Cessna 150 Rotax Conversion

SkyDog58 said:
I knew that there wasn’t a large number of them flying but I would have thought there’d be more than that. However I have a strong tendency to believe you and your numbers so my assumption on their numbers is very likely wrong.
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I appreciate that. My "94" number is right from the FAA registry database, anyone can verify that.

The problem is with those 4,000 homebuilts that don't identify the engine. There are folks who will claim that the vast majority of those are auto engines. No way to prove or disprove that, of course. I've got my own process, which I've described a couple of times earlier in this thread.

One thing I like to do is look take another approach to issues. My January 2019 FAA registry shows 498 EAB aircraft with Continental A65 engines. My 1998-2017 accident database shows 40 accidents occurring to EAB with this engine. That's about eight percent.

The same database shows 18 Honda accidents. If we assume the same reliability, it should probably see the same ratio. 18/0.8= 225 aircraft. Not that far off the 154 that I compute (94 that we know of plus the 60 that I estimated).

However, that assumes that the Honda and the A65 have the same failure rates. My overall analysis of auto engine conversion vs. traditional engines is that the auto engines fail almost twice as often. So I think my 154 estimate is probably pretty good, if not a bit high.

Ron Wanttaja
 
Ok. Reeling in thread drift a little bit.

Other than the Rotax conversion, does anyone have opinions or info about converting a regular C150 to a 150 hp 150/150? Can all models get the conversion? Is there a gross weight increase?
 
Matthew Rogers said:
Ok. Reeling in thread drift a little bit.

Other than the Rotax conversion, does anyone have opinions or info about converting a regular C150 to a 150 hp 150/150? Can all models get the conversion? Is there a gross weight increase?
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The 150/150 I am familiar with does not have an increased gross weight. It has a 400 pound useful load. With full fuel, you have 244 lbs tp play with. Of course, no one said you have to fill the tanks.
 
My 80hp uncertified roatax 912 has done 4800 on nothing more than routine maintenance.

As for my experience with the O-200 it isn't that good. My last 4 haven't met TBO.
 
How do Rotax engines do on aerobatic ships? Do they hold up ok with the g-forces and rapid power changes, etc? Are there inverted oil systems available?
 
C-1 PILOT said:
Looking back on this thread, it appears you are the only one, well and the Capt. that have negative opinions on Rotax engines. It’s also evident that The majority responding, me included, couldn’t care less and are happy flying behind a Rotax. To each, his or her own. It’s ok to agree to disagree. The Rotax series of engines, like their legacy counterparts, will
never please everyone, but they are solid power plants, and they continue to develop at a faster pace than Lycoming or Continental.
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Well put.

I think the most important thing is that each pilot make his very own decision about the engine(s) (s)he flies behind. I wouldn’t want to influence someone to decide on an engine type or whether or not to fly behind a particular engine in less than perfect mechanical condition. If something were to happen to them, I sure wouldn’t want to wonder if my influence was responsible for their mishap. Such decisions are serious and each person must decide for themselves based on the criteria they choose for themselves.

My $0.02
 
ilpilot said:
How do Rotax engines do on aerobatic ships? Do they hold up ok with the g-forces and rapid power changes, etc? Are there inverted oil systems available?
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No inverted systems that I am aware of. The oil system is somewhat quirky and personally I would not recommend a rotax for aerobatic operation. For everything else they're just fine.
 
This post is quite old , but I have been thinking about this subject for some time , rather than using a 912 the newer 145hp 915 with an MT variable pitch prop would get even better performance than a 150/150 without the weight penalty and fuel burn that have always been the downside of a high performance 150 ...
 
Good old certification issues. Can’t do anything else other than the exact STC. But I agree with you. 3-9 gallons per hour and full power to 15,000’.
 
Can a 150 or 152 airframe handle the stress of 145 hp? Also - with that extra HP one could drop the CS prop? Keep things simple.
 
