ROTAX UPS THE STAKES

THE NEW ROTAX 916IS PROMISES A LOT OF POWER FROM A SMALL PACKAGE. NICHOLAS HEATH FINDS OUT MORE.

Words Nicholas Heath | Images ROTAX

Rotax engines are one of the most important engine manufacturers in the recreational aviation category. So, when Rotax drop a new engine, we are always interested. But this time, it’s a bit different. The new Rotax 916is looks a lot like all the Rotax family – especially the 915is. It’s a familiar horizontally opposed, liquid/air cooled engine we have come to know and love. It’s recognisable by the coloured valve covers which, on this edition, are grey/white. Well, they might be. The art department at Rotax has made all the pictures and the video kind of washed out and blue. Very creative. Kind of gloomy, but creative. So, let’s go with grey.

So, why would Rotax build this? Well, the 160hp mark is right in the sweet spot for the IO-320 Lycoming and the continental equivalent. Interestingly, the new engine produces a peak power of 160hp against the 915is which produces 141hp from exactly the same capacity – 1352cc. The weight gain is just 3.6kg. I spoke to David Grigg, Manager at Bert Flood, local agents for Rotax in Australia, New Zealand, South East Asia, India and the Maldives.

He is very positive about the new engine. “It has greater power, plus the 916 has a 2,000 hour TBO.” He went on to explain, “It’s still 1352 cc. The extra power comes from engine management.” I asked how long that power was available for. He said, “160 hp, at 5800 for a maximum of 5 minutes, then 137hp continuous at 5500. It’s always been like that with the Rotax engines, max 5800 for 5 minutes then cruise all day at 5500.”

When asked what type of aircraft he saw it going in to, he suggested I give Ole Hartman a call – Chief Design Engineer of Australian Aircraft Kits based in Taree. The company designs and manufactures the Hornet STOL and is an approved Rotax Service Centre and RAA maintenance workshop. They are currently working on developing a new transport aircraft designed to fit category G (up to 760kg), which will serve as a bush/ utility aircraft.

The new aircraft is being designed to accept the new Rotax 916is engine, and the prototype is ready and waiting for this engine to be installed. According to Ole, the decision to use the 916is was based on its power/performance matrix, which is perfectly suited to the new airframe. Ole explained that he started with the engine specifications and designed and built the airframe around it, ensuring that the performance envelope and airframe requirements are matched correctly to create a well performing aircraft for this category. Spoken like a true engineer! I think we might have to circle back and have a look at this aircraft when Ole has it ready to fly.

What I think you’re getting in a 916is is really a souped up 915is, with a longer TBO. That extra 20-odd horsepower for very little extra weight will be just the thing to kick a STOL aircraft up and in to the air. Of course, it will have applications for high speed, economical cruising at altitude for almost any airframe suited to the 912/914/915 engine, while being a pretty viable alternative to the Lycoming and Continental engines with a significant weight advantage.