Twas the night before Christmas, when all through the shop not a rivet was stirring, not even a pop; Well you get the idea … Merry Christmas from DOG Aviation!!
Earlier in the day, in an effort to move forward
with the project no mater how small the task, a small amount of time was spent machine
countersinking the VA-195A mounting plate for the stall warning indicator’s
micro-switch. The mounting plate has two holes that accept #4 screws used to
mount the micro-switch for the stall warning indicator system. These two holes are
drilled out to #30, then machine countersunk using the 100 degree #30
countersink bit until the #4 screws set flush into the VA-195A mounting plate.
Machine countersinking the two holes on the
VA-195A mounting plate which
will accept the #4 mounting screws for securing the
stall warning micro-switch.
The VA-195A has another hole that receives a #8
screw which also requires machine countersinking … this hole is drilled out
using a #19 drill and machine countersunk using a #20 countersunk bit. This #8 screw
will be both a mount and pivot point for a vane that has a downward bend where
it protrudes through a small slot in the wing’s leading edge and into the airflow.
The theory behind this assembly is simple … under
normal flight conditions, because the vane is bent downward, the wind will push
down on the vane preventing the vane from rising and tripping the micro-switch.
However, when the angle of the wing becomes higher (as when approaching a stall)
the airflow will get under the vane, lifting it, thus tripping the micro-swich
causing alarms to sound in the cockpit.
Finished VA-195A mounting plate, machine
countersunk and ready for assembly.