Building the Da Vinci Model

The model came in a large box full of wood strips, blocks of wood, cotter pins, wire, beads, and other items we would refer to as “hardware”. There were many pages of written instruction with diagrams and one large full scale set of plans. We decided to divide the tasks between us; Dave would build the “body” and Bill would build the wing and tail.

We agreed to make some changes to what was supplied in the kit box. The kit used cotter pins as the fairleads/pulley guides for the numerous ropes on the model. We would make eyelets from 32 thousand brass rod and substitute these for the cotter pins. The “pulleys” in the kit bore no resemblance to those on the drawings, the pictures or what one would describe as a pulley. We found some ship model wooden “deadeyes” that when sanded flat were perfect match to the pulleys on the plans. The leather furnished in the kit was much too thick and stiff, so thinner more flexible leather was substituted.We also decided the eliminate one of the working features on the body which would eliminate the possibility of the model working, i.e. the wings flapping. This was done for ease of construction and because we felt the completed model was too fragile for someone to be tugging on the “ropes” to make the wings go up and down!

Wings: The first step was to make the ribs. Two forms were made from plywood as shown on the plans. Two strips of thin wood would be bent over these forms and glued together, making one rib. The wood was steamed first to make it more pliable. A total of 30 ribs were made; 26 of one shape and 4 of another. Some ribs were used as the curved ribs you see on the wing. The others were used for the wingtips and other curved parts of the wing. The wing ribs were tapered and rounded then coated in CNA glue for additional strength
DaVinci designed a joint or knuckle to allow the tip of the wing to flex up and down similar to the action of a bird’s wing. This was built at the end of the wing spar with a “spring” to bring the wingtip back to its original position after flexing. All ribs and other pieces were attached to the main spar, a 3/16 wood dowel. The ribs and other pieces were first glued into position using the full scale plan as a guide and then lashed using sewing thread. On the real plane, lashing would have been the method of joining the pieces.
The attachment of the wing to the body was called a “hinge” and was built by carefully enclosing a ball inside two blocks of wood. The glued blocks of wood were then carved to a smaller shape and lashed to the wing spar. The wings were attached to the body by a rod passing through the hinge and a piece on the neck ring of the body. This ball joint allowed the wing to have movement in more than one plane.

Body: Although the body looks small and simple, it has 10 pulleys, 12 pulley guides/fairleads, three cleats and a very difficult crankshaft to bend. The body began as a rectangular piece of wood to which various other pieces were glued. A hoop called the “neck ring” was shaped around a form in the same manner as the ribs and then attached to the front of the rectangular wood. The wings would attach to the “neck ring”. Numerous holes were drilled in exact locations to receive the pulleys, guides, wings and cleats. All these pieces had to be made from brass rods, the deadeyes or small blocks of wood. Finally, the thin leather was used to make the straps for holding the person to the machine.

Tail: The tail ribs followed the same construction technique as the wings. The “mounting bracket for the tail” is a piece of music wire bent to fit yet another form and then covered with leather to which the ribs are glued. The bracket also served as another strap to hold the person to the machine, hence the buckle.

Rigging: The “rigging” or ropes provide power to the wings and control flexing of the wingtip.
There are ropes from the spars to the body which are to power the wings movement up and down. One each side of the hinge are “up” and “down” ropes which pass through those numerous pulleys and guides on the body and exit at the back terminating in “stirrups” for the person’s feet. Another set of ropes run from the “bellcrank” at each side of the body, through pulleys on the neck ring/hoop and terminate at handles.
A set of ropes above and under the spar flex the wing tips. These pass through the eyelets/fairleads from the wingtip and attach to the neck ring.

How the Flying Machine Works:
Imagine a person lying on the body with head through the “next ring”, arms stretched out in front and legs sticking out the back through the tail bracket loop. To make the wings go up and down, the person used arms and legs to work the ropes. The hands gripped the handles hanging from the neck ring and the feet fitted into the stirrups hanging from the back of the body. Pushing with the left foot and pulling down on the handles made the wings go down. Pushing with the right foot and easing off on the handles pulled the wings up. As the wings moved up and down, the fixed ropes on top and bottom of the spar would alternately tighten or slack which would flex the wingtips up or down, the opposite of the wing direction.
The kit was given to us in June and required several hundred hours of construction time.
Bill Powers
Dave Webb