Melbourne, Florida-based Liberty Aerospace has selected the 100-horsepower Rotax 912S air- and liquid-cooled engine as an alternative to the Teledyne Continental IOF-240-B. Liberty president and CEO Keith Markley says the new engine option is a response to international demands from customers in Southeast Asia, where aviation fuel can reach prices as high as $20 per gallon. The 912S prefers automotive fuel, though it will also burn avgas.
“One of the biggest problems we had with the Rotax was the TBO,” Markley says, referring to previous considerations of selecting the engine during the initial certification of the XL2. The TBO for the certified 912S was recently increased from 1,500 to 2,000 hours.
The company’s initial goal is to achieve an STC for the Rotax, but ultimately the engine will be added to the type certificate of the XL2. Markley also says that, in order to maintain the same useful load and speed with the lower horsepower engine, the gross weight for the Rotax version will decrease from 1,750 pounds to 1,653 pounds. The upper and lower sections of the engine cowl have been redesigned to fit the smaller Rotax engine, but no other modifications to the airframe are expected. There will, however, be definite changes in the electrical system, and in weight and balance.
Burning only five gallons per hour, the 125-horsepower fadec-equipped Teledyne Continental IOF-240-B that is certified in the XL2 is already very efficient. “I don’t think we will see the fuel burn being significantly different, but we don’t know what it will actually be until we get the airplane to the testing phase,” Markley says.
