Non-rotax engines

[FL510]

I've already heard several Kitfox pilots that don't care for the Rotax style 2-stroke engines. I'm talking more about the TBO time and the lack of long-term reliability, not additional horsepower.

Is it possible to fit a 4-stroke engine on a already built Kitfox with a Rotax? How much does this cost and what type of engines do people prefer?

Most used Kitfox have the Rotax 582 it would seem, but I'm not sure from the stories I've heard I would be interested in keeping such a engine.

Thanks for the replies & discussion!

[Dave F]

Nothing wrong with Rotax 2 strokes
the idiots that run them are the issues alot of the time.
503/ 582 - work great. 2 strokes are VERY simple ENGINEs
some try to re-invent the wheel. Feed them the proper gas and oil and warm them up thoroughly and you will have little troubles.

Some are focussed on the fact they do not sound like an "airplane engine"
neither do the 912 series but very popular and great performer.

Check my youtube videos - I have hundred of videos with Kitfox flying on Rotax engines. Some are in very remote areas adn over 50 miles of open water.

Any engine can puke at anytime.

I have thousands of Rotax hours and many more in certifeid A/C as well.

[Dorsal]

Certainly some have converted from the 2-stroke Rotax to the 4-stroke Rotax if that is of any value.

[rogerh12]

FL510;

That's not a good question for this forum, you are in the land of ROTAX ONLY on this site !!!! Check the internet, and also what people have done with the Avid flyer too for some ideas. There are a number of 4-stoke installs possible that are non-Rotax. I for one am installing the Great Plains direct drive VW firewall forwared kit on my Model 4-1200, but then again it's an engine I had on a couple other planes and know it well, though it might not be right for you (especially if you like in a hot area of the country).

Oh, what is typically left off of the Rotax lovers comments is that the two strokcs drink lots of fuel for the HP, like all 2-stroke they have a low effective compression ration. A Subaru EA-81 engine probably has 1/2 the fuel burn for the same HP, or close to it. The 2-stokes are also subject to quiting if any little thing goes wrong, like your exhaust pipe cracks and falls off, or you shock cool the enigne and sieze it up on power up (that is what happend to my model 2). Also, the Rotax is a foreign sourced engine, and subject to price hikes due to the dollar value dropping (and you won't find them in any junk yards).

Hope this helps
Roger

[Dave F]

Roger wrote
Subaru EA-81 engine probably has 1/2 the fuel burn for the same HP, or close to it. The 2-stokes are also subject to quiting if any little thing goes wrong, like your exhaust pipe cracks and falls off, or you shock cool the enigne and sieze it up on power up (that is what happend to my model 2). Also, the Rotax is a foreign sourced engine, and subject to price hikes due to the dollar value dropping (and you won't find them in any junk yards).

• E81 weight is also near double of a 582
• You seized your engine so all ROtax are junk because the operator broke it ?
• a Good percentage of the product on the shelves in USA is from off shore -- not just Rotax .
• Dollar dropping? it will faLL MORE YET.
• Makes it more attractive for us Canadian investors buying US assets for 40% cheaper than 8 years ago.

Cheers

[HighWing]

FL510;

That's not a good question for this forum, you are in the land of ROTAX ONLY on this site !!!! Roger

Not exactly true Roger as there are several who are using alternative engines. I do have to say, though there is a long long history in the Kitfox world and really nothing new under the sun - exception see below. The history shows that alternative - read auto conversions - work, but they don't usually measure up to the performane levels of the Rotax. The factory once supported the EA-81, but not for long. People choose what is best for themselves for many reasons and no one on the forum regardless of enging choice is offended when aother member chooses something other than Rotax - what does burr a bit are the not so subtle claims of prejudice.

There are a number of new aircraft specific engines out there and some have chosen them for their projects. There is not much information on them yet and I suppose the jury is still out. If a person feels a little pioneering spirit go for it. But, for well known performance with tons of information and support - this forum, two additional Kitfox forums and the vast number of Service Bulletins, there are not many unanswered questions out there.

I considered the NSI EA-81 and watched their website for years. They had a tech bulletin page and there was never a single item posted there - not even an under construction sign. A close friend opted for that engine because he was concerned with the number of Service bulletins on the Rotax site and the NSI site was clean. In about fifteen years, he has just over 40 hours on the airplane - that to me says a lot. To believe that since NSI or any other engine has no service issues or reliability issues posted means they are reliable is not a good assumption. And to assume that all comments regarding an engine are based solely on a brand prejudice is foolhardy at best.

What you said about the two strokes are true, but the failure modes are worst case scenarios. Every engine has one of those - or two or three. What Dave F says is precicely true. The two stroke is not conducive to neglect, but if attended to as it should be will give many hours of safe flight. One of our flight of six in the early years of our annual Idaho back country flights flew behind a 582 and this was with a weeks of stuff including camping gear on board. It didn't climb as well as the 912, but never hiccupped - ever. The only thing that set him apart was that every fuel stop meant he popped the hood.
Lowell

[Geowitz]

Not exactly true Roger as there are several who are using alternative engines. I do have to say, though there is a long long history in the Kitfox world and really nothing new under the sun - exception see below. The history shows that alternative - read auto conversions - work, but they don't usually measure up to the performane levels of the Rotax. The factory once supported the EA-81, but not for long. People choose what is best for themselves for many reasons and no one on the forum regardless of enging choice is offended when aother member chooses something other than Rotax - what does burr a bit are the not so subtle claims of prejudice.

There are a number of new aircraft specific engines out there and some have chosen them for their projects. There is not much information on them yet and I suppose the jury is still out. If a person feels a little pioneering spirit go for it. But, for well known performance with tons of information and support - this forum, two additional Kitfox forums and the vast number of Service Bulletins, there are not many unanswered questions out there.

...

Lowell

Ditto.

EDIT - Age old question. Do you want to engineer, fly, or both?

FL510 - This is what I would do - If you really just want to fly and tinker now and then I would get a Kitfox with a 912 if possible. There are plenty of customizations you can do with the plane to get your fix for working on it. If all you can buy right now is a Kitfox with a 582 I would still go for it. Get the motor checked out by someone who is familiar with them. Learn everything you can about 582's. Treat it right and fly the heck out of it. See how you like it. If you take care of the 582 it will keep you in the air for a whole lot less headaches than switching to an auto conversion. I would argue that a well maintained 582 is significantly more reliable than any auto conversion. For the cost of the conversion you could pay for a lot of fuel too. A 912 is still relatively easy to install down the road. Who knows, you may end up liking the 582.

If you want to engineer go for the alternatives, but don't let pride keep you from cutting your losses if it's not working out.

[Dorsal]

Personally I like reading about the alternatives, can't wait to hear how J-Pitkin's Corvair powered Fox flies.