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 they 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.
Like the original USN H-5s, the early Swiss version had leather tabs with snap-on buttons fitted. The one on the left had a peculiar shape with an additional snap-on fitting to optimize A-14 mask installation if required. If such installation was not required, the fitting was blanked.
The early installed visors maintained the original shape, but when A-13 A/ MS22001 oxygen masks and cast oxygen mask receivers were introduced, the visors also underwent some modification. Visors were grinded/sanded in order to not interfere with the new equipment fitted to the helmet. Those pictures are showing visors with original and modified shape cut.
Like all Swiss AF pilot equipment, the visor part numbers includes the acronym P.A. (Pilotenausruestung).
This refurbished early H-5 shows the original rear comm cable exit set-up. It is obvious that the cable is under tension, due to the narrow bending radius which could lead to internal cable break.
To overcome the mentioned problem, another modification was implemented. This resulted in the cable exit to be displaced by 45° to the left , thus eliminating the tension. The metallic cable holding bracket was cut in half and installed on the helmet with a single screw instad of two as before. On this helmet the original installation holes are still visible. They 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.
The comm plugs were fixed to the helmets by leather tabs sewn onto the helmet shell with waxed string. 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 wiring with a SPH-4 harness.
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. This modification was initiated by the former chief instructor of air combat and proved to be more successful than the proposal described next.
The 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.
This proposal was 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.