Considering a Onex Build

[deafaviator]

I've been bouncing the thought of building a kit around in my mind for quite some time now. I think I have finally narrowed it down to the Onex.

First off, a little bit of a background:

I'm a 34-year-old with a Private, currently working on my Commercial, Instrument, and Tailwheel, and my primary job is aerial application support crew, usually driving helicopter platform trucks. I work for nearly 6 months straight with no days off unless weather cancels all flight ops, and usually 100+ hours a week. So when I started the job, I realized that it would be a good opportunity to use the relative free time during the Fall & Winter seasons to build an airplane.

I've briefly had a taste of owning certified, and quickly realized that even a Cessna 150 can be a pain in the ass even when trying to do as much work on it behind closed doors as possible. Not worth the hassle unless you have a bigger wallet than I do at this time.

So like I said, I researched numerous models, and while I really would like an RV or even a Sling 4, I just couldn't swallow the idea of spending $80-120k.

Enter the Onex. I originally was looking into the Sonex, but the Onex caught my eye. I've spent the last few days researching it and I'm feeling pretty confident that this is my steed of choice. I'd like the second seat of a Sonex, but I'd rather have the folding wings, additional performance, and cheaper build of the Onex.

So here's what I'm thinking:

- Onex Sub Kits (Starting with Tail, of course) - I am aware this will be more expensive in the long run, but this will most likely be what I end up doing. Built as a dual-setup for the gear - primarily taildragger but a buddy of mine is a nose-dragger LSA pilot, and I'd like him to be able to fly it as well.

- Both the Machined Angle kit and the Pre-Assembled Spar kit

- UL Power 350iSA (Prop undecided at this time) - including alternate spinner/cowling and other components for this engine. Still researching this part of the build.

- Dynon SkyView avionics, to include the D1000, autopilot control head with pitch/roll servos, full ADSB In/Out system, including GPS, Comm, and CRS/HDG bug control panel, AOA/Pitot kit, etc

Estimated cost of the build:
Kit - $22,000
Engine & FWF - $27,000 (Includes all harnesses, accessories, prop, cowling, spinner etc)
Avionics - $15,000
Misc & Paint - $5,000
Total - $69,000

I'd ideally like to apply as many of the "this will really make the Onex a better airplane" mods as possible. I was also wondering about seeing if Sonex would be willing to sell me one of the original canopies instead of the current raised one. I think the original looked sleeker and better, and I am a short guy, so with the lowered seat, the original canopy will most likely be a perfect fit for me.

This will be my first time tackling a kit like this. I have done some A&P schooling, so I know that building is something I will enjoy. However, I really do like a balance between building and just getting it in the air, hence the upgrades. The Quickbuild, however, is far too expensive and it looks like they all but build the whole thing for you.

So... I'm primarily making this post to get some feedback on a number of things:

1. What would be my approximate performance numbers with that motor at 8,000'? Climb rates, speeds, etc
2. What tools should I get, outside of what Sonex lists?
3. General advice, feedback, and guidance for the Onex in general?
4. Resell value if built as outlined above?
5. How difficult is it to change the engine later to a different model? i.e. AeroVee to UL Power.
6. How difficult is it to gradually upgrade the panel? i.e. Start with the basics and grow into the full panel I'd like to have.
7. Are those wing fold pins really strong enough for 6+ G aerobatics? Seems like a weak point in the wing...
8. Anything else you can think of :D

I know y'all must think I am nuts... maybe I am. I actually am on the fence with the engine and the avionics, to be honest with you guys. The build as outlined above would be one mean, badass machine and a great cross country cruiser which I will be doing a LOT of (I would be commuting frequently between Iowa, Colorado, and Lousiana). Part of me thinks that it would be worth investing into a great panel and engine. The other part of me thinks I'd be just fine with the AeroVee and a sub-$5k panel and there's no reason to spend $20,000 extra on 30 more horses and more bells and whistles. The two primary driving factors behind both of these though:

UL Engine - I am a very "active", and seat-of-the-pants pilot, and I am actually working towards getting a seat in an Ag aircraft, so it makes sense that I want a bigger motor for better fun! Also, for those frequent long cross-country trips, I'd have a bit more speed and reliability. No turbo to fiddle with.

