Aircraft template

Source: Aerokurier 1970
Antonius Raab and Dipl.-Ing. Kurt Katzenstein are among the most prominent and successful pilots of the 1920s. In 1925 they founded the Raab-Katzenstein aircraft factory
together. The next reports in our series are about the aircraft from this factory, which are mostly unknown to the younger generation. The hallmark of this Company was flexibility.
Projects and aircraft were created almost overnight. There was hardly a problem of the time that the Company did not take on. They even worked on the construction of a small lull
ship and a rocket plane. Raab and Katzenstein were undoubtedly pioneers in advertising aviation, which they were the first to launch; they also built the first air tow train, a glider
and a locomotive. They knew how to advertise the sport of flying convincingly. They demonstrated the high art of aerobatics on their own aircraft at countless air shows. They made
the population "air-minded" and, not least, created the most successful aerobatic aircraft of the late 1920s, which helped Gerhard Fleseler to his first global successes (Schwalbe
and Tigerschwalbe).
Comet-like rise
We have already reported on the creation of the Raab-Katzenstein aircraft factory here (see aerokurier 6/69, page 427/28) as part of our series of articles on Dietrich-Gobiet aircraft
construction. Due to disagreement with a new financier and the departure of the main financier Gobiet, Dietrich aircraft construction collapsed in 1925. At the end of 1925, the core
of the workforce, led by Antonius Raab and Dipl.-Ing. Katzenstein, moved into a rented hall of the former Deutsche Werke on the opposite side of the Street in Kassel-Bettenhausen
with a total of 26 men and founded the Raab-Katzenstein works there. The workforce increased by the end of October 1927 to 200 men. Sales in 1926 amounted to around
700,000 RM and in the first 7 months of 1927 had already risen to 900,000 RM. In the first two years, around 63 aircraft were built. - A remarkable number for that time. It should
not go unmentioned that the factory received no support from the Reich government, unlike the large aircraft factories of the time. It also received no public contracts and was
completely dependent on the private sports aircraft market and exports.
Lightning repairs
In addition to the actual aircraft construction, a repair department was operated that dealt with the overhaul and repair of damaged aircraft. "Der Sportflieger", the company’s
Company magazine, reports on how the repair department worked at the time. A pilot had an accident with a Raab-Katzenstein aircraft on a Sunday, and the aircraft was 70 percent
damaged. He had committed to a flight day the following weekend and had to fulfil this commitment. He therefore insisted that his aircraft be repaired, re-flown and registered
within a week. The factory managed to transport the aircraft 250 km to the factory the night after the accident. The aircraft was flying again the following Friday and the official
inspection took place on the same day. The approval arrived by telegram on Saturday and on Sunday the pilot was able to take part in the scheduled flight day. Flying school
Raab-Katzenstein also had two flying schools. One was at the factory in Kassel and another in Bonn-Hangelar. Both were run by Kurt Katzenstein. All pilots first received 6 months
of thorough training as aircraft mechanics. Only after they had acquired sufficient theoretical, technical and practical knowledge did they receive flight training. This meant that the
pilots could help themselves in the event of minor damage to the aircraft, which were still very vulnerable at the time. Flying events Raab-Katzenstein organized no fewer than 65
of its own flying events in 1928. The pilots of the Raab-Katzenstein aircraft factory also took part in many regional events and competitions organized by the clubs of the German
Aviation Association. On some Sundays, three events were held at the same time.
These flying days were also the best advertising campaigns for the sale of the company's own aircraft. What these flying days were for the 1920s was equivalent to the success of
the Burda squadron in the 1960s, which achieved more than 500 flying days. The program of these air shows organized by Raab-Katzenstein included demonstrations by Veteran
pilots, such as a Bleriot monoplane of type XI from 1909, which our readers know from our report on the Reims Rally (see aerokurier 8/69, page 518). This was followed by
aerobatics demonstrations on various Schwalbe models of the factory with individual aerobatics, formation flights and aerial dances. Finally, balloons were chased, such as as is
known from the Burda squadron. Obstacle landings, relay flights, aerial games and, as a special attraction, the tow train were also part of the program. At a certain height, the tow
plane would release and land in a gliding flight in front of the spectators. The factory put up to three such tow trains into the air.
