Henschel Hs 129

Introduction
Description
Development
Variants
Service Record
Eastern Front 1942
Eastern Front 1943
Eastern Front 1944-45
North Africa
Statistics
Books

Introduction

The Henschel Hs 129 was a dedicated ground attack aircraft, and a capable 'tank killer', but was never available in large enough numbers to have any significant impact. Early versions of the aircraft had a poor reputation, but most of its problems were fixed in the Hs 129B, the only version of the aircraft to enter service, and it

Description

The Henschel Hs 129 was a twin-engined monoplane, with thick low mounted wings. On the Hs 129B (the only version to enter service) they had a straight leading edge and tapering trailing edge. The cockpit was built as an armoured trough, with a single curved class windscreen and clear Perspex sides and roof. This gave the pilot excellent visibility, although the aircraft has never quite escaped from the poor reputation justifiably attached to the prototypes and Hs 129A. The main fuel tank, ammo containers, carburettors, oil coolers and engines were also given some armour protection.

The aircraft was of standard stressed-skin construction. The wing was built in three sections - the centre section, which was integrated into the fuselage, and the two outer panels which were bolted on.

The most distinctive feature of the aircraft was its very slim fuselage with a triangular cross-section, wide at the bottom and narrow at the top, with the armoured cockpit close to the front of the aircraft.

The standard armament of the Hs 129 saw it carry two 20mm cannon and two machine guns, mounted on the side of the fuselage. It could also carry a number of different bomb loads, and was later used with a wide range of anti-tank guns. On most aircraft the guns were the MG 151/20 cannon and the MG 17 machine gun. Both guns were mounted some way behind the pilot, with the cannon on top and the machine gun close to the wing root.

Development

The Hs 123 was designed in response to an RLM (German Air Ministry) specification issued in April 1937. The specification called for a small but heavily armoured aircraft, with at least two 20mm mm MG FF cannon and 7.9mm machine guns, 75mm glazing in the cockpit windows, and all using low-powered engines.

The specifications were issued to four companies - Hamburger Flugzeugbau (better known as Blohm und Voss), Gotha, Focke-Wulf and Henschel. Gotha didn’t respond, and the Hamburger proposal was soon eliminated, leaving the Focke-Wulf and Henschel designs as the only contenders.

The Focke-Wulf design was for a modified version of the Fw 189 reconnaissance aircraft. This was a twin-boom aircraft, with a glazed central nacelle carrying the crew. In the ground attack role this would be replaced with a heavily armoured nacelle, which would carry a crew of two.

Henschel produced the only original design, for a twin engined single seat monoplane. On October 1937, after examining both designs, the RLM decided to award both companies development contracts.

Henschel began detailed design work in January 1938, giving the new aircraft the designation P.46. The official designation Hs 129 followed in April, and the first visual mock-up was completed in May. A construction mock-up was ready by late July, and by August the design was finalised. Its weakest point was the Argus As 410A-0 twelve-cylinder inverted-vee air cooled engine, which didn’t provide enough power for the new aircraft. Argus had claimed that they would provide 465hp, but in use they only produced 430hp.

The Hs 129 V1 made its maiden flight on 26 May 1939. A number of changes were made after this first flight, before on 24 June the first prototype was damaged in a crash-landing.

By the autumn of 1939 both designs had been subjected to trails. Neither was particularly impressive - both suffered from a lack of power and poor visibility, but the Henschel machine cost a third less than the Focke-Wulf design, and so the RLM decided to place an order for the Hs 129.

Two more prototypes were built, both of which were delayed by shortages of key equipment. In the case of the V2 one propeller mechanism caused the first delay, but then an entire engine was taken to repair the V1, and the V2 didn't make its maiden flight until 30 November 1939. Even after both of the first prototypes were flying the test programme suffered from the unreliability of the engines. At the same time the weight of the aircraft was increasing, and its performance falling. The aircraft was particularly difficult to pull out of a dive, and on 5 January 1940 the V2 was destroyed when it failed to pull out of a dive.

The V3 didn't make its maiden flight until 2 April 1940. It was used to test the improved Argus As 410A-1 engine, which was still unreliable. This aircraft was damaged in June 1940, and was out of service until March 1941, leaving the V1 as the only flying prototype.

