Zenith Zodiac CH-640 four seater

The CH-640 is a conventional four-seater, with a 2 + 2 seating configuration.

The prototype Zenith Zodiac CH-640 is powered by a 180-hp Lycoming O-360 engine. The design features a fixed tricycle landing gear, large dual gull-wing doors, a wing span of 31.5 feet and an overall length of 23 feet.

Heintz developed the new design in response to demand from kit aircraft builders for an affordable and simple four-seater. While there are literally hundreds of two-seat kit aircraft designs available for construction, there are few modern four-seat designs on the market: The available designs are either complex high-performance planes (such a the Lancair IV) or “utility” designs such as Murphy’s Super Rebel and Heintz’ own STOL CH 801.

The new ZODIAC CH 640 is designed to bridge the gap between these utility designs and the fast and expensive composite designs – to make it a practical and useful aircraft for the “average” pilot/builder. The CH 640 has a useful load of 1,000 lbs., making it a “true” four-seater.

Furthermore, the success of the kit industry has attracted many pilots from the “general aviation” field – pilots seeking the value, choices, and building challenge offered by kit aircraft. The high cost and lack of innovation in general aviation has convinced many pilots to build their own aircraft. Based on a production aircraft, the CH-640 has the handling characteristics that conventional pilots are most familiar with, and even comes with a dual yoke control system instead of the control sticks found in most kit aircraft. The heavier weight of the aircraft makes it well suited for pilots transitioning from Cessna or Piper aircraft. While the rear seat in most four-seaters is only occasionally occupied, a larger aircraft offers the pilot (and passengers) more space (both elbow room and space for overnight bags) and more stability, especially useful in aircraft operated under IFR. The increased room and payload make the Zodiac CH-640 a true cross-country aircraft, well suited for long cross-country trips.

The kit aircraft industry has matured over the years and many customers are now second or third time builders: “The CH-640 offers more aircraft to builders – an aircraft that is more than a weekend toy.” Heintz explained. “Also, many of today’s kit customers are demanding more ‘utility’ in a kit aircraft. Wives are getting more involved in the decision-making process of which airplane to build, as well as being more involved in the building and flying of the aircraft. Obviously, a back seat for the kids and baggage is important.”

The ZODIAC CH-640 four-seat kit aircraft is based in large part on Chris Heintz’ ZENITH CH2000 aircraft design, a versatile two-seat production aircraft. The modern design makes use of advanced technologies, while using proven design concepts and simple systems for easy assembly and maintenance. Developed for the first-time builder and demanding recreational pilot, the CH-640 has been developed to be easy to build and to maximize flight performance and efficiency.

While most production aircraft are relatively complicated and would not be well suited for construction by amateurs, the CH2000 aircraft was designed to be the least-expensive type-certified aircraft.  To achieve this design Chris Heintz made the aircraft parts and assemblies simple by drawing on his extensive experience producing kit aircraft for first-time builders. This simplicity has made the aircraft not only easy and affordable to build, but also easy to maintain and has kept the cost of replacement parts lower than originally thought possible. The CH2000 aircraft was certified by the Federal Aviation Administration (FAA) on July 31, 1994 with the issuance of Type Certificate No. TA5CH. The CH2000, as presently produced, is approved for spins, and when configured with the appropriate option package, is certified for IFR operation.

Certified in the Utility Category (+4.4 / -2.2 g at max. gross weight), the aircraft was designed with a design safety factor of two, compared to 1.5 for standard FAR 23 certified aircraft. The extra safety factor gives the aircraft +8.8/-4.4G ultimate load factor. Recently, the CH2000 was the first aircraft to be fully approved by the new European Certification Committee, certifying the aircraft in all European countries simultaneously. The CH2000 airframe has no ” life time limit” since it has been proven that if an aircraft is designed by using classic construction methods and materials, and if the design safety margin is 2, it will not fatigue appreciably during its projected lifetime. While a two-seater, the CH2000 design features a large cabin and easy-access dual gull-wing doors.

