Notek

VW Kübelwagen with camouflage headlights (center)

Opel Blitz A (all-wheel drive) with Notek headlights

Notek was a trademark of Nova-Technik GmbH, Munich and the name for their night marching device, which was mounted on almost every vehicle of the Wehrmacht . In addition to this, its most famous product, the company also built camouflage spotlights for stationary use on buildings or in the field.

The Notek night march device was a system for lighting motor vehicles under darkening conditions , similar to the camouflage light used by the Bundeswehr . Vehicles or columns equipped with this could move safely on the road in the dark without being visible from a great distance from the ground or from an aircraft. The system consists of the front camouflage headlight, the rear distance light and the step switch with built-in series resistor.

The night marching device was used on almost all Wehrmacht vehicles such as Kübelwagen and Kettenkrad up to battle tanks , but not on motorcycles and motorcycle sideboards.

history

After attempts with slit diaphragms in front of the actual vehicle headlights had not brought satisfactory results, a device was developed by the Army Research Department for Motorization in cooperation with Munich-based Nova-Technik GmbH, which covers the area in front of the vehicle over a width of 30–40 m Could illuminate 25 m width. An additional cover made it possible to detect the vehicle by enemy observers only at a distance of 50 m, and then only from a lying position.

Camouflage spotlights

Camouflage headlights
1 = reflector
2 = light bulb
3 = diffuser
4 = housing

The front camouflage headlamps gave the driver a sufficient view of the lane when it was darkened, while the vehicle was no longer visible to an observer from the ground or from the air from a certain distance. This distance was between 500 m (switch position V1) and 1500 m (switch position V3).

This camouflage lighting was achieved by a rotationally elliptical reflector , which, by means of a 35 watt incandescent lamp, threw the stronger light from the center into the distance and the weaker light from the edge of the reflector nearer. No light could penetrate upwards or to the side through a cover. The driver of the motor vehicle could change the brightness values of the headlight by means of various switch positions or switch them off completely.

An operating and installation regulation from 1939 regulated the assembly and installation of the devices on the vehicle as well as the application in the area of use. For example, when driving into a battery position , moving into standby rooms or similar journeys under enemy surveillance, the lowest light intensity was required with the distance rear light switched on.

Only one camouflage headlamp was used per vehicle. This should be mounted on the front left of the vehicle.

Step switch

The brightness (light intensity) of the camouflaged headlights could be regulated in three stages (V1 – V3) using the step switch. This was done with a series resistor. Therefore, the step switch had to be adapted to the operating voltage of the vehicle (6, 12 or 24 V). The respective operating voltage of the tap changer was printed on the outside of the housing.

In the brightest level (V3) the series resistor was bridged and the camouflage headlight received full voltage. The series resistor did not affect the distance rear light. This received full operating voltage in all switch positions.

In addition, there was a switch position "H" in which only the distance rear light was switched on and the camouflage headlight was not.

The step switch was usually connected to terminal 15, so the night march device only worked when the ignition was switched on.

Distance rear light

The distance rear light consisted of a combination of the vehicle tail light, the license plate light, the brake light and the distance light, which could also be darkened by cover plates.

The distance light shone green and consisted of four separate, horizontally arranged rectangular lights, each 3 cm high. The outer lights had a width of 2 cm each and a distance of 1.6 cm to the respective inner light. The two inner lights were only 1.8 cm wide and 3.8 cm apart. With the help of this arrangement, the driver of a vehicle following behind could estimate the correct distance in a column even in complete darkness as follows: Within a distance between about 300 m to 35 m (distance too large) the distance light was only recognizable as a single rectangular area . Two adjacent areas could be seen at a distance of about 25-35 m (correct distance for traveling in columns). If the distance was less than 25 m (too short), all four lights could be seen.

The function of the distance light is based on the limited resolution of the human eye: two points can no longer be distinguished from a certain distance, but seem to merge. Since the luminous areas are arranged at two different distances, there are two “mergers” (of two or all four lights) depending on the viewing distance. This enabled the driver to better estimate his distance to the vehicle in front when catching up or approaching in a convoy and to keep the marching distance at night.

