Construction of the ZODIAC wings is typically the next stage in the modular assembly process - the tail sections and wings do not require a lot of space for storage once assembled, unlike the fuselage / center section assembly.
The outboard wing spars are built up "C"-beams with spar cap angle extrusions at the top and bottom. The center section spar is similarly fabricated. Upon completion at the factory, the three wing spar sections are positioned at the dihedral angle of 6.5 degrees and joined by two 1/8-inch splice plates. This step ensures that the wing assembly maintains the correct wing alignment once the center section is attached to the fuselage. In the kit, the spars are supplied factory-built, with the wing dihedral already preset.
The nose ribs and rear ribs are positioned along the spar and drilled and riveted (with the Avex blind rivets) into place. The wing spars are supplied with pre-drilled rib stations. A rear "Z" spar channel is attached along the end (trailing edge) of the rear ribs.
Before the top skin is drilled and riveted, care is taken to level the spar/rib assembly on the flat work bench. The wing has no washout twist so it is a simple matter to align the flat ribs bottoms in one plane (flat on the workbench). The drilled surface sheet-metal skins are blind riveted using Avex rivets to the main spar and the rear wing ribs, leaving the trailing edge temporarily unattached, where the aileron skin will be positioned later.
Chord-wise "L" angle stiffeners are located and riveted in the middle of each rib bay. Structural reinforcement angles are added to specific areas of the wing tip and the luggage locker. Most skins in the kit are pre-drilled, are cut to size and are pre-formed, ready for assembly.
The wing assembly is then turned over on the workbench, and the bottom wing skin is positioned, drilled and riveted to the wing assembly.
The next step is the attachment of the leading edge skin. The preformed skin laps over the top and bottom skins. Working from the bottom rear to the front, the located skin is drilled and clecoed into the spar and nose ribs. Using ratchet straps the skin is pulled tightly over the front wing ribs. With the wing aligned, additional holes are drilled, clecoed and finally riveted.
The unique "hingeless" ailerons are made up of a simple pre-formed single sheet-metal skin with five internal ribs. Eight equally spaced rivets attach each rib to the aileron skin. A aileron horn is riveted to the inboard rib. A unique feature of the Zodiac is the addition of wing washout to the ailerons (as the wing is built flat with no twist). A slight twist is created by shimming the aileron tip and riveting the assembly closed. The 40 mm extension of the upper aileron surface acts as a hinge when riveted to the rear of the wing (between the skin and the "Zee" section layers).
The top aileron skin extends to the wing trailing edge, where it is riveted to the wing assembly. The top aileron skin flexes to provide aileron deflection, while providing a very effective gap seal. A piano-hinge can be substituted for the hingeless aileron.
The wing baggage locker is positioned behind the main spar, between the first and second rear ribs, and a rear panel is positioned. The baggage door is supplied pre-formed, and is hinged at the front for opening. "Dzus" fasteners are used to fasten the door closed. Optional wing tanks can also be installed in the wing baggage lockers.
The center wing section is built next, constructed the same as the outer wing sections. The center section assembly consists of the main spar, the rear spar channel, ten nose and rear ribs, and the outer skins. Reinforcement brackets are positioned where the main landing gear will be installed.
The center wing assembly will become part of the forward fuselage / cabin assembly.
Wing Assembly Overview
© Zenith Aircraft Company: 2008-09-10