Thursday, October 1, 2009

The Arado Ar 234

The Arado Ar 234 was the world's first operational jet powered bomber, built by the German Arado company in the closing stages of World War II. In the field it was used almost entirely in the reconnaissance role, but in its few uses as a bomber it proved to be nearly impossible to intercept. Twin-engined and single seater, was produced in limited numbers. It was the last Luftwaffe plane to fly over England, in April 1945.

It is commonly known as Blitz ("lightning"), though this name refers only to the B-2 bomber variant, and it is not clear whether it was ever formally applied instead of being derived from the informal term Blitz-Bomber (roughly, "very fast bomber"). The alternate name Hecht ("pike") is derived from one of the units equipped with this plane, Sonderkommando Hecht. The Ar 234 (and the Messerschmitt Me 262) showed in which direction plane technique should develop.
Ar 234


Role
Reconnaissance Bomber
Manufacturer
Arado Flugzeugwerke
Designed by
Walter Blume
First flight


15 June 1943

Introduction
September 1944
Status
Retired
Primary user
Luftwaffe
Number built
210

Background and prototypes

In the autumn of 1940, the RLM offered a tender for a jet-powered high-speed reconnaissance aircraft with a range of 2,156 km (1,340 mi). Arado was the only company to respond, offering their E.370 project, led by Professor Walter Blume. This was a high-wing conventional-looking design with a Junkers Jumo 004 engine under each wing. The projected weight for the aircraft was approximately 8,000 kg (17,600 lb). In order to reduce the weight of the aircraft and maximize the internal fuel, Arado did not use the typical retractable landing gear; instead, the aircraft was to take off from a jettisonable three-wheeled, nosegear-style trolley and land on three retractable skids, one under the central section of the fuselage, and one under each engine nacelle.

Arado estimated a maximum speed of 780 km/h (490 mph) at 6,000 m (19,690 ft), an operating altitude of 11,000 m (36,100 ft) and a range of 1,995 km (1,240 mi).

The range was short of the RLM request, but they liked the design and ordered two prototypes as the Ar 234. These were largely complete before the end of 1941, but the Jumo 004 engines were not ready, and would not be ready until February 1943. When they did arrive they were considered unreliable by Junkers for in-flight use and were only cleared for static and taxi tests. Flight-qualified engines were finally delivered that spring, and the Ar 234 V1 made its first flight on 15 June 1943. By September, four prototypes were flying. The eight prototype aircraft were fitted with the original arrangement of trolley-and-skid landing gear. The sixth and eighth of the series were powered with four BMW 003 jet engines instead of two Jumo 004's, the sixth having four engines housed in individual nacelles, and the eighth flown with two pairs of BMW 003s installed within "twinned" nacelles underneath either wing. These were the first four-engine jet aircraft to fly. The Ar 234 V7 prototype made history on 2 August 1944 as the first jet aircraft ever to fly a reconnaissance mission.

Ar 234B

The RLM had already seen the promise of the design and in July had asked Arado to supply two prototypes of a schnellbomber ("fast bomber") version as the Ar 234B. Since the aircraft was very slender and entirely filled with fuel tanks, there was no room for an internal bomb bay and the bombload had to be carried on external racks. The added weight and drag of a full bombload reduced the speed, so two 20 mm MG 151 cannon were added in a remotely-controlled tail mounting to give some measure of defence. Since the cockpit was directly in front of the fuselage, the pilot had no direct view to the rear, so the guns were aimed through a periscope mounted on the cockpit roof. The system was generally considered useless, and many pilots had the guns removed to save weight.

The external bombload, and the presence of inactive aircraft littering the landing field after their missions were completed (as with the similarly dolly/skid-geared Messerschmitt Me 163) made the skid-landing system impractical, so the B version was modified to have tricycle landing gear. The ninth prototype, marked with the Stammkennzeichen (radio code letters) PH+SQ, was the first Ar 234B, and flew on 10 March 1944. The B models were slightly wider at the mid-fuselage to house the main landing gear, with a fuel tank present in the mid-fuselage location on the eight earlier trolley/skid equipped prototype aircraft having to be deleted for the retracted main gear's accommodation, and with full bombload, the plane could only reach 668 km/h (415 mph) at altitude. This was still better than any bomber the Luftwaffe had at the time, and made it the only bomber with any hope of surviving the massive Allied air forces.

Production lines were already being set up, and 20 B-0 pre-production planes were delivered by the end of June. Later production was slow, however, as the Arado plants were tasked with producing planes from other bombed-out factories hit during the Big Week, and the license-building of Heinkel's heavy He 177 bomber. Meanwhile, several of the prototypes were sent forward in the reconnaissance role. In most cases, it appears they were never even detected, cruising at about 740 km/h (460 mph) at over 9,100 m (29,900 ft).

The few 234Bs entered service in the fall and impressed their pilots. They were fairly fast and completely aerobatic. The long takeoff runs led to several accidents; a search for a solution led to improved training as well as the use of rocket-assisted takeoff. The engines were always the real problem; they suffered constant flameouts and required overhaul or replacement after about 10 hours of operation.

