyve lived a rough life so Continental must have figured why have the legal exposure just to supply a competitor with a few mags. Even a Goldman Sachs executive could figure that one out.

With more and more Rotax engines out in the field, it makes sense that there is a growing market of aftermarket parts and accessories. However, this is purely good news for owners of Rotax engines on experimental aircraft, including E-LSAs. For owners of S-LSAs-factory complete LSAs not registered as experimental-the usefulness of these parts depends on what it is and which aircraft they own. S-LSAs don’t use the STC process many aircraft owners know and love (or not). Instead, almost any modification can be made with a letter of authorization (LOA) from the aircraft manufacturer. These LOAs are supposed to be issued on an aircraft-by-aircraft basis. So, just because your hangar neighbor with the same LSA has an LOA for a particular change, that doesnt give you the right to do it. That said, the more organized LSA manufacturers keep common LOAs ready to go for customers who request them.

As we attempt to keep our legacy aircraft flying longer and more efficiently, more pilots look to the avionics upgrade path as a means of improving utility and safety. And while the glass-panel primary flight display and multifunction display have both earned their fair share of attention, its also correct to suggest that the combined engine monitor-shorthand for a screen that includes powerplant and airframe system monitoring-is on many owners radar. Who isn’t eager to get rid of those wiggly needles, anyway? J.P. Instruments has been a household name in add-on engine monitors, making popular the bar-graph style of EGT and CHT monitoring. Many pilots are familiar with the firms 2.25-inch gauges and while some of them can include monitoring of other engine parameters besides EGT and CHT, the limited display size reduces the number of items you can watch at once.

Think of it: If you had an aircraft engine that burned two to three gallons less than the competition, delivered the same horsepower, weighed more or less the same and burned fuel that isn’t threatened with extinction, as 100LL is, wouldnt you sell the hell out of it? Youd think so. But while SMA, the French daughter of aerospace giant SAFRAN, has such an engine in the SR305 aerodiesel, buying one is at best a rarified experience. There arent many of these engines flying, so judging their merits has been largely a paper exercise. So when the Paramus Flying Club, a long established New Jersey co-operative, invited us to examine their SMA-converted Cessna 182, we realized it represented a rare opportunity to take the measure of this engine in the wild. The club has been operating it for nearly a year and while its too soon to declare it a walk-away success, the airplane has proven to be the most popular among the clubs 46 members, its dispatch reliability has been excellent and the engines initial operating costs look promising.

Owners buying engine overhauls have more or less adjusted to the idea that cylinders, cams and crankshafts have become a crap shoot. But valve lifters, too? These got added to the list of problem parts last fall when TCM announced that a massive batch of faulty lifters made it into the supply chain. Some showed failure wear in as little as five hours of operation. Although only engines built after June 19th, 2009, appear affected, the sudden demand has disrupted the supply chain for lifters to the extent that the industry-and the FAA-are relenting on the standard recommendation that lifters be replaced. Further, the market for overhauled lifters has become red hot and, at least we’ll into 2010, they may be hard to come by. Only owners who had engines built after the June date need be concerned about bad lifters and not all of them may be affected.