Does anyone have experience with oxygen masks fitted to helmets in civvy applications? I'm involved in a project where we are doing aerial photography and filming from a range of altitudes from sea level to 14k, mostly at night. While 14k's not up in the flight levels, we still need o2. Additionally, as for a lot of the missions we are operating door-off and photographer in harness, we've been looking into helmets for photographer and technician, for crash protection (they are on short tethers instead of secured with seatbelt) as well as birdstrike protection, and for better comms when one's head is out in the airstream.
I've seen the Gentex MBU-12/P masks (Pressure Demand) as well as the ALPS-M (Constant Flow). The Gentex is of course designed to work with helmets, but the pressure demand system is massive overkill for what we need. The ALPS-M system doesn't seem to work well with helmets, or at least would have to be donned separately.
What are helmet-wearers doing for oxygen (besides cannulas) in helicopters? Cannulas aren't an option as they wouldn't fare well in the door-off and moving-around environment.
EDIT: Found some information about ALPS-M conversion for helmet usage (
http://www.mhoxygen.com/index.php/co...s/download/645 ). Any feedback on these or other systems?