The Rotax 912 has been fitted to the Cessna 150, by a French company under an STC. The problem technically in that application is that the smaller displacement engine needs a variable pitch propeller to do the same job as an O-200. […] I think a new training market engine (and airframe) would be a fine thing. I suspect the best overall design would have a similar displacement and rpm to the O-200, but be improved in detail design..
And yet the Cessna LSA which used both the #1 brand name in the industry and the superb O-200 engine instead of the troublesome Rotax was the biggest failure in a very long time.
BTW: the Rotax powered Cessna 150 is a fine training aircraft, it’s the most frequently flying aircraft at my airfield. Also much quieter and problem free.
The o-200 is not a superb engine financially. The o-235 is better. I can get 2880 hours out of a 235. Yet only 2160 out of an o-200.
Also I can count 0.1 taxing out and 0.1 taxying in. So for an hours flying lesson it only 0.8 of the Hobbs.
Rotax wise it 2000 hours and the hours count from the moment the engine starts. So in the real world u get something like a 1000 more hours out of a 235 than a 912.
I have to say I liked the look of the rotax c150. But its 65000 euro conversion and the running costs are no cheaper than an o235.
It so simply doesn’t make financial sense and toa flying school that’s all that matters.
The only new aeroplane that the numbers actually work on is the c42 hence the large uptake of them.
Both Continental and Lycoming have since long had their own “LSA” powerplants. Lighter weight and semi-modified versions of their 100+ HP engines. Maybe they have sold a couple each. Even though they are good and practical powerplants, they cannot even start to compete with Rotax, Jabiru and ULPower, and D-motor is also coming fast. People want Jabiru for the price, light weight and the 6 cylinders (3300). They want ULPower for the FADEC and excellent quality and power. But most of all, they want Rotax 912 because it has proven itself to be the most reliable and easy going aircraft engine throughout the entire history of piston aircraft engines.
The only reason to chose Lycoming/Continental is nostalgia. Nothing wrong with that, but in a time of carbon fiber and glass cockpits, people also want an engine with the same level of “tech”.
A Rotax 912 is very similar to an electric car. You can find all kinds of reasons why it is a poor choice. It is complex, it is watercooled, it has a propeller speed reduction unit, it has an external oil tank and so on. Hence it must be unreliable and unpractical, if not downright dangerous. The reality is, once you have some experience with it, you just can’t help wondering what Lyc/Cont have done wrong all these years.
The point is, the Rotax 912 is like it is because it is the technological answer to a very specific question. The question is: How to make a reliable and configurable 80-120 HP powerplant that can be used to power every conceivable light airframe.
The only reason to chose Lycoming/Continental is nostalgia
I would add another reason, perhaps applicable much more in the USA: the ability to get it overhauled/repaired easily.
In Europe, the engine shop scene is dire (probably why Thielert etc prefer to get their engines back to the factory for anything beyond changing the oil… do they know “something”? – you bet! 
) but the USA is very different and an O-200 is a pretty bulletproof motor which gives you loads of options for when it needs looking at in the field.
And we all know that in GA one of the big objectives is not ending up bent over a barrel, because that leads to the same result every time 
you just can’t help wondering what Lyc/Cont have done wrong all these years
You may be forgetting this
In Europe, the engine shop scene is dire (probably why Thielert etc prefer to get their engines back to the factory for anything beyond changing the oil… do they know “something”? – you bet! ) but the USA is very different
Then we would see more in-flight engine shutdowns in Europe. However, we don’t see those so I don’t agree with your statement. There is no difference between aero engine reliability in the US and Europe.
I agree; I was referring to the ease of in-field servicing.
In the USA you have a big choice of engine shops.
Here the choice is much smaller. In the UK for example, there is just one shop on which due diligence comes up positive (Nicholson McLaren).
From the POV of a US based operator, Rotax (etc) engines are an uphill battle. They also earned a bad name in years past and US consumers don’t easily forget that sort of thing, especially in the ultra conservative US GA market.
From the POV of a US based operator, Rotax (etc) engines are an uphill battle. They also earned a bad name in years past and US consumers don’t easily forget that sort of thing, especially in the ultra conservative US GA market.
Maybe 80-90% of all US LSA are powered by Rotax. Besides, the US GA market is increasingly going Experimental, and this market is all kinds of things, but certainly not conservative. EI has since long been the standard for experimental aircraft for instance, on Lycomings and clones. For the 120+ HP there have never been any real alternatives until now. The 130 HP ULPower 350iS is very popular there for instance.
