Why are Rotax engines limited to 150/160hp?

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MountainDude

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Rotax seems to be loved by a lot of people, even preferred over the Lycoming/Continental in many situations.
Why don't they produce engines up to 300 hp to compete with Lyc/Con? Is there something fundamentally limiting in their design?
It seems like there would be a huge market if they can make engines for Cessnas 172/177/180/182/185/210s, Bonanzas, etc.
 
The four cylinder Rotax is a point design with small cylinders, focused on relatively low horsepower applications, initially 80 HP. In order to expand to significantly higher power using the same approach, more cylinders would be required. A six cylinder version might work at say 180 HP, but a 300 HP engine is three or four times the power of the original Rotax concept. Rotax did try to develop a different, higher powered V6 engine but it was not a success, the project was canceled and it was never introduced to the market.

Along the same lines, Honda had a nice looking 180 HP prototype engine that they planned to market with Continental about 20 years ago. Given their wide range of engine development experience that seemed to me a potential winner but it never went anywhere either and Continental was instead sold off to the Chinese government. The commercial market isn’t there to fund new engines.
 
Tusayan said:
Honda had a nice looking 180 HP prototype engine that they planned to market with Continental about 20 years ago
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And don't forget the Porche and Toyota engines that made it through FAA certification. Toyota even built a TC eligible airplane around their engine and the Porche flew in Mooneys. Yet those projects all dropped due to no demand or market. However, Honda, Toyota, Hyundai, and others have re-entered the aviation side again to the tune of 100s millions. Unfortunately its not to give TCM or Lycoming or Rotax any new competition.
 
Rotax owns the 160 minus hp market.

Why burn the resources to compete with the established dominant players for a slice of their market when Rotax dominates its own segment?
 
GA isn’t exactly known for change. Just read some of the threads on PoA

There was a lot of negativity early on with comments like “lawnmower engines” and worse. Plus there is the gear reduction and folk piling on about other designs that used them. So, It’s taken them this long to establish credibility and I won’t be surprised to see them enter the higher horsepower market.
 
Rotax started and established a name with their 2-strokes (which despite 2-strokes bad reputation had a reliability close to 4-strokes when operated properly). Then they developed the 91x series, which are at least as reliable as a Lycosaur. I would expect they'll move into larger engines when they're ready. Remember, (radial engines aside) Continental started with the 37HP A-40 and gradually worked up into larger and larger engines.
 
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Dana said:
Rotax started and established a name with their 4-strokes (which despite 2-strokes bad reputation had a reliability close to 4-strokes when operated properly). Then they developed the 91x series, which are at least as reliable as a Lycosaur. I would expect they'll move into larger engines when they're ready. Remember, (radial engines aside) Continental started with the 37HP A-40 and gradually worked up into larger and larger engines.
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Agreed. I think they've been slowly inching their way up in HP/displacement. Right now they've got a really good foothold in the homebuilt/experimental market, and some of the LSAs. The sales volume for light, piston GA is where they currently reside, so it makes sense to have the product line they currently have. Trying to replace a 235-300HP Lyco/Conti would be designing an engine that hardly has any aircraft currently being sold. You'd pretty much be looking at Cirrus or C182 aircraft, and those probably aren't going to switch to a Rotax anyway (Cessna being owned by Textron/Lycoming especially). I do think they will eventually get up to a 180HP model that might be able to work for light-twins, but you're still looking at lots of STC costs for any retrofit on certified aircraft.
 
SoonerAviator said:
Agreed. I think they've been slowly inching their way up in HP/displacement. Right now they've got a really good foothold in the homebuilt/experimental market, and some of the LSAs. The sales volume for light, piston GA is where they currently reside, so it makes sense to have the product line they currently have. Trying to replace a 235-300HP Lyco/Conti would be designing an engine that hardly has any aircraft currently being sold. You'd pretty much be looking at Cirrus or C182 aircraft, and those probably aren't going to switch to a Rotax anyway (Cessna being owned by Textron/Lycoming especially). I do think they will eventually get up to a 180HP model that might be able to work for light-twins, but you're still looking at lots of STC costs for any retrofit on certified aircraft.
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This makes sense to me: the problem is that new planes are not being designed in the 230-300 HP range, and Rotax needs to be included in the design phase. Otherwise, getting an STC to install a Rotax in a C182 would be cost-prohibitive?
 
I think Rotax has been expanding its HP offerings at a steady clip, so I wouldn't be surprised if it continues right up to the 200 HP high-performance threshold.

