Rotax Popularity?

[NCPilot]

Why is the Rotax 912 so popular in the LSA world? I mean I could think of at least two aircraft engines that may weigh more than the Rotax, but are simpler in terms of design. You have the Continental O-200, which is an air cooled direct drive engine, The Jabiru 2200 & 3300, both of them also direct drive and air cooled. Then you have my personal favorite, the ULPower 260is, a fuel injection, direct drive, air cooled aircraft engine.

I do consider air cool and DD to be an advantage over the Rotax 912 because it's a simpler machine, it's easier to work on and it comes with less parts.

I made this rant because it seems like the only way to get a LSA without the Rotax 912 would be to build a kit, either that or find a way to replace the Rotax with an engine of your choice on an ATSM certified aircraft. I dunno if you can do that though.

Just a little rant of mine.

[roger lee]

I would love to talk about this and present facts and ideas, buttt

This question is so loaded it will get sharp responses towards whom ever answers one way or the other.
It is like talking politics and religion at the same time. There is no right or wrong answer and no matter who answers this they will be right in some eyes and an LSA saboteur in someone else's eyes. No matter how good the argument on either side there is no winner. To discuss this question will require tolerance and an open mind. This was discussed once before and neither of those traits prevailed through the thread. In the last thread about this there were way too many out of line verbal assaults. Read this forum under Light Sport Aircraft and Rotax Leading.

Chevy's and Ford's.
Most like one or the other, but they both get you there.

I have a preference like others, but my suggestion would be to get a piece of paper and do some good old fashion research. Research the web, ask the owners and take a class or two. You'll then know more than most here and will have all the answers without individual bias.

[drseti]

Why is the Rotax 912 so popular in the LSA world?

Several reasons. Forty years of history (OK, twenty for the 912) with proven reliability -- 2000 TBO, with many engines going far beyond that. Excellent parts availability worldwide. Reasonable price ($19,000 US, new in the crate, for a 912 ULS -- ever price a Lycoming?) Good availability in production quantities, off the shelf with little lead time -- that's important for a manufacturer who's cranking out hundreds of planes a year. Rigid adherence to Austrian quality workmanship standards (those folks are perfectionists!) Best power to weight ratio in the industry. Engines that run exceptionally cool, due to the combination of air cooled jugs, water cooled heads, and an excellent oil radiator design. Engine turning at optimum torque while prop turns at optimum thrust, thanks to gearing. Amazingly good documentation -- just take a look at their installation manual, operator's manual, light maintenance manual, heavy maintenance manual, and overhaul manual, all frequently updated, and all available for free as online PDFs. Much lower oil consumption than the industry-standard engines, due to the tighter tolerances facilitated by running the engine at very constant temperatures. Finally, a great training program so AMTs can learn the peculiarities of these engines. I've taken the Lycoming course, which was good, and last year two Rotax courses, which were better.

I mean I could think of at least two aircraft engines that may weigh more than the Rotax, but are simpler in terms of design. <snip>
I do consider air cool and DD to be an advantage over the Rotax 912 because it's a simpler machine, it's easier to work on and it comes with less parts.

Don't get me wrong; the Continental and Lycoming are indeed simple, easy to work on, and are reliable designs dating back 70 years. But they are heavy, and generally need a top overhaul halfway to TBO. Changing a jug in a Rotax is an extremely rare occurrence.

OK, it's true that with a Rotax you have to do a carb overhaul every 200 hours, and a gearbox teardown every 900 (or 600 if you're running leaded fuel). But, those costs are low, especially compared to replacing four jugs at $1000 each (plus labor) every 500 to 1000 hours.

build a kit, either that or find a way to replace the Rotax with an engine of your choice on an ATSM certified aircraft. I dunno if you can do that though.

For an S-LSA or E-LSA, an engine swap would nullify ASTM compliance, unless the manufacturer issues a Letter of Authorization. Considering the liability implications, I rather doubt that manufacturers will provide one. Even a kit plane must use the manufacturer's recommended aircraft, unless it's licensed as an E-AB (experimental, amateur built). But, if you want to use a Jabby, Continental, Subaru or whatever, that's always a viable option.

[roger lee]

Hi Paul,
I agree with everything you said.

