THE SWISS H-5
In 1951, at the beginning of the helmet test campaign, the import and logistic of the helmets to be tested was contracted by the SAF to the Sportex company of Zürich.
In 1946 Sportex started to import motorbike crash helmets from France. They realized the helmets needed some improvements and developed a new pattern with bonnet manufacturer Fürst in Wädenswil.
That's where Sportex got a reputation as specialists in crash helmets.
In 1954, SAF asked Sportex to find out a way permitting to install a British Mk.2 visor on P-3s and H-5s. The visor is installed on a track which is shaped with a different radius than the one of the helmet‘s shell. Sportex designed a wood shim/adapter, later made of Nylon, which compensated for those two diverging radii. Prototypes were fabricated and the visors installed.
At the end of the evaluation, the AF ordered a total of 400 H-5s. The helmets were delivered to the Sportex facility, where company’s personnel under the supervision of two Swiss AF representatives carried out the modification work. The modified helmets were then shipped to Dübendorf AFB and stored in the heavy cardboard boxes also produced by Sportex.
As the USN helmets of the era, delivered Swiss H-5s were originally gold painted because it was established that this colour provides efficient thermal protection against solar radiation. Other colours have a tendency to make the helmet warm and therefore uncomfortable. The only colour more effective in reflecting the sun's rays than gold is white.
Due to this in 1949, after some time and assessments made in service, to improve heat protection all helmets were painted white.
Likewise, the early Swiss version had leather flaps with pull the dot fittings installed. The one on the left had a peculiar shape with an additional snap-on fitting in order to optimize, if required, the A-14 mask installation. If not required, the fitting blanked.
The early installed dark visors maintained the original shape, but when A-13 A/ MS22001 oxygen masks and cast oxygen mask receivers put into service, the visors were modified. As not to bump them, the visors were shaped accordingly the new fitted equipment.
To overcome the problem, another modification implemented. This resulted in the cable exit displaced by 45° to the left, thus eliminating the tension. The metallic cable-holding bracket cut in half and installed with a single screw instead of two as before. The original installation holes were normally filled with small size flush head rivets.
The mask-boom mike communication selector switch was made inoperative by contact bridging. Both helmet’s comms connectors were active at the same time.
Like any Swiss AF pilot's equipment at the time, the helmet and its main components had an identification number.
For the H-5, assigned one at the time of delivery was P.A. (Pilotenausruestung) 590, later changed to P.A.591.
During the introduction phase, a number of H-5s were distributed to various squadrons, equipped in most cases with DH-100 and DH-112, in order to get first-hand feedback on their use in the operation.
Based on feedback received, in order to facilitate cockpit preparation and to make it easier to reach, the communication cable that originally came out straight at the back of the helmet was modified by installing a leather support so that it folded to the left. It is obvious that the cable is under strain, due to the narrow bending radius which could lead to internal cable conductors break.
Waxed string secured the communication harness sockets to the helmets by leather tabs sewn onto the helmet shell.
When the H-5 was withdrawn from service, it was assigned to helicopter loadmasters, therefore had the comm wiring modified. This was performed in a somewhat "rude" manner, by replacing the original harness with a SPH-4 one.
Helicopter helmets retained the boom mike MT-522 A/U "Banana Mount" during all service life, unlike the jet ones where the mount was never installed or removed with the resulting holes blanked by flush head rivets.
Afterwards, due to changes in the SAF operational philosophy, in some cases the mounts were refitted, in many cases reworked/ modified as pictured.
The most evident and "classic" Swiss modification was the "gullwing cut", designed to improve/enlarge the pilot's field of vision.
Another proposed modification consisted in cutting and re-shaping the rear edge of the helmet in order to improve the pilot's capability to move his head upwards towards the vertical axis.
The proposal rejected by the Air Force Medical Institute reportedly due to a major exposure to possible injury of the pilot's head. Despite the refusal, some pilots personally modified their helmets, anyway.
The picture gives an example of a not modified (left) and a modified (right) H-5.