Mixed Operation
The flight days brought interested parties and customers for the factory’s aircraft. The factory even received export Orders abroad, to Africa, and delivered several Pelicans and the
Warbler on floats to China. In order to stand on two feet, a steel furniture construction department was attached to the Company, which manufactured furniture in series and
delivered it especially to schools and hospitals. The aim was to compensate for the quiet winter months in aviation in order to prevent the layoff of high-quality personnel.
Ra-Ka teamwork
Antonius Raab highlights the excellent teamwork in the factory and writes: "Even if the construction plans and drawings had to be signed with the name of a designer in
accordance with the DVL regulations, this was by no means proof that all the ideas came from him. The Ra-Ka works worked as a team, both the management and the foremen.
The head of the team - who had the best ideas and always had the book 'Ford - my life and work' under his pillow - was Gammelin. A simple engineer with amazing ideas. He
appeared practically every morning with new ideas. The factory only had two graduate engineers, namely Kurt Katzenstein and Mann. All the others, up to 15 technicians, were
simple engineers and foremen with a lot of practical experience. Raab's motto was: There are graduate engineers a dime a dozen, send them to the DVL. We need practitioners.
Everything was discussed together, decisions were made quickly and mostly even carried out immediately in shifts and night shifts.
It was teamwork between practice and theory, in the workshop, on the drawing board and at the airfield.
The three managing directors Raab, Katzenstein and Gammelin worked with the design Office, the technicians Hall, Kalkert, Bauer, Knüpfer and the foremen in perfect harmony
and at a speed that corresponded to the roles in aerobatics. They ate together, but design issues dominated the table conversation. Such achievements were achieved by paying a
dividend equal to the same to the Partners - to the entire workforce - and also performance bonuses for fast work (without DVL objections). Today we hear about staff involvement
and co-determination as a novelty. Ra-Ka did that in 1925. And nobody knew that. Pioneering work too!"
Characteristics of the Raab-Katzenstein aircraft
Most Raab-Katzenstein aircraft, of which we have already seen one of the most outstanding designs, the RK-25 (see aerokurier 12/69, page 879), are designed according to
uniform principles. They were cantilevered or braced biplane cells with torsion N-beams. The wings were made of wood with fabric covering. The fuselages were made of a steel
tube construction, as were the tail unit and the rudders, and were mostly covered with fabric, sometimes with plywood.
Raab also points out an important invention: "The factor A = 6 applied to the arresting at that time, that is, 6 times the breaking load multiple. While up to 1925 the straps of the
wooden spars were mostly made of solid wood internationally, one at the top and one at the bottom, The Raab-Katzenstein works came up with the idea of laminating the spars.
Seven layers of wood were glued from the "block", tapering towards the wing tips, with the grain glued in different directions. This resulted in a slight increase in weight, but allowed
the factory to increase the factor A from the normal 6 to 12.5 for the first time in the world.
Today this is common knowledge. It was only thanks to this idea that Fieseier and other pilots were later able to perform their forward loops.
The old war planes Kranich and Marabu, built under license, were largely made of wood in their original design. The simple and conventional structure of the planes and the
adherence to the undemanding biplane made the factory flexible. With the help of these simple designs, it was always able to adapt to the buyers and their special wishes. In
addition, these simple designs were inexpensive and easy to repair. These were important features in the hard times of the time after inflation and the looming economic crisis with
6 million unemployed (1929), and they seemed more important to the Company than highly developed aerodynamics. The pilots of the time were not so much concerned with flying
fast, but rather with getting into the air at all, and doing so with as little effort as possible. This economic development, forced by the hard times of the time, This economic
efficiency, which was forced by the hard times was one of the most important characteristics of the Raab-Katzenstein constructions
The bitter end
Despite all its flexibility, business acumen and great success, the factory was forced to cease operations in 1930. Without state support, a factory that was solely focused on sport
aviation could not exist in a time of enormous economic crisis, in which almost one in three people was unemployed and countless factories went bankrupt.
No other German aircraft factory was as closely linked to German sport aviation as Raab-Katzenstein. With the large number of flight days, the flight school and the inexpensive
aircraft designs, the factory played a decisive role in the development of sport aviation in the 1920s. And for this, the two very elderly owners, Antonius Raab, who now lives in Italy,
and Dipl.-Ing. Kurt Katzenstein, who lives in South Africa, deserve the thanks of today's sport pilots in the Federal Republic, who learned to build a sport aviation Company from
nothing after the collapse in 1945 and therefore appreciate the achievements of these two men very much.