AeroVee Turbo - FAR cheaper to purchase. Less fuel burn. Performance is adequate and isn't excessive. The plane is built to run this engine so it's a good match-up. Doing this engine makes the build actually make financial sense. Using the UL engine means I am now in RV price territory... not exactly what I want when I am choosing the Onex for it's low cost.

Full Dynon Avionics - Primarily because of all the cross country travelling I'd be doing, that avionics panel makes perfect sense. Extremely capable, with all flight info, GPS, engine monitoring, weather, and traffic all on one single display, tied into the paired Comm unit and Autopilot. Would make for an excellent cross-country machine.

Smaller Dynon avionics (D700) with no autopilot - Same as the AeroVee, Cheaper and adequate for the mission. Would require hand-flying for many hours but at many thousands' of dollars in savings. Less complexity during installation. However, I would only save about $3,000... at that small of a savings when looking at the big picture, I would probably go with the full suite and enjoy the savings on the engine side of things.

If I went with AeroVee Turbo and a much simpler avionics suite, I could probably keep the build under $45k. I really want to make sure I build something I will be happy with though...

Anyways... looking forward to hearing all of your thoughts!

Todd

[Concorde]

( Built as a dual-setup for the gear - primarily taildragger but a buddy of mine is a nose-dragger LSA pilot, and I'd like him to be able to fly it as well.)

Welcome .
How are you planning on doing this ?

[kmacht]

It sounds to me like you really want an RV but don't want to spend crazy money on one. Why not buy a used RV instead of building new?. There is an RV-3 on barnstormers right now for 19k. RV-4's can be had for 30k and RV-6's for 50k. The sonex/onex is a great airplane for the $100 hamburger run but isn't the best choice for regular long distance commuting.

Keith
#554

[NWade]

Hi Todd,

I'm just nearing completion of my Sonex, so let me offer a few insights and tips after 800 hours of building and learning:

First, you've got a lot of avionics & systems listed in your potential build. While it can really be tempting to pile on those things, I would urge you to think long and hard about whether you'll really need them - and want to spend the money on them, and spend time setting them up and dialing them in, and want to maintain them over time. Every thing you add (like autopilot) means more weight, more complexity, more money, and a longer timeline before you get to fly.

Although the kits from Sonex Aircraft are much easier and faster to put together than when I began in 2009-2010, they still take hundreds of hours of work. So my advice is to put all of the Avionics & Extras out of your mind, for now. They won't really affect most of the basic construction of the airframe, and who knows what will be available on the market when you complete your aircraft in a few years' time? Focus on learning how to build a good airplane and then concentrate on that; then worry about avionics and engines & FWF as you near the finish-line.

Now despite my advice, I'm going to circle back to the autopilot and a couple of your items because you seem to be considering a setup that is a bit muddled in terms of your mission. All aircraft are compromises (trading weight & size for strength & speed, among many other factors) - and the more compromises that you pile on, the poorer the overall performance your aircraft will have. Its really important that, either before you build or during your build, you really think long and hard about your mission. What are you actually likely to do in the aircraft, and how often will you do it? Build the airplane that meets the mission you will be performing 80% - 90% of the time, and accept that it won't be ideal for some other things. Don't try to make it a "do everything" aircraft or you'll end up with something that does everything poorly. :P
Here are some tidbits to roll around in your head...

