Alfred Maul (engineer)

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Alfred Hermann Carl Maul (born November 27, 1870 in Pößneck , † August 27, 1942 in Dresden ) was a German engineer and one of the pioneers of aerial reconnaissance. Maul, who owned a machine factory, experimented with rocket photography as early as 1900.

Life

Alfred Maul was the son of the businessman Karl Ernst Julius Maul and his wife Ottilie Christiane Rosine nee Schröter. After attending the community schools in Pößneck and Dresden, he graduated from the Dresden Conservatory , who was also musically gifted and an excellent piano player, and finally studied at the engineering school in Reichenberg .

In 1897 he received a business license and installed electrical and telegraphic systems as a mechanic. From around 1900 he experimented with the use of rockets for aerial reconnaissance. From 1904 he ran a technical office. He developed and produced machines for dosing, filling and packaging for the pharmaceutical and chemical industry and for a cigarette factory in Dresden. In the field of rocket photography alone, he received more than 20 patents in various European countries and the USA. From 1931 he owned his own machine factory. He died in 1942 of complications from diabetes mellitus .

Alfred Maul was married to Sema Marie nee Meyer from Kirchberg (Saxony) and had three daughters.

Development of rocket photography

Development until 1900

William Congreve developed a missile weapon at the beginning of the 19th century that was used by the British Army in the Napoleonic Wars and in 1812 in the British-American War . After William Hale (1797–1870) had managed to improve the accuracy of the weapon around 1840, the military of other countries also set up missile troops. By the end of the century, however, these were disbanded due to competition from the rapidly developing artillery . Missiles served only as fireworks and signal rockets .

The rapid advances in photography enabled aerial photography to emerge using tethered balloons in the second half of the 19th century . The first experiments by the French photographer Nadar at the end of the 1850s were followed by the first experiments of the Prussian military by Hugo vom Hagen in 1886 . With the invention of the dragon balloon by Hans Bartsch von Sigsfeld and August von Parseval , battlefield reconnaissance established itself from the air.

The risks of a reconnaissance from the balloon - depending on the wind conditions, shelling by the military opponent - led to alternative approaches such as carrier pigeon photography or kite aerial photography , which the French Arthur Batut first realized in 1888. In the same year, his compatriot Amédée Denisse invented rocket photography by using a fireworks rocket tethered to the ground to raise a camera with twelve lenses . The exposure was triggered with the help of a fuse , and a parachute opened at the same time, allowing the rocket to return gently to the ground. Neither the rocket nor the photographs have survived. Denisse has not patented his idea, which he published on September 22, 1888 in Gaston Tissandier's La Nature magazine . The Saxon industrialist and inventor Ludwig Rohrmann received the first patent for a photo rocket in 1891 . It is not known whether a prototype was built. The Swedish chemist Alfred Nobel patented a photo rocket in 1896, whose camera, fitted with a parachute, was detonated from the rocket by a powder charge .

Alfred Maul's photo rocket

Alfred Mauls rocket 1906
Aerial photo of Laußnitz from the rocket 1906

Alfred Maul began experimental work on his photo rocket around 1900 in a field near Weinböhla . He was familiar with Rohrmann's work, which he referred to in some of his patents. In his first patents from 1903, he deviated from the design principle of his predecessors in that the viewing direction of the camera was oriented sideways to the direction of flight. This enabled the camera shutter to be released at or shortly before the culminating point of the flight path . The advantage was that (1) the photo could be taken in a stable flight phase instead of during the descent on the parachute, which led to blurred images, and that (2) the camera could be aimed specifically at the terrain of interest instead of vertically to be oriented downwards. The lateral alignment of the camera also brought some problems with it. The rocket was not allowed to change the camera's line of vision, i.e. not rotate around its longitudinal axis, and the photo had to be released at a precisely defined point on the flight path. Maul managed to solve these problems in the years up to about 1912.

In the patents from 1903, the camera housing and a guide rod several meters long were equipped with guide surfaces to stabilize the rocket's flight behavior. Apparently the results were unsatisfactory because Alfred Maul was temporarily experimenting with a symmetrical arrangement of the camera with the lens in the direction of flight in the tip of the rocket. In the end, however, he returned to his original idea, but housed the camera in a rotating housing that was connected to a gimbal-mounted top . Before the rocket was launched, the camera was aligned and the gyro set into rapid rotation. This fixed the optical axis of the lens even if the rocket rotated around its longitudinal axis during the ascent.

To trigger the camera shutter, the inventor worked with a time fuse system which was dimensioned in such a way that a stoppine burned out at the moment when the rocket reached its greatest height. The camera shutter was released via a tensioned spring and a photo plate was exposed. After that, the camera body separated from the rest of the missile. Both parts were attached to the opening parachute with cords of different lengths, which meant that the rocket and its command staff reached the ground earlier and additionally slowed down the fall of the valuable camera.

From the beginning, the military use of the new recording technology was the primary focus. As early as 1903 Maul was able to carry out his experiments on an infantry firing range of the Saxon Army near the later military training area in Königsbrück . On August 22, 1906, a secret demonstration of the photo rocket in front of military observers took place on the Glauschnitz firing range .

In 1912, Alfred Maul's rocket was fully developed. The inventor had constructed a movable and collapsible launch ramp that could be aimed at the area of ​​interest using a target device, taking into account the wind speed. The rocket was ignited electrically from a distance of 200 m, which first set the gyro into rotation and only then fired the black powder rocket. When this reached its highest point, a single photo was taken and fixed at a focal length of 28 cm on a 20 × 25 cm photo plate. Immediately afterwards, the missile split in two and the parachute unfolded. At a height of 800 m, scenic details could be shown sharply at a distance of up to 3.4 km. The payload of Maul's rocket was 41 kg.

Alfred Maul's missile was of little military importance. The Bulgarian army successfully used them in the First Balkan War to explore the Turkish positions at the Battle of Çatalca . In the First World War , however, it was probably not used, as aerial reconnaissance from the aircraft had already prevailed beforehand .

A rocket built by Maul can be seen today in the Deutsches Museum in Munich.

literature

Notes and individual references

  1. ↑ a b marriage certificate 1331/1900 Dresden
  2. ↑ M. Knopp lists 19 patents in Germany, Austria, Great Britain, Switzerland and the USA. There are also at least five more in France and Denmark.
  3. ↑ Patent DE64209 : Method for taking photographs of terrain from a bird's eye view by means of a cannon or rocket projectile. Registered on July 14, 1891 , published on September 6, 1892 , inventor: Ludwig Rohrmann. ‌
  4. ↑ Patent CH3794 : Device for taking photographs from a bird's eye view . Registered July 27, 1891 , published December 15, 1891 , inventors: Ludwig Rohrmann, Richard Rauthe. ‌
  5. ↑ Patent DE162433 : Rocket apparatus for photographing certain sections of the terrain. Registered June 5, 1903 , published August 2, 1905 , inventor: Alfred Maul. ‌
  6. ↑ Patent CH29581 : rocket apparatus for photographic recordings. Registered June 6, 1903 , published September 15, 1904 , inventor: Alfred Maul. ‌
  7. ↑ FH Winter, p. 87 f

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personal data
SURNAME Maul, Alfred
ALTERNATIVE NAMES Maul, Alfred Hermann Carl (full name)
BRIEF DESCRIPTION German engineer, pioneer of aerial reconnaissance
DATE OF BIRTH November 27, 1870
PLACE OF BIRTH Poessneck
DATE OF DEATH August 27, 1942
Place of death Dresden