EDS (Electronic Oxygen Delivery System), nasal cannula, System No. I
All gliders carried EDS from Mountain High as the primary oxygen system. These systems had their own O2 -bottle, independent of a second system.
Stemme had two EDS Systems attached to one 5 ltr bottle. It seemed to work correctly, but it had to be routinely checked for proper operation. It consisted of two systems connected to one valve.
All bottles used were German Standard with 200-bar / 200 ATA pressure carrying a 3 or 5 ltr bottle.
EDS worked excellently in most of the flights excellently.
In a few cases EDS was likely to run low on battery power, without the pilot noticing and without realizing the audio-warning, if not monitored closely! This was dangerous and a point of concern!
If more than one pilot is flying in an aircraft, some additional cross checking has to be done to insure adequate battery power. Alternate options should be discussed, like regular battery change or another permanent power resource such as solar panels.
There has to be some technical test capability on the site available to be able to check such an apparatus, especially when it ages and more malfunctions occur. These systems have no regular "Quality Test Regimen", as other aircraft equipment and technical maintenance rules require.
Diluter Demand Systems , with face mask; system No. II
Stemme S10 VT,115 hp, had a certified Bendix diluter demand system, the standard system GAF F4F/ Alpha Jet.
The Bendix system met all legal technical and maintenance requirements.
It was equipped with masks, which were attached with Velcro tape on German military textile caps. This seems to be an excellent solution and fits tightly.
There were long elongated hoses for convenience.
The system is built into the panel (one for each crew member), so it can be operated individually.
The 5-ltr bottle was the primary O2 resource.
For higher or longer flights there was a battery of six individual 1 ltr bottles, which fitted behind one seat with specially constructed attachments and pressure valves.
Some pilots stated that they put the mask on in case of use at high altitude above 20 000 ft / 6000 m sometimes over the "nasal-cannula" of the EDS. They considered this a "Backup-System", in case the diluter demand system ran out of oxygen.
ASH25 M, 54 hp, had two EDS Systems attached to the one EDS valve on two connected 3-ltr bottles.
A big 5 ltr bottle was positioned parallel to the front of the aft seat. It served two Draeger diluter demand systems, similar to the Stemme System.
Nimbus 4 M, 40 hp, single seat, was equipped with EDS and a small independent diluter demand system, two independent 5 and 2 ltr O2 -bottles.