• The Sonex & Onex can fly longer distances if you really work at it, but they will never be long-distance cruisers like an RV or a LongEZ. So ask yourself: Will I be in the air long-enough to really warrant an autopilot & additional avionics, or can I stand to hand-fly the aircraft for 2-3 hours at a stretch (and how are you with long car-drives, by comparison)?
• Will I really be flying in bad weather with such a small aircraft and need an IFR-type panel with a CDI/HSI gauge, or is simple VFR & GPS navigation with a single-panel Dynon or MGL unit good enough? Weather is a huge factor in using a small aircraft to reliably commute long distances for work or other time-sensitive engagements. Can you stand to be 1-3 days late to arrive somewhere (regardless of avionics)?
• Am I really going to do enough aerobatics to want to spend a bunch of extra money on the biggest possible engine? And will that extra avionics gear help me with aerobatics or hurt me (in terms of extra weight and cramped space)?
• How much performance am I willing to lose in order to figure out some way to have the support-structure in place to mount different landing-gear types? Can I accept a slower climb? Worse aerobatic performance? Given the direct-steering nature of the Sonex Aircraft tailwheel, its super-easy to handle... Maybe your buddy can just learn to fly a taildragger and be OK without all the complexity of trying to swap the gear around?

The key is that adding each one of these items will pull down the aircraft's ability to perform some other part of your desired activities. It isn't easy, but you need to focus on which 1 or 2 activities are most-likely and most-important, and then focus the aircraft around them.

Regarding your questions on engines and avionics:

• You express some concern over the UL Engine, but I can't see what has you hesitating over the turbo (as a much cheaper engine with strong power)? Can you explain what you think there is to "fiddle with" on a turbo? (For reference, I'm building an AeroVee turbo and can say that there are a few extra components to install and a few extra hoses to run, but otherwise its operated just like any other engine)
• Dynon makes a great product. But the MGL systems offer a similar feature-set and the "Lite" (single-panel) models can net you good savings while still controlling a radio, transponder, etc. Whatever you go with, remember that every extra wire and system you run is going to increase your build-time and increase your ongoing maintenance hours & budget. [Full disclosure: My Sonex panel will have an MGL Discovery Lite, a V6 Radio, and a Trig transponder. I have experience with the Radio & Transponder in my sailplane and am very happy with them. I've also considered using an MGL Xtreme mini-EFIS and an iPad with ForeFlight or WingXPro, to save another ~$1000 because that amount of money still buys a lot of AvGas]

And finally, here are some thoughts about the other questions you asked:

1. I'm not flying yet so I can't speak to this completely; but have you checked out the Sonex Flight podcast? In the AeroVee Turbo episode they talked performance numbers, which might give you a baseline...
2. Lots of tools. :) I urge you to use the "Search" feature at the top of the Forum webpages and look for tools threads from the past - there are many with good advice. Here's a quick (but incomplete) rundown of my key tools - discounting common items like Sharpie pens, hammers, screwdrivers, wrenches, etc:
   
