Which engine

[Southern fox]

Hi, I’m new and looking for which engine would be better for me, would it be better to get a stock rotax 915 or a edge performance engine? I’m looking for horsepower anywhere from 120 to 150. Thank you all for answering all of my questions.

[desertdave]

My opinion only.......... Every potential Kitfox buyer would buy a plane with a factory Rotax motor. Not every potential Kitfox buyer would buy a plane with any other engine. If you are building it to keep forever go with what your heart tells you. If there is a sliver of a chance you may one day sell it than you may want to consider what I posted.

[Maverick]

Major ditto for DesertDave's comment.

[Billy]

Do any of you with the 915 rotax engines have the total weight of what the engine ,prop , including the mount , exhaust , " ready to run" weights are ? Curious , billy

[Mitch]

You are building the airplane for you, not for the next guy. I feel if you are going to devote that chunk of your life & labor to the project build it the way you want it. It is pretty hard to stick to a project when you have to consider how you build it for when you sell it down the road but when you are building it exactly the way you want it the enthusiasm stays there a lot better.

I am building a 7 and I am just about to order my 7U Verner radial from Ted Myers at Myers Aviation because that is what I want in it. I even have a brand new 912 ULS in the crate along with a firewall forward package to go with it, I am still going to order the radial because I don't want to listen to 5000 rpm in cruise. I know the Rotax is a good engine and I know the Kitfox will probably perform the best with it, but it is not what I want. I know I will probably sell it at some point but I am going to put the radial in it anyway. I know I will get shunned for life from the Rotax cult group but I have been shunned before and I don't care. This is my opinion to your engine question, build what you want. It is your money & time, not theirs.

A better question that you may want to ask is the Edge Rotax engine you have in mind a reliable piece and is it worth the extra money it will cost you. You need feedback from people that are using the engine you want, I think that would be of more help to you.

I am not trying to ruffle any feathers, this is just my opinion.
Mitch

[Benbell4140]

Yep. I agree with this. I’m going with the continental o-200 on mine. I know it will really hurt the resell value compared to a rotax but that is fine with me. Nothing against the rotax except for the price. And the recent price increase. I’m fine with an old continental and I know it will still out perform a cub (J-3) which is perfect for my mission.

[airlina]

Continental IO-240 engine here on my 18 year old Series 5 with no look backs , very happy with the performance and suits my missions pefectly. I plan on flying this airplane till I tip over . Bruce N199CL

[TuckerNielson]

Do any of you with the 915 rotax engines have the total weight of what the engine ,prop , including the mount , exhaust , " ready to run" weights are ? Curious , billy

Well my wire is sent - as soon as I receive my 915 I plan on weighing it in a variety of configurations because that information is frustratingly difficult to pin down. Luckily, Rotax just released a webtool that gives precise weights for the different engine/setups.

However I'm not sure why you would include the mount in that weight. For me, the mount is part of the aircraft, not part of the engine. Propeller, oil, muffler, all good questions. But I never thought of weighing the mount.

[Danzer1]

My opinion only.......... Every potential Kitfox buyer would buy a plane with a factory Rotax motor. Not every potential Kitfox buyer would buy a plane with any other engine. If you are building it to keep forever go with what your heart tells you. If there is a sliver of a chance you may one day sell it than you may want to consider what I posted.

Okay, so I'm going to probably ruffle some feathers here: An opinion is a non conclusive statement. This statement has concluded that "Every potential Kitfox buyer would buy a plane with a factory Rotax motor". Totally not true. Many builders/flyers of many kit aircraft including the Kitfox do not like or want a Rotax engine for a variety of reasons - not to start a ****ing match - but to each his own. As stated by someone else - it's your money buy, install and fly what suits you, your budget and your mission.

Would a Kitfox with a Rotax attract a buyer faster at a higher price? Probably, but they are not the only buyers either. To be considered for sure, but also should consider what your insurance rates might be with various engines - Rotax being the most proven "might" get you better rates than say an auto conversion. Many factors can contribute to the decision - it's your plane and money - go for it!

[alexM]

I know of more than one builder that came to the conclusion they enjoy the build process more than flying. Those people are likely to fly the plane for a while and sell it so they can move on to the next build. If that is the case then a mainstream engine selection is the way to go, and many have decided that the Rotax 91* series is ideal for the Kitfox airframe.

In the current market those planes will sell quickly, no contest. Then there are builders who just want to follow a known formula so they can get in the air. They don't want to work out the bugs of a cooling system or make a cowl from scratch. The build process can drag on for long enough so it's easy to see the logic there too.

I'm neutral on the Rotax 912 series. They have evolved to the point where reliability/longevity are on par with legacy engines. They've also reached parity on the price. Several years ago I got checked out in an Evektor which had a 912 and I did not love it. More recently I flew the Stick & Rudder SS7 with 912iS+big bore kit and I did not hate it, and certainly don't have anything negative to say about it.

