Seeking advice on buying a used kit

[samiam]

I'm just about done with my tail kit, so it's time to move on to the wings! I am close to pulling the trigger on the used complete kit on Barnstormers, but before I do, wanted to seek out the wisdom of the board. I have some potential concerns:

1. It's not a "B" model. This is something I have done some soul searching about and can live with. I decided to build a Sonex before it existed anyway.

2. It's from 2009. Not sure about the condition of the parts, especially things like the canopy, after being in storage for so long.

3. It's from before the kit was post-2012 "match drilled." This is a big one for me, but he does have the machined parts upgrade and the prebuilt spars, which should offset some of that factor. Additionally, with the money savings from the used kit, I would probably invest in buying a lot of the individual parts from Sonex, especially the ones that are critical to get right to keep the airplane straight.

Anyone with experience with a used kit have any thoughts? Other things to consider? General wisdom from the board? Thanks!

[gcm52]

I built a Zenith 701 that was not "match drilled" and am now building a Onex that is, and the difference is tremendous. Much more fun (the tedious parts of laying out rivet lines is gone) and everything is completely straight and true with the Onex. How much are you saving with the used kit? It better be a lot!

[fastj22]

Having the machined parts will save you a ton of time fabricating all the little bits. Not having the match holed will require you learn about proper blue lining, hole layout and part alignment. If you are a novice, you will probably screw up a few pieces and have to replace them. I have a large trash bin with my learning pieces in them. I wouldn't fear a non-match holed kit. That kit looks like a good bargain.

[NWade]

Sam -

I'm coming into the home-stretch with my Sonex, which I bought in late 2009 (before there were matched-hole parts available). :-) I started out scratch-building and after 50 hours I decided that my busy life demanded a kit, if I was going to have any shot at completing the thing. Below is a recounting of my experiences, and some thoughts on a used kit at the end...

So I bought a tail sub-kit in 2009. I built it in ~102 hours. (Note: no matched-holes. Plus I decided to go with flush pulled rivets on all skins/exposed areas. That adds at least 15-20% more work, since you have to dimple or countersink every single hole and the aircraft was not designed with this in mind. I am a sailplane pilot, so drag is my enemy and I felt compelled to build a smoooooth aircraft; but if I had to do it all over again I'd probably go with standard rivets as it really does slow things down to "do it right")

Between the scratch-build and the tail-kit experiences, I proceeded to buy the remaining kit with the machined angle components, but without the pre-assembled spars. I am super happy I bought the machined angle components! They have saved a ton of time working on fiddly bits, and even the best parts I fabricated from scratch cannot match the precision and professional appearance of the machined components. [Note that they still require a little edge-cleanup and some hole-drilling, and an occasional bend].

I was unwilling/unable to spend the money on the pre-assembled spars (but having done it now, if someone has the money I would recommend it). The spars were not difficult, but they were time-consuming! And I had the misfortune of misinterpreting the drawings slightly, and I put the solid rivets in from the wrong side on the first spar. This resulted in me taking a year off from the project (depressed/demotivated), and then an extra 30+ hours of labor were spent carefully drilling out every rivet and re-driving them from the opposite side. Total time on the wings (including pulled flush rivets throughout): ~390 hours.

At the start of this year I had the wings & empennage complete, and as of last night I put about 100 hours into building the fuselage and hit 600 hours total on the project (again, note that I'm building carefully and doing a whole lot of dimpling & countersinking). The good news is that the aft fuselage is just about ready to rivet, and it really looks like an airplane now!

Over the years, I've bought 5-6 replacement parts from Sonex - a couple of angles that I messed up, and a replacement skin when I tore a hole dimpling it too-aggressively with a C-Frame (d'oh!). I also gave in to laziness when I began working on the fuselage, and I ordered about a dozen individual matched-hole parts from Sonex (...various vertical reinforcing channels and horizontal cross-ties that you normally fabricate from "Z"-stock components), because I am itching to wrap up the project. It was a total extravagance and probably saved me 10-20 hours of labor, maximum. But they're precise, and it was nice to unwrap them and be able to immediately cleco them to the (pre-made) fuselage skins! :-) I've also emailed Sonex Tech support 3-4 times with questions about parts that didn't seem to come out quite right, or ways to salvage a big part that I'd slightly mis-drilled. They've been great; as long as you don't expect a fireside chat or a pep-talk every time you check in with them (its a business; they're going to give you a friendly-but-succinct solution, and then turn to their next customer while you to get back to working on your plane). BTW, this site is great for pep-talks and encouragement. :-)

