SonexBuilders.net

Hello all,

Sorry to bring up this topic yet again, but I have been trying to decide for several months now which kit I will be building, and have been hung up on the pros and cons. I figured I would post here and see if any Sonex owners can push me over to their side.

Basically, I like everything about the sonex except for two main things: the size and the fuel capacity. I think I can get over the size, especially since my wife is 5'1" and our combined weight is about 250#. But the low fuel capacity severely limits xc abilities (especially with a Jab 3300 up front). I have seen some people get creative in adding aux fuel, but it seems to be a bit of a challenge.

The other major consideration for me has been the RV 7/9, which would solve both of those problems. Unfortunately, and the biggest deterrent for me, is that I don't want my build to go on for 5+ years. At that point we will probably have young children and xc would be out of the question anyway. Blind rivets is a HUGE selling point for me as well.

FWIW, I have considered the RV-12, but it is just too expensive (for how quickly it is built; I could amortize the payments on an RV-9 over the years it would take to make). I really like the Zenith 650 model, but I have some concerns over how "fun" it would be to fly, and the zenith low-wing owners don't seem to be as thrilled about their homebuilts as the sonex/RV crew.

Thanks for any thoughts. I know this debate has been posted 1000 times on various forums, but I've read just about everything and am still debating.

Sounds to me based on your pro's and con's that you have already made up your mind .If you need that extra little push then do a cost comparison.( hint,price your engine options for the RV's and Zenith)Sonex will win hands down but I'm guessing you already know that.
Cheers,
Mike

If XC and kids factor in heavily, maybe a 170/172 is a better choice. I would have gone that route if my wife liked to fly. It is a good XC and family aircraft. If you see the XC going away in 5 years due to kids, do you want to optimize on a short time period? Or does it make sense to build for the 5 year away situation, live with the XC compromise for 2 or 3 years, and then have the right airplane?

If cost and build time were no issue, I would have an RV. I was short sighted putting the RV4 aside for the hummelbird, because if I realized how long it would take me, I could have spread the money out over a long time. The Waiex is better for my kids though because of the size by side seating. No regrets.

The Sonex marketing byline is "Reality Check." You have to take a good look at your situation and see if the extra $ for an RV buys you what you need, and if it will keep you flying.

Here's a bit of motivation for you ...

http://www.youtube.com/watch?v=hLuZhy4L_GA

I would also suggest that you make a pilgrimage to the American Sonex Association gathering next weekend in Crossvill Tennessee.

Dale
N319WF

samiam,
It sounds like you've got the money right now for an RV-7 or -9 kit. If so, you've got enough to buy an already built Sonex (or one nearly done). Finished, flying RV's tend to be pricey (I think partly because they tend to have high-end avioncs and a certified engine). So, if the build itself isn't the goal, maybe buy a flying Sonex now and see if it meets your needs.

Thoughts on Cross-country: If you build light, and given the weights of you and your wife, you could still have 75 lbs for bags and aux fuel with a full tank, even with the Jab 3300. Just because you have the 120HP doesn't mean you have to use it, you can throttle back on your cross-countries and sip fuel at 4-5 gph for a long leg just like an Aerovee powered plane, while still having the 120 HP available to get off the ground and do more spirited acro. But, if flying long legs at max gross and high speed (170+ MPH) is your goal, then an RV probably makes more sense. I'd recommend doing the math on "dollars per hour saved" for your anticipated use (realistic number of trips and avg distance) before making any firm decisions. Include fuel burned, insurance, "opportunity cost" for the dollars tied up in the airplane, reserve for engine rebuild, etc. Comparing the all-in costs for an RV and Sonex (flying or kits), you may find that taking an extra hour or so on a long trip due to slower cruise speed and an extra fuel stop might be a real money saver. I guess we could consider this exercise part of Sonex's "Reality Check." And, if you stop every 3 hours or so for fuel, your bladder might thank you, too. :)

Hey Sam,

Great question! Both the Sonex and the RV-7 have a lot in common. Both are great airplanes with a loyal customer base. Both have excellent flying qualities and are a blast to fly without being challenging or tough to fly. Both are aerobatic capable (if that happens to be your thing).