But advances in airframe tech and modern design testing mean you can get a lot more speed and useful load from lower HP engines. And the new MOSAIC rules will incentivize Rotax and AC manufacturers to collaborate on more capable LSA that will greatly improve the current (mostly artificial) limits on speed and gross weight.
 
It would need to be a clean sheet engine to get into higher HP. The reduction unit might be the biggest issue. I suspect they have something under development but it’s probably 10 years away.
 
Jeff767 said:
It would need to be a clean sheet engine to get into higher HP. The reduction unit might be the biggest issue. I suspect they have something under development but it’s probably 10 years away.
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Why does it need to be "clean sheet"? If the current turbo 4-banger arrangement is working well for them, I'd guess they would just expand to a 6-cylinder variant on the same architecture. I mean, sure, it's a new block, but not sure that it needs to be full-on starting from the drawing board. They'll just need more cylinders to make more power (and a gearbox capable of that additional power). Weight and physical dimensions are probably the main constraints, but Rotax generally does well on HP/weight compared to their old-school counterparts.
 
Bell206 said:
And don't forget the Porche and Toyota engines that made it through FAA certification. Toyota even built a TC eligible airplane around their engine and the Porche flew in Mooneys. Yet those projects all dropped due to no demand or market. However, Honda, Toyota, Hyundai, and others have re-entered the aviation side again to the tune of 100s millions. Unfortunately its not to give TCM or Lycoming or Rotax any new competition.
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FYI, it was not lack of demand, but lack of continued interest by Porsche in the Porsche Mooney. It needed some more development and a bit more power, but Porsche was not interested.
 
Dana said:
Rotax started and established a name with their 4-strokes (which despite 2-strokes bad reputation had a reliability close to 4-strokes when operated properly).
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I'm going to disagree with this. Rotax has been in other off-road engine categories for a very long time, and their big hitters were originally 2-stroke engines in motorcycles and snowmobiles, followed by go-karts. Their first aircraft engine was, in fact, a 2-stroke (the 642). 4-strokes generally and aircraft specifically are new-comers to the Rotax brand.

History of motor sport

100jahre.rotax.com 100jahre.rotax.com
100jahre.rotax.com

Type 642

Aircraft engine
100jahre.rotax.com 100jahre.rotax.com
 
StraightnLevel said:
I'm going to disagree with this. Rotax has been in other off-road engine categories for a very long time, and their big hitters were originally 2-stroke engines in motorcycles and snowmobiles, followed by go-karts. Their first aircraft engine was, in fact, a 2-stroke (the 642). 4-strokes generally and aircraft specifically are new-comers to the Rotax brand.

History of motor sport

100jahre.rotax.com 100jahre.rotax.com
100jahre.rotax.com

Type 642

Aircraft engine
100jahre.rotax.com 100jahre.rotax.com
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Sorry, typo... I meant to say, "Rotax established a name with their 2-strokes..."
 
This thread is much too sensible. I blame aliens. :devil:
 
UL power has a 200hp engine. I don’t see it threatening Rotax is terms of market share or sales. Doesn't seem like they have much pressure to keep going up another few hp.
 
Rotax is mostly an E/AB engine. If any certificated airplanes use it, its gotta have production numbers in the low double digits, as I can't think of one that does. Most E/ABs are designed to not need 200hp+ engines. Also Rotax motors are geared... possibly the weight or bad harmonics limits the 4 cylinder platform?
 
Rotax began developing a 300 HP version but shelved it years ago.

The 300hp experimental market is pretty small. On the certified side of things it's only slightly bigger. If it was available I'd imagine it be lighter than an io540 and might be an intriguing STC for nose heavy pa32's

www.aviationconsumer.com

The Big Engine That Didn't - Aviation Consumer

At Lycoming, executives roll their eyes when they hear Lycosaurus used to describe the lack of innovation in aircraft power plants. That suggests that the market hungers for engine innovation, but the reality is something different, as Rotax discovered in 2006.ü
www.aviationconsumer.com www.aviationconsumer.com
 
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pfarber said:
Rotax is mostly an E/AB engine. If any certificated airplanes use it, its gotta have production numbers in the low double digits, as I can't think of one that does. Most E/ABs are designed to not need 200hp+ engines.
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Historically, yes, but most new SLSA aircraft seem to be using Rotax engines nowadays. There are also a fair number of military drone applications.

The EAB market is a great way for a manufacturer to test the waters and do external beta testing. Rotax figured that out long ago, as has Garmin and other avionics manufacturers.
 
