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Sitting On The Fence Between A Sonex And Kitfox

Posted By:
Jim Goudy
#1 Posted: 6/26/2011 22:36:06

I could use some input from the Sonex and Kitfox SuperSport/S7 people. I am looking at building, but can't decide between the Kitfox and Sonex. Would anyone care to comment.

1. What was your build time compared to what was advertised?

2. How does it handle in crosswinds?

3. Have you done any cross country trips?

4. Can you take a passager that is on the plus side of the FAA 190 lb average - meaning can two regular six people fly in it safely?   And, is it still comfortable - with one or two?

5.How does it handle turbulence?

6. Are you still flying it? If not, why did you sell it?

7. Knowing what you know now - would you still build the kit?

8. Have you ever flown it from 3 and 5 thousand foot airstrips?

9. Are you happy with visibility?

10. Do you fly in the winter - meaning below 32 degrees and snow on the ground?

11. Any words of wisdom about the planes not posted or published you would like to pass on?

I've been on both of the forums.  Looking here for some unbiased input.  I've also been in both planes, but still looking for input?

Thanks in advance!

Note: If this is not the appropriate forum - please let me know. - Thanks!

Joe LaMantia
Young Eagles Pilot or Volunteer
#2 Posted: 6/29/2011 09:50:39

Hi Jim,

While I've not built or flown either of these aircraft I will venture in and give you my 2 cents.  I took the Sport Aviation introduction course at Oshkosh back in the 90's with Ron Alexander.  What I discovered over the 3 days was that I wasn't all that keen on building a plane.  The course allowed us to get some hands-on experience in building pieces that ranged from traditional aluminum construction, to composite, with tube and fabric in the middle.  I would highly recommend you investing in the course or at least getting a copy of "Kitplane Construction" by Ron Wanttaja.  I love homebuilts and kitplanes, but I don't have the mental headset required to handle all the problems that come with building.  I found the tube and fabric types to be the best in terms of building ease, and composite the worst...I hate sanding!   

You can find both of the aircraft your interested in completed and for sale on several web sites.  Many of the Sonex builders choose the 100HP Jibaru over the 80HP VW conversion.  Flying out in Montana, I would guess you'll need the 100HP.  If I were going to own one of these it would be the Kitfox, but that is just my personal preference.  It's like choosing a blue one over a red one, their both good aircraft that are very affordable to build, buy, or own.



Joe Delene
#3 Posted: 6/30/2011 06:38:27

  I thought about building for years. I do realize this is the EAA site. That said I went out & bought a Warrior. The reason being my kids are in prime time now, for flying & for me the building may not be realistic. It's also a better time to buy a plane now than sell one, if your in position to do so.

Carl Orton
Young Eagles Pilot or VolunteerHomebuilder or CraftsmanAirVenture Volunteer
#4 Posted: 6/30/2011 14:55:32

Hi, Jim;

I tried to reply the day you posted your question, but the forum software was being its problematic self and wouldn't post.  Hope this one does.

I, too, considered the Sonex vs Kitfox. I went with the Sonex, and am *this* close to completion.

Sonex told me a good approximate build time is 1200 hrs. I"m at 1150 right now, and am finishing up. There's at least one builder who did it in 600, and several who have over 2000 in it.

Lots of builders fly long cross-countries in 'em. At least one builder has gone to the Bahamas more than once. Several Sonex have flown all lower 48 states. Many make the trek to AirVenture every year.

Several builders have given test flights to 250-pounders. With just about anyone, though, the best comfort is achieved by having the passenger put his/her left arm on the crossmember right behind the seat. Frees up several inches of valuable shoulder room.

Turbulence is more a factor of wing loading, not Sonex vs anything else. A C-150 gets bounced more than a C-182 for the same reason.

I would still build the Sonex. I tried the metal and fabric workshops at AirVenture. I became convinced that I didn't want to spend all the time rib-stitching. Maybe it's not that bad; just not for me. Also, with the Sonex, I was most interested in support. I have never gone more than 24 hrs during the week w/o receiving a response from Sonex to any question I have. MOST (like 98%) are resolved within 6-8 hrs.  Additionally, the user support community from Sonex builders is outstanding.  I have NOT checked into this for Kitfox, so I"m not bashing them.  With Sonex, you get the full set of plans with every dimension. This was important to me because, lets face it. Some kit mfgrs have gone tango-uniform over the past several years. If you need a part and can't buy it or build it, (as in, w/o the dimensions on the plans) you're hosed.

3-5000 strips are a no-brainer. Lots of guys fly out of 2000-2500 (don't know your altitude, though, which would be a factor with density alt).

Visibility is great with the bubble canopy except directly below you, the same as any other low-wing plane.

Winter flying is a non-issue, at least from the plane's perspective. The pilot may get a bit chilly, though!  Some guys have built heater muffs around the exhaust; others have worn battery-powered heated socks and underwear.

Lastly, I haven't looked up the numbers, but there are quite a few more AeroVee powered Sonex than Jab 3300 - mostly due to the 12000$ difference between the two. The AeroVee is a proven platform and is not penalized by insurance companies like some other auto-conversions.

Feel free to PM me if you have any other questions. http://mykitlog.com/corton

- Carl
Bob Hassel
Homebuilder or Craftsman
#5 Posted: 6/30/2011 23:24:34

Hi Jim,

Great questions and I can't wait to see more answers by those that are actually flying those aircraft.  Of course I've rarely ran across anyone that weren't actually passionate about their models!  Any of the available models will treat you right and give you years of fun!

I'm going through similar questions about LSA kits in general.  YMMV, but I put together a spreadsheet of various models with associated costs.  This was based upon features that were important to me.  What I've been able to come up with on just the specs is the Sonex is a little smaller than the others in terms of cockpit size.  A Sonex is 38 inches wide at the hips and 40 at the longerons.  Most of the other LSA models are in the 43" - 45" range.  The Sonex max gross is 1100 with the VW and 1150 with the Jabiru 3300 although some that I have talked to have bumped that to 1200 #'s GW.  That's still under the LSA limit where most of the other LSA aircraft are at 1320# GW.  I live at high density altitudes so the VW (according to local builders/pilots) is a marginal performer with more than one person on board at least at my size,  On the plus side Sonex is coming out with an add-on turbo that should bump the 80 hp Aero-Vee up to somewhere around 100 hp (spec are yet still being determined).  A turbo Aero-Vee changes things for me so even with reduced gross weight compared to the rest of the LSA market the Sonex is still in the running. A turbo Aero-Vee in a lighter weight airframe should really cook!  BTW, my personal airframe is definitely over standard weight so the weight issue is a big deal for me.  The fuel tank is pre-made but limits you to 16 gallons.  What's your fuel flow going to be?  Does it matter that you may have a shorter range?  One thing I have noticed with the Sonex aircraft is that you can almost buy a completed flying aircraft for the cost of the full build.  In all honesty I'd probably have a cheaper build on the Sonex because I just couldn't fit much stuff on the panel. It's too small for the bigger EFIS's and probably room for only one even if it is smaller.

Apples for apples, kits generally run within a couple of grand of each other. with a few exceptions.  For plans only/kit metal considerations I've looked at there's Sonex, Zenith CH-650B (the rest of the Zenith line CH750, etc), Ran's S-19 along with the rest of the Ran's line and of course the Van's RV-12.  I'm also keeping an eye on a 2 passenger CX-4 design by Dave Thatcher called the CX-5 (uses VW engine).

Out of those, I've heard that the S-19 is built like a tank and the kit reminded one builder that I talked to of an RV-6 in the way it was constructed.  The Ran's S-19 airframe is a little more expensive than some of the others on this list with the options I'd put on (YMMV). The S-19 also has a slightly higher empty weight than some of the other models (although the end result is up to you).    The Zenith line supports many different engine options (probably the most of the kits listed).  The Zenith has a ton of options to numerous to mention.

