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Building a kit plane: Kitfox S7 versus Rans S21 (or continue dreaming of a RV)?

It’s dream time again for me: I’m thinking about building either a Kitfox S7, a Rans S7 , or a RV9/14 “somewhen” in the foreseeable future. Do you have any type specific recommendations?

So far, the maximum I have built successfully include several products from IKEA (and they are still functioning). My day job is to juggle with numbers and running Excel, so my motivation to build a plane includes working on something visible and real, next to forcing myself to dig deeper into the technical side of aircrafts (which has not been my primary focus yet). So it would a big learning project for me. Family would be ok with that, but it should not become a neverending story to complete the kit…

My typical “mission profile” are local flights and trips up to around 250/300nm. Maybe that will change once my kids are older. Should I need four seats I can still rent a plane from the club. Dreams also includes looking at ‘Gentlemens off-runway stuff’ such as flying to Italian Aviosuperfici or ‘easy’ French Altiports one time, which is why I arrived at Kitfox and Rans.

So my summary on the mentioned planes:
RV: The number of kits and flying aircraft speak for itself. Builders say the kits would be close to “idiots proof”, whatever that means…. Finally, the flight performance is amazing – but no off-runway stuff. Quickbuild indicated around 1200h.
Kitfox: I like the Cub-feeling but want side-by-side seating. To me perfect for ‘low and slow’. But fabric covering not ideal for weather… Quickbuild indicated at around 800h.
Rans: Basically as Kitfox, with the advantage of an ‘all-metall’ approach rather than fabric stuff. Build time indicated with 550h….??

Looking at the current project list issued by the Swiss experimental association and comparing these three models, most people seem to go for a RV, followed by Kitfox. But no one seems to go for the Rans. Is that a hint?

LSZF Birrfeld, LFSB Basel-Mulhouse, Switzerland

I know very little abut the Rans, but I haven’t heard anything bad about them. I was offered to buy a Rans S7 (I think) a long time ago, but had no interest at that time. The RV-4 and 3 (and 6) are very far from idiot proof. I wouldn’t call the other idiot proof either, but they are as easy as it gets as far as aluminium construction goes. Still, nothing like a Carbon Cub. All things considered a CC with 180 HP is cheaper than a RV-14, and much easier to build.

Have you looked at the Savage Cub from Zlin? It’s probably too finished for experimental (more than 51% finished), but a very good plane indeed, and it use a Rotax. The RV-14 need a powerful and expensive 200 hp Lycoming. The -9 flies good with a 320 (no acro though). The -7 is acro and flies well with a 360 using mogas. What about the RV-12?

If you can get by with a Rotax instead of Lycoming, then do it. Life is so much easier with Rotax. Runs all the time, can be fixed everywhere by anyone with a little engine experience. If not, then chose a plane that flies well with a low compression Lycoming, so you at least can use mogas. They also last longer than the high compression ones (RV-14 and CC with the hottest engine). RV-7 with 170 HP Lycoming is ideal.

The elephant is the circulation

Reading your post, I remember not knowing any homebuilder (except one who owns a prototype machining enterprise*) not in the retirement age. Even the RV7 takes more than 1000h to build for an airplane mechanic. If you are not retired, did you calculate using all your spare time to build your plane over several years? The estimated built times advertised are mostly grossly understated. If not, they are outright lies. >10 years to built a RV part time is no exception. If you dont have mechanical skills already aquired, calculate more …

Concerning money, 130000€ to built a RV and 60000-80000€ for a more modest plane may be realistic. You choose extremes, RV and Kitfox are very different airplanes. For altiports, you need a good power/wing loading ratio, thus a RV will be fine. I don’t know about the actual position of the swiss CAA towards ultralights, but some of them have better performance than Kitfox/Rans.

How about buying a plane? You will get something modest, but perfectly flyable for 20000€ and something to have fun with for years for 50000€. Even an experimental, if checked carefully – there are factory built ones around.

Have you been to the Aero fair at Friedrichshafen? April 10-13, if you spend several days there, you will definitely run into people who can give very valuable advice. German and french experimental builder cooperations use to have booths there.

*he built the MC100 which is extremely laborous to built and swore not to repeat it.

Last Edited by a_kraut at 03 Feb 17:03
Bremen (EDWQ), Germany

a_kraut wrote:

I remember not knowing any homebuilder (except one who owns a prototype machining enterprise*) not in the retirement age. Even the RV7 takes more than 1000h to build for an airplane mechanic.