The advantages to the RV is that it's the faster of the two, and probably generally regarded as the better long distance cross country platform. A lot of people install a 180 or 200 horsepower Lycoming in the RV, giving 170-180 knot cruise speeds. Combine that with the practical ability to build IFR capability into the airplane, and you have a fast, capable sport plane.

The Sonex also has some very good advantages as well. First off, the cost to build and operate is a great deal less with a Sonex. While building a nice RV runs a lot of people $80,000-100,000 a nice Sonex is literally half that. Operating costs are also much less; 180 h.p. RV's seem to burn around 8-10 gallons per hour, while Sonexes once again are literally half of that. Even the 120 h.p. Jabiru 3300 will only burn around 5-5.5 gallons per hour, or less if you're just out having fun. Think of it like this...the Sonex will give you 75-80% of the performance of an RV at only 50% of the cost!

Secondly, building a Sonex is much faster, especially now that Sonex has provided the matched hole construction. You don't need to dimple every rivet hole in the Sonex, and riveting can be done by yourself. This saves a ton of time, maybe even half! I normally hear 1200 hours to build a Sonex, and 2400 hours to build an RV.

Finally, don't forget that the Sonex qualifies as a Light Sport airplane while the RV is not. Hopefully it won't matter, but if you ever have a medical issue this could make a huge difference.

As for the cross country portion of your concerns; I completely understand the dilemma but remember that, even in stock form, 2.5 hour legs in a Sonex really isn't an issue. In my experiences, I'm more than ready to get out and stretch after that much time anyway so the amount of fuel the Sonex carries really isn't an issue. Like Mark said, you and your wife will have tons of flexibility for carrying cargo, fuel, etc.

In the end, I'd say build whatever your heart tells you to build! If 99% of your time is flying long distances, by all means go for the RV. If you're more interested in saving some money while still having a blast flying an airplane you built much faster, than go for the Sonex!

Mike,
Excellent summary, well written. I had forgotten to mention light sport. Though I hope to build and fly other airplanes other than the Waiex, that is the airplane that I will likely finish in someday, hopefully well in the future.

Thanks for all the advice. Mike, you broke it down very well. It seems to just make more sense to build the sonex for me. I will not be flying long xc (anything that would even require a fuel stop in the sonex) more than a couple of times a year I suppose, and the sonex just looks like so much fun to do some casual weekend flying in. The construction looks very straightforward. Now I just have to reach out to the local EAA and see if my local Waiex builder will give me a flight!

So two questions for you sonex gurus out there. First, do you think it makes sense to order the plans first, and get some aluminum angle from Spruce, and make up the parts prior to ordering the whole kit? And second, I can't find much information on anyone who has added an aux fuel tank to their sonex, but it seems like it would be possible to get a 5-gal tank behind/beneath the seats. Any experience with this?

If you are eventually going to buy the full kit then I would suggest just doing that. If you are unsure about building then start with the tail kit. Just ordering and looking at the plans is pretty daunting as there are alot of pages and until you start building they don't really start to make sense. As far as additional fuel, I would send an e-mail to Aaron Knight. You can find his contact info on the sonex website. He added a tank that goes just behind the seat to do longer cross countries. He is also the guy that has done the youtube videos flying to the bahamas and the grand canyon. He can give you alot of insight on what does and doesn't work for long cross countries in a sonex.

Keith
#554

There are a few options for extended range fuel tanks on the Sonex. If you want a permanent addition to the fuel, a permanent tank behind the seats or tubular tanks in the holes of the forward ribs of the wings are both options that have been used. Also, there are several options for adding a fuel tank in the passenger seat and running a line to one of the fuel tank ports if you want a "semi-portable" system.

As for getting the plans early... like Keith said, I personally wouldn't bother with it until it's time to get the kit. You will get all of that material anyway, and I believe the lead times to get a kit from the factory is pretty small, so you could be buildng soon regardless! Speaking of which, are you considering the purchase of the pre-made angle pieces? Personally, I'm more of a pilot than a builder and if you're the same, I recommend you consider that extra purchase. It will make the kit go together that much faster by saving you a lot of time! The pre-assembled wing spars are also nice but that's fairly easy work. Between the two options, I highly recommend the pre-made angle pieces.

Where are you located Sam?