The license plate light with dimming slide, a normal rear light and a brake light were also integrated into the distance rear light. The distance rear light was switched between normal operation (tail light and brake light visible) and camouflage operation (four green distance lights visible) via a movable sheet metal flap.

Camouflage operation with green illuminated areas
Normal operation with red (tail light) and orange (brake light) illuminated area
Back of luminaire

literature

Reinhard Frank: Wehrmacht trucks. German and captured wheeled vehicles in action. Technology - painting - badges - accessories. History and organization of the supply troops. Podzun-Pallas Verlag, Friedberg 1992, ISBN 3-7909-0466-X .
Survey of Optical Instruments . In: Herbert Gross (Ed.): Handbook of Optical Systems . tape 4 . Wiley-VCH Verlag , Weinheim 2008, ISBN 978-3-527-40380-6 , pp. 22 (English).

Remarks

↑ The resolution of the human eye is normally around a minute of arc (1 ', corresponding to a visual acuity of 1). At night the pupils are dilated; if the eye were an objective , its resolution under these circumstances (larger aperture) would be better (i.e. smaller than 1 '). In humans, however, the physiological fact must be taken into account that in the dark only the rods and not the cones are sensitive to light. Since fewer light receptors are active, the resolution is generally poorer in the dark. According to the “Survey of Optical Instruments” (see literature), a person with normal vision only has a visual acuity of 0.3 or 0.1 (resolution of 3.3 'or 10') in twilight or in the dark. If you take the mean value (visual acuity 0.2 corresponds to a resolution of 5 ') and consider the distances between the center points of the luminous areas (outside ; inside ), the smallest distance is still 24 m (all four luminous areas distinguishable) or the largest distance still recognizable from around 39 m (outer luminous surfaces merge). This corresponds roughly to the information given above (the dimensions chosen were probably determined through practical tests). The relationship between point spacing , viewing distance and viewing angle is used for the calculation . ${\ textstyle 1 + 1 {,} 6 + 0 {,} 9 = 3 {,} 5 \, \ mathrm {cm}}$ ${\ textstyle 0 {,} 9 + 3 {,} 8 + 0 {,} 9 = 5 {,} 6 \, \ mathrm {cm}}$ ${\ textstyle \ tan {\ frac {\ varphi} {2}} = {\ frac {a} {2d}}}$ ${\ textstyle a}$ ${\ textstyle d}$ ${\ textstyle \ varphi}$

Web links

Description Notek distance rear light with pictures , accessed on September 7, 2011.

[1] The resolution of the human eye is normally around a minute of arc (1 ', corresponding to a visual acuity of 1). At night the pupils are dilated; if the eye were an objective , its resolution under these circumstances (larger aperture) would be better (i.e. smaller than 1 '). In humans, however, the physiological fact must be taken into account that in the dark only the rods and not the cones are sensitive to light. Since fewer light receptors are active, the resolution is generally poorer in the dark. According to the “Survey of Optical Instruments” (see literature), a person with normal vision only has a visual acuity of 0.3 or 0.1 (resolution of 3.3 'or 10') in twilight or in the dark. If you take the mean value (visual acuity 0.2 corresponds to a resolution of 5 ') and consider the distances between the center points of the luminous areas (outside ; inside ), the smallest distance is still 24 m (all four luminous areas distinguishable) or the largest distance still recognizable from around 39 m (outer luminous surfaces merge). This corresponds roughly to the information given above (the dimensions chosen were probably determined through practical tests). The relationship between point spacing , viewing distance and viewing angle is used for the calculation . ${\ textstyle 1 + 1 {,} 6 + 0 {,} 9 = 3 {,} 5 \, \ mathrm {cm}}$ ${\ textstyle 0 {,} 9 + 3 {,} 8 + 0 {,} 9 = 5 {,} 6 \, \ mathrm {cm}}$ ${\ textstyle \ tan {\ frac {\ varphi} {2}} = {\ frac {a} {2d}}}$ ${\ textstyle a}$ ${\ textstyle d}$ ${\ textstyle \ varphi}$