The Cessna 150 already has a 150hp STC conversion, with a heavier conventional engine, so yes it can obviously handle the stress.

A 140 HP turbo engine with long range tanks wound make a very sweet plane. You can dial the power back to 3.8 gal/hour or full power takeoffs up to 15,000’.

But not much different than many of the current experimental STOL options.
 
Didn’t know that. Thanks!
 
My experience with 912s has been good. If there was a STC to put one on my Luscombe when the A65 expires, I would SO love to try that.
 
RyanShort1 said:
My experience with 912s has been good. If there was a STC to put one on my Luscombe when the A65 expires, I would SO love to try that.
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I believe a guy in Brazil has done it, but not as a certified conversion. The 912 with a fixed pitch prop would probably work OK given that the Luscombe was originally flown with 50 HP, but perhaps not as well as a C90 with its broad power band maintaining power in a reduced RPM climb. There is a reason why the 912 needs a CS prop when mounted on a C150.
 
Kevin Beriault said:
but I have been thinking about this subject for some time , rather than using a 912 the newer 145hp 915 with an MT variable pitch prop
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FYI: depending how serious you are, you do have a path to put a Rotax on a 150 without buying an STC. You could work toward obtaining a One-Only STC for a specific S/N aircraft. It's cheaper than a standard STC process and in some cases streamlined more like the field-approval process. At a minimum you could work out the Rotax install and get a Special AWC Experimental Research and Development and fly it before pursuing the STC. Know of several One-Only STCs used for engine swaps to include one owner who pursued a One-Only STC to re-engine a WACO even though there was an existing STC for the same engine swap.
 
So many opinions on Rotax, without any experience on them.

I've taught at many schools and flown 95 models so far. A thousand hours behind Rotax.

In my experience, these engines are far quieter, more reliable, longer lasting. The fuel and maintenance savings alone are enough to pay for the entire airplane in in 2 to 3 years in a flight school environment. The weight savings in a 150 or 152 would directly relate to climb rate.

The sling with the fuel injected 912 that I fly almost every day right now, out of a field that is almost 5000 msl, climbs at a very steep climbing which feels so much safer to me than flying behind a worn out Lycoming and only being at treetop level after 6,000 of runway.

I much prefer the 912is injected. My normal fuel burn is 3.2gph of mogas. Before Biden, that was $10/hr vs $40/hr in my Cherokee-180.

The designers of the Sling flew one with two guys and extra fuel tanks around the entire world. Sounds pretty reliable. We have a crazy 12hr endurance at normal cruise.
 
I have about 600 hours behind Rotax - the carbureted version.
Love the engine , in fact when looking for my next plane to be, if it is not Rotax 915/16 , it is not happening.
 
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N1120A said:
Also, the Rotax is substantially smaller in displacement to make the same power, which will increase efficiency.
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The opposite is more often true. Making the same power with less displacement requires higher RPM. Friction losses associated with higher RPM tend to reduce efficiency. The highest efficiency reciprocating engines (huge marine engines) run at very low RPM specifically because it enhances efficiency.

Brake-specific fuel consumption - Wikipedia

en.m.wikipedia.org en.m.wikipedia.org
 
I've got more than 250 hrs behind the Rotax 912. It's a rock solid engine.
"Burping" the engine can be a pain, especially in cold weather, BUT, if you do it after you fly, it's 2 or 3 flips and you are done.
The 5 year "rubber" change is an expense, but not as bad as some of the things some of you are paying for right now. The "ever broken" retracts on the 177 RG comes to mind. (2 hangers down from mine).
If I could swap out my C-85 for a 912is, I'd gain fuel injection, 15 hp, lose enough weight to add a starter battery, a wing tank, nearly double my range, gain more than 200 hrs on my TBO, and still meet the 1150 lb MGTW for the PA-17. My A/P and I did the math.

Oh yeah. You can actually get parts for a Rotax. As some of us know, parts for the Contis and Lycs are getting sparse.
 
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