I'm not going to lie: Matched holes would probably save another 10-15% on labor over the 2009 kit. However, the machined angle parts do contain a lot of pilot holes, as do the basic kit skins. So between the two you do get some labor-savings. Often times what you wind up doing is measuring and aligning a part (without holes) up against a part that does have pilot holes. Then you clamp the two in-place and drill through the (Sonex-supplied) pilot-holes into the "blank" part. Insert a few clecos as you go, and then go back and updrill all the holes. Voila! Not that hard. :-) Mostly I lay out blue lines on things like ribs and stiffener flanges, so that I can visually see through the pilot-holes on skins and ensure I've got the undrilled part lined up properly. My rivet fan hasn't been used in a few years! :-P

OK, this is getting very long and rambling so here are some quick thoughts for you:

• Before you buy the kit, check this person's work VERY CLOSELY. Nothing sucks worse than buying something and having to re-do what's already been done because of sloppiness or unsafe modifications. If they stuck to the plans, deburred the holes, and didn't put huge scratches in the material then you're good to go; but watch for any of those common mistakes - as well as sloppy hole placement that violates your edge-distance minimums. Establish your own sense of acceptable workmanship (realizing that we're all amateurs!), and then don't let the excitement push you beyond what you're comfortable with.
• Check the canopy and windscreen material for scratches. If the original builder left the protective cover on them, they're likely to be fine. The only thing that's happened to my canopy is that the masking tape lines (which indicate roughly where to trim off the excess material) have come unstuck as the adhesive failed over time and with temperature fluctuations in my workshop. Otherwise its fine. IIRC, around 2009 is when they switched to using the "Sonplex" material for the canopy - which is very soft and malleable. I haven't had any signs of embrittlement or cracking, with it sitting around in a variety of positions for years.
• If you buy the kit, spend some time at home with your computer, a pen, and the plans laid out on a table or on the floor. The plans have received many tweaks and updates over the years! Most of the revisions since 2009 are minor (like fixing typos on the plans) and are not "required"; but still its best to get the changes recorded onto your plans so that you have the best build experience. Peruse the Sonex website and note down all the drawing revisions that apply to your plans - and do so ON the plans. Trust me, you'll appreciate this later!
• However many clecos you think you'll need, buy more. You only need a handful of Black clecos & Gold clecos (for bolt-holes), but you'll want several hundred silver clecos & bronze clecos.
• Use clecos to hold parts together for as long as you can. There are many places where you do not want to rivet components together until the entire area is ready to be finalized. SIDE-NOTE: 1 or 2 clecos is usually not enough to hold something securely - especially if you're still drilling on it. 1 or 2 clecos will still allow a part to slide/shift by small amounts. I tend to cleco every-other hole, or every-third hole (on big assemblies/skins).
• Hold off on installing bolts (or at least torquing them down) until you're ready for final assembly of the aircraft. I made the mistake of torquing some tail bolts when I finished the tail; and now that I'm on the fuselage - 6 years later - I'm having to take them all apart because it turns out the bolts need to go through the aft fuselage! Of course, you don't want to forget torquing bolts later, so figure out a system to remind yourself which bolts need tightening. And by that I mean figure out a system that involves writing, or colored pen marks, or something permanent; not in your head where you'll forget over the months & years!

I'll post more if I think of things throughout the day; but hopefully this (titanic) post is helpful!

Take care,

--Noel
Sonex #1339
TD, Center-stick, Acro-ailerons, flush-pulled-rivets, Turbo AeroVee

[jjbardell]

Just my $0.02...

Make an offer on the 90% completed plane on Barnstormers that comes with the Aerovee engine. Asking price is only $2k more than the '09 kit. Buy it, sell your tail kit (which has even more value since it can be attached to a B model sub kit), sell the engine, sell the motor mount and have an air frame ready to finish for $7k+. Then put the power plant and avionics you want in it with the cash saved.