All true. I’m surrounded by homebuilders and would add that in addition to retired people building homebuilts, single people build them too. Only a few married with children. My grandmother in her 80s used to say there is a time in life for everything, so do it while you can because that time will be gone and another will come. She was correct.

My dad was a disciplined, responsible family guy and built a (no kit) homebuilt while I was a teenager, spending a little time virtually every night plus one day per weekend, and never pausing for long… It took 5 years…

a_kraut wrote:

How about buying a plane? You will get something modest, but perfectly flyable for 20000€ and something to have fun with for years for 50000€.

This was my choice after realizing how many wonderful planes are out there already, and at reasonable prices. And I really like projects, building things and so on… Maybe someday, after retirement, if time allows and a half built Falco comes my way again

Last Edited by Silvaire at 03 Feb 17:18

From your username, I take it you’re already a pilot. I’d suggest getting a flight in each of the three. I’ve had flights in RV4, Kitfox, and Rans S?, where I handled the controls. Free, in return for flights in the Jodel DR1050.
If you’re not a pilot, learn to fly before getting near to build completion. All are more tricky and vulnerable than Cessna and Piper trainers. Maybe the modern Rotax-engine trainers are nearer.

EGPE, United Kingdom

Thanks a lot for your feedback so far! No doubt, real/true building time may be massive and probably beyond the indications given by the kit producers; and there is a reason why >50% of kits don’t get completed. While the precise number is somewhat irrelevant (how exactly is one tracking his building time), rough numbers, i.e. 500 / 1000 / 2000 hours might give a broad idea of the really required committment…

@LeSving – I had a look at the Savage Cub, but I prefer side-by-side. Indeed, the RV-14 has a $-pickup compared to the -9 and I missed the little detail on the larger engine. It seems the -7 is the still choice for building an RV… The -12 is a nice plane, but in my view, if looking for an RV then take a real RV (that’s more driven by sentiment and only to a lesser extend by logic)….

@a_kraut – Well, that’s the million dollar question, how long does someone take. but it appears more and more trending towards a retirement project……. Buying an Experimental build by someone I don’t know….. Not sure about this (just my gut feeling)… And the beauty is to build something new instead of buying something used for 50k which could be older than myself. But I guess this might be a road to go…

@Silvaire – You have a wise grandmother!

@Maoraigh – Of course I will not buy something without having flown that type before. In an ideal world I would have hoped for someone having gone through the pro’s and con’s of buying one type over the other, i.e. buying Kitfox over Rans for xyz reason, or vice versa.

Regarding Aero – Guess like for most of us it is also a fixed entry in my calendar – maybe we meet there (I have seen the other thread on that topic) :-)

LSZF Birrfeld, LFSB Basel-Mulhouse, Switzerland

I can only comment on RVs, since it’s the only one I know well. I flew my RV8 in 2010 and it took me a little over 4 years to built from a quickbuild. Total cost at the time was around 100K € ex VAT, with a new angle valved 200HP Lycoming, C/S prop, EFIS ect.. My “background” was building model airplanes and constructing various things and engineering. I did not have the Pilots licenses when I started building but was flying a TB9 with my father who was retired airline pilot.

A word of warning first I always give people that want to build a plane:

It takes A LOT of dedication to build a plane. Don’t think the manufactures sunshine stories of low build times to be representatives of normal people with somewhat of a life outside aircraft building. Over the 4½ years I consistently used three long days a week which now would be incompatible with my family life with children. On top of this a lot of time ordering parts, looking through catalogs, thinking how to solve a problem or what is next in the process ect. There is a real risk a project like this can lead to disaster in family life as has been seen many times before.. Be honest with yourself can you dedicate the time it takes?

People build for a number of reasons, I was building to get a flying aircraft and during some parts of the project was really tired of it. Other people really enjoy building and don’t care much for the flying after. But if you don’t put the necessary hour into the project consistently it runs the risk of being something that takes 20 years to complete or worse which is also quite common. Another note about build time is that anytime you stray from the kit plans it can take a mindboggling amount of extra time. This is especially true if you modify anything significant. Aircraft designers are pretty clever people, have a real good reason to make modifications. The typical trap here is trying an engine that was not intended for the model.

