CZAW Lake Sport Mermaid
WetAero M6 Mermaid
In the US, the very early stages of prototype 1 used a Rotax 100HP as the power plant. This installation was refined over the next two years with probably no less than 6 different configurations using the Rotax. After essentially complete redesign of the prototype number one in the U.S. with this power plant, the next one and half years of performing flight and water testing gave good results. Even though adequate in horsepower, performance should be better on hot and heavily loaded days, and there were propeller inefficiencies from some of the after body aerodynamic interference.
During one of the demo flights a customer from Australia suggested it might have better performance with a Jabiru 125 HP power plant. During initial flight tests this power plant proved to perform slightly better than the Rotax. But the installation was still lacking its full potential until repositioned higher above the after body structure. This one modification substantially increased the performance of the M6. The Jabiru was a tough engine to cool in the pusher configuration. After almost a year perfecting this engine installation they were capable of running on step taxi without limitations.
But then one customer insisted on the Rotax installation.
Dan Card received the first production Mermaid in parts and began construction in December 2005. Parts and pieces to make the fuselage, bulkheads, tail, and wings arrived from Czech Aircraft Works, where they were previously partially assembled using the factory jigs. Dan still had much of the aircraft to build. The challenge to build the first customer-built Mermaid began with assembling the aircraft for fit and finish while meeting the individual aspects of being “the first.” The construction of the Mermaid is very conventional as far as riveted aluminum monocoque construction goes. With plenty of traditional rivets to squeeze and buck, the fuselage in essence emerges in one piece, from nose to vertical stabilizer, including a robust center section to which the wings attach. The V hull is reinforced with a boxed section (at the bow) that houses the nose wheel when it’s retracted and closed off by its doors. It’s also triangulated with a flat floor onto which the seats, rudder pedals, and center console get fastened. With a series of 10 bulkheads, about a foot apart, completing the structure, the hull area below the seats becomes exceedingly robust.
The wing center section extends past the cockpit just far enough to support (or be supported by) the repositionable (not fully retracted) hydraulically actuated main gear. The wings are attached just outside the main gear bay via three bolts in the main spar and one in the drag spar, but in each instance, there is no carry-through of either spar. The ailerons on the Mermaid are actuated by push-pull and torque tubes, not cables. The flaps stop at the butt end of the wing and do not extend through the center section and die into the fuselage. They are slotted and use a displaced hinge pivot similar to the RV-10, a Cirrus SR22, or a Lancair Legacy; not really clean, but simple. The center section is also used as a platform for supporting/carrying ancillary systems like the battery, fuel pumps and filters, strobe pack, solenoids, disconnects, and relays, but it also serves as the main attachment for the engine pylon.
This Mermaid’s inaugural flight took place in September 2007 and was conducted over the rural farmlands of Fresno, California.
The Mermaid received ASTM certification #19.
Stall: 35 kt / 40 mph / 64 kmh
Engine: Jabiru 3300, 120 hp
WetAero Mermaid M6
WetAero Mermaid M6