For at least a year, Rotax has been hinting at a new higher horsepower engine and on Tuesday at AirVenture, it delivered. The new, 135-hp turbocharged 915 iS is a follow-up to the 912 iS introduced in 2012. Although the new engine shares similarities with the 912 iS, it has a reinforced crankshaft, newly designed pistons and, of course, a turbocharger. To handle the higher torque, the 915 iS will also a new gearbox. Complete dry weight is expected to be about 84 kg or 185 pounds. With a turbocharger compressor ratio of 1 to 3.5, the 915 iS will have a critical altitude of 15,000 feet.
Rotax’s Marc Becker said the new engine will operate on high-octane mogas and will eventually be available in both experimental and FAR 33 versions. Although it hasn’t flown yet, Becker said the 915 iS has accumulated about 2000 hours in the test cell and Rotax is making arrangements with airframers to begin flight tests.
Like the 912 iS, the 915 iS has a dual channel ECU, but with the addition of an integrated turbo controller. It has dual electronically controlled fuel injection with dual spark plugs. As with the 912 iS, the ECU will be provided by Rockwell Collins. Becker said the engine will have a 2000 hour TBO and is expected to be available in about two years.