"Marc Ramsey" wrote in message
om...
I used the EDS D1a that came with my DG-600 for the first time, yesterday.
This was a 6 hour flight in the 15 to 17.9K range. Up to this point, all
of my gliders have been equipped with continuous flow systems and Oxymizer
cannulas. This EDS setup was using the standard XCR regulator, supplied
tubing, EDS cannula, and a fresh 9V battery installed. I set (and verified
several times during flight) D5, which is supposed to be a fully automatic
mode of operation. According to the manual, it should sense the start of
inhalation and send a shot of oxygen at that point. Instead, it seemed to
be sending oxygen at fixed intervals of a few seconds, then sounding an
alarm (I assume the apnea alarm) if I didn't happen to inhale just before
the next shot. To keep the thing happy, I had to sync my breathing with
its cycle, and make sharper than normal inhalations (i.e snort). By the
end of the flight, I was feeling signs of being mildly hypoxic. Questions:

1. Is this the way an EDS is supposed to operate, operator error, or
possibly a defective unit?
2. Why do EDS buyers insist upon getting those puny carbon fiber cylinders
(I used more than half the capacity in that one flight)?
3. Does anyone really like these things?

Marc

We just sent a couple of the older EDS A1 units back to the factory for
warranty service/recalibration. Several pilots had complained of hypoxia at
low-teen altitudes. When I tested these units on the ground, it seemed to
me that the pulse of O2 wasn't exactly synchronized with inhalation. In
fact it seemed to as much random as sychronized.

My own newer EDS D1 unit works just fine as determined by my pulse oxymeter.
I did have to learn to breathe slowly. Rapid, shallow breaths will deplete
the O2 supply much quicker than slow deep breathing. Breathing through your
mouth while wearing a cannula will get you hypoxic in a hurry.

I note with interest that Mountain High now offers a rubber mask for the EDS
systems. That might solve some problems for mouth breathers.

Bill Daniels