Series 5 build engine choice

[Airfoil]

I feel fortunate to have come across a unstarted series 5 kit, with the speedster mods and wing. I am coming from heavier aircraft so this will be my first light weight build. A IO240 is also available, but being the speedster version I am concerned about the extra weight, I am trying to decide whether I should build it as is, trade the I/O 240 off for a 914uls, or possibly buy the STI wing. Of course the easiest approach is to build it as is, a series 5 speedster with that I/O 240 I’m sure it would be a beautiful plane. I would love to hear the opinions from you guys with tons of experience.

[Esser]

I love my 914. 4.5 gph. I can redline in level flight and I see 1500+fpm climbs.

[PapuaPilot]

Are you wanting to build it for maximum STOL capability? Are you building it as an LSA at 1320# GW? If so you might want a Rotax 912/914/915 engine.

The Kitfox is a great STOL plane even with the standard wing and the IO-240 engine, but the extra weight and more forward CG do add to the takeoff and landing distance. Never the less I typically can takeoff and land in 250-500 feet depending on weight and density altitude.

The IO-240 is a great engine and I burn 5.2-5.5 GPH and use mogas when available.

[jmodguy]

Build it!
The STi wing will drop 10mph off your cruise. Trents series 5 is around 930 lbs with the upgrades and 915 engine. In one of his vids I believe I heard him say it flies better now.
There are plenty on this forum that will tell you to drop everything and get a Rotax. There are also several on the forum with Continentals. Pick their brains as well. The 240 is factory supported and has been a great engine for these birds. Enjoy the build and the flying!.

[airlina]

Depends what your mission is. If you intend to land on gravel bars and mountain tops you gotta go light and the rotax would be a better choice. Out east where I live , we don't have gravel bars and mountain tops so I built my Series 5 , IO-240 powered Kitfox the way I wanted it: and it is fat-960 lbs empty weight. (most kitfoxes with the IO-240 come in around 950 lbs empty.) So the question is ,am I sorry about building a fat airplane? Not in the least- my mission is an everyday fun flyer that I keep at a grass strip, fly crosscountry at a reasonable 120 mph TAS and takeoff and land anywhere I want in these parts. I have yet to come across a strip that I can't get in and out of. Solo takeoff -300-350' and lands in 500' without heavy braking. Useful load even at 960 lbs is still close to 600 Lbs which means with 2 people and full fuel you can still add bags. Been flying my airplane for 15 years now (900 hrs) and the IO-240 has bullet proof with nothing other than routine maintenance.
One consideration however is the condition of the engine you have with your Series 5. Hopefully it has been preserved properly to prevent corrosion if it has sat for years. Google Continental Sil99-1 for how this is supposed to be done, and as a final measure , I would at least boroscope the cylinders to check for corrosion.
Lots of help on this forum , so don't hesitate to ask for it , if you have questions. Gotta go fly -see ya. Bruce N199CL

[N981MS]

I love my IO-240 but cannot compare as I have not flown a Rotax powered Kitfox. At the time I wanted what I thought was a "real" airplane engine. If I were building right now I would more strongly consider the Rotax. I have absolutely no regrets but it would be lighter with a Rotax and from my reading it seems that the Rotax is the sweet spot engine choice. I still might end up with the IO-240 though. Performance is great. Sounds great (to me), so it is pretty sweet too.

Pros for keeping the IO-240:
1 It is a bird in the hand that may not be that easy to sell. Not many aircraft flying it compared to say an O-200.
2 If you have a firewall forward kit from Kitfox it will not sell well either.
3 The rumble sounds great. To me anyway.
4 You will have something a little different among the Kitfox clan.

If you want to be sure what you like try to get a ride in each. If you can get to Georgia I would be happy to give you a ride.

[Av8r3400]

As the last two posters have said: FIRST & FOREMOST, evaluate YOUR mission for the plane.

If you are wanting just a fun little puddle jumper with a decent cruise and good grass field capability build it as it is and pocket the additional money for gas or panel upgrades.

If you want a better STOL plane, consider a lighter power plant for the weight of the engine and needed fuel to power it.

If you want a STOL monster, do the STi wing and a lighter engine for peak performance.

[Airfoil]

Thanks for the advice, I’m glad to hear there are other successful and happy IO240 users. Having all the parts at once is a huge plus, being retired I don’t have the patience to wait 3 to 6 months for parts from the manufacturer. There is a eagle 150 in my neighborhood with a 240 that sounds fantastic when it launches out of here! He loves it as well.

[Maverick]

I am in the process of building my second Kitfox-5. For my first build, I went with the C-0200 because I already had it and am very familiar with the smaller Continental engines having had many.

Once flying, my comparison of my plane to others was with a Kitfox-5 w/Rotax 914 and a Kitfox4 w/Rotax 912ULS. Both out-performed the C-0200 The weight difference was key. The C-0200 was at least 100 lbs heavier. While a C-0240 is likely near the weight of the C-0200, the C-0240 obviously is more powerful which could make up the difference in performance however; All of the guys I spent time flying together with our Kitfoxes, they were running Rotax engines and they all out-climbed and out-ran me. And, they did not have to top off their tanks near as often as I did. With Avgas over $5/gallon, the long term cost needs to be considered. The Rotax motors provide good reliability, performance, and economy so, if I had it to do over again... oh, I do so, all of the advantages of the Rotax made it the choice for this current Kitfox-5 build.