The A-0 aircraft went to Erprobungskommando 129, a special unit formed to bring the type into operational service. They had first seen the aircraft on 19 November 1940, when they criticised it for being under-powered and having very limited visibility. Henschel wanted to move onto a new larger aircraft, the P.76, but this would have caused unacceptable delays, and they were instead ordered to fit captured French Gnome & Rhône radial engines to a number of completed A-1 airframes to produce the first Hs 129B.

The Hs 129B-0 proved that the new engine worked, although the aircraft was still somewhat underpowered. It would always have a very long take-off run, and a poor climb rate, but as it was intended for very low level operations this wasn't a major problem. The visibility problems were solved on the B-1, which had a new canopy design. 

Variants

Hs 129A-0

The Hs 129A-0 was the first pre-production series of the aircraft. It was similar to the prototype, but had the 20mm MG FF cannon replaced by two belt-fed MG 151/20 cannons, which were much more effective. It retained the two 7.9mm MG 17 machine guns of the prototypes. It was powered by two Argus As 410A-1 engines, which finally provided the 465hp promised for the A-0 engines.

The main problem with the Hs 129A was the terrible armoured cockpit. In an attempt to reduce the amount of 75mm glass this was given two very small front windows, in a 'V' configuration, and surrounded by very heavy frames. The sides and roof of the cockpit were solid metal.

Hs 129A-1

By the summer of 1940 Henschel had received an order for 12 A-1 production aircraft, later increased to 16. Work on these machines began in June 1940, but they would never be completed as A-series aircraft. In September 1940 it was decided to abandon the A-1, and attempt to fit captured Gnome & Rhône engines to the almost-complete airframes, to produce the B-0.

Hs 129B-0

Work on the Hs 129B-0 began in September 1940. They were powered by a pair of Gnône-Rhône 14M radial engines, which came in pairs that operated in opposite directions. The B-0 used the 14M4 (port) and 14M5 (starboard) engines, which were rated at 700hp for takeoff and 650hp at 13,100ft. At first the 14M engines were a little unreliable, and prone to overheating. Most of these flaws were eventually ironed out, although it took some time to find a good dust and sand filter, and they continued to run hot.

The V3 prototype was given the new engines at the start of 1941, and began flight tests in March. The sixteen A-1 airframes were then given their new engines in December 1941-January 1942.

The B-0 included all of the improvements that had been planned for the A-1, including a modified cockpit with better visibility.

Hs 129B-1

Series production of the B-1 finally began late in 1941, and the first three B-1s reached a service unit in January 1942, alongside two B-0s. The main changes between the B-0 and B-1 came in the cockpit and canopy.

On the A-0 and B-1 the cockpit had been built in two layers, with flat armour plates covered with a light metal outer surface. Improvements in manufacturing techniques meant that the B-1 could use curved armour plating. This meant that the armour could become the outer surface, increasing the space inside the cockpit and improving the view.

The B-1 also saw the adoption of a much improved canopy. This time the two front windows were replaced by a single piece of curved armoured glass, and the sides and top of the canopy were made from Plexiglass. This solved the visibility problems of the earlier models.

The B-1 and B-2 could be used with a number of conversion kits, or Rüstsatz. The Hs 129 technical handbook records four that were given Rüstsatz numbers. Rüstsatz I was used to describe the built-in armament. Rüstsatz II was a pack that could carry four MG 17s in a pack under the fuselage. This was first tested late in 1941, and was apparently not popular with the pilots. Rüstsatz III, also tested late in 1941, was a pack containing a 30mm Mk 101 cannon. Rüstsatz 8 was similar, but with a Mk 103 cannon (thanks to Martin Pegg for providing further information on the Rüstsatz sets).

The B-1 could also carry an optional bomb rack, which could carry one 250kg bomb, four 50kg bombs or ninety-six 2k SD 2 anti-personnel bombs.

The B-1 also came with under-wing bomb racks as standard. These could carry one 50kg SC 50 bomb or twenty-four 2kg SD 2 bombs.
46

The B-1 and later models of the Hs 129 were assembled at Henschel's plant in Berlin, but the components were made at factories in occupied France. This results in some delays in 1941-42 as production got underway, and effectively ended production of the aircraft in the second half of 1944 as the Allied armies captured the factories.

