The Brakemeter / Dynometer is a hand-made precision instrument that
mechanically measures both deceleration and acceleration. The instrument
consists of a finely balanced pendulum, free to respond to any changes in
speed or angle, working through a quadrant gear train to rotate a needle round
the dial. The dial is black with silver white graduations and has a linear
length of 5 1/2 inches (114 mm). The unit is filled with a special fluid which
damps out all vibration. Other than a calibration every 2 years, which is
carried out by Bowmonk, no maintenance is necessary. The dial is calibrated in
percentage "G", the accepted standard throughout the world for measuring
acceleration and deceleration. There are no connections to the vehicle other
than mounting - either with two self-tapping screws onto a heavy stand or by
using the suction cup operated by the small side lever.
Test the vehicle on reasonably level road. The meter is set to zero by
releasing the thumbnut, tilting the bowl in its pivots until the main needle
points to zero and re-tightening the thumbnut. The meter is now ready for use.
It is not necessary to watch the instrument continuously as it is fitted with a
recording needle. Depending on the test to be performed the recording needle is
positioned to left or right of the main needle by turning the centre chrome
knob, and will accurately record the maximum deceleration/acceleration reading.