Next ask yourself if you have the necessary skills or have the ability to learn them. While many will say that if you pick up a screwdriver you can built an aircraft – I don’t agree, even with quickbuilds, prepunched sheets and CAD manufactured parts. It takes a fair amount of technical skills to achieve a SAFE aircraft and I can think of many people I know who would never be able to complete such a project.

The metal work itself is mostly not difficult on the newer models just a lot of repetition which take time. The build stages are to be checked by an EAA person (inspector) but the best security is making sure what is done in the first place is acceptable. Especially faulty engine/fuel system installations is a top killer amongst homebuilders. Envision the engine running and vibrating… can something come loose or grind against each other leading to a failure. Can the fuel line flex enough? is it far enough away from the exhaust ect. Are all bolts torqued correctly and is everything safety wired correctly? A lot can still be done wrong. Not too long ago Vans aircraft set out a SB telling owners to check for missing wingbolts as apparently some builders are forgetting to install some of them. The good thing is that its cheap to order the empanage kit of an RV and to complete that gives a fair idea of what is required down the road.

Do you have a workspace to complete such a project? I built the narrow bodied RV8 in a single car garage until final assembly so it does not require a lot of space but I does require a dedicated working space with good light.

Do you have the necessary financing? While you probably already know this there are some things to consider. The kitprice for RVs only make up a fraction of the costs. Freight, tools, paint, instrument, propeller and engine are extra. If you get a used engine be sure you know what your getting. A simple VFR daytime RV with a used engine and fixed prop and simple paint scheme can be a lot cheaper than one with new engine, fancy avionics and 3 blade C/S prop. In any case a homebuilding is not exactly cheap if you factor in your own time. Its often a much better deal buying a used.

Paperwork…. There is a significant amount of paperwork required although I think this is different from country to country and with the more well know models the CAAs have become more relaxed.

Testflying. Many people that have spent years building and not flying and are not really current for testflying a new small aircraft. Get hours in a similar model before if possible.. What kind of further testing is required is individual to each CAA. I had to do a 50 hour testflight program which I found to be quite fun. That included stuff like calculating best glide, best climb, the cruise performance at various altitudes, making sure it was stabile at CG range (oscillations will not increase if you pitch up the plane and let the control go fx). Also did a flutter test going 230 Kts (VNE is 200) and slapping the controls.

So which plane is right to build? Speaking only of the RV series, they have such sport feel to them that I personally think it’s a shame to build one that is not aerobatic. If you fly from grass strips I would say the tailwheel models have an advantage. They have a tough landing gear and are not prone to kind of gear collapse even on landings less than perfect, although the risks of ground loop comes into play. The RVs overall are fun to fly with a good combination between sport and utility. And one positive thing over the experimental world is lowered operating cost. I have a leg in each camp (have also a TB21) and I can testify that it is significantly cheaper to operate an experimental plane. Most of this comes from the fact that you can do everything yourself including maintenance and that parts are much cheaper because they are not certified.

…that turned out to be a long post. Hope you can use some of it :-)

EKRK, Denmark

People build for a number of reasons

Yes. You may end up liking it more than flying. Right now I’m in no need for an aircraft. I can fly more than I have time to do in a row of aircraft, for free, still I’m building two aircraft, extended my house by 50 m2 etc.

This means I’m in no hurry. This translates to periods of building and periods of flying.

If you build because you want to have an aircraft flying, then it’s probably vise to chose the easiest route possible. Carbon Cub possibly or this Zlin Cub (if possible).

The elephant is the circulation

MikeWhiskey wrote:

and there is a reason why >50% of kits don’t get completed.
That’s maybe the number Vans is publishing. Never heard of such a high success rate anywhere else. I heard completion rates in the range 1:4 for kits and 1:10 for plans built planes.
While the precise number is somewhat irrelevant (how exactly is one tracking his building time), rough numbers, i.e. 500 / 1000 / 2000 hours might give a broad idea of the really required committment…

Double these numbers. The fastest builders claim they needed 1000h. 4000h to 6000h for more complex planes in a part time projects is not uncommon 10000h for pristine aircrafts.

BTW, if I sound a bit pessimistic: I fly an experimental and I like it.

Last Edited by a_kraut at 04 Feb 09:07
Bremen (EDWQ), Germany
Shoreham EGKA, United Kingdom
87 Posts
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