   • Bandsaw (tabletop unit)
   • Drill Press (tabletop unit)
   • Scotchbrite wheel
   • Harbor Freight 1"x36" belt sander with scotchbrite-type belts
   • 30-gallon air compressor (get the biggest one you can)
   • 2 ATS Pro Palm Drills (tiny, light, fast, and still not that expensive. I struggled with heavier cheap air drills for a long time and getting these palm drills were a revelation, without breaking the bank)
   • Cleco Pliers & Lots of extra silver & brass clecos (you can never have enough)
   • Harbor Freight pneumatic rivet-puller
   • Hand files (multiple flat & round files, vixen file)
   • Scotchbrite abrasive pads (I find the maroon color is a good grit for surface-preparation and smoothing scratches)
   • Multiple deburring tools
   • Wiss Sheet-metal Snips and sheet-metal shears
   • Small Bench-mounted bending-brake (not used a ton, but great for bending small plates, clips, & gussets that ship as flat parts from Sonex)
   • Bench-mounted vise (with some soft-jaw inserts)
   • Rubber/Plastic mallet
   • Unibits (also known as step drills)
   • Cordless drill with extra batteries
   • Dremel tool with quick-change metal cut-off wheels
   • Fluting pliers & Seaming pliers (not used that often, but easy and fast when needed)
   • Hand-actuated sheet-metal "nibbler"
3. Can't speak to the Onex itself, but the Sonex has been a good project that's been pretty straightforward. Go to a SportAir sheet-metal workshop or go to the Sonex builder's seminar and you'll have a good understanding of how to build it (I also recommend reading Ron Wanttaja's "Kit Airplane Construction" book). At first you'll have some hiccups and need to remake a few parts, but over time you'll quietly build up skills and get really good at it.
4. Sonex Aircraft, due to their small size and simple construction, do not have great resale value. A completed Sonex may go for roughly what you have into it (or slightly less); but the value of your labor will essentially be $0. These are not high-dollar show aircraft that retirees or wealthy hot-rodders will pay a lot to buy... These are planes you build so that you can have your aircraft and fly it. :)
5. AFAIK, the Onex is like the Sonex: When you get the fuselage kit you specify the engine you want, and they'll ship you the proper engine-mount for it. So if you change your mind and you haven't yet mounted the engine, its a simple as swapping out that one part (and maybe some shims to align the engine mount properly to the fuselage). But once you start mounting your firewall forward items, it gets complicated and expensive in a hurry!
6. Panels for Sonex Aircraft are easy to make and easy to replace. Changing up the wiring may require some uncomfortable work under the glareshield of a completed plane; but its not terribly hard to add a few wires, add a fuse/CB, and get it working. The key is to plan your avionics bus from the beginning with expansion in-mind.
7. I can't speak specifically to the Onex pins, but keep in mind that none of the Sonex designs are hardcore aerobats. You won't be doing Lomcevaks or snap-rolls. You'll be doing Loops, Rolls, Spins, Immelmans, etc... You'll only pile on the G's if you majorly screw up one of those maneuvers. :P

Lots more can be said, but its 5am and I'm only awake because I have a cold; plus I'm sure others will chime in here to fill in more info. :)

Good luck, stay focused, and build & fly safe!

--Noel
Sonex #1339
Aerovee Turbo, Taildragger, Acro-ailerons, Flush Pulled Rivets, Center-Stick
Wings & Empennage complete, Fuselage nearly complete, Working on fuel system & Landing Gear

[fastj22]

What's your mission? Yank and bank for an hour or a cross country machine?
Onex is not the latter, not enough baggage or fuel capacity.
And the former, you certainly don't need anything more than basic avionics. And you really don't need the extra HP if you are trying to keep costs down.
If looking at a quick build, I'd first look at rescuing a project, half the cost of a quick build.

[builderflyer]

Todd, I'm with Keith on this one. If you can give up on the folding wing, then you are a prime candidate for an RV. For the money you are willing to spend, an RV4 would be an excellent choice for you...........plus, you gain an extra seat. My neighbor has an award winning -4 that he built about 25 years ago but with many upgrades added through the years (like a Dynon Skyview in the panel). He and his wife have flown it everywhere in the USA and as far away as the Bahamas and Alaska. He has raced the airplane many times and loves his aerobatics as well. You can build one of these for your price or buy an already flying one for 2/3 your price, or less. No, I don't work for Vans. Just something to consider.

Art............Sonex taildragger #95............Jab3300 #261

[gcm52]

Typically kit builders sell there completed airplanes for less than the cost of the parts in them, so if you are mostly interested in flying, you probably will get a better deal if you buy a completed Onex. Then you can fly it for a while and figure out what upgrades you really want.
If you are mostly interested in the building process, which by the way is very fun, then building a Onex is the way to go. I would not worry about the avionics and engine until you are close to finishing the airframe, because a lot can change in terms of avionics and engines during your airframe build. For example, I almost bought a Camit 3300 for my Onex. I decided, fortunately, to wait a while, and boom, one day Camit goes out of business. That experience caused me to decide to completely build the airframe before installing an engine so as to delay the engine purchase as long as possible.

