The first production model was the Hs 129B-1 fitted with two air-cooled, 700 hp, Gnome Rhône 14M Engines. The Hs 129B-1 could reach speeds of up to 407.1 km/h at 3,830 meters, and had a maximum range of 690 km. Internal fuel was stored in three separate tanks - two in the wings holding 204.75 litres each, and one in the fuselage holding 200.2 litres.The armament of the Henschel Hs 129B-1 was one 30mm MK 101 canon, two 20mm guns, and two MG 17s. The loaded weight of the Henschel was about 5249.8 kg and length was 9.7 meters.The service ceiling of the Hs 129 B-1 was approximately 9,000 meters while its wingspan was about 14.1 meters. One of the major defects of the Hs 129 series, even the B-1, was that it was severely underpowered, using two captured French engines.
The first variant of the B-1 was the B-1/R3 and the only modification was that it had four 7.9mm MGs mounted in a ventral gun pack. Like the other "R" variants, the R3 only had very few differences to the original B-1 model. The next "B-1/R" variant, the R4, was capable of carrying up to 250 kg of bombs. Following the R4 was the B-2 variant, and its modifications were far more extensive.
It, like the R4 could carry bombs, except the new maximum bomb load was 100 kg. These could be two 50 kg bombs our numerous anti-personel bombs. Another change in the B-2 was the new 30mm MK 103 Autocannon mounted under the fuselage. It could fire much faster than the original MK 101 Autocannon that was mounted on the B-2. The B-2's wingspan was very slightly increased to 14.2 meters and the loaded weight remained the same. Similarly to the B-1/R variants, the B-2/R variants were mainly changes in weaponry. The first B-2/R variant was the R3 and it had a 37mm cannon mounted under the fuselage. The R4 similarly had a 75mm main gun mounted.
The final variant, the B-3 was produced in very few numbers and was developed to counter ever increasing tank armor. That is why it mounted a 37mm Bordkanone BK 37 Autocannon that was originally fielded on the Junkers Ju 87 Stuka. Some Hs 129 B-3s were even had a mounted PaK 40.
In April 1937, the technical department of the RLM issued a specification for a small, twin engined, ground attack aircraft to Hamburger Flugzeugbau, Focke-Wulf, Gotha and Henschel. After examining the four designs, the RLM issued development contracts on October 1, 1937 to Focke-Wulf, for the Fw 189c, and to Henschel, for the Hs 129. Detailed work for the Henschel aircraft, designed by Dipl Ing Friedrich Nicolaus, was completed by the middle of 1938, with the first prototype, the Hs 129 V1, flying in the Spring of 1939. The next advancement that was delivered right before the B-1 was the A-0, but it was found to be severely underpowered, so it did not see mass production. The Henschel B-1 was used extensively in the Eastern Front and was used up until the end of the war. Some were also sent to North Africa and to Germany's ally Romania. However, they were withdrawn from service in North Africa after many engine failures.
- Reprint of Janes Fighting Aircraft of World War II edited by Leonard Bridsgeman, Tiger Publishing
- German Aircraft of the Second World War by Antony L. Kay and J. R. Smith, Putnam Aeronautical Books