Of course probably no kit goes together as fast or contains as much as the RV-12.  If you build it as an experimental aircraft meeting LSA guidelines (as Van himself did) you have options of where you save your dollars.  Jabiru is putting together a FWD kit that runs about 10K cheaper than the Rotax.  Flight testing is currently being conducted by Jabiru USA on that package.  The airframe kit has everything but paint & fluids.  If you build it as Van intended then the fly off time is only 5 hours.  Maintenance is also slightly different on the standard RV-12.  Since you are basically building it just like Van's did for certification it falls into a different category from the standard Experimental licensed aircraft.  Furthermore the kit has just about everything pre-drilled.  Many of the other kits may have some parts like some of the skins pre-drilled but I can't think of another kit that does what the RV-12 does in their kits or even the other RV models.  That's one of the reasons why the kit goes together quickly.

It's a buyers/builders market.   I didn't touch on the composite models (like the Lightning) or of course the kitfox.  I'd be remiss not to include those in the mix.  The Kitfox has a great following, is a well developed design and is another 'go together quickly kit that is a great bang for the buck.  The Lightning was actually developed and sold by Jabiru USA - guess what their engine is!

In all fairness the design goals between the aircraft are different and that's reflected in the differences between the kits and the final product.  Build yourself a spreadsheet that lists features that are important to you.  Does a center stick bother you or do you prefer dual sticks?  Would you like wing lockers for additional storage?

The various models I've mentioned all have their support/builder sites that are helpful.  Let's not forget the great support by EAA members that you can tap into even if they don't have the same aircraft as you.  The best thing?  Go to Oshkosh, take a drool rag, lot's of sunscreen and a backpack for all the flyers and stuff you'll carry.



Jim Heffelfinger
Homebuilder or Craftsman
#6 Posted: 7/1/2011 01:05:34

Got agree here.  Go to AV and try on each plane - if it's a kit of any meret then it will be at AV.   Consider the Fisher Line as well.  I know some are uncomfortable with wood but you save a bunch on bad aids alone.   Both the KitFox and Sonex are small planes and a tight squeeze if you are big.  I toured the Sonex factory in Feb and I suggest you do the same while at AV.  

Carl Orton
Young Eagles Pilot or VolunteerHomebuilder or CraftsmanAirVenture Volunteer
#7 Posted: 7/1/2011 13:44:16

Just a few follow-on comments; Bob's response above stirred some thoughts.

Cost may be a consideration. My Sonex will be about $33,000 when completed. I got the kit with all the optional pre-build parts, etc. I also live under DFW Class B, so I had to have a transponder. I went with the compact MicroAir comm & xpnder; they're expensive. I also went with the MGL Enigma color EFIS / moving map GPS. Turned out it was actually less $$$ than buying all new analog gauges.

My neighbor completed an RV-12 last year; flew it to AirVenture with 7 hours total on it!!!! (well at the start of the trip). He has over $60K in it before he had it painted this year. It was built exactly to Van's plans for an ELSA. It's a VERY nice plane. I've got several hours in it myself. Nicely built, nicely equipped. Nice touches here and there.

Another consideration will be what you plan to do with it. The RV-12 may be nice, but the spars are quite shall we say, less meaty than the Sonex. The RV12 is not cleared for aerobatics, I don't think. The Sonex is. Like I said, if you want to strafe some boats on the local lakes, that may be an issue for you.

Lastly, any of the LSA-class/size craft you're looking at may limit you're in-air duration. My buddy with the -12, even though he has far more hiproom than I have, can't stand being in the air more than 3 hours in it. As a result, fuel capacity may not be an issue for you. My Sonex will supposedly average around 3-4 gph in cruise. With 16 gallons, that's more air time than my bladder or butt can endure!  But that's me. As others say, YMMV.