Dana said:
Historically, yes, but most new SLSA aircraft seem to be using Rotax engines nowadays.
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My January 2024 FAA registration database shows that Rotax/Bombardier engines are installed in about 12,600 aircraft...that's about 4% of the fleet. This will include the two-stroke engines as well as the more modern 912/914 series. 228 have Standard airworthiness (not EAB, not Light Sport).

In contrast, there are about 86,500 aircraft listed as having Continental engines...about 29%. Of course, this includes aircraft built almost 100 years ago and includes those produced in the "spike" in GA production after WWII.

If we count only the Continental-powered aircraft built since, say, 1990, there are only ~11,200 examples. Counting Rotax-powered aircraft built since 1990, the total is about 10,700. Roughly the same.

In the Lycoming world, there are a bit more of them than Continentals, ~96,500 (32% of the total). About 25,700 of them are on aircraft manufactured since 1990.

Ron Wanttaja
 
Bell206 said:
And don't forget the Porche and Toyota engines that made it through FAA certification. Toyota even built a TC eligible airplane around their engine and the Porche flew in Mooneys. Yet those projects all dropped due to no demand or market. However, Honda, Toyota, Hyundai, and others have re-entered the aviation side again to the tune of 100s millions. Unfortunately its not to give TCM or Lycoming or Rotax any new competition.
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Maybe Textron's new piston jets would be able to use these :)
 
What I'd love to see is a cost effective FADEC capable turbine in the 150-300 hp range. THAT would be a nice advancement. Get a small turbine down to the cost of a new Lyco / Conti I guarantee the STCs would start popping up to retrofit the legacy fleet. Since 99.99999999999999999999999999% of people learning to fly today only care about their "1500 hrs bro, airlines are hiring! There's a $900,000K sign on bonus blah blah blah" getting started in a turbine environment from day 1 would be a shoe in

Diesel might have a chance.. you see them in some Euro and Piper fleets, and Diamond.

Hell, the Piper Lance already has the cowl for it!
 
Pinecone said:
FYI, it was not lack of demand, but lack of continued interest by Porsche in the Porsche Mooney. It needed some more development and a bit more power, but Porsche was not interested.
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Interesting. I had heard it was the lack of market acceptance by other OEMs as it was installed/prototyped in about a dozen aircraft types. And when they were approached to use it in the mid-90s they declined and stated the financials didn't work out which led Porsche to surrender the TC back to the FAA. Too bad they didn't just sell it to someone.
 
The problem with the Porsche engine was that it was heavy, heavy enough to require a longer fuselage on the Mooney, and despite being smooth and easy to operate offered lower installed performance than the Lycoming. As a result it failed in the marketplace, embarrassing Porsche and damaging their unearned sense of superiority, who then decided to forget about the whole thing. The then-president of Porsche was quoted as saying “maybe aircraft engines really are just industrial engines,” trying and failing to be Germanically snide - because what he said was actually correct and he just made himself look uninformed. Aircraft engine are near constant speed industrial engines that benefit from field serviceability (unlike a Porsche car you can’t haul them behind a tow truck to the dealer) and even more so from simplicity and the light weight that comes with it.

I think the V6 Rotax was lining itself up for the same reception but they were smart enough to pull the plug on it before offering it for sale. They’d do better by adding two cylinders to the 912 but I suspect if they were ever going to do that in the last 35 years they would already have done it.
 
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I really like the direction (half-step?) they took with the 916is:
Basically a bit more boost over a 915, time-limited but it’s enough to give a little extra for takeoff roll and initial climb, which is where you really need it anyway.
 
A probably bigger untapped market for Rotax would be to fund/develop STC's to get their current engines into the training fleet. Tons of C150/152 out there for starters. Get the engineering to make dropping the lighter and more fuel efficient Rotax into the existing spam cans approved and suddenly the 150/152 gains useful load by both the lighter engine and the fact that less fuel is needed for the mission.

Sure it wouldn't be a cheap development, but I bet it's a lot cheaper than what would end up being a clean sheet design to go 200+hp.
 
Rotax - powered Cessna 150
rotax-cessna.com

ROTAX CESSNA

rotax-cessna.com rotax-cessna.com

Rotax-powered Diamond DA20

Has been discussed for the Liberty XK2 as well

The Rotax 916iS might be a good retrofit for the PA28-161, but the financial numbers will probably not work out. Somewhere in the ballpark of 60k for the engine plus prop, engine mount, perhaps some mods to the cowling and STC .... At the end of the day I guess we are looking at 100k.
 
