Replacement Stall Warning Micro-Switch
In spite of surviving the end of the Mayan calendar,
Christmas hustle & bustle, and the first winter storm of the season
requiring the use of DOG Aviation’s emergency snow removal equipment, RV-12 construction
at DOG Aviation is about to resume. The project has been in somewhat of a
holding pattern waiting for a micro-switch, some wire and tools. Now the micro-switch is here but still waiting on the shielded wire for the strobe light
wiring which was ordered a week ago and will be needed real soon.
About that the replacement micro-switch for
the stall warning assembly ... behind
the scenes, DOG Aviation’s research department is constantly looking into
modifications that improve on the already excellent RV-12 design. One such
modification pioneered by Joe (the RV-12 builder in Michigan who came up with the AOA
modification) is to replace the stall warning micro-switch with one having a
slightly longer arm … this makes fine tuning the stall speed warning alarm much easier.
I ordered a new switch from Mouser which requires much less force to operate, it
is Cherry part number E22-50KL. The replacement Cherry switch is the exact same
switch electrically as the original, it differs physically in that the roller
arm is moved forward to give a better mechanical advantage.
Is this modification really necessary?
Truthfully, … nope. That said, to me it makes good sense because once the wing
is assembled, adjustment access through the small inspection port is well, at
best, challenging so at $4 and change for a micro-switch, why not go for it if
it makes fine tuning the stall warning easier?
I ran two mounting screws through the two
micro-switches in the photo bellow to keep the switches in alignment so it is
easier to see the subtle difference between the original Cherry switch shipped
in the parts from Van’s and the replacement Cherry switch purchased from Mouser.
The original micro-switch from Van’s is on the
bottom and the replacement micro-switch purchased from
Mouser is on the top.
One can easily see the slightly longer arm on the replacement micro-switch.