- Carl
Ron Voss
Homebuilder or CraftsmanAirVenture Volunteer
#8 Posted: 7/1/2011 18:16:19

The Kitfox and Sonex are both great airplanes, but it depends on what you are looking for.  I an just about finished with my second Sonex from plans (not the kit).  I also build an RV-6.  I flew the first Sonex 90 hours before selling and flew the RV-6 115 hours before selling that one.  Not sure how long I will keep this one.  Both Sonex' are VW powered and I considered that marginal for takeoff and climb, but fine for cruise.  I didn't fly the Sonex much in the winter for these reasons; The cabin heat was marginal with one muff installed on one exhaust pipe, and the wings are very low and plowed snow could be a hazard.

I have several friends with Kitfoxes (a couple model 3's and one IV) and they are fine aircraft.  Flaperon controls make things a little different, especially on the model 3's and prior, but they changed some things on the IV.  High wing aircraft generally make much better ski-planes.  They are slowen that the Sonex by a long shot, but that isn't always bad.

As far as how the Sonex flies, it is great and similar to the RV-6 I had only slower.  Crosswinds and turbulence were no problem with my taildragger.   I built my forst Sonex in 1350 hours (over 3 years) and bought the engine mount, fuel tank, windscreen, and canopy from Sonex.  That one even had the original spar caps that required cutting down.  I probably have that much time in my second one also, but that is only because I used flush AN rivets on almost all exterior skins.  I also made a few changes and did all my own welding on this one.  I expect that I could build one from their kit in less than a year and maybe 5 or 600 hours.  BTW, I normally fly off a 2500 ft grass strip.  Visibility is great in the Sonex, provided you have the right glareshield fabric.  My first one was horrible looking forward until I changed the fabric.

I hope this information helps, but the best advice I can offer is to track down a plane of each type and get rides and some stick time.

Ron Voss

Bob Hartunian
Homebuilder or Craftsman
#9 Posted: 7/2/2011 10:09:40


I have flown in both from 6800' high, paved airport with equivalent 80 hp engines ( 912 for Kitfox and Aerovee for Sonex). I prefer the Sonex for a little more shoulder room and forward visibility than Kitfox. I also prefer the Sonex for cruise speed. Both planes flew in winter but from paved surface. Sonex builder help is probably better. The Sonex metal construction goes together quickly with predrilled holes and is durable, especially if plane will be outside.

Bob H

Tom DeWinter
Vintage Aircraft Association Member
#10 Posted: 7/6/2011 15:18:58

I know you asked specifically to compare kits and Sonex versus Kitfox.

But from your altitude etc if you considered plans built, the Luce-Air Buttercup may fit your needs well.  It has high lift leading edge flaps and several have been built within LSA and honest to goodness airplane cont. C-85 or O-200 engines.  Which you may get used for the same or less price than a new Rotax or Jabiru.  Both are great engines but they are pricey!

Also you might consider the Xenos model by Sonex without the wing tip extensions.  I think it would still be LSA but NOT motorglider eligible.  The extra wing area/span would maybe give you the performance at high altitude you might find attractive.  But again the low stance and snowbanks with long wings might get to be a problem.

Rans S-6 or S-7 may also be good to consider as well.

Just a couple more thoughts to consider.

Jim Goudy
#11 Posted: 7/7/2011 01:07:47

thanks for the great input!

Eric Witherspoon
Homebuilder or Craftsman
#12 Posted: 7/8/2011 21:37:34

Where I'm coming from - built ~80% of a Sonex airframe (from plans) and sold that project.  Built another Sonex from plans, completed and flying for ~3 years now.

1.  Build time - had about 1250 hours into it at first flight.  Since then about 100 more hours with finish-ups, modifications, changing things.  "From plans" = I bought the welded parts and pre-bent long sheet metal from Sonex, so it's not as "from plans" as one could possibly get, but I still hand cut every sheet and hammered out all the ribs.  Kits can greatly reduce this number, and Sonex offers the option to use as much or as little of their kit parts and quick build options as you want to pay for.

