LSA Potential Draws Small Shops into Market

by ANN Correspondent Paul Plack

Looking around at the recent US Sport Aviation Expo in Sebring, FL, it was hard not to conclude that it's a great time to be Rotax. While homebuilders on tight budgets like to grouse about the company's pricing, the engines -- both two- and four-stroke -- have earned their status. In addition to good power-to-weight ratios, the engines have been thoroughly proven, and enjoy broad parts and service availability. The geared reduction drives allow driving large, efficient propellers. Volume production means quick delivery. For many LSA manufacturers, Rotax is just hard to beat.

But people keep trying! In years past, engine development was a capital-intensive process best left to big companies (or skillful stock pitchmen). Today, the blooming capabilities and falling prices of CNC (computer numeric control) machining equipment and CADD (computer-aided drafting and design) software allow small-time experimenters to quickly turn new ideas into running prototypes. In fact, a designer can now export CADD files to CNC machine shops thousands of miles away to have parts made.

The light sport segment is drawing some of these engine designers out of their garages. A few 80+ horsepower, LSA-class engines were represented at Sebring, and the stories of the companies can be as interesting as the engines themselves.

Jabiru started its engine line because it had to. True pioneers, Jabiru founders Rodney Stiff and Phil Ainsworth started work on their "LSA 55/2K" aircraft in the late 1980s. In 1991, just a month after the plane received a type certificate from Australia's CASA, the lightweight, Italian-sourced four-stroke engine around which the plane had been designed was pulled from the market. Nothing else available at the time met the company's needs for power-to-weight ratio. Of necessity, Jabiru became an engine manufacturer.

Jabiru's first engine was a debutante at Oshkosh in 1994. The current 2.2L, 85-horsepower, horizontally-opposed four-cylinder (above) and the 3.3L, 120-HP six-cylinder variant are now proven four-stroke engines with long TBO and appealing price tags. They were displayed at Sebring, although penetration of the LSA segment may be limited by the engine's direct-drive configuration. Requiring a propeller speed of 3300 RPM to make peak power, the engines don't accommodate the large, slower-turning props favored by most LSA designers.

Jabiru still machines its cylinders from blocks of 4130 alloy steel, and heads from solid aluminum. It's a more expensive process than casting, but produces a high quality level and allows revisions without the costs of developing new molds. The company recently increased the total surface area of the cooling fins on its cylinder heads, (see picture above, old head held in front of new engine,) which would not have been easy using cast components.

UL Power Aero Engines is a newcomer which displayed the UL260i, (above,) a 95-HP, horizontally opposed, four-cylinder, four-stroke with some exciting features. The company's Russell Pescod described the small Belgian manufacturer as four partners who brought various racing, engine development and CNC machining skill sets to their collaboration. While it features computer management, multi-point fuel injection and redundant, electronic ignition, it makes peak power at the same 3300 RPM prop speed as the Jabiru, putting it at the same disadvantage in the LSA segment. Its price in US dollars is above the Rotax 912, so it's not clear what advantage potential customers will see in buying this engine, unless an air-cooled engine or direct-drive are specific design goals.

Some of the bigger crowds all weekend were gathered around the Vulcan Aircraft Engines display (above), and the Raptor 105 aircraft turbodiesel. Vulcan's Kevin Sweeney is an aerospace engineer and former motorcycle and drag racer. His other company, Nivek R&D, has developed larger, two-stroke diesels for marine markets and the US military. His goal with Vulcan is clear. He's not bashful about setting his sights on Rotax's LSA market share, and says he hopes one day to serve the wider general aviation market. He believes a diesel in this class will distinguish him from all the other small engine developers nipping at Rotax's heels. Given the market reception for aviation diesels lately, and the crowds around his display at Sebring, he's probably right.

Only a few examples of this single-overhead-cam, electronically fuel-injected engine have been built for testing, and Sweeney says they have easily met their design goals for power output and fuel consumption. The engine has a preliminary rating of 105 continuous horsepower to at least 7,500 feet, and Sweeney expects testing to extend that to 10,000 feet. At 179 pounds, the engine is heavier than the Rotax 912, but makes 10 per cent more power. The Raptor 105 may actually be a closer match to Rotax's turbo 914, offering the same continuous HP rating, weighing only a few pounds more, and using less fuel.

The display engine lacked intake and exhaust manifolds and other accessories. One story floated among bystanders was that the engine was laid bare to allow a better view, but Kevin confessed that the pre-production manifold castings are just not pretty enough for a display. The evaluation engines are built on an automotive block with Vulcan's own heads, but a unique Vulcan block casting is in the works. CNC techniques have been used to build molds for the new block, which will then be cast by a subcontractor. The engine uses a quiet, enclosed chain reduction drive, which allows full power output at a prop speed of 2450 RPM. Not coincidentally, the redrive is configured to place the prop output flange in the same spot as that of the Rotax 912.

As you might imagine, internet message boards are already buzzing about the coming of a 105-HP turbodiesel for US $15,800. But the experimental market will not get this engine at retail, at least not right away. Sweeney says his priority is to get the first ten engines into the hands of LSA manufacturers, help them develop mounts and evaluate the design, then sell to them as an OEM. Any decision to tackle the customer support nightmare that comes with retailing to thousands of individual homebuilders will come later.

Just because the little guy can now build a running prototype doesn't mean the big engine manufacturers are endangered. In fact, it's easy to imagine that some of the better new engine designs will draw buyout offers from the big guys. One thing is certain -- the next few years are going to be a fascinating time for engine enthusiasts at aviation shows, even if some of the engines being displayed aren't "ready for prime time."

FMI: www.rotax-aircraft-engines.com/, www.jabiru.net.au, www.ulpower.com, www.nivek-rd.com, www.vulcanaircraftengines.com