Oxygen Regulator Balances Pressure in Oxygen Mask and G-Suits for Navy Pilots

When F/A-18 pilots take a hard, 3.5-g turn, they stay conscious thanks to an oxygen regulator that automatically sends pressurized O₂ to both their oxygen mask and thoracic g-suit. The g-suit, a specialized vest, fills with air, squeezing the pilot’s thorax and lungs as the plane experiences high acceleration. And the higher the acceleration, the greater the oxygen pressure routed to the g-suit and mask, going from 0.1 psi at 3.5 g to a maximum of 1.0 psi at 9 g. Pressurized oxygen sent to the mask lets pilots breathe easier and increases the partial pressure of oxygen in the pilot’s bloodstream, greatly reducing the risk of losing conciseness. The g-suit makes it easier for pilots to breathe. The g-suit and O₂ mask let pilots withstand an additional 2 gs of acceleration above their normal limit without blacking out.

Key to the 13-oz O₂ regulator’s performance is an electrodeposited-nickel bellows from Servometer/PMG, LLC, Cedar Grove, N.J. The bellows mounts between the aircraft’s acceleration-sensing air-regulator valve and the pressure valve in the regulator worn on the flight crewman’s parachute harness. As the bellows fills and expands, it closes the regulator and increases the pressure of the oxygen going to the pilot’s mask and g-suit. The thin-walled bellows has quick, consistent responses and is smaller and lighter than other control mechanisms such as a piston setup. Because the bellows has thin walls, which is possible though nickel electrodeposition, it also has a lower spring rate for minimal resistance. This lets pressurized air expand the bellows without using much force. And this force is consistent from unit to unit. The bellows has an estimated service life of more than 100,000 cycles. And the Navy says the new regulator experiences fewer breakdowns than the previous model.