2.  Crosswinds?  It's pretty robust, but still a tail dragger.  So know what you're doing.  Nothing wicked, tricky, or dangerous about the handling.

3.  Longest leg I did was 1.5 hours each way.  That's about all I wanted to sit in the seat.  So no, it's not a great x-c machine for me, but I fly EXACTLY the Sonex mission - mostly solo, less than one hour, local area.  So weights and capacities aren't an issue.  What kind of flying do you really do?

4.  Payload.  Payload is just a trade.  My Sonex came in at 660 lbs empty.  Total payload is 490 lbs.  Fuel can be up to 100 lbs of that payload.  Trade off whatever is left for people in the seat.  One nice thing about the 3300-powered Sonex is so long as it is within gross weight, it doesn't matter how the 490 lbs is traded between people and fuel.  It runs out of gross weight before it's loaded out of cg.  With the lighter-engined Sonex's, particularly the Jabiru 2200 option, it can go out of aft cg due to the lighter engine.  That's probably one reason the gross weight is lower - to reduce the chance of loading out of aft cg.  And since the fuel is forward of cg, as it burns off, cg moves aft.  So one could take off in a lighter-engined Sonex and burn fuel to have to land out of cg.  So with those, you need to pay attention.

5.  As someone else said, turbulence is a function of wing loading.  The Sonex is at around 11 lbs / ft^2, so a bit higher than even some of the 1320-pound LSA's, so it's still a light airplane, but pretty solid.  More solid than a C-150 / C-152, if that's what you could compare it to.

6.  Still flying mine.

7. Didn't build the kit, either time.  "From plans" - not that I'll build another, but I think it's good that Sonex keeps the "plans build" option available for those with more time than money (or who just want to try it - it's not hard).  One option I would consider is the pre-built spar.  By far, the most time-consuming page in all of the plans is the page with the main wing spar.  Paying for pre-built there is some money pretty well spent to accelerate your project.  The other pre-fab stuff they offer?  Not as great of a value as far as time saved per dollar spent, but I hear it's well done.

8. My home field is at 2100 MSL, with density altitudes regularly above 4000.  With the big engine, it gets up and goes.  But it's noticeably less enthusiastic with 2 people on board.  For hot/high, I'd say the big engine is the way to go.  But I would say that about ANY plane.

9.  Forward visibility - as a taildragger on the ground, it's about as good as it gets because the glare-shield / panel slopes down on the sides allowing almost straight forward visibility.  The wrapped polycarbonate windshield is a bit wavy to look through, so in flight forward vis - you can lose the plane on downwind ahead of you, but you get used to it.  Most of the visibility is out the bubble over your head, and if you're cranking and banking as the plane was intended, most of your looking is through the bubble, which is just fine.

10.  Not much snow around here, but yes, I'll run it below freezing.  3300 with the Aerocarb starts right up, no problems.  I do not have any sort of heating system - just run long underwear, and the big bubble overhead provides a surprising amount of solar heating, even when it's pretty cold.

11.  I have visited two Kitfox builders.  One seemed to have struggled through a very long build.  One problem he said he had was motivation - most of the time you're working on a collection of tubes that he felt never looked "finished".  Then, nearing the end, it gets covered and suddenly looks much more like an airplane.  He thought with riveted metal, it might be more motivating because when you rivet up a Sonex rudder or tail or whatever and hang it on the wall, it's ready to bolt on and fly.  The other builder I visited might be having the same sort of issue.  I don't know - he's owned the project a mighty long time without a whole lot of working on it happening.  Sonex does seem to be beating some of the "conventions" I've heard about homebuilts - that 80% of them never get done, and those that do get done are on their fourth owner when they fly.  Sonex has about 30% completion ALREADY - and it seems a large majority of the rest of them are actively being worked, and they are OFTEN completed by the builder who starts them.