Bruce Loos
Automotive Hobbies
Sonex Aircraft Project

I've wanted to fly a self-built aircraft ever since 1967, when I first obtained my FAA Airframe & Powerplant Mechanic certificate.  Since I tend to be a risk averter, especially when it comes to flying homemade aircraft, I considered many designs before selecting the Sonex.  The Sonex is a very strong, all-metal design, offering exceptional performance per dollar.  My reason for building it is very simple.  I like to build stuff in my garage. 

The Sonex can be built in a variety of configurations including three engine choices, center or dual control stick, and tricycle or conventional (tail wheel) landing gear.  Mine will have center stick, conventional gear, and a 80 horsepower AeroVee engine.  My first engine choice was the more powerful, 120 HP Jabiru engine but the price difference plus the fact I'm really more interested in building rather than flying the airplane led me to settle on the AeroVee.   Center stick configuration will allow the pilot to comfortably fly solo while seated in the center of the aircraft.  For carrying an occasional passenger, two occupants will be able to sit side by side, with the control stick between them.

Sonex Specifications

Sonex Plans are extremely complete.  I purchased these plans in 2002 and began fabricating wing ribs and machined aluminum angle parts shortly after.  The plane can be scratch built using only raw materials and plans.  To speed up the construction process, a kit featuring many prefabricated parts, is available.  I will be using a combination of scratch built and prefabricated components.

Shop tools used to build the Sonex are surprisingly simple.  My wife and I attended a builder's seminar at the Sonex factory in Oshkosh, Wisconsin.  I was surprised to learn they recommended cutting aluminum angle components with a wood cutting band saw.  I was really skeptical but I tried it anyway.  I used a 1/2" wide blade w/8 teeth per inch and waxed the blade before each cut.  It worked great! 

One of my absolute favorite shop tools is my grandfather's 1939 Homecraft drill press.  I can't explain it but I just feel good every time I use it.

Here are some machined angles I cut with the band saw and drilled with the drill press.  My plan is to make as many small parts as possible, prior to assembling anything, in order to conserve shop space.  With most of the small stuff completed, assembly should go rather quickly.  At least 200 Sonex aircraft are already flying.  I'm not breaking any new ground here. Many builders have published excellent web sites.  I plan to focus on building an excellent airplane, rather than making a great web site.

Several of the aluminum angle pieces needed to have their angles opened or closed prior to machining.  These steps, milled into vise jaws, worked well for closing the angles.

I purchased several 4' x 12' sheets of 6061 T6 aluminum for the wing ribs and bulkheads.  The supplier rolled the sheets and shipped UPS.  The shipping charges were very reasonable.

I cut the 26 forward wing rib blanks with hand shears and used a flycutter in my drill press to make the lightening holes.

Outer flanges of the ribs are bent over the form blocks with a rubber mallet.

Flanging dies were used to add stiffness to rib webs around lightening holes.

Modified Vise Grip pliers were used to flute the rib flanges.

Here are some completed forward ribs.  Check back from time to time.  I'll be adding more photos as the project progresses.

Completed rack of ribs

My pile of scratch-built parts has now grown and I have just ordered the complete Sonex Kit less components already fabricated.  The kit will be shipped during the week of 9/24/2012.  I am anxious to actually begin assembling some parts.

I took delivery of the Sonex kit today!

Horizontal Stabilizer Frame Buildup

Beginning assembly of horizontal stabilizer, vertical stabilizer, elevator control horn, and elevator trim tab

Vertical Stabilizer, Rudder, & Elevator Trim Tab Complete

Aileron Assemblies Complete & Balanced

Flap Assemblies Complete.  White stuff is protective plastic film to protect aluminum surface until removed.

Horizontal Stabilizer & Elevator Assembly Complete

Main spar web drilling setup

Countersinking holes in main spar center sections

Main Spars pinned and joined

RH Aileron Bellcrank Assy

RH wing structure

RH Wing main spar carry-thru

Both Wing Boxes Complete

Rear Fuselage - Riveting Complete

Forward Fuselage and Main Spar Tunnel Construction

The engine is an air cooled Volkswagen, converted for aviation use.  It features a forged stroker crankshaft, two spark plugs per cylinder, and dual ignition systems.  Total displacement is 2180 cc. It is rated at 80 HP at 3200 RPM.  It is supplied in kit form and must be assembled by the builder.  All components are brand new.

Fully assembled AeroVee engine, less accessory section, on engine stand

This photo shows the dual rudder pedal installation.  

Motor mount and landing gear installation  --  Drilling the titanium landing gear legs and maintaining proper wheel alignment was a little tricky.  Mine is close but not perfect.
Engine ready for installation

Fabrication & Assembly of Engine Cooling Baffles

I made the instrument panel twice before I was satisfied.  On the first attempt, the toggle switches were too close to the support channel at the bottom of the panel.

The wings were installed and rigged inside my workshop garage.  Once the wings were rigged, they were removed to facilitate access for further fuselage assembly.

Routing instrument panel wires was a matter of trial and error to find optimal routing and wire lengths.  The large bundle of white wires is the prefabricated generic harness supplied with the MGL V-6 transceiver.  Many of the wires were longer than necessary and several were not necessary at all in my simple little airplane.

First power-up of instrument panel -- everything lit up and nothing smoked -- that's good!

Tools for persuading forward canopy bow into proper shape

Canopy Installation Complete --  this was a very tedious process

Canopy hinges toward right side of aircraft -- pilot & passenger enter and exit on left side

Finished instrument panel and interior

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