Category Archives: Reconnaissance

Reconnaissance

Arado Ar 231 (Airmodel, Vacu-formed)

TYPE: Observer, reconnaissance aircraft

ACCOMMODATION: Pilot only

POWER PLANT: One Hirth HM 502 six-cylinder inverted inline engine, rated at 160 hp

PERFORMANCE: 106 mph

COMMENT: Designed from the outset for use on U-boat “cruisers”, like the Type XI B, the Ar 231 was a light parasol-wing aircraft. The aircraft was powered by an inline engine, weighed around 2,200 lb, and had a 33ft wingspan. The design led to a simple and compact aircraft that could be fitted into a storage cylinder only 6.7 ft in diameter. For ease of storage, the Ar 231’s wings featured detachable sections that two operators could remove in less than six minutes. One unusual feature was an offset wing design, with the right wing root attaching to the wing’s tilted center section (elevated above the fuselage, as on all parasol-wing designs) and lower than the left wing root, to allow the wings to be quickly folded up. Testing soon revealed the Ar 231s to be fragile, underpowered, and difficult to fly even during calm weather, and as a result, development ended in favour of the Focke-Achgelis Fa 330 gyro glider. Some of the testing was done on the auxiliary cruiser “Stier”. Only six prototypes were built (Ref.: 24).

Blohm & Voss Bv 238 V1, (Airmodel, Vacu)

TYPE: Long-range Transport, Maritime Patrol and Bomber Flying Boat

ACCOMMODATION: Crew of 12

POWER PLANT:  Six Daimler-Benz DB 603G, rated at 1,900 hp

PERFORMANCE: 264 mph at 19,685 ft

COMMENTS: First prototype flew in April 1944, but was sunk early 1945 by strafing Mustangs. At the end of WWII the second prototype was virtually complete and construction of the third was in an advanced stage

 

Heinkel He 51B-2 (Hasegawa)

TYPE: Reconnaissance floatplane, trainer

ACCOMMODATION: Pilot only

POWER PLANT: One BMW VI 7,3 Z liquid-cooled engine, rated at 750 hp

PERFORMANCE: 205 mph

COMMENT: The Heinkel He 51 was a single-seat biplane which was produced in a number of different versions. It was initially developed as a fighter, it was also developed as a ground-attack aircraft and a floatplane.
In 1931, Heinkel Aircraft Company developed the Heinkel He 49, officially an advanced trainer in fact it was a fighter. The first prototype flew in November 1932, and was followed by two further prototypes with a longer fuselage, and a revised engine. The type was ordered into production for the still secret Luftwaffe as Heinkel He 51, the first pre-production aircraft flying in May 1933. Deliveries started in July of the next year.
The He 51 was a conventional single-bay biplane, with all-metal construction and fabric covering. It was powered by a BMW VI engine, with an armament of two machine guns mounted above the engine. The He 51 was intended to replace the earlier Arado Ar 65, but served side-by-side with the slightly later Arado Ar 68. The He 51 was outdated the day it entered service, and after an initial run of 150 production fighters, the design was switched into the modified He 51B, with approximately 450 built, including about 46 He 51B-2 floatplanes. With begin of WW II the Heinkel He 51B-2 was only used in a role as trainer (Ref.: 24).

Dornier Do 18G-1 (Matchbox)

TYPE: Patrol and reconnaissance flying boat

ACCOMMODATION: Crew of four

POWER PLANT: Two Junkers Jumo 205C-4 liquid-cooled diesel engines, rated at 605 hp each

PERFORMANCE: 155 mph at sea level

COMMENT: In 1934, the Dornier Flugzeugwerke started development of a new twin-engined flying boat to replace the Dornier Do J Wal (Whale) in both military (Do 16) and civil (Do JI and Do J II) roles. The resultant design, Do 18 retained the layout of the “Wal”, with a metal hull fitted with distinctive stabilizing sponsons, and powered by two engines above the wing in a push-pull layout, but was aerodynamically and hydrodynamically more efficient. It was planned to be powered by two of the new Junkers Jumo 205 diesel engines. Although heavy, these promised to give much lower fuel consumption than conventional petrol engines of similar power.
The Do 18G, 62 units built, was an improved version, powered by two 880 hp Jumo 205D engines, armed with a 13 mm MG machine gun in the bow, and a 20 mm MG 151 cannon in a power-operated dorsal turret.
In German Luftwaffe service, the Dornier Do 18G was obsolete by the outbreak of World War II, but – as the only military flying boat – 62 (58 serviceable) aircraft in five squadrons were in use mainly on North Sea reconnaissance missions. In 1940 some squadrons changed their base to Norway. The vulnerable and underpowered flying boat was soon relegated to training and the air/sea rescue role. In the middle of 1941, only one squadron was still operational on Do 18. The Blohm & Voss Bv 138 had superseded the Dornier Do 18G.
A Dornier Do 18G was the first German aircraft to be shot down by British aircraft during the war, when one of a formation of three was caught over the North Sea by nine Fleet Air Arm Blackburn “Skua” fighter bombers of 803 Naval Air Squadron flying from HMS “Ark Royal” on 26 September 1939 (Ref.: 24).

