snip
Maintaining a constant attitude in the test you describe will require
a pitch control input and that input controls what happens to the
glider as the devices are deployed. *To put it another way,
maintaining pitch attitude is an arbitrary choice. *You could have
specified constant sink rate, constant glide path, constant airspeed,
etc etc. *That close to the ground my intent is to control sink rate
and the controls interact to achieve that.

In my experience deploying my top surface devices with stick free
results in nose down pitch, increased sink rate, and airspeed remains
essentially constant. Who can define the name of the device that
causes that?

Andy

Yes, I specified constant attitude simply because I can obviously stop
the descent by pitching back up. I was just trying to Isolate the
effects of the various drag devices which as you point out is simlar
no matter what the initial steady state is.

One other feature I have noticed on Spoilers is they tend to be ON/OFF
as opposed to Airbrakes that tend to be more proportional. I.E. in my
example if you slowly apply the Spoilers at a certain point the glider
will just drop. Where as the Airbrakes will tend to gradually become
more effective.

Brian