LeSving, I think you’ll find that the most popular LSAs in the US market are the Cub replicas… Which I suppose do sell partially because they are pleasantly evocative of an earlier time, and also because they have the best performance for ‘off field’ type flying. That has proved to be the best practical purpose for new factory built LSA category aircraft in the US market. Rotax powered LSAs are not common, on my field of IIRC 700 based aircraft I can think of five with 912 Rotaxes, one of which is a twin, so six engines.
I have never seen a UL power engine in the field, but I hope to some day. They have made no dent in the market as yet. If they prove to be good engines over the next 10 or 15 years, perhaps some popular airframe designs will be designed around them and substantial support will be available. That is the existing situation for Lycomings. The idea that larger over 100 HP engines from Lycoming more generally sell on the basis of nostalgia would be false, and I think hopelessly naive. They sell because they continue to be pretty good engines, they have enough power for the job, and because the most active sectors of GA use them, notably RVs in today’s world. People love those aircraft for what they do in terms of performance, for how practical they are, and for the relatively low price for which they do it. Engines like the O-360 Lycoming are a substantial part of that capability, obviously, and more to the point in the real non-fantasy market there is nothing else that has so far been able to compete.
LeSving, I think you’ll find that the most popular LSAs in the US market are the Cub replicas…
That’s a nice, and I guess “politically correct” assumption, in an old-school US-centric nostalgic manner, but it’s not correct
Here are some statistics
What I find surprising, is the number of Skycatchers, but I knew there were some of Cubs around (only about 17-18% though). Otherwise Rotax rules, with well above 50% share. Also surprising is the number one, the CTSW from Flight Design. Anyway, the statistics is not complete. It does not count the RV-12 for instance. More than 350 of those have been reported flying, and they use the Rotax 912. The same goes for the majority of Zenairs.
The most popular LSA in the US market, is sheared between Flight Design CT and Vans RV-12, and they both use the Rotax 912.
Just for the record, I love flying the Cub, that is what I fly the most.
They sell because they continue to be pretty good engines, they have enough power for the job, and because the most active sectors of GA use them, notably RVs in today’s world.
Most of them are not Lycomings, they are clones. There may be little, or no practical difference for the pilot/owner, but for Lycoming this is a slow but certain death. Anyone with a minimum of modern machine equipment and some know how can make a Lycoming clone, and by the looks of it “anyone” does, and they do it better than Lycoming. The “Lycoming” may live on forever I guess, because of this situation. But that does not make it a good engine in modern terms. A modern engine runs for 2000h, at least, with absolutely nothing happening to it. The same goes for the VW Beetle engine. It was first made 70-80? years ago, and is still going strong both in the air and on the ground (although as an engine in the car industry, it has been dead for decades).
LeSving, thanks for looking up the LSA statistics – I was mentally adding up Cub Crafters and Legend Cub as being one aircraft type (464 units combined) but you’re absolutely correct that if you consider them as different types the Flight Design is higher than either at 359 since the inception of LSA sales. We have one Flight Design aircraft at our field of 700 planes, one factory built RV12 and two LSA Cub replicas – I don’t know which types those are. The big user of Rotax engines is an Air Cam, with two of them. I think the thing to bear in mind is that the entire factory built LSA thing in the US is barely noticeable in the grand scheme of GA activity.
There used to be (and maybe still is) a Tecnam P96 on the field that didn’t fly. I tried to buy it but the owner wasn’t interested in selling at any reasonable price. He had several other planes and I think the P96 served mainly as an insurance policy against the potential loss of his medical.
Re Lycoming clones. I know of (says he counting mentally) about 12-15 Vans aircraft in the immediate hangar complex where I’m based (I don’t know how many in total on the field). All of the ones I know and can recall started life as factory Lycoming engines but many of those have PMA parts, and a lot of them were built by the owners into experimentally configured engines. Perhaps half of the total were bought new from Lycoming. The ‘entirely experimental from Day 1 Lycoming Clones’ don’t seem to be so popular by my observation, but I’m sure they sell some. Engine support is in any case provided by a web of OEM, PMA and used parts, and there are a lot of companies involved.
Someday when you want to go flying, come visit There is not one cloud visible though my window as I write.
PS It seems like every time I drive to the field a Sky Catcher is on the upwind, but there is only one based locally as far as I know. It must be a local flight school or club aircraft.
