On Sep 8, 12:09*pm, ContestID67 wrote:
I am in the midst of a project to install a gear/airbrake warning
system on my glider based on the built-in capability of my Cambridge
302. *This system is better than the simple "airbrakes open, gear up"
warning system (http://www.wingsandwheels.com/pdf/gear%20warning.pdf)
as it also alerts the pilot to "airbrakes open on tow".

My "sensors" will be strategically placed reed switches and associated
magnets (and tefzel wire of course). * My primary question revolves
around how to do a pre-flight test of the system.

From the manual...

"Warnings depend on presence or absence of airspeed as well as the
switch contacts. Here
is the logic: Unlocking the airbrakes connects pin 7 to ground. When
airspeed rises above 25 knots, the
alarm sounds. The alarm is cancelled when the airbrakes are locked.
During flight with the
landing gear retracted, unlocking the airbrakes connects pin 7 to
ground and sounds the
alarm. Lowering the landing gear opens the connection between pin 8
and ground and
cancels the alarm."

Reading from the above it would seem that the alarm system is totally
inactive until the GPS indicates I am moving 25+ knots. *If so, how
can I test this system on the ground? *Anyone else install this system
and have any experience? * This weekend I will experiment to see if
the 302 programming is smart enough to allow testing while I am
standing still.

Thanks, John DeRosa

Launch, release from tow, open spoilers with gear up, listen for
warning horn.