Dornier Do 16 „Militärwal“(“Military Whale”) (Huma)

TYPE: Reconnaissance, transport and training flying boat

ACCOMMODATION: Crew of two to four plus 8-10 passengers or equivalent freight

POWER PLANT: Two BMW VI liquid-cooled engines, rated at 700 hp each

PERFORMANCE: 143 mph

COMMENT: The Dornier Do J “Wal” (“Whale”) was a twin-engine German flying boat of the 1920s designed by Dornier Flugzeugwerke. The Do J had a high-mounted strut-braced monoplane wing with two piston engines mounted in tandem in a central nacelle above the wing; one engine drove a tractor and the other drove a pusher propeller. The hull made use of Claudius Dornier’s patented sponsons on the hull’s sides.
The Do J made its maiden flight on November, 1922. The flight, as well as most production until 1932, took place in Italy because of the restrictions on aviation in Germany after World War I under the terms of Treaty of Versailles. Dornier began to produce the “Wal” in Germany in 1931; production went on until 1936. The Dornier J I and its  variant J II “Wal” were some of the most famous flying boats of the periods between the world wars.
A military version was the Dornier Do J II d and was in service with the German Luftwaffe as Dornier Do 16 “Militärwal” (“Military Whale”) according to the aircraft designation system of 1934 by the ReichsLuftsfahrtMinisterium (Reich Air Ministry, RLM). It was used as a reconnaissance and transport aircraft. A crew of two to four rode in an open cockpit close to the nose of the hull. There was one machine gun position in the bow in front of the cockpit and one or two amidships.  Some 30 Dornier Do 16 “Militärwal” being delivered for the Luftwaffe in 1935. Eventually these were replaced by the Dornier Do 18 and the “Militärwal” was relegated to training roles.

Note: In many publications the Dornier J II d “Military Whale” is cited as Dornier Do 15. So done on my website, too, (but now corrected). The proper designation is Dornier Do 16 (Ref. 24).

Dornier Do 26D-0 (Airmodel, Vacu)

TYPE: Transport and reconnaissance flying boat

ACCOMMODATION: Crew of four

POWER PLANT:  Four Junkers Jumo 205D liquid-cooled, opposed-piston diesel engine, rated at 880 hp each

PERFORMANCE: 208 mph

COMMENT: The elegant Dornier Do 26, sometimes referred to as the “most beautiful flying-boat ever built”, was of all-metal construction. Originally designed as a civilian transport aircraft for the “Deutsche Lufthansa”, the few aircraft built before  and immediately at the beginning of WW II were pressed into military service at the outbreak of the war in Europe.
The hull had a central keel and a defined step; the wings were of gull wing configuration, the outer sections being equipped with fully retractable narrow stabilizing wing-floats, instead of Dornier’s famous “water-wing” sponsons extending from the lower hull for lateral stabilization.
Its four Junkers Jumo 205 diesel engine, were mounted in tractor/pusher pairs in tandem nacelles located at the joint between the dihedral and horizontal wing sections. The rear (pusher) engines could be swung upwards through 10° during take-off and landing, to prevent contact between the three-blade airscrew and water spray created by the forward propellers. The tail unit was of conventional design, comprising a horizontal tail-plane and a single, vertical fin with rudder. Armament consisted of one 20 mm MG 151/20 cannon in a power-operated bow turret and three 7.92 mm MG 15 machine guns.
Only six aircraft were built and put into Luftwaffe service. They were used in the Norwegian campaign for transporting supplies, troops and wounded to and from the isolated German forces fighting at Narvik. During this campaign three of them were lost. Another Dornier Do 24C was lost on 16 November 1940, killing its crew, after being launched at night from the catapult ship “Friesenland” in Brest, France. The fate of two remaining aircraft, which in 1944 were still assigned to the “Erprobungsstelle” (Test Unit) in Travemünde, Germany, is unclear (Ref.: 24).

