Raab-Katzenstein RK 25
| Raab-Katzenstein RK 25 | |
|---|---|
 An RK 25 at the RaKa airfield Kassel-Waldau |
|
| Type: | Sports and touring aircraft |
| Design country: | |
| Manufacturer: | |
| First flight: |
1928 |
| Production time: |
1928 |
| Number of pieces: |
3 (4?) |
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The Raab-Katzenstein RK 25 is a German sport and touring aircraft from the 1920s.
development
The RK 25 was developed in 1928 on behalf of the Essen Aviation Association , which also took over the financing, for a fast touring aircraft with a long range. In order to keep the design as light as possible, the designer Paul John Hall and his deputy Richard Bauer, who joined the company in April of that year , deviated from the use of conventional building materials. Instead of aluminum, the ailerons and other assemblies were made from a magnesium alloy called electron and used for the first time by Raab-Katzenstein. The low-wing design was also used for the first time in a RaKa aircraft. A British Cirrus II with 80 hp acted as the drive . The prototype with the serial number 085 was built over the summer, the subsequent flying in did not cause any problems and in September the RK 25 was D–1489approved and handed over to the Essen Aviation Association. Raab-Katzenstein received a bonus of 15,000 Pr from the Reich Ministry of Transport for the successful construction . Then two more RK 25 with the serial numbers 106 and 107 were issued and approved as and .
D–1701D–2344
commitment
From August 4th to 16th the European sightseeing flight from 1929 took place, for which two RK 25s were registered, on the one hand that of D–1489the Essener Verein für Luftfahrt, flown by its member Friedrich Altemeyer with the start number B 2, and on the other hand that directly from Raab -Katzenstein reported D–1701. The latter received a more powerful 115 HP Cirrus Hermes engine and the designation RK 25a for the competition . Originally, Antonius Raab and Kurt Katzenstein had agreed that one of them should pilot the aircraft, but after a financial offer from the Canadian John Carberry, he was able to take over the plane for the sightseeing flight and take off with the number B 3. He achieved the best average speed of 155 km / h and ultimately came third in the overall ranking, while Friedrich Altemeyer with his RK 25 was eliminated from the competition after an emergency landing. The at least partially successful participation of a Raab-Katzenstein sample at this prestigious event could not hide the fact that the company was in a crisis. The chief designer Paul John Hall had already switched to BFW at the end of 1928 ; his successor Richard Bauer followed him before the competition began at the beginning of August 1929. The poor order situation was added and Raab-Katzenstein had to file for bankruptcy at the beginning of 1930.
In the midst of the subsequent legal disputes and the allegations against him of breach of trust, fraud and embezzlement, Antonius Raab founded Raab Flugzeugbau OHG in Krefeld in April 1932 , where Erich Gammelin revised the RK 25 for participation in the 1932 European tour . It received a closed cabin as well as folding wings for the technical evaluation of the competition, for which the aircraft required a space of only 3.00 × 3.00 × 7.00 m. An As 8 was selected as the drive , which was provided free of charge by Argus Motoren Gesellschaft . In August 1932 the acceptance flights were carried out at the DVL in Berlin-Adlershof and the RK 25/32 was then approved for the Greiling Zigarettenfabrik GmbH with the registration number D–1489that had already been used on an earlier RK 25. Participation in the sightseeing flight was disappointing. Raab and Gammelin were eliminated on the first stage from Warsaw to Rome due to engine failure and the RK 25/32 with the competition expert C 8 only came last in the overall ranking with the lowest number of points. The plane was cannibalized in November 1936.
construction
The RK 25 is a cantilever low- wing aircraft in a composite construction . The fuselage frame is a tubular steel construction that is planked with duralumin in the area of the engine and covered with fabric in the rest of the area. The wings consist of a wooden frame covered with fabric. The conventionally designed tail unit is self-supporting. The chassis consists of the non-retractable main wheels connected to an axle and a grinding spur at the rear.
The wings of the RK 25/32 can be folded up. In addition, they are provided with Ksoll slotted leaves on the rear edge.
Technical specifications
| Parameter | Data (RK 25) | Data (RK 25a) | Data (RK 25/32) |
|---|---|---|---|
| crew | 1-2 | ||
| span | 9.3 m | ||
| length | 6.48 m | 6.50 m | |
| height | 2.18 m | 2.00 m | |
| Wing area | 13 m² | ||
| Wing loading | 53.8 kg / m² | 54.0 kg / m² | |
| Power load | 8.8 kg / hp | 6.1 kg / hp | 5.4 kg / hp |
| Empty mass | 295 kg | approx. 390 kg | 430 kg |
| Payload | 405 kg | approx. 310 kg | 270 kg |
| Takeoff mass | 700 kg | ||
| drive | an air-cooled four-cylinder four - stroke in - line engine |
||
| Type | Cirrus II | Cirrus-Hermes | Argus As 8 |
| power | 80 hp (59 kW) | 115 PS (85 kW) | 130 hp (96 kW) |
| Fuel volume | 300 l | approx. 200 l | k. A. |
| Top speed close to the ground |
200 km / h | 235 km / h | |
| Climbing time to an altitude of 1000 m |
6 min | approx. 4.5 min | |
| Service ceiling | 3500 m | approx. 4300 m | 4500 m |
| radius | 2400 km | approx. 1500 km | 1200 m |
literature
- Rolf Nagel, Thorsten Bauer: Kassel and the aviation industry since 1923 . Bernecker, Melsungen 2015, ISBN 978-3-87064-147-4 .
Web links
Individual evidence
- ↑ Nagel, page 393/394