Questions I would be asking myself are:
- Do I want to build it all, or will I be happy with it mostly built
- Is budget a consideration, if so, is a motor and panel more important than building
- Am I a builder or a flyer

Note: I have no affiliation with either kit. :)

[fastj22]

Even buying a 90% finished kit will require a great deal of effort to finish. Especially if you haven't built before. All the skills you acquire during the normal build will need to be learned and refined to finish up someone else's work (and rework). That final 10% is a lot of work. My buddy Mike bought a 95% complete plane from an estate. I thought it would take at most a month to finish. Three of us (Jeff Schultz, me and a Long EZ guy) and Mike took over 6 months to finish it up and get it in the air working most weekends. Mike had no building experience. I had built my plane, Jeff had built two Sonex.
My two cents and worth every penny....If you want to fly, buy a flying plane. If you want to build, buy a mostly unfinished kit. Buy a partially completed kit only when its a great deal.

[samiam]

Thank you to everyone for the ongoing support and for the really excellent advice in this thread. A couple of follow up notes:

1. Only the tail has been started. Everything else is untouched. I already finished my own tail, so I wouldn't be relying on anyone else's construction quality.

2. I definitely want to build. That is the dream for me. I know that it will take years and be very frustrating at times, but it is still the dream.

At this point I am definitely leaning towards picking up this used kit. It will definitely take longer without the matched hole parts, but I will likely be ordering at least some of them from Sonex to help the build.

[samiam]

Often times what you wind up doing is measuring and aligning a part (without holes) up against a part that does have pilot holes. Then you clamp the two in-place and drill through the (Sonex-supplied) pilot-holes into the "blank" part. Insert a few clecos as you go, and then go back and updrill all the holes. Voila! Not that hard. :-) Mostly I lay out blue lines on things like ribs and stiffener flanges, so that I can visually see through the pilot-holes on skins and ensure I've got the undrilled part lined up properly. My rivet fan hasn't been used in a few years! :-P

I think this is key for me. I am mostly afraid of drilling completely virgin holes (like in the control surfaces) as that leaves the biggest room for error. As long as most of the time at least 1 piece has holes in it, I will feel a lot better!

[NWade]

One more "food for thought" item:

jjbardell mentioned buying a kit with an engine. I personally would never do this; or at the very LEAST I'd buy it with the intention of only keeping a few of the engine components (or, with selling only a few components from the engine).

Why? ...Because *most* aircraft engines rust out long before they wear out (BTW, I highly recommend the EAA video Webinars with Mike Busch). The best way to have an engine start corroding is to leave it sitting around unused. Without oil regularly splashing up on the metal components (during engine operation), general humidity in the air will allow corrosion to begin forming in various places. Few amateurs/first-time-builders know how to properly "pickle" engines for long-term storage (with special oil that forms a long-term film on the metal). As a result, I would be generally suspicious of any engine that's been sitting around for more than a handful of months - especially if its been assembled (since that makes inspecting the internals much harder). I'm not saying such engines are automatically scrap; I'm just saying that I would start from the assumption that its not in the best shape, and go over it with a fine-toothed comb before pronouncing any part of it as good/usable. As a rule, Avionics and Engines best left unpurchased until the very end of the project!

--Noel

[NWade]

I think this is key for me. I am mostly afraid of drilling completely virgin holes (like in the control surfaces) as that leaves the biggest room for error. As long as most of the time at least 1 piece has holes in it, I will feel a lot better!

samiam -

You will very rarely need to do this (mostly with bits of channel stock that you cut & tweak, as well as the control surfaces). And I know this is "easier said than done", but try not to be too intimidated by laying out & drilling holes! It gets better/easier with time, and the Sonex design is fairly forgiving. I know you've already completed the tail subkit, but have you been to a Sonex workshop, or an EAA SportAir workshop? The EAA basic metal class is well worth a weekend!

I also highly recommend Ron Wanttaja's "Kit Airplane Construction" book. Its full of tons of good information!

Enjoy,

--Noel