Heinkel HD 39

Heinkel HD 39
Type:	Newspaper cargo plane
Design country:	German Empire
Manufacturer:	Heinkel
First flight:	1926
Commissioning:	1926
Number of pieces:	1

The Heinkel HD 39 was a German cargo plane that was used by Ullstein Verlag in the 1920s to transport newspapers. The abbreviation "HD" stands for "Heinkel Doppeldecker".

development

In the mid-1920s, Ullstein Verlag placed an order with Albatros Flugzeugwerke for the construction of two aircraft specially designed for the transport of newspapers. They should manage a speedy delivery of the gazettes and help to implement the claim of the BZ am Mittag , which was published by Ullstein, to be the "fastest newspaper in the world". In response, the L 72 a was developed under the direction of Albatros' chief designer Gustav Lachmann and the technical director Rudolf Schubert . When Ernst Heinkel found out that the order had been placed, he immediately intervened with the publisher's own editor, Walther Kleffel, in order to expand the order in his favor. Kleffel, himself a former flight officer and also the responsible specialist editor for aviation, had already initiated the order for Albatros and reached the publishing house management to increase the order for a third aircraft, for which Heinkel received the construction contract. The so-called "Heinkel-Tempo", a further development of the HD 27 and the one-off production of the HD 39 with the serial number 238 , was then created in a very short time at Heinkel's parent plant in Warnemünde. As a special feature, it was equipped with a dropping device in the cargo hold with which Ten 50 kg newspaper packages, which were transported hanging, could be individually selected using cables and levers and thrown through a roller door located in the fuselage floor. A BMW IV engine with 230 hp was selected as the drive .

The HD 39 was approved on February 4, 1926 by the Interallied Aviation Guarantee Committee (ILGK) and received its approval with the mark D–889. On April 8 of the same year, the aircraft was named BZ I in a festive ceremony at Berlin-Tempelhof Airport, together with the two L 72 a, which were also completed , while the two Albatros models were named BZ II and BZ III . All three aircraft had striking black and yellow stripes on the fuselage and the BZ lettering on the wings and on the nose. The license plates were only attached at a later date. Hamburg, Leipzig, Halle / Saale and Chemnitz were initially approached as cities, landing and unloading in the former, but only dropping the cargo in Chemnitz. The newspapers were then delivered immediately; they were often started to be distributed immediately after landing on the aircraft. Later there were routes in mainly north and east Germany, including to Plauen and Swinemünde; in Stettin and Binz / Rügen the cargo was only launched again. The official owner was Ullstein AG, the owner and user was Luft Hansa . During this time, the HD 39 performed better than its two competing models, whose operation was impaired by complications with the cooler and the still immature Lachmann slotted flaps. The Heinkel model was therefore able to complete more than double the number of flying hours than both L 72s together by the end of 1926.

In April 1931, Deutsche Luftfahrt GmbH took over ownership and flew the HD 39 until June of the following year. Then it was removed from the aviation role and became the property of the German Aviation Collection, where it disappeared like many other objects in the turmoil of the Second World War.

construction

View of the driver's cab of the HD 39 on the left

The HD 39 is a single-handle, tensioned double - decker in wood construction with a rigid chassis. The fuselage is made up of four longitudinal spars with a square cross-section, which end in a cutting edge towards the stern. In the bow area, the cladding consists of removable aluminum sheets, in the remaining part of plywood. The cargo hold is behind the engine fire bulkhead and in front of the pilot's cabin. To the right of the pilot's seat there is a foldable emergency seat for the flight attendant. The structure is staggered and connected to each other by N-struts. The wings with a slight V-position (above 1 °, below 2 °) have two spars, between which the planking as well as the leading edge of the wing are made of plywood, the rest is covered with fabric. The 300 liter fuel tank is located in the upper wing. The tail unit consists largely of a tubular steel frame covered with fabric, only the fin is made of wood. The braced horizontal stabilizer can be adjusted in flight, all rudders are balanced. The rigid chassis has a track width of 3.26 m and no axle, there is a grinding spur at the rear.

Technical specifications

Three-sided view

Parameter	Data
crew	2
length	10.55 m
span	above 14.3 m below 12.7 m
height	4.18 m
Wing area	52.3 m²
Empty mass	1320 kg
Payload	840 kg
payload	400 kg
Takeoff mass	2160 kg
drive	a liquid-cooled six - cylinder four-stroke in - line engine
Type	BMW IV
Starting power continuous power	275 PS (202 kW) 230 PS (169 kW) at 4000 m
Fuel volume	300 l
Top speed	166 km / h at an altitude of 500 m
Landing speed	68 km / h
Rise time	6.6 min at 1000 m 15.4 min at 2000 m 29.5 min at 3000 m
Summit height	3800 m with maximum payload
Flight duration	5.5 h
Radius of action	850 km
Take-off run	295 m

literature

• Volker Koos: Ernst Heinkel Flugzeugwerke 1922–1932 . Heel, Königswinter 2006, ISBN 3-89880-502-6 , p. 95/96 .

Web links

Commons : Heinkel HD 39  - Collection of pictures, videos and audio files

Individual evidence

1. ^ The Albatros L 72 cargo and transport aircraft, p. 9ff , accessed on November 9, 2017 (a contribution from the German Aviation History Working Group).