Just these two small details.
Old engines that don't meet the new 2000 Hr TBO may get the 600 hr. gearbox inspection and or use 100LL more than 30% of the time. The ones that do meet the newer 2000 Hr TBO are 1000 hr gearbox inspections if you use unleaded auto fuel. A gearbox inspection is easy. If you use 100LL all the time then your slipper clutch most likely won't function correctly by 800 hrs unless it is cleaned because of the lead paste that builds up between the slipper plates. I see these from all over for inspections due to hours or prop strikes.
No where in the Rotax manual does it tell you to overhaul a carb based on time. The 200 hr. mark is an inspection only. I get carbs from all over the US to overhaul and some have never been touched for 10-15 years or 800-1200 hrs. I absolutely don't recommend this, but it is a testament to their reliability. It takes me 1 hour to rebuild both carbs top to bottom and replace all the parts, not just the "O" rings.
The inspection times are in the Line Maint. Manual in section 05-20-00 on pages 15 and 16 in the latest revision.

[NCPilot]

How hard is it to work on and maintain a Rotax compared to a Jabiru, Continental, or a ULPower engine?

[roger lee]

A simple answer to your question is the Rotax is no harder to work on than any other, it's just different. (It might be the Chevy or the Ford)

All engines have different items to address.
Any engine maint is easy if you know what's going on. That applies to any of the engines you listed. Having a little maintenance back round does help a little. No matter what engine you choose and anyone can learn to work on any engine. I would highly recommend that you attend one of the schools for that engine. Education is the key for everything in this industry. Your life will be much easier with a class or two behind you. Soon many items just become second nature. Kind of like learning to walk, we fall down a lot in the beginning, but then walking is second nature. When I first started learning the Rotax things were slow and I had to think things through. Now after years of time it is all second nature. The other piece of advice is no matter what engine you get and no matter if you get an SLSA or an ELSA do the required maint at the recommended time tables. In the long run it will save you money, time and possibly stop that cornfield landing. Some experimental pilots that try to skip maint until a problem arises (if it ain't broke, don't mess with it), well they are the same people that think bailing wire fixes everything.


I'm still not in this thread to promote one engine over the other, but believe that different engines work better in certain applications than others.

[jnmeade]

Some experimental pilots that try to skip maint until a problem arises (if it ain't broke, don't mess with it), well they are the same people that think bailing wire fixes everything.

I can't speak about experimental pilots, but know that there is quite a bit of discussion in the aviation maintenance field about doing maintenance based on time versus based on condition. One group says do something every XX hours; the other group says when the item is no longer in acceptable condition do something.

Mike Busch of AvWeb is a proponent of maintenance on condition. He cites WWII studies that showed that problems were more likely to occur after scheduled maintenance then later. Airline maintenance practices have included this philosophy of don't fix it if it ain't broke. Mike's Cessna 310 engines are double past TBO. He is an A&P.

Some mechanics want to work on TCM cylinders when the compression ratio is low. Others know that this is not the sole criterion. I ran my T210M lean of peak, an idea that is gaining advocates but some still disagree with. In other words, just because the old, old timers say do something one way doesn't mean we should not be receptive to alternate legal means of making repairs.

The objective in all cases should be to have a mechanically sound and dependable airplane that meets legal requirements. The debate will be on what it takes to make it mechanically sound and dependable. Spending money on schedule is not the only way and not necessarily the best way.

[slsaowner]

Anybody know what a Lycoming YO-233-B2A is? Tecnam is apparently going to offer this as an option in the Eaglet. The biggest drawback to a Rotax 912 (which I've owned for 5 years now) is that issue of maybe needing to find a Rotax-certified mechanic to work on it (I still haven't heard whether or not that issue has been resolved).

[7900]

I made this rant because it seems like the only way to get a LSA without the Rotax 912 would be to build a kit, either that or find a way to replace the Rotax with an engine of your choice on an ATSM certified aircraft. I dunno if you can do that though.

Help is on the way as four LSA manufacturers ( American Legend, Falcon, Tecnams's Eaglet, and Zenith's CH 750 ) just recently announced they're going to be installing Lycoming's new IO-233 LSA engine. It's reasonable to expect other manufacturers will follow assuming the engine performs well.

Lycoming says the engine will be certified by the end of the 3rd quarter of this year. It's about time, they've delayed it's introduction several times so hopefully the wait will be worth it.