Hs 129B-2

The Hs 129B-2 was similar to the B-1, but with tropical equipment. Even before the disastrous debut of the B-1 in North Africa in November 1942 Henschel had been working on producing a tropicalised version of the aircraft. This involved fitting BMW air-filters and a new oil filter. Tests with one of the B-0s in March-May 1942 proved that the equipment wordked, and in May it was decided to end production of the Hs 129B-1 after the 50th machine had been completed, and switch to the B-2, complete with the new filters.

As with the B-1 the B-2 could carry the 30mm Mk 101 or 103 cannon or four MG 17 machine guns under the fuselage. The cannon armed aircraft would become increasingly common during 1943, and would turn the Hs 129 from a ground-attack aircraft into a potent anti-tank weapon. The vast majority of Hs 129s produced would be B-2s.

Hs 129B-3

The Hs 129B-3 was the last version of the aircraft to enter production, and was armed with a massive 7.5cm anti-tank gun. Work on mounted the 7.5cm PaK 40 anti-tank gun in an aircraft began early in 1942, when attempts were made to fit a manually loaded version of the gun in a Junkers Ju 88. This wasn't a great success, but did provide some useful experience for later attempts to install an automatic version of the gun in the Hs 129.

In Luftwaffe service the 7.5cm PaK 40 was known as the BK 7.5, BK standing for Bordkanone, which translates as cannon. The gun was built into the structure of the aircraft. The barrel itself was carried in a cradle mounted below the fuselage, and projected 3ft ahead of the nose of the aircraft. The 12-round magazine and automatic loading device were both built into the fuselage. The magazine was a rotating drum, and shells were fed into the gun electro-pneumatically.

Tests with the first three B-3s began in August 1944. Problems with the shell-case ejection meant that the gun was only cleared for limited operation use. A small number of B-3s were then issued to 13.(Pz)/SG 9 for service tests. These revealed problems with the reloading mechanism in front line conditions, and a specialist team spend all of November attempting to fix this problem. By then it had become clear that prolonged use of the BK 7.5 caused damage to the airframe. This hadn’t happened with the test aircraft, and differences between these aircraft and standard production aircraft were one of the possible causes, along with possible problems with faulty ammo. The experts were unable to come to any firm conclusions before in January 1945 the unit was forced to destroy all of its aircraft.

The original plan was for the B-3 to completely replace the B-2 on the production lines by October 1944, and for production to continue at least until February 1945. This plan was dramatically disrupted when the Allies captured the French factories producing components for the Hs 129, and in August 1944 Henschel was ordered to cease production. Only twenty five B-3s had been built when construction ended in September 1944. A small number of these aircraft reached the front line, where they were said to be very effective, but they were soon swept away by the Soviet advance.

Hs 129C

The Hs 129C was to have been armed with two MK 103 cannon, mounted side-by-side in remote controlled mountings with a limited range of movement. It was to have been powered by new engines, either the 840hp Isotta-Fraschini Delta IV inverted V-12 or the 820hp Gnôme-Rhône 14M38. In the summer of 1943 the RLM ordered 600-700 C-1s, with production to start in April 1944, and in August 1943 the only C-1 made its maiden flight, powered by the 14M38. The Gnôme-Rhône engines were soon dismissed because they were prone to overheating, while access to the Italian Isotta-Fraschini engines was lost after the Allied invasion of Italy. Work on the C-1 series was officially abandoned in March 1944.

Service Record

Eastern Front 1942

In the first few years of the Second World War the Luftwaffe didn't have a dedicated ground-attack wing. The only ground attack unit was II.(Schlacht)/Lehrgeschwader 2, in theory an experimental unit, equipped with the Henschel He 123 biplane and the Bf 109. By the end of 1941 it was clear that this was not long adequate, and it was decided to form the first dedicated ground attack geschwader. II.(Schlacht)/LG 2 was withdrawn from the front at the end of 1941, and its personnel used to form Schlachtgeschwader 1. This unit was to be equipped with a mix of Bf 109s, Hs 123s and the new Hs 129, which was to equip the second group, II./Sch.G.1.