The most notable use of the Ar 234 in the bomber role was the attempt to destroy the Ludendorff Bridge at Remagen. Between 7 March, when it was captured by the Allies, and 17 March, when it finally collapsed, the bridge was continually attacked by Ar 234s of III/KG 76 carrying 1,000 kg (2,200 lb) bombs. The aircraft continued to fight in a scattered fashion until Germany surrendered on 8 May 1945. Some were shot down in air combat, destroyed by flak, or "bounced" by Allied fighters during takeoff or on the landing approach, as was already happening to Messerschmitt Me 262 jet fighters. Most simply sat on the airfields awaiting fuel that never arrived.

The normal bombload consisted of two 500 kg (1,100 lb) bombs suspended from the engines or one large 1,000 kg (2,200 lb) bomb semi-recessed in the underside of the fuselage with maximum bombload being 1,500 kg (3,310 lb). If the war had continued it is possible that the aircraft would have been converted to use the Fritz X guided bombs or Henschel Hs 293 air-to-surface missiles.

Overall from the summer of 1944 until the end of the war a total of 210 aircraft were built. In February 1945, production was switched to the C variant. It was hoped that by November 1945 production would reach 500 per month.
  • Ar 234B-0 : 20 pre-production aircraft.
  • Ar 234B-1 : Reconnaissance version, equipped with two Rb 50/30 or Rb 75/30 cameras.
  • Ar 234B-2 : Bomber version, with a maximum bombload of 2,000 kg (4,410 lb).

[Ar 234C

The Ar 234C was equipped with four BMW 003A engines, mounted in a pair of twin-engine nacelles based on those from the eighth Ar 234 prototype. The primary reason for this switch was to free up Junkers Jumo 004s for use by the Me 262, but this change improved overall thrust, especially in take-off and climb-to-altitude performance. Airspeed was found to be about 20% faster than the B series and, due to the faster climb to altitude, range was increased. Although Hauptmann Diether Lukesch was preparing to form an operational test squadron, the Ar 234C was not developed in time to participate in actual combat operations. There were two primary versions of the C: the C-1, a four-engine version of the B-1, and the C-2, a four-engine version of the B-2. At least seven other versions of the C were designed or were in the planning stages before the war ended, including bombers, armed reconnaissance, night fighters and a heavy bomber. 14 prototypes of the Ar 234C, which included the C-1 and C-2 models, were completed before the end of the war.
  • Ar 234C-1 : Four-engined version of the Ar 234B-1.
  • Ar 234C-2 : Four-engined version of the Ar 234B-2.
  • Ar 234C-3 : Multi-purposed version, armed with two 20 mm MG 151/20 cannons beneath the nose.
  • Ar 234C-3/N : Proposed two-seat night fighter version, armed with two forward-firing 20 mm MG 151/20 and two 30 mm (1.18 in) MK 108 cannons, fitted with a FuG 218 Neptun V radar.
  • Ar 234C-4 : Armed reconnaissance version, fitted with two cameras, armed with four 20 mm MG 151/20 cannons.
  • Ar 234C-5 : Proposed version with side-by-side seating for the crew. The 28th prototype was converted into this variant.
  • Ar 234C-6 : Proposed two-seat reconnaissance aircraft. The 29th prototype was converted into this variant.
  • Ar 234C-7 : Night fighter version, with side-by-side seating for the crew, fitted with an enhanced FuG 245 Bremen O cavity magnetron-based centimetric (30 GHz) radar.
  • Ar 234C-8 : Proposed single-seat bomber version, powered by two 1,080 kg (2,380 lb) Jumo 004D turbojet engines.

Ar 234D

The D model was a two-seat aircraft based on the B-series fuselage, but with a new, enlarged two-seat cockpit, intended to be powered by a pair of more powerful Heinkel HeS 011 turbojet engines. The HeS 011 powerplant never reached quantity production, and no 234D was produced.
  • Ar 234D-1 : Proposed reconnaissance version. Not built.
  • Ar 234D-2 : Proposed bomber version. Not built.

Ar 234P

The P model was a two-seat night fighter version, differing in powerplant options and several options of radar. Several were in the planning stage, but none made it into production.
  • Ar 234P-1 : Two seater with four BMW 003A-1 engines; one 20 mm MG 151/20 and one 30 mm (1.18 in) MK 108.
  • Ar 234P-2 : Also a two seater, with redesigned cockpit protected by a 13 mm (0.51 in) armour plate.
  • Ar 234P-3 : HeS 011A powered P-2, but with two each of the cannon.
  • Ar 234P-4 : as P-3 but with Jumo 004D engines.
  • Ar 234P-5 : Three seat version with HeS 011A engines, one 20 mm MG 151/20 and four 30 mm (1.18 in) MK 108s.
General characteristics
  • Crew: 1
  • Length: 12.63 m (41 ft 5½ in)
  • Wingspan: 14.10 m (46 ft 3½ in)
  • Height: 4.30 m (14 ft 1¼ in)
  • Wing area: 26.40 m² (284.16 ft²)
  • Empty weight: 5,200 kg (11,460 lb)
  • Max takeoff weight: 9,850 kg (21,720 lb)
  • Powerplant: 2× Junkers Jumo 004B-1 turbojets, 8.80 kN (1,980 lbf) each
Performance
  • Maximum speed: 742 km/h (461 mph) at 6,000 m (19,700 ft)
  • Combat radius: 1,100 km (684 mi) with maximum bombload
  • Service ceiling: 10,000 m (32,800 ft)
Armament
  • Guns: 2 × 20 mm MG 151 cannons in tail firing to the rear (optional)
  • Bombs: up to 1,500 kg (3,309 lb) of disposable stores on external racks

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