I think the Rotax was one of the reasons why LSAs were so slow to catch on. LSAs have been out nearly seven years and yet at many airports you still can't get them serviced. IMO that was a big mistake and it kept me from buying anything with a Rotax. I just didn't want the extra hassle.

Lycomings can be serviced at virtually every airport and I hope the manufacturers wake up and at the very least offer buyers a choice in engines.

[roger lee]

This is the correct answer as you quoted it:

"I can't speak about experimental pilots, but know that there is quite a bit of discussion in the aviation maintenance field about doing maintenance based on time versus based on condition. One group says do something every XX hours; the other group says when the item is no longer in acceptable condition do something."

If you have an SLSA you have very few options, may be very specific and you must abide by the Maint. book setup by the aircraft MFG. which is not the same as some of the GA rules.
You do what your maint manual tells you for that aircraft or engine. You have times to abide by and you have condition of parts to abide by. You have owner types that are always on top of things and a head of the maint. (I like to fly with these guys.) Then you have the guys that use the bailing wire method and won't turn loose of a penny. (I won't even get in the plane or work on it) We all know people like this. Then there is everyone else, the average guy in the middle. The bottom line is to do the right thing. There are cheap, uneducated and lazy mechanics too. Getting the lowest priced mechanic may not always be in your best interest. There are a lot of "MIF's" out there. (mechanic induced failures)
Trying to skimp on maint. puts many out of airworthy and they don't even know it because they listened to the guy next door or an uneducated A&P tell them they didn't have to do it. The owner is the responsible party for knowing the regs and how they apply to there aircraft. That's the person the FAA will violate. Many have insurance and think they are covered, but once you get out of airworthy whether you know it or not then you might as well forget your insurance. If you fail to follow the maint. guidelines for that plane and practice due diligence then forget that insurance.

As far as Rotax mechanics there are many of them out there and many more joining those ranks all the time. Most people just don't know how to look for them. Look on the Rainbow Aviation and the Rotax Flying Safety Club websites. Then there is the new FAA ruling as to who can work on a Rotax which opened it up for more regular A&P's. They don't have to be trained by Rotax, but they still need training and the proper tools. No matter what engine you have you wouldn't want someone with now real training or experience to work on your engine.


To me this entire discussion is based on education for the plane you own, all the regs that affect you and not listening to the guy next door without doing your own research.

Cheap with the money, lack of time invested and lack of education don't make a good mix for any aircraft owner.

It's your life whether it's your plane or the other guys. If he is cheap on maint. do you really want to fly with them. Take a good look at all the aircraft accidents on the FAA website each year. There are way too many. If I fly with someone I want them on the top of the education curve for his aircraft maint and skills not on the bottom.

[zaitcev]

Then you have my personal favorite, the ULPower 260is, a fuel injection, direct drive, air cooled aircraft engine.

ULPower is an excellent design as far as characteristics are concerned, but its reliability is a big question. The redundancies were not designed in, but rather made an add-on. So, only the 2xECU/2xBat configuration protects from an internal short in the battery, for example. That costs money and weight.

[NCPilot]

Then you have my personal favorite, the ULPower 260is, a fuel injection, direct drive, air cooled aircraft engine.

ULPower is an excellent design as far as characteristics are concerned, but its reliability is a big question. The redundancies were not designed in, but rather made an add-on. So, only the 2xECU/2xBat configuration protects from an internal short in the battery, for example. That costs money and weight.

Hmm I didn't realize that about ULPower engines. Well TBH, the thing that won me over about ULPower is the EFI, I mean it's 2011, and aircraft engines are still running on Carburetors? C'mon, it's time for fuel injection on all new engines man!

[drseti]

there is the new FAA ruling as to who can work on a Rotax which opened it up for more regular A&P's.

For those not familiar with this particular controversy, a bit of background:

The LSA rule and ASTM standards say that it is up to the manufacturer to determine who can do what to whom. Rotax initially insisted that only Rotax factory-authorized and factory-trained mechanics could work on their engines used in LSAs. This was a company policy, not an FAR. The policy was challenged to the FAA, who ruled last autumn that, as far as the FARs were concerned, any A&P with proper skills and tools could legally work on the Rotax engines.

