Here are some excerpts from the article:
“As the propeller blades dissolved into a shimmering blur, the exhaust sounded a pleasingly crisp bark of power. Flying is a visceral experience − the sight, feel and even the smell of an aircraft all combine to make aviation the immersive experience that it is, and sound plays an important part too.
I’ve always admired the Rotax 912 series: its undoubted efficiency, excellent reliability and good power-to-weight ratio have ensured that it has been for many years the undisputed world champion of ultralight engines. However, while low noise is one of its virtues, the sound it puts out has never really appealed. In contrast, the eager growl of the ULPower 350iS tucked under the latest Zodiac’s cowling definitely grabs one’s attention. And of course, the fact that this engine produces thirty per cent more power than a 912S is no bad thing either!
The impressive exhaust note hadn’t come as a total surprise. Even from the other side of the taxiway, I could clearly see that ‘Four Zulu Zulu’ was very different from any other Zodiac that I’d flown. Not only did it seem slightly taller, but the bulged cheeks of the cowling hinted that a more powerful engine lurked within. I’ve always been a firm believer in the old maxim “never fly a new type of engine in a new type of airframe” and, as the ULPower 350iS is one of the newest engines in the GA market, I was pleased to see it was housed in a fully developed light sport aircraft (LSA) with real pedigree; the Zenith Zodiac.” [...]
“As you’d imagine, the type has evolved considerably over the last 28 years and there are a significant number of differences between an early 601 and the current 650B; the most significant one being the engine, so let’s start at the spinner.
As mentioned earlier, the original aircraft was powered by a 116hp Lycoming O-235 and over the years probably a dozen different engine types have been tried, with different cylinder configurations, drive arrangements and cooling systems. With the ULPower engine the wheel has (sort of) turned full circle, as − just like the O-235 − it is a direct-drive, air-cooled flat-four.
However, that’s where the similarities end. The 350iS is more powerful, yet smaller and lighter. It has electronically controlled multi-point fuel injection and ignition, as a 21st Century engine should. It is quite tightly cowled and, as there is only a small hatch for access to the oil dipstick, a more detailed pre-flight inspection requires the cowling to be removed, although this didn’t appear to be too onerous. It is fed from an integral welded aluminium fuel tank in each wing, with a combined capacity of 91 litres, and turns a two-blade, ground-adjustable Whirlwind prop.” [...]
“Once again, I really liked the great rate of climb provided by the 130hp engine, and I think instructors will too. No more wheezing slowly up to altitude as if you’re riding an asthmatic albatross, this thing climbs like it means it!” [...]
“At 5,000ft and 2,800rpm the 650’s TAS is around 126kt, but the motor is burning about 28lit/hr. A more comfortable rpm is 2,500, which gives a TAS of approximately 110kt, while the fuel flow drops to a much more respectable 19lit/hr. With full tanks, this makes the still-air range 450nm, with at least 30 minutes reserve.”
Nice comments after all! You can read the full article here.