Pützer buzzard

Pützer buzzard
Type:	Test vehicle
Design country:	Germany
Manufacturer:	Alfons Pützer KG
First flight:	February 1959 (V-Leitw.) July 12, 1961 (Ring-Leitw.) Approx. 1972 (conventional)
Number of pieces:	1

The Pützer Bussard was a test vehicle designed as a training aircraft by Alfons Pützer KG .

history

In the mid-1950s, the German Air Force showed interest in an inexpensive training aircraft for its budding jet pilots. Based on his experience with the Pützer jackdaw , Alfons Pützer proposed a propeller-driven piston aircraft for this purpose, the pusher propeller of which was arranged at the rear of the aircraft between a double tail unit.

Pützer Bussard as a long-distance wave test vehicle SR-57

Alfons Pützer and Karl Lürenbaum had already tried out a long-distance wave between the motor located in the fuselage and the propeller at the stern as part of the Pützer Dohle, which, however, had only delivered unsatisfactory results. Karl Lürenbaum therefore applied for the Institute for Engine Dynamics at RWTH Aachen University for funding from the Ministry of Economics and Transport for the further development of existing long-distance wave concepts under the project name SR-57. As part of the research project, the construction of a test vehicle for the drive was also planned, which Alfons Pützer KG operated under the name Pützer Bussard. Alfons Pützer originally envisaged a similar design for this test vehicle as for the jet trainer Fouga Magister with two seats arranged next to each other and a low-wing construction, which had the double tail system known from the Pützer Dohle and a fuselage wedge to protect the propeller at the stern. Walter Horten , however, suggested the use of a V-tail unit instead of the jackdaw's double tail unit due to the loss of power observed in the Pützer Dohle due to turbulence in the rear propeller. For the first time, Pützer also provided a retractable landing gear for the Bussard. The Continental C90 -12F drive known from the Elster in Pütz was used as the motor.

Problems were caused by the 6 meter long long-distance wave running through the entire fuselage, which showed frequent failure of dynamic components on the long-distance wave test stand in Aachen and whose vibration behavior only showed satisfactory results after a completely new conception in the form of a three-part wave. In January 1959 the drive was installed in the test vehicle in Bonn. The German Aviation Research Institute (DVL) in Cologne-Wahn was commissioned to test the test vehicle. There the Pützer Bussard started in February 1959 with the provisional traffic approval D-EHIV for the first flight. In the subsequent tests, the Pützer Bussard showed satisfactory results at the DVL until the end of 1959, especially in the take-off and landing phase. In May 1959, the Pützer Bussard was presented to the public for the first time at the ILA in Hanover.

After the introduction of the jet trainer Fouga Magister , the Federal Air Force changed its training concept for its jet pilots. In the new training concept, the use of inexpensive upward trainers was no longer intended. Despite the positive tests, the Luftwaffe was therefore no longer interested in purchasing the Pützer Bussard in 1959. With the end of the SR-57 project, the test vehicle was parked in autumn 1959.

Pützer Bussard as a test vehicle for ring tail units

At Bölkow GmbH in Nabern, Erich Ufer worked on the development of ring tail units since 1956. As part of this development, Bölkow GmbH planned to build the Bölkow P.103 test vehicle. After Ludwig Bölkow and Erich Ufer had not received any funding from state programs for the test vehicle until 1959, Alfons Pützer suggested converting the long-distance test vehicle Bussard, which was no longer needed, to accommodate a ring tail. Apart from the redesign of the entire tail unit area with the ring manufactured by Bölkow in GRP construction, the Pützer Bussard received a new landing gear, also designed by Bölkow as part of the P.103, which ensured the necessary ground clearance for the ring tail unit. Due to the heavy weight of the ring tail, Alfons Pützer swapped the Continental C90 engine for a 145 HP Continental O300, for which Karl Lürenbaum made the necessary changes to the long-distance shaft in Aachen. The reconstruction of the Pützer Bussard and the wind tunnel tests necessary in advance were financed by the Federal Ministry of Defense from the end of 1959.

After completing the model tests on the wind tunnel in Stuttgart, the Pützer Bussard was converted by the end of 1960, which was then given the designation SR-57-2K. In order to gain further experience with the ring tail, another wind tunnel program took place before the first flight in early 1961, in which the completed prototype was aerodynamically examined. On July 12, 1961, the Pützer Bussard made its first flight with a ring tail in Bonn-Hangelar. Satisfactory results were demonstrated in a three-month flight test. On March 22, 1963, the Federal Aviation Office issued a preliminary traffic permit for the SR-57-2K ring tail carrier. With the submission of the final report in June 1964, the test vehicle was again turned off. The further development of ring tail units was finally given up in Germany in the mid-1960s.

Pützer Bussard as a study object for bypass engines

The Pützer Bussard came to the Institute for Engine Dynamics from Karl Lürenbaum in Aachen after completing the ring tail test. Together with the Rhein-Flugzeugbau RF-1 developed by Hanno Fischer at Rhein-Flugzeugbau , the Bussard was used in Aachen for ground and test bench tests to develop ducted turbines, as they were first used in 1968 by the motorglider Rhein-Flugzeugbau Sirius . The Pützer Bussard was largely dismantled during these tests and was later stored in Merzbrück near Aachen.

Pützer buzzard in conventional construction

Walter Horten took over the dismantled Pützer Bussard in 1971. With the support of the Oskar Ursinus Vereinigung (OAV), Horten replaced the ring tail with a conventional tail and expanded the long-distance shaft. Instead, the engine in the bow was connected to a bow propeller in a conventional design. The wings, landing gear and central fuselage with cockpit remained unchanged.

Presumably, the Pützer Bussard in this configuration was still used as a touring aircraft by the OAV for a few years. It is said to have been destroyed later in a hall fire.

Technical specifications

Parameter	SR-57 (V-tail)	SR-57-2k (ring tail)
crew	1	1
Passengers	1	1
length	6.30 m	? m
span	12.00 m	12.00 m
height	2.20 m	? m
Wing area	18.00 m²	18.00 m²
Empty mass	600 kg	? kg
Max. Takeoff mass	760 kg	840 kg
Cruising speed	180 km / h
Top speed	? km / h
Service ceiling	? m
Range	? km
Engines	1 × 70 kW Continental C90 -12F	1 × 145 PS Continental O300

See also

• List of aircraft types

literature

• Paul Zöller, Hanns-Jakob Pützer: Pützer aircraft , Dec. 2018, ISBN 978-3-7481-2096-4
• Heinz Dieter Schneider: From the Elster to the Bussard Airplane Classic 4/2007

Web links

• Alfons Pützer homepage, Bussard picture archive

Individual evidence

1. ↑ ^{a b c} Alfons Pützer homepage, Bussard picture archive
2. ↑ ^{a b c d e f} Paul Zöller, Hanns-Jakob Pützer: Pützer-Flugzeug , Dec. 2018, ISBN 978-3-7481-2096-4
3. ^ Heinz Dieter Schneider: From the Elster to the Bussard Airplane Classic 4/2007
4. ↑ Flugrevue: Spicy novelty: SR-57 Bussard , FR 6/59, page 24
5. ↑ Flight International: Sport and Business , Aug. 1959, p. 1867
6. ↑ FliegerRevue October 2010, pp. 56–59, The constructions of Alfons Pützer - Kurzer Höhenflug der Elster
7. ^ Rolf Wurster: 50 years of German powered aircraft. ISBN 978-3-8311-1854-0