So, the question becomes: what are proper skills? They derive from proper training. The Rotax Service Specialty, Maintenance Specialty, and Heavy Maintenance Specialty courses taught by CA Power Systems, Lockwood Aviation, Leading Edge Airfoils, and others certainly impart the proper skills. Traditional A&P schools using Lycoming and Continental engines do not, because those engines don't typically use dry sumps, or gearboxes, or flywheel-mounted generators. Rotax engines are different from Lycomings and Continentals; this gives them both their advantages and some disadvantages. With proper training, any mechanic can learn their peculiarities. Those A&Ps not willing to invest $500 and one weekend on a Rotax course probably shouldn't be working on them, regardless of what the FAA says.

Next, consider tools. The Rotax engine requires some specialized ones, which can't be bought from NAPA or Snap-On or Harbor Freight. To work on these engines, even a well-equipped mechanic is going to have to invest about $5000 on those tools. Those who aren't willing to shouldn't be working on a Rotax, regardless of what the FAA says.

When I owned a Lycoming-powered aircraft, I paid the money to take the Lycoming course, bought the Lycoming tools, and tried to stay up on Lycoming documentation. Why should any mechanic expect to do otherwise with a Rotax? And, whether you like the Rotax engine or not, more and more of your potential customers are flying behind them -- so, it just makes good business sense to get trained, and equipped. But please don't think that just because you've been working on Continentals for half a century, you're safe to call yourself a Rotax mechanic.

[drseti]

Lycoming says the engine will be certified by the end of the 3rd quarter of this year. It's about time, they've delayed it's introduction several times so hopefully the wait will be worth it.

I'm sure the 233 is going to be a great engine. As it happens, I know the Lycoming folks well, live in Lycoming County, am retired from teaching at Lycoming College, and have owned a couple of Lycoming engines (but have no commercial affiliation with the company). So, I've talked to the engineers on this project. The IO-233 is a variant of Lycoming's ubiquitous O-235, which was used in Tomahawks, Skippers, and 152s, as well as quite a few Long-EZs and other homebuilts. I owned an O-235 in the 'seventies, and it was a lovely engine. This variant will have lighter weight accessories, fuel injection, and maybe a little more power than the original. They will still be on the heavy side of the LSA engine continuum, and at least one Lycoming engineer has told me he has concerns that more weight needs to be shaved off to make the engine viable in LSAs. Remember that in an LSA, the engine typically accounts for more than 25% of the empty weight.

What worries me mostly about the 233 is that certification process. Lycoming is going for Part 23 certification, which means the engine will be usable beyond the LSA community. This is good, because you need Part 23 certification to be IFR legal, for example. But FAA certification takes far longer than just demonstrating ASTM compliance, and costs more to achieve. Hence, the delays already cited. Let's just hope the engine becomes available, in production quantities, before the window of opportunity has passed.

[NCPilot]

Lycoming says the engine will be certified by the end of the 3rd quarter of this year. It's about time, they've delayed it's introduction several times so hopefully the wait will be worth it.

I'm sure the 233 is going to be a great engine. As it happens, I know the Lycoming folks well, live in Lycoming County, am retired from teaching at Lycoming College, and have owned a couple of Lycoming engines (but have no commercial affiliation with the company). So, I've talked to the engineers on this project. The IO-233 is a variant of Lycoming's ubiquitous O-235, which was used in Tomahawks, Skippers, and 152s, as well as quite a few Long-EZs and other homebuilts. I owned an O-235 in the 'seventies, and it was a lovely engine. This variant will have lighter weight accessories, fuel injection, and maybe a little more power than the original. They will still be on the heavy side of the LSA engine continuum, and at least one Lycoming engineer has told me he has concerns that more weight needs to be shaved off to make the engine viable in LSAs. Remember that in an LSA, the engine typically accounts for more than 25% of the empty weight.

What worries me mostly about the 233 is that certification process. Lycoming is going for Part 23 certification, which means the engine will be usable beyond the LSA community. This is good, because you need Part 23 certification to be IFR legal, for example. But FAA certification takes far longer than just demonstrating ASTM compliance, and costs more to achieve. Hence, the delays already cited. Let's just hope the engine becomes available, in production quantities, before the window of opportunity has passed.

Personally I think Lycoming should offer a certified IO-233 and a non-certified IO-233. Mainly because LSA is all about keeping the cost down, and a non-certified engine will be cheaper than a certified one.