Henschel Hs 129

https://en.wikipedia.org/wiki/Henschel_Hs_129

The Henschel Hs 129 was a World War II ground-attack aircraft fielded by the
German Luftwaffe. The aircraft saw combat in Tunisia and on the Eastern Front.

A key requirement of the original specification was that the aircraft be powered
by engines that were not in demand for other designs. This limited it to
low-power engines, with most models using a 700 horsepower (520 kW) French
engine. In spite of being very small and relatively light, the design was
generally underpowered. Attempts to fit more powerful engines were thwarted for
a variety of reasons, including the Allied capture of Italy.

The design was relatively effective when it was first introduced, and saw
service on the Eastern Front in a variety of front-line roles. As the war
continued and anti-tank support became the main goal, the aircraft was
continually up-gunned, eventually mounting a 75 mm gun in the anti-tank role
that left the plane barely flyable. Only a small number of these B-3 models were
produced, late in the war.

The Hs 129 was designed around a single large "bathtub" of steel sheeting that
made up the entire nose area of the plane, completely enclosing the pilot up to
head level. Even the canopy was steel, with only tiny windows on the side to see
out of and two angled blocks of glass for the windscreen. In order to improve
the armor's ability to deflect bullets, the fuselage sides were angled in
forming a triangular shape, resulting in almost no room to move at shoulder
level. There was so little room in the cockpit that the instrument panel ended
up under the nose below the windscreen where it was almost invisible; some of
the engine instruments were moved outside onto the engine nacelles'
inboard-facing surfaces, as on some models of Messerschmitt's Bf 110 heavy
fighter, and the gunsight was mounted outside on the nose.

Henschel's plane came in 12% overweight with the engines 8% underpowered, and
understandably, it flew poorly. The controls proved to be almost inoperable as
speed increased, and in testing, the V2 prototype flew into the ground from a
short dive on 5 January 1940 because the stick forces were too high for the
pilot to pull out. The Focke-Wulf design proved to be no better. Both planes
were underpowered with their air-cooled, inverted-V12 Argus As 410 engines, and
very difficult to fly.

The RLM nevertheless felt they should continue with the basic concept. The only
real deciding factor between the two designs was that the Henschel was smaller
and cheaper. The Focke-Wulf was put on low priority as a backup, and testing
continued with the Hs 129 A-0. A series of improvements resulted in the Hs 129
A-1 series, armed with two 20 mm MG 151/20 cannons and two 7.92 mm (.312 in) MG
17 machine guns, along with the ability to carry four 50 kg (110 lb) bombs under
the fuselage centreline.

Role
Ground-attack

Manufacturer
Henschel

First flight
25 May 1939

Introduction
April 1942

Retired
1945

Primary users
Luftwaffe
Hungarian Air Force
Romanian Air Force

Produced
June 1940 – September 1944

Number built
865

Hs 129 B-3

It was decided that the 7.5 cm (2.95 in) semi-automatic Rheinmetall PaK 40
anti-tank gun, which had already been adapted for use in the Junkers Ju 88P-1,
would be further modified for use in the Hs 129. This resulted in the BK 7,5
(Bordkanone 7,5), which, even though it weighed 1,200 kg (2,600 lb), was lighter
than the PaK 40. Fully automatic, it featured a new, hydraulic recoil-dampening
system and a new, more aerodynamic muzzle brake. An autoloader system, with 12
rounds in a rotary magazine, was fitted in the empty space behind the cockpit,
within the rear half of the wing root area. The gun and its recoil mechanism
occupied a substantial gun pod under the fuselage, and a circular port at the
rear of the pod allowed rearwards ejection of spent cartridges immediately after
firing. While this new variant, the Hs 129 B-3, was theoretically capable of
destroying any tank in the world, the added weight worsened the aircraft's
general performance and it was inferior to previous variants.

The Bordkanone 7,5 was the heaviest and most powerful forward-firing weapon
fitted to a production military aircraft during World War II. The only other
aircraft to be factory-equipped with similar-calibre guns were the 1,420
examples of the North American B-25G and B-25H Mitchell, which mounted either a
75 mm (2.95 in) M4 cannon, or lightweight T13E1 or M5 versions of the same gun.

Specifications (Hs 129B-2)

General characteristics
Crew: 1
Length: 9.75 m (32 ft 0 in)
Wingspan: 14.2 m (46 ft 7 in)
Height: 3.25 m (10 ft 8 in)
Wing area: 29 m2 (310 sq ft)
Empty weight: 4,020 kg (8,863 lb)
Max takeoff weight: 5,250 kg (11,574 lb)
Powerplant: 1 × Gnome-Rhône 14M-4 14-cylinder air-cooled radial engine, LH
rotation, fitted to starboard, 522 kW (700 hp) for take-off
Powerplant: 1 × Gnome-Rhône 14M-5 14-cylinder air-cooled radial engine, RH
rotation, fitted to port, 522 kW (700 hp) for take-off
Propellers: 3-bladed constant speed propeller

Performance
Maximum speed: 407 km/h (253 mph; 220 kn) at 3,830 m (12,570 ft)
Cruise speed: 315 km/h (196 mph; 170 kn) at 3,000 m (9,800 ft)
Range: 690 km (429 mi; 373 nmi)
Service ceiling: 9,000 m (30,000 ft)
Rate of climb: 8.1 m/s (1,590 ft/min)

Armament

Guns: * 2 x 7.92 mm (0.31 in) MG 17 machine guns, later models from 1943 to 1944
replaced the MG 17s with 2 x 13 mm (.51 in) MG 131 machine guns
2 x 20 mm MG 151/20 cannon
or(Hs 129B-2/R2) with a 30 mm (1.181 in) MK 101 cannon in a conformally mounted
gun pod.
or(Hs 129B-2/Wa) with a 30 mm (1.181 in) MK 103 cannon in a ventral pod.
or(Hs 129B-2/Wa) with a 37 mm (1.457 in) Bordkanone BK 3.7 cannon in a ventral
pod.
or(Hs 129B-3/Wa) with a 75 mm (2.953 in) Bordkanone BK 7.5 cannon in a ventral
pod.
Rockets: various experimental installations of 80 mm (3.150 in) Panzerblitz I
rockets, 88 mm (3.465 in) Panzerblitz II rockets, Flammenwerfer Gero, SG113A
Förstersonde automatic mortar, 210 mm (8.268 in) Wfr.Gr 21 rocket tubes and 280
mm (11.024 in) Wfr.Gr 28 rocket tubes
Bombs: *2 x 50 kg (110 lb) bombs on underwing hardpoints
4 x 50 kg (110 lb) fragmentation bombs on belly racks




*