TYPE H-3 PROTECTIVE HELMET

Construction
The liner is available in five sizes; small, medium, intermediate, large, and extra large. The size of the liner can be adjusted by means of a nylon strap and buckle that is sewn on the back of the liner.
The oxygen mask is attached to the cheek flap by means of two Pull-the-Dot snap fasteners. The matching female fasteners on the mask have a dot on their outer surface, and unlock in one direction when pulled apart away from the dot. This provides positive locking action, insuring the pilot of keeping the oxygen mask even if he loses the protective helmet during a high-altitude bailout.
The earcups on the liner have been designed to accommodate wafer type receiver. The wafer-thin construction of the receiver decreases the lateral dimensions of the helmet, thereby decreasing the frontal area exposed to the windblast during bailout and facilitating head movements within the confines of the cockpit canopy. The earcups have been designed to provide sound attenuation against ambient noise, and to increase radio reception.
One male snap fastener is locate on each side of the shell exterior between the two buckles for adjusting the headband. This also provides a means of attaching the goggles to the shell. In addition, a fitting is secured to the right side of the shell exterior for attaching a boom type microphone. This microphone is very fragile and should be handled with care.
The rigid protective shell is composed of laminated and mat Fiberglas compounded with polyester resin. The rigidity oh the shell is increased by reinforcing-ridges located on its outer surface. A black rubber beading around the borders of the shell protects the wearer from sharp edges and provides a decorative finish.
The protective shell is available in four sizes; small, medium, large, and extra large. Tests have shown that the Navy’s protective helmets will withstand an impact force in excess of 64 foot-pounds and a static load in excess of 600 pounds without structural failure.

WARNING: The wearer of the protective helmet should be instructed to not place any metal objects on the shell, especially above ear level. Under crash conditions, these additional metals may be driven into the head as secondary missiles.

Additional protection against injury from impact is provided by energy-absorbing padding inside the helmet shell, consisting of four pieces of Royalite cemented directly to the shell interior and small pieces of leather-covered foam rubber placed circumferentially between the adjustable headband and the shell. Deformation of all parts of the padding under impact absorbs the impact energy, thereby decreasing the injury potential of a blow delivered to the helmet shell.
The shell is fitted to the head by means of a sling suspension having an adjustable headband. Buckles for adjustment are located on both sides of the shell exterior just above the ear level. The most protection against impact is obtained when the headband is adjusted to fit snugly. Pilots and aircrewmen should be instructed in the proper procedure to adjust the slings very carefully prior to use.
A modification to the H-3 consists of installing stabilizing straps and chinstrap to provide the additional stability needed when catapulting, on arrested landings, and in maneuvers involving high "g" accelerations. To attach the straps to the liner and outer shell on any protective helmets that have not already been made by the manufacturer, follow the procedure illustrated in figure 14-4.
The wearer need not separate the assembly after it is modified since it can be utilized as a one-piece helmet. The modified cloth underhelmet (liner) should not be worn by itself since attempts to anchor the webbing by additional fasteners on the liner may increase the possibility of serious head injury in emergencies.