Engine choice

[Tom Downey]

when the kit requires a 100 horse power engine would you rather a Rotec, or a 0-200? /IO-240?

Sell ability is the issue.

[hydroguy2]

what airframe? some times those radials just look like they belong

[D.grimm]

Tom,I would think 0-200. Cost, available engine parts, prop availability,maintenance availability. Looks would go to the Radial!Dave

[Chris In Marshfield]

Rotec or Rotax? Rotax 912ULS is in the same class as the O-200/IO-240. Rotec is a different animal. She's a radial.

Rotax
http://www.flyrotax.com/engines/product-range/carburator/912-100hp/description.aspx

R (http://www.flyrotax.com/engines/product-range/carburator/912-100hp/description.aspx)otec
http://www.rotecradialengines.com/0RotecR2800/R2800.htm

T (http://www.rotecradialengines.com/0RotecR2800/R2800.htm)hat being said, I don't think you could go wrong with either. You'll probably find a better selection of O-200s on the used market, though, and at a better price point.

~Chris

[Joe LaMantia]

The up-front cost of buying a new engine may favor the Rotax 912ULS slightly, but the O-200 has a huge "installed base" so a used low-time O-200 would probably be considerably cheaper to acquire. The I/O-240 maybe a bit more then 100 hp, it's operating cost should be a bit lower since it is a FEDAC engine, also a bit more reliable. The Rotax has FEDAC qualities and has been around along time, Van has enough faith in it to put it into his RV-12, in my opinion that is more than enough to recommend it. I have seen the Rotec R-2800 and it would be a great choice in some of the simple designs like the Pober Ace or Bakeng Duce. Whatever you choose you'll have a good engine.

Joe
:cool:

[Tom Downey]

We were considering the ROTAX 912, but that radial is a sweetie.

what do you consider the resale factors on the radial would be?

[Dave Prizio]

If weight is a consideration the Rotax 912 is by far the best bet. Its installed weight is a good 30 pounds or more less than even the lightweight Continental O-200-D. I have heard of complete FWF weights in the 170 pound range for this engine.

The Continental O-200-A is a bit heavy but has the advantage of being plentiful and easily available as a used engine. The new O-200-D is pretty light at about 200 pounds but it is only going to be available as new.

The Cont. IO-240 has not been very popular in kit planes because of the extra weight and complexity.

The Lycoming O-235 is another option, but it is sort of a boat anchor weight-wise. A new possibility is the Lycoming O-233-LSA, which makes 118 HP and only weighs about 210 pounds.

Another lightweight choice (about 15 pounds more than the Rotax 912) is the Jabiru 3300, which makes 120 HP, but it is harder to set up and more of a maintenance hog than the other engines. Lastly the Rotec radial is very nostalgic looking but obviously produces a lot of drag. It has its place but not on every plane.

Lots of choices.

Dave Prizio

[Joe LaMantia]

Tom,
What aircraft kit are you building or planning to build? What does the kit manufacturer recommend, and how many have already been built and are flying? The 100 HP recommendation in something Cub-like, say a Kit Fox would favor the 912. Are you going for an E-LSA, or are you open to a higher gross take-off weight?

Joe
:cool:

[turtle]

when the kit requires a 100 horse power engine would you rather a Rotec, or a 0-200? /IO-240?

Sell ability is the issue.

O-200, no contest. Look at the TBO, ADs and SBs for the Rotax. There's a reason most Rotax owners are first time buyers. If Diamond didn't switch to the IO-240 in the DA-20 they'd be out of business by now. Most pilots aren't used to / don't like high revving, buzzy engines.

The Jabiru looks good on paper, if you can ignore the occasional catastrophic failures.

[Chick]

I've had my 912 seven years and couldn't be happier with it!

[Piet]

I like the Rotax 912 ULS. Don't own one but my brother does. It has about 250 hours on it and has been flying since 2006. We already had to change the engine mount rubbers. Engine got to flopping around particularly when it shut down. I don't like the mount on his Skyranger but the engine is fine. Zero oil leaks.
My preference is the Lycoming O-235 IF you can handle the 240# dry weight. It has a 2400 TBO. I am building a Pietenpol Aircamper on the cheap. I have flown small Continentals more than Lycomings. The Continentals on the used market are more apt to have 6000 hour TT on them. I wanted an O-200 Continental because of the weight(200# versus 240#) but found in my price range they were bad worn.I bought a Lycoming O-235 with 2000 hours on it. Did a major on it pretty cheap because it was low time. Another thing I like about the O-235 is it is not nearly as prone to have carb ice with the carb bolted to the oil sump.

[dbcrn]

How about a Corvair? 100-120HP, about 220# all up, smooth, cheap to build, really cheap to overhaul..... www.flycorvair.com (http://www.flycorvair.com)

[steveinindy]

O-200, no contest. Look at the TBO, ADs and SBs for the Rotax. There's a reason most Rotax owners are first time buyers. If Diamond didn't switch to the IO-240 in the DA-20 they'd be out of business by now. Most pilots aren't used to / don't like high revving, buzzy engines.

The Jabiru looks good on paper, if you can ignore the occasional catastrophic failures.

Bingo. I'd prefer not to be flying around with an engine that sounds like it belongs on a Weed Whacker rather than an airplane.

[kscessnadriver]

Bingo. I'd prefer not to be flying around with an engine that sounds like it belongs on a Weed Whacker rather than an airplane.

The Rotax 912 is one of the smoothest, best flying engines I've ever flown behind. I'd pick a 912 over a O-200/235/240 any day of the week. Just have a mechanic who is willing to follow the book on the 912, you won't have any issues. The biggest issues is stubborn old pilots and mechanics who are too closed minded to understand the 912 and it's operational and mechanical limitations.

[CarlOrton]

Bingo. I'd prefer not to be flying around with an engine that sounds like it belongs on a Weed Whacker rather than an airplane.

Steve: Not dissing you; just giving my personal experience.

Like you, there was no way, no how, that I'd go with a Rotax. Same thing - weed whacker "feeling".

Until I flew one.

Once in the air with it, I really didn't notice it. A few oddities (burping it, oil temp, etc.), but otherwise OK.

Of course, I'm not putting one in my Sonex, but a few flights behind one definitely changed my mind about it. If you have a chance sometime, try one on. You might be surprised.

[Frank Giger]

I think y'all are talking past each other.

The 912 is a four stroke engine, and a darned good one. As stated, one just has to know how to maintain them.

The two cycle Rotax engines are the weedwhackers, and I'll agree that they're not my cup of tea, either.

[steveinindy]

Steve: Not dissing you; just giving my personal experience.

Like you, there was no way, no how, that I'd go with a Rotax. Same thing - weed whacker "feeling".

Until I flew one.

Once in the air with it, I really didn't notice it. A few oddities (burping it, oil temp, etc.), but otherwise OK.

Of course, I'm not putting one in my Sonex, but a few flights behind one definitely changed my mind about it. If you have a chance sometime, try one on. You might be surprised.

I've flown aircraft powered by one. I'm not impressed by it but then again I haven't found anything in that class that I am particularly thrilled with. It's one of the major reasons why I have kind of outgrown that aspect of aviation. The only reason I've bothered to fiddle around with it was my need to use building an LSA as a test run for building the real airplane that I want. It's a lot cheaper to work out the bugs in the design of subsystems (fuel tanks, etc) in something small and cheap instead having to figure it out once the primary design is actually built. Plus, I'll either have something to lower the local bug and songbird population in or something to sell to fund the construction of the primary design. If it works out well, I might create a company to sell the plans through.


The two cycle Rotax engines are the weedwhackers, and I'll agree that they're not my cup of tea, either.

OK....so dirtbike or snowmobile instead of a Weed Whacker. Either way, a whole lot of noise for not a lot of power.

[Joe LaMantia]

Another great discussion!

I think all of the engines discussed have proven to be good choices in various aircraft and thanks to Carl for sharing his experience with the 912. Most of us have not flown anything with a Rotex engine, but if you look at all the various LSA models you'll see the 912 is the usual engine choice. That makes sense on the "turn-key" models where all the manufactures want to meet all the LSA performance specs. The lighter engine means more range and lower fuel burn, they're all stuck with 1320 lbs. GTW and a max speed of 138MPH. These same specs apply to the "you build it kit LSA's" (E-LSA). If your building a regular "Experimental" then your not limited to some FAA rules, just plain old physics regarding performance and your choice of power is wide open. It all comes down to "knowing your mission" as Steve has indicated in the post above mine.

One last thought regarding the resale value of the R-2800 radial, I don't think they have sold enough of these to really give us a good handle, but the cost of a new engine is "competitive" with the list of flat fours. If I remember right the 2800 is a 5 cylinder so an overhaul may be higher. Just a guess on my part.

Joe
:cool:

[S3flyer]

An interesting alternative to all the above is a new 110hp engine from Viking built for aviation using Honda components: http://www.vikingaircraftengines.com/default.htm Half the price of Rotax 912 ULS and around the same size/weight. Might hurt resale but could be offset by the savings.

[Mike M]

from Viking built for aviation using Honda components

just so's y'know, the viking is a product from the same guy who sold subaru conversions a while back.

http://www.meyette.us/engine.htm#egg
http://www.meyette.us/RedLine.htm
http://www.rv8.ch/article.php/20080529210403339

[Bob H]

You can't just throw out a question without knowing the sensitivity of the particular plane to engine weight and CG effect. If you choose a heavier engine than the plane was designed for, flying qualities will be altered. So I'd analyze the engine weight the designer intended and then be in better logical shape to make comparisons. If most of the engines you listed are too heavy, the question may be already decided. I fly with a 912 and weighed it on a scale complete with everything required to fly, from mufflers to oil tank to radiators at 146 lbs total. It makes 100 hp at 4gph mogas.

[Mike M]

I fly with a 912 ...makes 100 hp at 4gph mogas.

uh, not quite. it makes 100 hp at 7.1gph mogas. burning 4gph it's making about 52 or 53 hp. check pages 5-5 and 5-6 of the rotax 912 operator's manual. rotax-aircraft-engines.com/portaldata/5/dokus/d04997.pdf

[flybuddy]

The main issue is really one of resale. Even though the 4 stroke Rotax has proved itself not everyone feels comfortable purchasing an aircraft that has one. Conversely, even those folks that prefer Rotax would not be put off by a continental. If you examine the LSA market where this mostly applies, its demographic is older pilots wanting to avoid the endless medical hassle. These are the more stubborn folks that would be more apt to shy away from Rotax