Indian Military

Haubits 77 (Field Howitzer 77 or FH77) is a Swedish 155 mm howitzer. It was developed and manufactured by Bofors. It was available in two versions, the original (sometimes referred to as Haubits 77 A) with a sliding block mechanism, and the later FH77 B export version with an interrupted screw breech.

Development

---

In the 1960s Sweden started to look for a replacement for the French Haubits F (Obusier de 155 mm Modèle 50). The American M109 howitzer was offered and tested. Though the price was low the Swedish Arms Administration found the high maintenance costs, the low rate of fire and the not so good mobility of the M109 made it worth the effort to develop a domestic howitzer.

The requirements for a new gun would be:

• High mobility.
• High momentary rate of fire.

The result was a compromise between a more expensive Self propelled howitzer and a less mobile conventional towed howitzer.

The FH77 was the first field howitzer featuring an APU to make it self-propelled for tactical movement.

The rate of fire was, at the time, exceptionally high for a 155 mm howitzer. The FH77 could fire 3 rounds in 8 seconds, or 6 rounds in 25 seconds. In a sustained firing role it could fire 6 rounds every second minute for 20 minutes.

FH77B

Though the haub 77 was a formidable gun it seemed impossible to export. There were two reason for this:

The maximum elevation was limited to 50°.

It did not use NATO ammunition.

Therefore Bofors developed a new version - the FH 77B. The main difference was that the B-model used a servo operated interrupted screw breech, instead of the sliding block action on the FH 77. The maximum elevation had been increased from 50° to 70°. The barrel is slightly longer, 39 calibres, and uses a single baffle muzzle brake as opposed to the pepper-pot style muzzle brake on the 77. The engine was a Mercedes diesel. Since the B-version used bagged charges it was somewhat slower than the original model - 3 rounds in 10 seconds compared to 3 rounds in less than 8 seconds. The maximum range, on the other hand, was increased to 24km and using base-bleed extended to 28km.

Nigeria bought 48 pieces in 1980 and in March 1986 India ordered 410 of the Bofors FH 77B. The Indian also got a contract option for additionally 1,100 howitzers.

Soon after the $1.4 billion contract with India had been signed two Swedish left-wing journalists reviled that Bofors had paid kickbacks to Indian public servants. As a result of this India declined to exercise their option on the second batch. A decision India has had all reasons to regret, as the FH 77B proved it self to be accurate, reliable and durable.

Bofors, who had been self-assured enough to start the production of the second batch, found them self with some 50 howitzers but no buyer. The Swedish government stepped in and forced the Army to purchase 51 of the B-model.

Specifications

---

• Name: 15,5 cm Haubits 77
• Type: Howitzer
• Nation: Sweden
• Manufacturer: Bofors
• Target: General
• Date: 1978
• Production Date: 1978 - 1984
• Service Date: 1978 - 2006
• Numbers Built: 720
• Operators:
  • Sweden - Approximately 220 FH77 delivered to the Swedish Army between 1979 and 1984.
  • Nigeria - 48 FH77B purchased in 1980.
  • India - 410 FH77B purchased in 1986. Option to license-produce 1000 examples was not exercised.
• Breech: Vertically sliding breech block, hydraulic ramming
• Barrel:5.89 m (19.32 ft) 38 calibres
• Elevation: -5 to +50°
• Traverse: ±30°
• Caliber: 155×787 mm (6.10 in)
• Carriage: Split trail with castor wheels
• Weight: 11,500 kg (25,353 lbs)
• Length: 11.6 m (38 ft)
• Shell Types: Se below
• Action: Semi-fixed ammunition, propellant charge is contained in a plastic cartridge case with a steel head.
• Muzzle velocity: 300 - 770 m/s (984-2,526 ft/s)
• Tactical range: 21 km (13 mi)
• Maximum range: 24 km (15 mi) (with base bleed)
• Rate of Fire: 3 rounds in 8 seconds or 6 rounds in 25 seconds, sustained fire 6 rounds every minute for 20 minutes
• Crew: 10 - 14
• Transportation: Self deployable with APU and towed using Scania SBAT111
• Miscellaneous: Perforated muzzle brake

Ammunition

---

The FH77 uses the m/77 (42kg) 155mm HE shell combined with a plastic casing, containing 6 increments. The FH77 could also use base bleed ammunition developed for the FH77B.

APU

---

The FH77 is powered by a Volvo B20 petrol engine. The engine is connected to three hydraulic pumps. Two pumps are linked to the wheels and one is used for traverse, elevation, ramming and ammunition crane.

Crew

---

The crew consists of 10-14 men. The minimum crew setup would be 5 men; commander, layer, loader 1, loader 2 and loader 3.

The commander direct all the activity of the crew from a platform to the left of the gunlayer.

The layer sits on the left hand side of the gun, operating the fire control computer and driving the howitzer when in self deployment mode.

Loader 1 is located to the right hand side of the gun and is in charge of supplying the shells form the loading table in front of him.

Loader 2 and 3 would be working on the ground, providing shells to loader 1 by means of a hydraulic crane and loading cases in the loading trough.

Driving & Deploying

---

The dedicated towing vehicle for the FH77 was the Scania SBAT111 (Tgb 40). The truck is equipped with a crew compartment behind the driving cab and a HIAB-crane for ammunition handling. The Howitzer's APU can be started and controlled by the driver of the towing vehicle to give an extra boost during off road driving. The maximum towing speed is 70 km/h (45 mph).

The FH77 is maneuvered by controlling the torque of the two main wheels. Speed is regulated by changing the RPM of the APU. The howitzer is deployed by spreading the trail legs, raising the castor wheels and drive the howitzer in reverse.

Source

http://www.soldf.com/fh77.html

FH77 Howitzer of the Indian Army