[SonexN76ET]

I did a 2200 mile cross country in four flying days last spring in my Sonex. It was very enjoyable. I kept my legs to two hours to two hours and twenty minutes and always landed with over an hours worth of fuel on board. While not a Beechcraft Bonanza, there are many of us who routinely take them on long cross countries in VFR weather.

As far as fiddling with the AeroVee goes, the only things I have had to tinker with are the AeroInjector mixture needle setting, cylinder head bolt torque, and valve adjustments. I have also spent considerable time ensuring my engine cooling baffles are properly sealed, but you will have to do that with any engine. If you are not an "engine guy" I would look at the UL Power or Jabiru as viable options.

I am sure you will be pleased if you choose the Sonex or Onex.

Good luck!

Jake

[tljones42]

I'm building a Onex Trigear with an Aerovee Turbo engine. I have comments regarding three areas of your thoughts. First, while the Onex can be built as either a tail wheel or nose gear airplane, reversing either form, once completed, would not be a simple task. The trigear uses an additional attachment to the motor mount which houses the nose gear strut and the trigear rudder and nose gear are linked so it is not as simple as turning the gear around and moving it forward to convert to a tail gear. Also if you are using the Sonex hydraulic brakes, the brake lines will be routed differently on each version. There is a bottom rib and stiffener that is position ed differently in each version. I think your main gear wheel pants on the trigear would also have to be reversed and potentially modified since the tail gear version turns the landing gear 180 degrees moving what was on the left to the right side, etc.

Secondly, regarding the turbo Aerovee on the Onex, I would offer the following cautions. The Onex firewall is relatively small compared to the Sonex and fitting the turbo into that space very much drives the location of other firewall accessories especially on the trigear. If you choose to build the trigear, space is further limited by the nose gear and the attendant cables, pulleys and steering arm and its freedom of movement . While I'm finding that with lots of thought the turbo can be fitted on the Onex trigear, if I were doing this again I would go get a tail wheel endorsement and build the tail wheel version thereby freeing up precious firewall space and simplifying the installation.

Lastly, as pointed out by someone else, if you are planning to use the Onex as a cross country machine, you will have almost no room for baggage given the weight limit in the baggage area. If you are able to travel very light between locations, maybe you can make it work. Just my thoughts and experiences. Best of luck.

Tom Jones
Onex 0133
Turbo Aerovee 0838

[SvingenB]

So... I'm primarily making this post to get some feedback on a number of things:

1. What would be my approximate performance numbers with that motor at 8,000'? Climb rates, speeds, etc
2. What tools should I get, outside of what Sonex lists?
3. General advice, feedback, and guidance for the Onex in general?
4. Resell value if built as outlined above?
5. How difficult is it to change the engine later to a different model? i.e. AeroVee to UL Power.
6. How difficult is it to gradually upgrade the panel? i.e. Start with the basics and grow into the full panel I'd like to have.
7. Are those wing fold pins really strong enough for 6+ G aerobatics? Seems like a weak point in the wing...
8. Anything else you can think of :D

1. I don't know, but as far as I know, you also have to make the engine mount etc etc. The ULPower is injected with electric pumps. It is quite a job to fit one in there, all in all.
2. As much as possible. There is no such thing as too much tools. Adjustable reamers for the wing pin/bolt is a must.
3. I'm building an RV-4 and I'm almost finished with my Onex. The Onex is MUCH simpler to build, maybe a factor 10. Still, there are lots of inaccuracies and poorly explained procedures. The wings and folding mechanism is much more delicate than what it looks like up front. Not difficult or anything, just requires accuracy and fiddling.
4. ??
5. Difficult, but it will be simpler with kits from AirWard (link to the right on this page)
6. Just remember there is almost no panel space. Again, use kit from AirWard, and you can easily make/change panels.
7. Yes. They will take at least 11g. Definitely not a weak point, but accuracy in reaming is important. Besides, AirWard has stronger pins.
8. Lots of fun building. Consider a Rotax instead of ULPower. Hummel and Revmaster are other more easier alternatives.