Driving mechanism
of the ornithopter model EV4
Components
(top down in the picture)
Drive unit with a cardan gear mechanism.
Main and control pins are provided with sliding blocks of polyamide.
(For spezification of the cardan gear mechanism,
please take a look at the report.
You also can see an animation
of the cardan gear mechanism.)
Main frame of the mechanism with side panels of rigid foam to adjust to the surface of the fuselage, also made of rigid foam rings.
Sloped control scotch yoke, made of 1 mm epoxy plates and slide of steel. The slot is at an angle with the axis of the slider like the path line of the control crank pin in the glide situation.
2 rods with spherical bearings
Lever arms to control the inner wing pitch, mounts onto the wing axis.
Wing axis was made of 6 mm spring steel, offset for a favourable fuselage-wing transition.
Wing adapter rollers, made of rigid foam and plywood and covered with epoxy-glass laminate, each with two inner 45 mm long lever arms.
4 plywood linkages
Swing
(frame of plywood)
with the pressure vessel (about 5 bar) for the pneumatical spring,
made of epoxyd-glass laminate. Ahead the frame is made of the
main scotch yoke. At it are mounted the bearings for the control
scotch yoke.
Cylinder or support ring made of epoxy-glass laminate, for the long-stroke bellows-like rolling-diaphragm below.
The piston of the pneumatic spring stands at the bottom of the fuselage and is not shown here.
Components mounted
The linkage for an active twisting of the wings is good to see:
- - from the control scotch yoke,
- - over the rods with spherical bearings,
- - to the inner pitch lever arm of the wing shaft,
- - to the outer pitch lever arm of the wing shaft.
The relative motion between the wing root and the wing root fairing more over was used, via a linkage in the arm wing, to actively twist the hand wing root.
Front view
without the driving mechanism.
The horizontal slotted main scotch yoke (with slide of steel) is good to see. The inclined slide of the control scotch yoke behind this is recognizable.
Bottom view
There is visible the opening for the piston of the long-stroke rolling diaphragm. It stands at the bottom of the fuselage.
Back view
In the lower opening the cylinder of the long-stroke rolling diaphragm is visible.