Me, I'm one of the weirdos. My plane is going to earn that "EXPERIMENTAL" placard.

[Eric Page]

...there are builders who just want to follow a known formula so they can get in the air. They don't want to work out the bugs of a cooling system or make a cowl from scratch. The build process can drag on for long enough so it's easy to see the logic there too.
Yep, exactly. I spent a ridiculous amount of time researching and diving down rabbit holes on alternative engines of every description before I finally took a step back and analyzed why I was building the plane in the first place. The answer was because I wanted a Kitfox to fly, not because I wanted to spend a couple of years chasing parts and fixing problems I don't know anything about. That realization, and the discovery that Kitfox Aircraft sells a very complete firewall forward installation kit for the Rotax 912iS (used on their S-LSA product) made the decision to use that engine a no-brainer.

I'd echo Alex's main point. If you're deeply interested in the experimentation aspect of this endeavor, and you're willing to endure some pain and trouble to achieve your vision of the perfect Kitfox -- or, if you're very knowledgeable about the type of engine you're planning to use -- then an "non-traditional" engine choice makes some sense. But, if you want a reliable plane to fly in a reasonable amount of time and with a minimum of hassle -- or, if you think you might sell the plane within a few years and want to have an easy time of it -- then a well-supported "mainstream" engine is probably a better choice.

Here's a cautionary tale. Alex and I have a mutual acquaintance who put one of the automotive conversion engines on his Kitfox. Because it's not an engine that had been used on a Kitfox before, he had to build the cowling from scratch. He had both coolant and oil leaks in flight, an engine stoppage due to a broken reluctor gear (on the ground, thankfully), and some kind of problem (ECU?) that made the engine refuse to start in the middle of a cross-country trip. He trailered it home, removed the engine and sold the plane.

[alexM]

Here's a cautionary tale. Alex and I have a mutual acquaintance who put one of the automotive conversion engines on his Kitfox. Because it's not an engine that had been used on a Kitfox before, he had to build the cowling from scratch. He had both coolant and oil leaks in flight, an engine stoppage due to a broken reluctor gear (on the ground, thankfully), and some kind of problem (ECU?) that made the engine refuse to start in the middle of a cross-country trip. He trailered it home, removed the engine and sold the plane.

I thought it was ECU too, but he has since told me it was seized up tight. I'm electing to not trash on an engine manufacturer here, as he was patient zero so it was bound to have some teething problems. I flew right next to that plane in formation for 2-3 hours total and it performed well. I came to the conclusion there is nothing wrong with (at least some) car engine conversions, but you have to keep the runny stuff inside. "Most of the time" isn't good enough.

[AlphaMike]

you are building the airplane for you, not for the next guy. I feel if you are going to devote that chunk of your life & labor to the project build it the way you want it.
Mitch

Major Ditto!

[pmpilot]

Good thread. IÂ’m in the same camp right now. Firewall forward kits are 4-6 months out right now so gotta plan ahead. Was leaning toward the Edge package because of my mission (base airport 3000Â’ in hot desert conditions, plan ok mountain flying and I ainÂ’t no lightweight and neither is my lineman copilot). Wanted more ponies but not interested in a snowmobile motor. Thinking 915 or Edge EP912STI, and leaning toward the Edge of I can get more reliability reports from builders.

[efwd]

Can't help but notice, your putting some weight behind "reliability" in your inquirey. Why are you not asking about reliability of the ROTAX? ;)

[SSFoxBuilder]

Factory Rotax 915 if you want that kind of horsepower with simplicity, reliability, and longevity. There is no substitute for the r&d Rotax puts into their engines and the support/communication they provide. I'll pay a few extra dollars and take the weight penalty all day long to ensure I have a reliable engine.

[TuckerNielson]

I'll pay a few extra dollars and take the weight penalty all day long to ensure I have a reliable engine.

In today's aviation environment there are actual alternatives to a 'factory' engine. Experimental aviation is the lifeblood of general aviation and those who try new things advance the state-of-the-art. Nevertheless, I have to agree with you; which is why I'm choosing the Rotax 915.

[SSFoxBuilder]

Unfortunately, what many people take for granted is the reliability aspect. Over 90% of experimental aviation incidents/accidents are a direct result of a loss of power, and the majority of those are powerplants or subsystems that have been modified from their original design. Until you are faced with an engine-out situation, you do not have the ability to fully appreciate what that exactly means, for you and your family. When we are talking experimental it's important to know what we are getting into. If someone is going to build you an engine it's a worthwhile question to ask about their qualifications/training....how many aircraft engines have they built....how many of those engines are still flying....
I guess my point is, know exactly what you are getting. There are "engine builders" out there claiming to be the know-it-all on performance upgrades or enhancements, when in reality some may have had several engines not make it to 100hrs without leaving the pilot with minimal options. Just my .02.