Design Improvements for the Zenith 601 HDS:
To improve the effectiveness of the toe brakes, the actuators of
the brakes have been redesigned.
Goal was an increase of the pressure exerted on
the pistons of the brake cylinders.
The increase has been so chosen that it still is impossible
to lock up the wheels on dry pavement.
In the new design, the bottom
of the brake cylinder is close to the bottom of the
rudder tubing, the "T" of the toe brake is extended, two
triangles are attached to the "T", and a "U" bracket
is added that converts
the downward rotation of the triangles into a
straight motion depressing the piston of the brake cylinder.
The original hinge of the "T" has been extended by a bit of tubing,
and a longer hinge pin is used.
The top of the "T" is extended correspondingly.
The increase in force depressing the piston is decided by the
ratio of the height of triangle divided by the length of the shortest
side of the triangle.
Note that the design requires that a remotely mounted
brake fluid reservoir is used. Such a reservoir is
highly recommended. First, if the reservoir is mounted
close to the oil tank on the firewall, then the fluid level
is readily examined as part of the preflight check. Second, the
reservoir is easily refilled if needed.
Last but not least: Thanks to my friend Les Palmer, who helped
patiently with the design and implementation.