The ZODIAC CH-640 features a redesigned cabin with the addition of rear seats, a larger wing and stabilator were designed for the additional load requirements of the four-seat ZODIAC CH-640.

The ZODIAC CH-640 aircraft is built of stressed-skin semi-monocoque all-metal construction, just like today’s factory-built planes, but adapted specifically for the kit builder. Sheet-metal construction is outstandingly the most widely used aircraft building method around the world, and has proven itself as the ideal aircraft material since the early pioneering days of aviation.The simple stressed-skin semi-monocoque construction of the ZODIAC CH-640 uses single curvature sheet-metal skins riveted to internal structural members. The sheet-metal skins, main wing spar, structural ribs, longerons, stiffeners and bulkheads are fastened together with Zenith’s proven riveting method using blind rivets, which are as easy to set as ‘pop’ rivets, requiring only a simple hand rivet puller. The corrosion-resistant rivets provide a permanent structural bond and tight low-profile dome finish, formed by the custom riveter head. The rivet stem becomes locked in after being set to provide a water-tight seal. The 1/8-inch and 5/32-inch Avex rivets used are very sturdy and durable fasteners, and may be used over a wide grip area. The blind rivets are much easier and quicker to set than bucked rivets, and don’t require the use of a noisy pneumatic rivet hammer or counter-sunk rivet holes. The primary structure, with the exception of the steel tube engine mount, steel nose gear strut, and other selected parts, is of 6061-T6 aluminum sheet metal riveted to aluminum extrusions with Avex rivets. This blind rivet, manufactured by Textron’s Avdel division, is similar to the traditional ” Cherry” rivets except that they can be pulled with any standard blind rivet gun. Major structural items such as the wing spar and landing gear fuselage support are solid riveted at the factory with standard control hardware are the AN/MS type. Some composites are used on non-structural fairings such as the engine cowling and wing tips.
Simple systems, modern materials, and design ingenuity minimize required maintenance, and make the ZODIAC CH-640 simple to build and fly, affordable, and very durable… an aircraft you’ll be proud to own and fly for many years.

While the ZODIAC CH-640 design is new, the simple construction techniques that have made the Heintz designs famous have remained the same.
Construction of the CH 640 kit aircraft is ‘modular’ – each section of the aircraft is built separately on a workbench. Many builders thus choose to buy ‘component kits,’ purchasing kit sections as they progress through the project. The modular construction of the kit means that required workshop space is minimal – most builders construct the kit in a single-car garage or basement workshop.
Once all the airframe sections have been assembled, the wing and tail sections are bolted to the fuselage and the landing gear, controls, and fuel system are installed.

The aircraft was designed with extra large maintenance access panels in the wings, and fuselage.
Under the rear fuselage, there is a huge 2×2 feet square access panel, which gives easy access to the control cables, and flap motor.

• Crew: one
• Capacity: three passengers
• Length: 23 ft 0 in (7.01 m)
• Wingspan: 31 ft 6 in (9.60 m)
• Height: 7 ft 4 in (2.24 m)
• Wing area: 150 sq ft (14 m²)
• Empty weight: 1,147 lb (520 kg)
• Gross weight: 2,200 lb (998 kg)
• Fuel capacity: standard tanks: 38 U.S. gallons (140 L; 32 imp gal), optional tanks: 46 U.S. gallons (170 L; 38 imp gal)
• Powerplant: 1 × Lycoming O-360 four cylinder, horizontally opposed, four-stroke piston engine, 180 hp (130 kW)
• Propellers: 2-bladed metal propeller
• Maximum speed: 160 mph (260 km/h, 140 kn)
• Cruise speed: 150 mph (240 km/h, 130 kn)
• Stall speed: 47 mph (76 km/h, 41 kn) flaps down
• Never exceed speed: 175 mph (282 km/h, 152 kn)
• Range: 510 mi (820 km, 440 nmi)
• g limits: +5.7/-2.9
• Rate of climb: 950 ft/min (4.8 m/s)
• Wing loading: 14.6 lb/sq ft (71 kg/m²)