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Design
Features
Design
Wings
Fuselage
Cabin
Tail
Photo Updates 1
Photo Updates 2
Photo Updates
3
The ZODIAC CH 640 wing design has a thick wing section which is common on many older designs like the DC-3. A thick cantilever wing provides maximum strength at minimum weight. It is also aerodynamically efficient since there is no drag-inducing exterior bracing.
The
wing has a high lift airfoil and Hoerner wing tips to maximize the CH 640's
effective wing span. The wing is of all-metal stressed-skin full-cantilever low-wing design consisting of two wing panels bolted to a spar box assembly in the fuselage. The cantilever wings are attached to each side of the fuselage by insertion of the butt ends of the main spars into a center spar structure which is an integral part of the fuselage. The center spar structure, located under the seat, provides in effect a continuous main spar with splices at each side of the fuselage. The fore and aft wing attachments introduce the wing torsion and shear into the fuselage. Thanks to the high strength of this spar, a relatively low number of wing ribs and stiffeners is needed, thus simplifying construction. The efficient use of parts in the design limits the number of parts required, reducing assembly and maintenance times.
The wings are not tapered and have no "twist," making them easy to build and maintain. Three separate spars make up each wing with the main spar being in the center of the wing. The three spars are fastened to the fuselage by means of AN bolts, making the wings easy to remove. The main spar is made up of four extrusions solid riveted to a web, similar to an "I" beam.
| At the wing tip, the CH 640 design utilizes ‘Hoerner’ tips to maximize the wing’s effective lift area and to minimize wing tips vortices. Hoerner wing tips provide the largest effective span for a given geometric span or a given wing weight. |  |
The ailerons and flaps make up the wing controls. The ailerons are made of formed aluminum skins held in place with ribs. They are light, easy to install, and do not have any counter balance weights. They are connected to push/pull rods which are connected to a simple bellcrank in the wing. Control cables are connected between the bellcrank and the fuselage torque tube, which is connected to the yokes. When painting an aircraft, there are no control surfaces that require any type of balancing, simplifying the painting process.
The wing trailing edge split flaps are electrically operated. Both the ailerons and flaps are fastened to the wing with piano-style hinges simplifying lining up hinges when installing and removing. The left and right flaps are connected together with a heavy 4130 steel torque tube, held in place with oversized nylon bearings which are impregnated with oil and bolted to the fuselage. The flaps are raised and lowered by an electric motor which rotates the torque tube. A momentary switch on the instrument center console activates the split flaps. A large mechanical flap location indicator is located beside the flap switch.
The optional stall warning system consists of an electric buzzer located behind the roll over bar on the cabin ceiling. It is activated by the airflow closing the contact on the right wing leading edge when the aircraft operates at a high angle of attack near the stall of the wing. The indicator activates at between five to ten knots above stall speed.
The aircraft fuel system is classic and includes wing tanks, a selector valve, a gascolator and fuel pumps.
|
Fuel Capacity (standard) |
38 U.S. gallons (2 x 19) |
144 liters (2 x 72) |
|
Extended Ranges Fuel Capacity |
46 U.S. gallons (2 x 23) |
174 liters (2 x 87) |
The aluminum welded wing tanks are installed forward of the wing spar, outside the walkway area, and held in place by the wing skin. The filler neck and vent tube are integral parts of the tank. Each tank has a easy drain sump. The finger strainer is at the tank outlet and accessible through the small inspection plate. Each tank feeds the "Left, Right, Off" selector shut off valve.
The fuel "Left, Right, Off" selector shut-off valve is located on the seat panel between the pilot and passenger. The handle points toward right for right tank and toward left for the left tank. It has a safety lock which has to be pushed down in order to shut off the fuel supply.
The Gascolator is located under the fuselage near the left wing leading edge. It has a Curtis-type easy-drain valve that can be opened to clean the fuel filter. Additionally, each wing tank has its own drain valve.
An auxiliary electric fuel pump is provided in case of the failure of the engine driven pump. The electric fuel-pump switch is located on the instrument panel. A steel manifold connects the fuel pump, fuel pressure sender and lines to the carburetor.
Lightning protection: The gas tank fuel caps are not vented so that lightning passing over the wing will not enter the fuel tank.
Update: 17 Oct 2007
Manufactured
and Represented by:
Zenair Ltd.
PO Box 235, Huronia
Airport
Midland, Ontario, Canada L4R 4K8
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