THE SWISS DH-151
In order to to overcome the problems experienced with the Gueneau 316, and since the evaluations made on Titlis, Gueneau ZEUS and Gentex H/ATS had not led to the definition of a winner, during the mid '80 the Swiss AF decided to purchase a serie of Gentex Bauer/ Protection, Inc. DH-151.
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DH-151 is a Gentex internal definition, "DH" means Designated or Design Helmet. Supposedly standardized as PRK-37/P, the DH-151 shell later became the base for most of the USN HGU's type helmets, afterwards, further trimmed, for the HGU-55/P.
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According their uses and the technological evolution, the Swiss DH-151s underwent a noticeable configuration evolution. In their last version, a number of them are still in use today.
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The Swiss AF complete helmet designation is DH-151 PA-594- followed by two main definitions : BAMF-1 and BAMF 2.
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BAMF stands for "Bundesamt für Militärflugplätze" (Federal Agency for Military Airfields), which managed all aspects - technical and operational - of the Swiss AF.
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BAMF-1 identifies a shell fitted with (modified or not) PRU-36 double visor assy;
BAMF-2 fitted with a "Bungee visor".
A DH-151 as it was delivered from Gentex Bauer: Padded black leather edgeroll,
PRU-36 double visor assy, cast oxygen receivers; everything in "Pearl White" livery;
a nape strap installed on request .
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Internally, the helmet was fitted with a Custom fit polyurethane foam liner (PRU-39/P) molded on crewmember's head and "elephant's ear" earphone pads. In some cases, a V-TEC liner was installed.
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Comm system : H-143/ AIC. After delivery, a "Swiss boom mike bracket" installed on the LH side of the shell.
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A first batch of helmets were provided completely assembled, with the pilot's name stencilled on the rear side; the stencils applied before the final clear paint coating.
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Later helmets, as the one picured, were assembled with spare (not named) shells.
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A standard DH-151, as it provided to F-5 E Tiger II pilots.
The contract - Work Order label of a "no name" large shell.
As well as on the label, the wording "NO NAME" written with a marker inside the shell.
The PRU-36 cover has been replaced with a "Plain White" one, decorated with a "Fliegerstaffel 1" decal.
The contract - Work Order label of a "no name" large shell.
DH-151 BAMF-1 "MIRAGE III S and RS (AMIR) "
The DH-151 was the standard equipment Mirage III pilots, nevertheless, because the upper initiating handle of the Mirage's Martin Baker Mk. 4 ejection seat could interfere with the standard double visor assy, a suitable locally designed and differently shaped visor cover replaced the standard PRU-36 ones. Mirage III S visor covers were left normally grey (not painted), Mirage III RS ones painted with the aircraft camo livery colors. Same visor covers were installed also on later HGU-55s.
On Mirage III S.
With the grey (not painted) version of the "Visierghäuse-BAMF", compatible with Mirage "bang seat" configuration.
...installed.
On Mirage III S.
As one of the possibly first DH-151 ordered, this helmet sports the pilot's name on its back.
The owner, also active test pilot in the GRD, (Gruppe für Rüstungsdienste - Armament Services Group) flew, among others, DH Vampires, Venoms, Hawker Hunters, Mirage III S/BS/RS, and various propeller aircrafts. He was active in the Squadrons 7, 9 and 17.
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He probably painted himself the cover in white.
The pilot's name painted on the helmet's rear side.
Gentex Bauer Work Order/ Contract label. Delivered as a complete unit, the label ("MED") helmet size, the PRU-36 double visor housing ("VH") and oxygen mask cast receivers ("O2 REC") ticked . Note the color specified to be "Pearl White, Flaked".
All the shells were provided pre-drilled for PRU-36 installation.
The pilot's name painted on the helmet's rear side.
During the mid-1980s, the Swiss AF was testing the aircrafts that would replace the Mirage III. Among these the Northrop F-20, Mirage 2000, F-16 and the F/A-18 which would then be declared the evaluation winner.
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A few years before a new pilot’s helmet concept, the HGU-55, entered service in the US Air Force, introducing new standards of weight, visibility and comfort.
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Although an improvement compared to the Gueneau 316 that it had replaced, the DH-151 was still of "old" design and considered no longer compatible, especially in terms of weight, with the performance of new generation jets.
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The H-5, after years of trustworthy service, due to ageing and lack of spares was in the process to be phased out. The AF launched a project to evaluate a new "light helmet" for the crews of the current and future AF aircrafts.
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Various models and solutions were considered, finally the HGU-55/P was chosen as the future helmet of the Swiss AF.
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However, before the end of the evaluations - most likely for economic reasons - a "local" and "ad interim" solution sought. Given the availability of spare parts, HGU-55 "lookalikes" were created with shells of grey painted DH-151 fitted with Gueneau 316 visors modified as “Bungee visor”.
A small quantity of this first version of the DH-151 "light" were still in service not long ago.
With HA-LP/PPB oxygen mask.
The originally pearl white shell has been re-painted in low visibility or "air superiority" grey. Often the DH-151 grey is of a lighter shade than that of the HGU-55.
A SOLAS taped DH-151 with HA-LP/ PPB oxygen mask on Pilatus PC-7.
With HA-LP/PPB oxygen mask.
Following the delivery of the HGU-55, based on its configuration, some improvements of the DH-151 took place.
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By replacing installed oxygen cast receivers with lightweight ones;
By swapping the Gueneau modified visors with the bungee ones of the HGU-55.
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A number of these helmets are still in use today, in their grey livery or SOLAS taped.
Below, an F-5 F crew. The front cockpit pilot is equipped with a HGU-55, the rear one with a DH-151 BAMF-2.
Photo taken from the book “Swiss Tiger Parallel Flight" by Peter Lewis, Goatworks 2017, published by kind permission of the author.