Current horizontally opposed four cylinder aero engines originated from the Continental A40 of about 1930, which oddly enough as a 37 HP horizontally opposed air cooled flat four with a propeller flange was designed as an aero engine! There were flat twins before that, but their manufacturers didn’t survive. The design intent of the A40 engine was essentially the same as the Rotax 912, and it promoted development of light planes like the Cub.
Saying that horizontally opposed air cooled aero engines are derived from farm equipment is slightly less sensible, although even more false, than saying Rotax engines are manufactured by a North American company… as one of the UAV manufacturers selling to the U.S. government does in its PR material (Rotax in Austria has been owned and controlled by a Canadian company since the 1960s). Those companies selling UAVs with other engines say they don’t use snowmobile engines, spinning the same data in the opposite direction.
Most companies, Rotax included, tend to write their PR material in a self serving way. I heard the story of the V6 through an aircraft manufacturing industry connection years ago, specifically that it failed multiple times in taxi testing. Obviously Rotax is not going to issue statements that reflect badly on the company, regardless of what actually happened. Believe whatever you want. FWIW here is a (non-American ;-) link that discusses the engine. http://avcom.co.za/phpBB3/viewtopic.php?f=1&t=91261 If you find a photo of the Rotax V6 in flight it’d be nice to see it.
Silvaire wrote:
and probably also being connected to an airframe that needs less average power in training service.
That is quite true. I can run the O-200 in the Junior with reasonable performance below 20 liters Mogas, and the C90 in the SF23 will need its 22-23 liters, because the airframe is so draggy, that much power output is required. The C150 will use in a flight training scenario (i.e. long full power fractions) around 22-23 liters Mogas and the C150 with the Rotax is said to take around 20 liters.
Many 91X are used in microlights and thus the low power requirements. The original Cub ran on 40 horses, the SF25-B on 45, many small Jodels on 60 or 65 horses (while being a bit heavier than modern Microlights). The 100 horses are not needed for a decent cruise speed in these light airframes, especially when they aren’t that draggy as a Cub or Falke. Thus, operating the engine on 55% for normal cruise of course gives low fuel consumptions. Nothing wrong with that, just not the basis of an honest comparison of the engines.
Silvaire wrote:
I think if they’d succeeded in making Rotax V6 serviceable and brought it to the GA market, it would’ve been a very slow seller.
You just have to look at the Thielert installations. Retrofitting is almost never economical feasable, as long as he engine costs (with STC and changes) more than the whole airframe. And there is no performance increase. that goes with the complexity.
Silvaire maybe you want to ask your industry connection how come the Rotax V6 clocked thousands of hours in flight testing on two different airframes if it was “repeatedly failing during taxi”.
It’s been widely discussed and understood that the thousands of hours development testing were on the dyno, not in flight. The engine was then mounted on an airframe (there are photos of the installation on the net) but the engine apparently then failed in taxi testing multiple times.
Whether it made a flight is in question – I’d genuinely love to see a photo of that.
Which airframes? Do you have more infos on the flight tests @Shorrick_MK2 ?
I just found a single in flight photo in this 2007 Rotax-produced slide presentation… They state that the first flight was in 2002, but I’m not aware of any flights to shows such as Friedrichshafen over the next 4 years during which Rotax said development was still in process. Were there any such flights in public?
https://www.ffg.at/sites/default/files/rotax.ppt
(see slide 8)
It’d be great to see evidence of successful long term Rotax V6 flight testing.
From what I remember reading it was a pure business decision. BRP Canada wanted to focus on recreational engines for the recreational market, not certified engines as the V6 was going to be. A wise decision (business wise). The recreational market is blooming, the certified market is dead.
Read just now that that Austro is testing a 3 cylinder turbodiesel at 120 HP, the AE-200. It will compete head to head with this new Rotax. It also means Austro is entering the recreational market (maybe).
It’s sooo much obvious for me, that it always surprises me when this kind of Rotax vs Lyco/Conti ‘war’ starts in any forum.
I only would give an advice to anybody wanting to know which engine is better: own a Rotax and own a Lyco/Conti. Then, after 2 o 3 years at the latest, you would have it crystal-clear. Believe me!
I know it because I’ve done it. Almost 4000 Rotax hours (2 different engines) versus 300hr of IO-360 Conti, both as owner (renting is another history).
I do not want to own a Continental never again. Never ever.
I do not want to own a Continental never again. Never ever.
Any reasons or “Just because”?
