Heinkel He 70

Infobox Aircraft
name=Heinkel He 70


caption=
type=Mail plane, Passenger, Reconnaissance Bomber
manufacturer=Heinkel Flugzeugwerke
designer=
first flight=1 December 1932
introduced=1933
retired=1945
status=Retired
primary user="Luftwaffe"
more users="Lufthansa"
Royal Hungarian Air Force
produced=
number built=324 + license-built in Hungary
unit cost=
variants with their own articles=

The Heinkel He 70 was a German mail plane, passenger, liaison, training and bomber aircraft of the 1930s. Although useful, it had a relatively brief commercial career before it was replaced by types which could carry more passengers. As a combat aircraft it was a not a great success because it rapidly became outdated. Nevertheless, the He 70 was a brilliant design for its day, setting no fewer than eight world speed records by the beginning of 1933.

Design and development

The Heinkel He 70 "Blitz" was designed in the early 1930s to serve as a fast mailplane for "Deutsche Lufthansa". The He 70 was developed in response to "Lufthansa" request for a faster aircraft than the Lockheed Vega and Orion (as used by Swissair) for employment on short routes. It was a low winged monoplane, with the main characteristics of its revolutionary design its elliptical wing, which the Günther brothers had already used in the Bäumer Sausewind sports plane before they joined Heinkel, and its small, rounded control surfaces. In order to meet the demanding speed requirements, the design minimised drag, with countersunk rivits giving a smooth surface finish and a retractable undercarriage, a novel feature for a German aircraft. Smith and Kay 1972, p.233.] It was powered by a BMW VI V-12 engine, cooled by ethylene glycol rather than water, allowing a smaller radiator and therefore reducing drag. The pilot and radio operator were seated in tandem, with a cabin housing four passengers on two double seats facing each other.

The first prototype flew on 1 December 1932,Smith and Kay 1972, p.234.] and proved to have excellent performance, setting eight world records for speed over distance, and reaching a maximum speed of 377 km/h (222 mph). Donald 1999, p.494.]

Operational history

"Lufthansa" operated He 70s between 1933 and 1937 for fast flight service which connected Berlin with Frankfurt, Hamburg and Cologne, as well as the Cologne/Hamburg route. "Lufthansa" He 70s were flown abroad from Stuttgart to Sevilla between 1933 and 1936. Remaining aircraft were transferred to the "Luftwaffe" in 1937.

Twenty-eight aircraft were sent with the Legion Condor, where they were used during the Spanish Civil War as fast reconnaissance aircraft. Their high speed gave them the nickname "Rayo" (lightning).

The He 70K, a fast reconnaissance airplane variant was used by the Royal Hungarian Air Force in early World War II during 1941-42.The "Luftwaffe" operated He 70s from 1935, initially as a light bomber and reconnaissance aircraft, later as a liaison and courier aircraft.

The main weakness of the He 70 design soon became obvious. The He 70 airframe was made out of so-called "electron metal", a very light, yet strong alloy of magnesium, which burns spontaneously in air when heated, and is only exhausted when covered in sand. A single hit from a light machine gun usually set the entire plane ablaze, killing the crew. The Hungarian He 70K fleet was promptly retired and replaced with vintage, high-wing He 46 monoplanes until modern Bf 109 fighter-recce and specialized Fw 189 "Uhu" medium altitude observation aircraft could be introduced.

Influence

While the He 70 saw only limited service in training capacities during World War II, it was the "Luftwaffe's" first "Schnellbomber" and served as the antecedent for the majority of bombers involved in both the Battle of Britain and the attack on Pearl Harbor.

The He 70 is known mainly as the direct ancestor of the famous Heinkel He 111 which used its distinctive oval wings and streamlined fuselage in a twin-engine configuration. One can also see the close similarity of the designs in the tail section and cockpit of the early He 111. The He 111, which began service with the "Luftwaffe" in 1936, went on to become the major bomber type in the early years of World War II.

Heinkel's pioneering design was also a model for the Heinkel He 112 fighter which competed unsuccessfully against the Messerschmitt Bf 109 to become the "Luftwaffe's" first monoplane fighter.Fact|date=February 2008 The He 112 was nonetheless built in small numbers and its performance proved once again the strength of the He 70's original design. The fighter was basically a scaled down version of the He 70 and shared its all-metal construction and inverted gull-wings.

The He 70 was exported to Japan for study and inspired the Aichi D3A (Val) carrier-launched light bomber.Fact|date=February 2008 This plane too shared the He 70's distinctive low-mounted oval wings and was only one of several collaborations between Heinkel and the Japanese aviation industry.