The first few aircraft arrived before these changes were complete. On 3 January the Ergänzungs-Schlachtgruppe of Lehrgeschwader 2 received two B-0s and three B-1s. Three days later the unit suffered its first fatacl crash, when a B-0 was lost.

The new arrangements came into force on 13 January 1942. After a period of training it was ready to take part in the German spring offensive of 1942, which was aimed at the oil fields of the Caucasus. 4./Sch.G 1, with fifteen aircraft, was the first to be deployed to the front, leaving Germany on 26 April to take part in the advance into the Crimea, intended to protect the flank of the main thrust. 5./Sch.G 1 followed in mid May, moving to the main part of the front. The two stafflen was used to fly close support missions, attacking Russian positions just in front of the German lines. The new aircraft proved to be robust in combat, able to survive quite heavy damage, but its poor dust filters were a problem, reducing the number of serviceable aircraft.

During 1942 Sch.G 1 was used to fight the Soviet offensive around Kharkov (May), to support the advance towards Stalingrad (July), and to resist the Soviet counter-attack at Stalingrad. According to figures from the unit between May and 17 August the Hs.129 squadrons had flown 2,500 operational missions. If this is the case then the Russian winter had a dramatic impact for the rest of the year, for the II./Sch.G 1 recorded 3,138 Hs 129 sorties during 1942 for the loss of 20 aircraft (in the same period it flew 1,532 Hs 123 sorties, losing 5 aircraft, and 1,939 Bf 109 sorties, losing 16).

In the summer of 1942 13.(Panzer)/Jagdgeschwader 51 was equipped with the Hs 129, after Göring decided that he wanted every fighter geschwader to have an anti-tank squadron. Between 14 August and 26 September this squadron flew 73 sorties, losing three of its eight aircraft. During this period it claimed to have hit 29 tanks. While the staffel was fairly successful, it didn't really fit in a fighter unit, and for part of the year came under the command of Sch.G 1.

Eastern Front 1943

In February 1943 Sch.G 1 was reorganised. 7.Staffel was to use the Hs 123, 4.Staffel and 8.Staffel the Hs 129 and the rest of the unit was reequipped with the Fw 190A-5. The two Hs 129 squadrons had their theoretical strength increased from 12 to 16, but even so this meant that if all three Hs 129 squadrons were at full strength there would only be 40 operation aircraft on the entire eastern Front!

Early in the year the role of the Hs 129 was changed. It was now to operate behind the German lines, attacking Soviet tanks that had broken through the front line. All three units came under the command of Oberstleutnant  Otto Weiss, before in mid-April 4./Sch.G 2 returned from North Africa, and its commander, Hauptmann Bruno Meyer, took over as Führer der Panzerjäger. By the summer of 1943 he had command of five Hs 129 staffeln, after 8./Sch.G 2 followed 4./ back from North Africa. In October the Hs 129 units came together to form IV./SG 9.

During the spring and early summer of 1943 the Hs 129 was used in the fighting in the Kuban bridgehead. They were then withdrawn and brought up to full strength in preparation for the battle of Kursk. This saw the debut of the 30mm MK 103, with its faster rate of fire, but as with other new weapons introduced at Kursk the MK 103 had a disappointing debut, suffering from frequent jams. Despite this problem the Hs 129 proved its worth at Kursk, destroyed large numbers of Soviet tanks. The problem was that with only five staffeln equipped with the type there were never enough aircraft to make any real difference to the outcome of the battle. The same was true during the retreat through the Ukraine that ended the year. The situation was made worse by the ever increasing strength of Soviet anti-aircraft guns and fighter forces, which meant that the slow Hs 129 suffered ever-increasing losses.

Eastern Front 1944-45

At the start of 1944 IV./SG 9 took part in the desperate attempts to stop the Russian winter offensive that followed their victory at Kursk. The unit was slowly forced to retreat, until by the spring it was based outside Soviet territory. In mid-April the entire group was concentrated in Romania, as part of an attempt to stop the Soviet advance towards the Romanian oil fields.