Blohm & Voss Bv 138C-1 (“Seedrache”, „Sea Dragon“), Supermodel

TYPE: Long-range maritime reconnaissance flying boat

ACCOMMODATION: Crew of six

POWER PLANT: Three Junkers Jumo 205D liquid-cooled, vertically opposed diesel engine, rated at 870 hp each

PERFORMANCE: 177 mph at 19,700 ft

COMMENT: Originally developed under the company name of Hamburger Flugzeugbau, the type was initially designated the Ha 138. Its appearance was unique in its combination of unusual design features with its twin boom tail unit, short fuselage and trimotor engine configuration. The short hull, with its hydrodynamic step beneath and flat sides, earned it the nickname “Der fliegende Holzschuh” (“The flying clog”).
Three piston engines were used. The central engine was mounted above the wing, driving a four-blade propeller, while the wing engines were lower, with three-blade propellers. The pre-production prototypes were powered by various makes of engines ranging from 650–1,000 hp. The first standardized version, BV 138B-1, was powered by three 868 hp Junkers Jumo 250D two-stroke, opposed-piston aircraft diesel engines. The engine cowlings also had an atypical appearance, due to the unique nature of the vertical orientation of the six-cylinder opposed-piston Jumo 205 diesel engines, and resembled the cowlings of 4 or 6-cylinder inverted inline engines found on smaller civil and utility aircraft from the Jumo 205’s propshaft placement, emerging forward at the uppermost front end of the power plant.
The booms of the twin tail unit, much like the smaller Focke-Wulf Fw 189 twin-engine reconnaissance monoplane, extended horizontally from the rear of the outer engine nacelles.
For hydrodynamic reasons, the hull featured a distinct “turn-down”, or “beak” at the stern. Two enclosed, powered gun turrets, each mounting a single MG 151/20 autocannon, were located prominently at the bow and stern. A third, fully open Scarf ring-like emplacement, behind the central engine and both above and forward of the rear turret, mounted a MG 131 heavy machine gun covered fields of fire obstructed from the other turrets by the horizontal stabilizer.
In all, 227 examples of standard service variants of the BV 138 were built. The first such variant, Bv 138C-1, began service in March 1941. While non-standard variants carried a variety of armament, the standard variant featured two 20 mm MG 151/20 cannons, one in a power-operated bow turret and one in a power-operated stern turret, up to three 7.92 mm MG 15 machine guns, and a 13 mm MG 131 machine gun in the aft center engine nacelle. It could carry up to 500 kg of bombs or depth charges (under the starboard wing root only) or, in place of these, up to 10 passengers. Both the B-1/U1 and C-1/U1 variants had racks under both wings to double the offensive load.
Some examples of the BV 138 were adapted to specialized roles. The Bv 138 was tested with the oft-used Walter HWK 109-500 “Starthilfe” (RATO) jettisonable rocket pod, used in pairs, for shorter take-off performance. One anti-shipping variant carried FuG 200 “Hohentwiel” low-UHF band maritime search radar. The BV 138 MS variant was converted for minesweeping (suffix “MS” means “Minen-Suchgerät”, “mine-search” aircraft, and carried magnetic field-generating degaussing equipment, including a hoop antenna with a diameter equal to the length of the fuselage, which encircled the hull and wings, which was also used on certain models of the Junkers Ju 52/3m trimotor transport used for the same duty (Ref. 24).

Heinkel He 114A-2 (Airmodel, Vacu)

TYPE: Reconnaissance floatplane

ACCOMMODATION: Pilot and observer

POWER PLANT: One BMW 132K radial engine, rated at 960 hp

PERFORMANCE: 208 mph

COMMENT: The Heinkel He 114 was a sesquiwing reconnaissance seaplane produced for the German Kriegsmarine (German Navy) in the 1930s for use from warships. It replaced the company’s Heinkel He 60, but did not remain in service long before being replaced in turn by the Arado Ar 196 as standard spotter aircraft.
While the fuselage  and flotation gear of the He 114 were completely conventional, its wing arrangement was highly unusual. The upper set of wings was attached to the fuselage with a set of cabane struts, as in a  parasol wing monoplane, whereas the lower set was of much lesser span while having approximately the same chord. This general layout is not especially unusual, and is known as a “Sesquiplane”, or a biplane which has a smaller lower wing. Typically, the lower wing is about 3/4 of the span of the upper wing, and has a smaller chord as well. The He 114 has a much shorter lower wing than usual, but has the same chord as the upper wing, which keeps the wing area ratio similar.
The He 114 was never a great success, was not built in large numbers, and served with the Luftwaffe for only a short time. While the Heinkel He 60 had handled very well on the water but been sluggish in the air, the He 114’s handling while afloat was poor and its performance in the air scarcely better than the aircraft it replaced (Ref.: 24).