It is also commonly believed to be an inspiration or influence for the Supermarine Spitfire's elliptical wing planformFact|date=February 2008, not without reason as a He-70G was flying in England as a Rolls-Royce Peregrine engine test aircraft at the time of the Spitfire's development.

Part of a letter that R J Mitchell wrote to Heinkel after seeing the aircraft perform with the Rolls Royce Kestrel engine fitted:

"We, at Supermarine Aviation, were particularly impressed, since we have been unable to achieve such smooth lines in the aircraft that we entered for the Schneider Trophy Races....In addition to this, we recently investigated the effect that installing certain new British fighter engines would have on the He 70, We were dismayed to find that your new aircraft, despite its larger measurements, is appreciably faster than our fighters. It is indeed a triumph."

Versions

;He 70a:First prototype.;He 70b:Second prototype with the crew of 2 and 4 seats for passengers.;He 70c:Third prototype armed with machine-gun for trials of versions for light bomber, reconnaissance and courier duties.;He 70d:Fourth prototype built in 1934 for "Lufthansa", powered by BMW VI 7,3 engine.;He 70e:Fifth prototype built in 1934 for "Luftwaffe" as light bomber, powered by BMW VI 7,3 engine.;He 70A:Passenger version for "Lufthansa".;He 70D:Passenger version for "Lufthansa", 12 examples built.;He 70E:Light bomber version for "Luftwaffe", later converted to F version.;He 70F:Reconnaissance / courier version for "Luftwaffe".;He 70F-1:Long-range reconnaissance version.;He 70F-2:Similar to the He 70F-1;He 70G:Passenger version built for "Lufthansa", after 1937 converted to F version.;He 70G-1:One aircraft fitted with a 604-kW (810-hp) Rolls-Royce Kestrel piston engine.;He 70K (He 170A):License-built Hungarian fast reconnaissance variant equipped with a licence-made 1000bhp WM-K-14 radial engine.;He 270 V1 (W.Nr. 1973, D-OEHF):Prototype with DB-601Aa inline engine.

Operators

Civil Operators

;flagicon|Germany|Nazi Nazi Germany: "Lufthansa" received the first two prototypes in 1933 and 1934 as well as three He 70D in 1934 and 10 He 70G in 1935.

;JPN: Japan received 1 aircraft for test.

;UK: Rolls Royce received 1 He 70G powered by Rolls-Royce Kestrel V engine.

Military Operators

;flagicon|Germany|Nazi Nazi Germany
*"Luftwaffe"

;flagicon|Hungary|1940 Hungary
*Royal Hungarian Air Force received 18 domestically license-built He 170A aircraft.

;flagicon|Spain|1939 Spanish State
*"Ejército del Aire" received 11 aircraft of the 30 that had served with Legion Condor.

pecifications (He 70F-2)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=Fact|date=May 2008
crew=2 (pilot and observer)
length main=12 m
length alt=39 ft 4.5 in
span main=14.80 m
span alt=48 ft 6.75 in
height main=3.1 m
height alt=10 ft 2 in
area main=
area alt=
empty weight main=2,360 kg
empty weight alt=5,203 lb
loaded weight main=3,460 kg
loaded weight alt=7,630 lb
max takeoff weight main=
max takeoff weight alt=
engine (prop)=BMW VI 7.3
type of prop=12-cylinder water-cooled inline engine
number of props=1
power main=
power alt=750 hp
propellers=metal, two-bladed
max speed main=360 km/h
max speed alt=224 mph
max speed more=
cruise speed main=
cruise speed alt=
Landing speed
range main=900 km
range alt=559 mi
ceiling main=
ceiling alt=
climb rate main=
climb rate alt=
loading main=
loading alt=
power/mass main=
power/mass alt=
Take off run=
Landing run=
guns=One 7.92mm MG 15 machine gun aimed from rear cockpit
bombs=Six 50 kg (110 lb.) or twenty four 10 kg (22 lb) bombs internally

ee also

aircontent
related=
* He 270
* He 111
* He 112
* Aichi D3A
similar aircraft=
* Lockheed Orion
see also=
lists=
* List of military aircraft of Germany

References

Notes

Bibliography

* Donald, David (ed.) "The Encyclopedia of Civil Aircraft". London:Aurum Publishing. 1999. ISBN 1-85410-642-2.
* Smith, J.R. and Kay, A.L. "German Aircraft of the Second World War". London: Putnam. 1972. ISBN 85177 836 4.

External links

* [http://stalag4d.atspace.com/page114.html Photograph of a Heinkel He 70 Luftwaffe ashtray taken from Halle airfield in May 1945]
* [http://www.eads.com/1024/en/eads/history/airhist/1930_1939/heinkel_he70_1932.html Heinkel He 70] EADS. Retrieved 16 February 2008.