IV./SG 9 wasn't involved in the opening phase of the Soviet summer offensive of 1944, which saw the destruction of Army Group Centre, but it was soon rushed north in an attempt to prevent disaster. All efforts failed, and from then until the end of the war the Hs 129 equipped group was involved in a near constant stream of desperate defensive battles. The number of Hs 129 equipped units began to decline, especially after production came to an end in the autumn of 1944. By the end of the war hardly any Hs 129s were still airworthy, and those that could still fly were often grounded by a lack of aviation fuel.

North Africa

Towards the end of 1942 a number of Hs 129 squadrons were withdrawn to form a second geschwader, Schlachtgeschwader 2. It had been hoped to deploy this second unit on the Eastern Front, but the Allied successes at El Alamein meant that it had to be rushed to North Africa instead. The first aircraft from 4.(Panzer)/ Sch G. 1 arrived at Tobruk on 7 November, and they were quickly thrown into the battle.

The Hs 129's deployment to North Africa was a near total disaster. The Gnome & Rhone engines were not suitable for use in the desert. Their poor dust filter and tendency to over-heat had caused problems in Russia, but in North Africa they combined to virtually destroy the unit

The staffel's first operation was flown on 17 November 1942, and was a relative success, but then the aircraft were caught in two sandstorms, which did terrible damage to the engines. After the first storm the aircraft's already long take-off run had doubled in length, and after the second they could barely take off. Only once their weapons and ammo had been removed could they be ferried west to keep up with Rommel's retreating army. On 31 December the staffel's seven surviving aircraft reached Castel Benito near Tripoli, and only ten days none of them were operational. Three were then destroyed in an Allied air raid on 13 January, and three more could not be repaired. The surviving aircraft managed to limp back to Tunis, while the staffel's personnel returned to Germany, before heading off to the Eastern Front. 

This didn't end the Hs 129's involvement in the fighting in North Africa. In October 1942 5./Sch.G 1 had returned to Germany from the Eastern Front to receive new Hs 129 B-2s (with tropical air and oil filters). The squadron then moved to Prussia in preparation for a return to the front, but the ever worsening situation in North Africa soon led to a change of plans. Bad weather slowed down the move, but the first aircraft reached North Africa on 29 November. The staffel began operations on the following day. This time the Hs 129 was more successful, and the staffel didn't suffer its first loss until 22 December. Three more aircraft were lost on 28 December, all to Allied fighters, and senior officers in Luftflotte 2 were beginning to worry about the cost of using the Hs 129 in an area where the Allies had air superiority.

At the start of 1943 the staffel was renumbered as 8.(Pz)/Sch.G 2. A shortage of equipment almost led the staffel to be reequipped with the Fw 190, but instead a large number of fresh Hs 129s arrived. The aircraft were now given a new role. They would operate behind German lines, attacking any Allied tanks that had broken through the front line and were thus without anti-aircraft defences. This reduced the risk of heavy losses, but also reduced the number of sorties that could be flown.

The end for the Hs 129 in North Africa was not far off. Allied control of the air meant that the aircraft needed to be heavily escorted if they were to be effective, absorbing fighter resources needed elsewhere. The number of aircraft available began to drop, and by 10 April only two of the surviving sixteen aircraft were serviceable. On 20 April 8.(Pz)/Sch.G 2 became one of the first Luftwaffe units to be evacuated from North Africa. It remained away from the front line until August 1943, when it moved to the Eastern Front.

B-2
Engine: Two Gnôme-Rhone twin-row radial engines
Power: 750hp each
Crew: 1
Wing span: 46ft 7in
Length: 32ft 0in
Height: 10ft 8in
Empty Weight: 8,162lb
Loaded weight: 11,266lb
Max Speed: 253mph at 12,565ft (without kits)
Service Ceiling: 29,530ft
Range: 348 miles
Armament: Two 20mm cannon and two MG 17 machine guns

Books

Hs 129 Panzerjäger!, Martin Pegg. The definitive history of the Henschel Hs 129, with good a good section on its development and early history, and an impressive level of detail on its front line career. Supported by some useful appendices, including one with a complete list of Hs 129 loses, with their date, aircraft number, pilot and cause of loss when known.
cover cover cover

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How to cite this article: Rickard, J (9 December 2009, modified 16 July 2017), Henschel Hs 129 , http://www.historyofwar.org/articles/weapons_henschel_hs_129.html

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