Todd82 said:
A probably bigger untapped market for Rotax would be to fund/develop STC's to get their current engines into the training fleet. Tons of C150/152 out there for starters. Get the engineering to make dropping the lighter and more fuel efficient Rotax into the existing spam cans approved and suddenly the 150/152 gains useful load by both the lighter engine and the fact that less fuel is needed for the mission.

Sure it wouldn't be a cheap development, but I bet it's a lot cheaper than what would end up being a clean sheet design to go 200+hp.
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As cool as that sounds, I think the economics will never work-out to install new engines in old airframes.Especially an aging fleet like the 150/152's, where the main driver is low-cost.

_unless_ they (magically) somehow make it cost-competitive with what an Engine Rebuild would cost, then private individuals and flight-school owners could make the justification to switch engines instead of a rebuild.

(edit to add: AggiePack's post above happened at the same time, yeah what he said: the prices just don't make sense)

Rotax - powered Cessna 150
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Why the heck does this have a CS prop? thats just silly, the whole point of a 150/152's (in utilization I've seen) is to be low-cost.
 
Todd82 said:
A probably bigger untapped market for Rotax would be to fund/develop STC's to get their current engines into the training fleet.
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Or you could try from the other end and procure a used 150 and Rotax, replace the O-200 with the Rotax, sell the O-200 for some cash to alter the cowling, switch the AWC to Experimental Exhibition, fly and develop some data, then call up Rotax and see if they're interested in funding you toward an STC? Or just stop there, develop and sell some 150/Rotax E/E kits and make a few bucks while you enjoy your Rotax powered 150. The side benefit is you could now work on your aircraft provided your mechanic will sign-off a condition inspection every year.
 
Bell206 said:
Or you could try from the other end and procure a used 150 and Rotax, replace the O-200 with the Rotax, sell the O-200 for some cash to alter the cowling, switch the AWC to Experimental Exhibition, fly and develop some data, then call up Rotax and see if they're interested in funding you toward an STC? Or just stop there, develop and sell some 150/Rotax E/E kits and make a few bucks while you enjoy your Rotax powered 150. The side benefit is you could now work on your aircraft provided your mechanic will sign-off a condition inspection every year.
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I didn't stay at a Holiday Inn Express last night so that's a bit beyond my skillset.
 
ChopAndDrop said:
Why the heck does this have a CS prop? thats just silly, the whole point of a 150/152's (in utilization I've seen) is to be low-cost
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Likely because it didn’t climb well without one. In addition to peak power, which is all you need to worry about with a CS prop, with a FP prop an engine needs to have a relatively flat spread of power to reduced RPM to allow good climb for a heavy plane. That characteristic tends to be associated with larger displacement, lower RPM engines although I’ve never seen data comparing the HP versus RPM curve of a 100 HP Rotax 912 and an O-200 Continental.

The French company that developed the conversion didn’t sell a significant number and sold to STC to a Scandinavian company that wanted to reinvigorate the idea but didn’t do so.
 
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aggiepack said:
Rotax - powered Cessna 150
rotax-cessna.com

ROTAX CESSNA

rotax-cessna.com rotax-cessna.com

Rotax-powered Diamond DA20

Has been discussed for the Liberty XK2 as well

The Rotax 916iS might be a good retrofit for the PA28-161, but the financial numbers will probably not work out. Somewhere in the ballpark of 60k for the engine plus prop, engine mount, perhaps some mods to the cowling and STC .... At the end of the day I guess we are looking at 100k.
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2000 hr TBO, 100 hr oil changes... that has to add up for $omething
 
Todd82 said:
A probably bigger untapped market for Rotax would be to fund/develop STC's to get their current engines into the training fleet. Tons of C150/152 out there for starters. Get the engineering to make dropping the lighter and more fuel efficient Rotax into the existing spam cans approved and suddenly the 150/152 gains useful load by both the lighter engine and the fact that less fuel is needed for the mission.

Sure it wouldn't be a cheap development, but I bet it's a lot cheaper than what would end up being a clean sheet design to go 200+hp.
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But who is going to do the spin testing?
 
I’m a Rotax owner and believer. The 914 I have is brilliant motor. It makes crazy power for its size/weight and flies beautifully well into the teens. I’m 1/4 of the way to my 2k hour TBO and not a single problem. While they are’cheaoer’, they aren’t cheap. At TBO I’m looking at $42k all-in.

I think FancyG nailed it. They’re absolutely crushing in the market share they command right now.
 
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