USES OF THE WALK-AROUND BOTTLE -- (1) As an ACCESSORY REGULATOR -- the A-13 regulator on the walk-around bottle is a demand type regulator without the "auto-mix" feature. It gives 100% oxygen on inspiration regardless of the altitude. By connecting the walk-around bottle FIRMLY into the portable recharger valve, one has an extra source of oxygen at that particular station. As long as the oxygen gauge at the station registers oxygen pressure the user is assured a supply of pure oxygen ... his supply is coming directly from the system. Remember this when reviving a passed out crew mate in the waist in the vicinity of the ball turret--the long recharger hose used to charge the oxygen bottle on the ball turret can be plugged directly into a walk-around bottle attached to the unconscious crew member's mask.
If other long recharger hoses can be obtained from Tech Supply they will be extremely handy attached at the pilots station, in the bomb bay and to the recharger outlet at the right waist gunner's station. This would permit the engineer, who in flight is continuously filling his walk-around bottle, considerable liberty. He could cover most of the ship, staked out on a long recharger hose connected to his walk-around bottle. It would also provide a readily accessible source of oxygen to revive crew members who pick such out-of-the-way places to pass out as: the bomb bay cat-walk, the bomb bay doors, under the flight deck, or in some remote part of the waist.
One or two extension portable recharger hoses shown in photograph page 22 should be standard equipment in heavy bombers.
Fig. 5
EXTENSION RECHARGER HOSE
(2) SOURCE OF OXYGEN FOR BAIL-OUT -- Above 20,000 feet, breathing of oxygen is necessary to reach your particular escape hatch. After this spot is gained you won't need oxygen ... unless you start fiddling with the rip-cord too soon. Go to your exit on the walk-around bottle, fill your lungs deeply five or six times from the bottle, HOLD YOUR BREATH, and take the dive. Continue to hold your breath during the descent as long as possible. By the time your lungs are bursting for air you'll be from 8 to 10,000 feet nearer the ground and won't need extra oxygen. Leave the mask on--it will protect your face. If the skies are filled with enemy planes it may be wise to continue the free fall. By now you can start breathing without danger of serious oxygen-lack. Any dimming of mental acuity would be of such short duration that you'd have plenty of time to pull the ripcord.
PRACTICE GOING TO YOUR ESCAPE HATCH ON A WALK-AROUND BOTTLE DURING OPERATIONAL TRAINING -- PRACTICE ON JUST HOW YOU WOULD CLEAR THE SHIP -- GO THROUGH ALL OF THE ROUTINE EXCEPT THE BAILOUT -- and that might not be time wasted, at least just once before the time comes when you might have to!
Above 30,000 feet you wouldn't want to open your 'chute even if you had plenty of oxygen. You'd freeze a hand or foot or both if you did. Under these conditions you'd free fall, holding your breath, as long as possible. Then, after three or four breaths of "thin" air, pull the rip cord. Your altitude should be in the vicinity of 10,000 to 12,000 feet below that when you abandoned ship, and the degree of oxygen-lack encountered here wouldn't be of dangerous consequence. You'll avoid freezing, and perhaps the gunfire of enemy interceptors.
(3) TO MOVE ABOUT THE SHIP For this the walk-around bottle is very useful ... and very tricky! The trouble is that the thing is good only as long as it gives oxygen. It will rarely, if ever, be fully charged so forget that 8 to 12 minute stuff. You can't fill your bottle any fuller than the pressure in the line you'll be drawing from. And the only time that will be fully charged is when the ship is on the ground, freshly charged with oxygen, ready for the take-off. When you need the walk-around bottle, three or four hours will have passed ... and the pressure in your filling line will be some fraction of the full charge. As a rule you'll do well to get the bottle half charged. And you're going to be moving about at altitude and needing 3 to 5 times as much oxygen as if you were sitting quietly in a corner. So plan on the walk-around supply lasting 1½ to 2 minutes ... then you won't be caught short! Refill the bottle frequently. Refill it every time you pass a portable recharger hose ... and there's one at every station. Failure to do this has caused more pass-outs in second and third phase training than any other single cause ... unless you include carelessness. And careless people don't last long in the kind of work you're specializing in! There's a check-valve on the walk-around bottle, so you won't lose anything if you plug into a system that reads less than the gauge on the bottle.
NOTE TO ENGINEERS: Because of its limited supply, the standard walk-around bottle is next to useless for many of your jobs which must be done in flight on a walk-around bottle. The ENGINEER NEEDS A LARGER WALK-AROUND BOTTLE. One, having a supply 5 TIMES AS GREAT as the standard portable cylinder, can be obtained as follows: