The Junkers Ju 88 was one of the most versatile and effective combat aircraft of World War II. Its closest counterparts on the Allied side were the Mosquito and Beaufighter. The German aircraft was larger and slower, but nevertheless very effective. 14,676 were built, including a staggering 104 prototypes for its 60 different versions.
Like the Mosquito, the Ju 88 originated as a fast bomber. In 1935 the Luftwaffe had a requirement for a so-called Schnellbomber, which should have a speed of 500km/h with 800kg of bombs. This was much faster than the biplane fighters that then equipped the German fighter units; it was even faster than the first models of the Bf 109 monoplane fighter. For this ambitious goal Henschel proposed the Hs 127, Messerschmitt the Bf 162, and Junkers submitted the designs Ju 85 and Ju 88. Later the Bf 162 achieved some fame when it appeared on German propaganda postcards, but this was disinformation, and the real winner was the Ju 88.
Chief designer was Ernst Zindel. The first prototype (Ju 88V1) made its first flight on 21 December 1936. The Ju 88V1 had an all-metal, stressed skin construction; Junkers hired two American engineers to acquire knowledge about the latest structural developments. The Ju 88V1 had a compact, well-streamlined cockpit roof and a pointed nose. It was powered by Daimler-Benz DB 600 engines, installed in cowlings with circular radiators. The inverted V-12 engines were installed in front of the wing leading edge, not under the wing. Because of the long cowlings the Ju 88 earned the nickname Dreifinger, three fingers. The Ju 88V1 was lost before performance tests could begin, but the type had already shown great promise.
From the third prototype onwards the engines were changed to Junkers Jumo 211, because the scarce Daimler-Benz engines were reserved for fighters. The fourth prototype, the Ju 88V4, featured the “beetle eye” cockpit of the production aircraft, a four-seat cockpit covered with a large number of small, flat transparencies. It also had the ventral gondola under the nose, from which a gunner could fire rearwards. In contrast, the Ju 88V5 was completed with a maximum of streamlining, and on 9 March 1939 it set a closed-circuit record by flying 1000km with 2000kg of load at an average speed of 517km/h. It was a sensational public debut.
Meanwhile, the general staff of the Luftwaffe made some fateful decisions. On the one hand the Ju 88 was given the highest possible priority, with increasing concern expressed as the war came nearer and production still remained behind schedule. On 15 October 1939 Dr. Heinrich Koppenberg was put in charge of it, and given the authority to requisition any production facilities he needed; but the results were still disappointing. On the other hand the Luftwaffe had requested that the Ju 88 would be converted into a dive bomber. This inevitably slowed down the development and reduced flight performance. Installing dive brakes under the wing was the smallest problem: The need to reinforce the structure for dive bombing attacks caused a considerable increase in weight. Larger internal bomb bays and external bomb racks for four 500kg bombs increased the problems, and when the first production aircraft came off the line in August 1939, a number of restrictions had to be imposed. Even after all necessary modifications had been carried out, pilots did not usually achieve dives steeper than 60 degrees, although the excellent flying characteristics and automatic dive bombing equipment of the Ju 88 did not make such attacks particularly difficult. But there was little operational need for dive-bombing, except for anti-shipping missions.
The Ju 88 was certainly an excellent aircraft. It was easy to fly, gentle, responsive, and manoeuverable, without vices. These were the characteristics which also made it an excellent nightfighter. A point of criticism for allied test pilots was the cockpit. The extensive framing of the many panels resulted in a fairly restricted view. In the bomber versions it was also rather cramped and inefficient, although the close grouping of the crew made communication easier.
- Crew: 4 (pilot, bombardier/front gunner, radio operator/rear gunner,
- navigator/ventral gunner)
- Length: 14.36 m (47 ft 2⅞ in)
- Wingspan: 20.08 m (65 ft 10½ in)
- Height: 5.07 m (16.63 ft)
- Wing area: 54.7 m2 (587 ft2)
- Loaded weight: 8,550 kg (18,832 lb)
- Max. takeoff weight: 14,000 kg (30,865 lb)
- Powerplant: 2 × Junkers Jumo 211J liquid-cooled inverted V-12, 1,044 kW (1,420 PS, 1,401 hp) each
- Maximum speed: 510 km/h (317 mph) at 5,300 m (17,389 ft) without external bomb racks or 433 km/h (269 mph) at 4,500 m (14,765 ft) at 14,000 kg (30,865 lb)
- Range: 2,430 km (1,429 mi) maximum internal fuel
- Service ceiling: 9,000 m (29,500 ft) at average weight, without bombs
- Rate of climb: 235 m/min (770 ft/min)
- 1 × 7.92 mm MG 81J machine gun on flexible mount in front windscreen, firing forward with 1,000 rounds.[N 4]
- 1 × 7.92 mm MG 81J machine gun on flexible mount in lower fuselage nose glazing, firing forward with 1,000 rounds.
- 2 × 7.92 mm MG 81J machine guns on flexible mount in the rear of the cockpit canopy, firing aft with 1,000 rounds each.
- 1 × 7.92 mm MG 81Z twin machine gun on flexible mount in the rear ventral Bola position, firing aft with 1,000 rounds.
- Bombs: Up to 1,400 kilograms (3,100 lb) of ordnance internally in two bomb bays rated at 900 kg (2,000 lb) and 500 kg (1,100 lb) or up to 3,000 kg (6,600 lb) externally. Carrying bombs externally increased weight and drag and impaired the aircraft’s performance. Carrying the maximum load usually required rocket-assisted take-off.
- Additional option for a pair of 7.92 mm (.312 in) MG 15 machine guns on flexible “Donut” mountings firing laterally, one on each side of the cockpit canopy.
- A single 13 mm (.51 in) MG 131 machine gun was sometimes used instead of the 7.92 mm (.312 in) MG 81J or MG 81Z machine guns in the A-Stand, B-Stand or ventral Bola positions.
- Aircraft may carry one 20 mm MG FF cannon in the nose for ground attack purposes, with 90 rounds of ammunition, in place of the Lotfernrohr 7 bombsight
- A modification of the Ju 88 A-4, the Ju 88 A-13 could mount the Waffenbehälter WB 81A or WB 81B (firing with 15° downwards deflection) gun pods on the external bomb racks for ground attack duties, each “watering can” containing three 7.92 mm (.312 in) MG 81Z twin machine guns, for strafing enemy troops.