HFB Ha 135
| HFB Ha 135 | |
|---|---|
| Type: | Trainer aircraft |
| Design country: | |
| Manufacturer: | |
| First flight: |
April 28, 1934 |
| Number of pieces: |
6th |
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The HFB Ha 135 was a German training aircraft . The small, two-seat biplane was designed in 1933 by the designers Reinhold Mewes and Viktor Maugsch for the recently founded Hamburger Flugzeugbau GmbH (HFB) for initial training and practice. The HFB was a subsidiary of the Blohm & Voss shipyard , which also wanted to make future-oriented aircraft construction its field of interest. In order to keep the as yet unpredictable risks away from the shipyard, a separate company had to be entered in the commercial register in June 1933.
history
In the search for suitable staff for the new area to be developed, the company boss Walther Blohm came into contact with two young design engineers who had just left Heinkel because they had a lot of competition in the form of the Günther brothers . Before that, Mewes (then only 35 years old) and Maugsch had been able to put the first two promising designs on the table for their boss Heinkel with the He 59 and He 60 . Your first job with the new employer was this training aircraft, which, in the form of a double-decker with two open seats arranged one behind the other, corresponded to the majority of the aircraft already in operation. These were mainly the Fw 44 and the He 72 . The team of designers is also likely to have been involved in the creation of the latter, so that a certain similarity of the aircraft now designated Ha 135 can be explained. A certain parallelism can also be seen with the beginning of aircraft construction at MIAG in Braunschweig, at Henschel in Kassel and at Adlerwerke in Frankfurt, all of which, until then, had been working in a different way, now wanted to turn to this new area. The first task at all of these companies was to build a school double-decker. Only Henschel was an exception. There, the entry pattern was a monoplane with an Argus As 10 C . Otherwise, the Siemens-Halske Sh 14 A required the same motor.
On April 28, 1934, the first aircraft with the designation Ha 135 and serial number (Wnr.) 101 was ready to take off at the HFB . Since Helmut Wasa Rodig , who was supposed to be the chief pilot, was still working as a flight instructor at the German Aviation School (DVS) in Warnemünde, it is very likely that Ernst Udet jumped in to fly it in. He probably also made the maiden flight with Wnr. 102 on July 14th, when he was in Hamburg to take part in the big flight day for the opening of the Hamburg-Altona airport the next day with his flamingo . The number 135 for the model was the first of a series of type numbers that had been assigned to the company by the Reich Aviation Ministry for its own future aircraft designs and which went up to 144. With the construction of the Ha 135, the aim was also to bring in a group of previously non-existent specialists for the hoped-for tasks in aircraft construction. Their colleague Hermann Pohlmann , who later switched from Junkers to Blohm & Voss and the creator of the Ju 87 , attested that Mewes and Maugsch had solved the task assigned to them in a remarkably short time . A sign of this is the fact that the second and the following 5 aircraft hardly differed from the first, so major changes were not necessary due to the experience of the first flights. Only the connection between the upper and lower ailerons has been changed. If the first aircraft, which was subsequently given the D-EXIL license plate, still had a bumper, the other two ropes were used. This change was also made to the first aircraft at a later date.
Who the further test flights with the Wnr. 101 and 102 is unfortunately not known. Joachim von Koeppen from DVL Adlershof , who is often entrusted with such tasks , could have done some of them . In any case, Rodig's flight log shows that he did not start flying at HFB until September 29, 1934. His first flight with an Ha 135 was not even registered until December 17th. It was already the Wnr. 103 that he has flown in.
This refutes the number of only two Ha 135s built in the literature, but even with Pohlmann. In truth, there were six planes, as Rodig's flight log shows. Five of them were flown in the following period at the Aviation Training Center in Hamburg-Fuhlsbüttel of the German Aviation Association (DLV), while the sixth was assigned to "Fluga", the flight department of the DVL in Berlin-Adlershof . There she was flown with pleasure in the flight engineer training for type training. With this aircraft, the Wnr. 112, D-EKME, Rodig had made the last proof flights for the final type certification of the aircraft on September 21, 1935 . When the Fluga moved to Braunschweig -Völkenrode at the beginning of the war , the D-EKME also came along, where it can be verified until 1940. Nothing is known about the fate of the others, with the exception of the Wnr. 103, which was deleted from the aircraft register in July 1938 without the reason being given.
construction
The Ha 135 is a braced double-decker in a conventional composite construction , i.e. with a welded tubular steel framework for the fuselage and with surfaces and tail units made of wood. The fuselage is oval in cross-section with wooden molding strips. The front part of the fuselage and partly the engine and the back of the fuselage are covered with removable light metal sheets. There is a lockable overhead locker behind the rear driver's seat. As usual, this is a little better instrumented than the one in front, the stick of which can be removed. The rigid chassis with oil-dampened spring struts and mechanically brakable wheels is supported by V-struts towards the fuselage. At the stern there is a steerable and lockable spur roller. The horizontal stabilizer with trim tabs on both rudder halves is held in place by struts downwards and tension wires to the fin. The largely identical wings, which are each connected by two stems crossed with tension wires, carry ailerons above and below.
Overview of the aircraft built
| Work number | Model | Mark | First flight | Pilot |
|---|---|---|---|---|
| 101 | Ha 135 V1 | D-EXILE | April 28, 1934 | Udet (?) |
| 102 | Ha 135 V2 | D-EKEN | July 14, 1934 | Udet |
| 103 | Ha 135 A | D-ESYT | December 17, 1934 | Rodig |
| 104 | Ha 135 A | D-ETEK | March 22, 1935 | Rodig |
| 111 | Ha 135 A | D-EDLA | August 8, 1935 | Rodig |
| 112 | Ha 135 A | D-EKME | August 5, 1935 | Rodig |
Technical specifications
(due to missing data partly by rough calculation)
| Parameter | Data |
|---|---|
| crew | 1-2 |
| length | 6.9 m |
| span | 9.0 m |
| height | 2.96 m |
| Track width | 1.6 m |
| Preparation mass | 535 kg |
| Takeoff mass | 860 kg (P3) 740 kg (S4K) |
| Engine | a Siemens-Halske Sh 14 A |
| Top speed | 195 km / h |
| Cruising speed | 170 km / h |
| Flight duration | 3.5 h |
| Service ceiling | 4000 m |
| Range | 600 km |
literature
- Hermann Pohlmann: Chronicle of an aircraft factory . Motor book, 1979.
- Ha 135 . In: Jet & Prop . No. 4/99 .
