Haubits FH77


Fälthaubits 77 or FH77 is a Swedish 155 mm howitzer. It was developed and manufactured by Bofors. It was available in two versions, the original with a 38 calibre barrel and sliding block mechanism, and the later FH77 B export version with a 39 calibre barrel and an interrupted screw breech.

Design and development

Overview

In the 1960s, Sweden started to look for a replacement for the French Haubits F. The American M109 howitzer was offered and tested. Though the price was low, the Swedish Arms Administration found that the high maintenance costs, the low rate of fire and the limited mobility of the M109 made it worth the effort to develop a domestic howitzer.
The requirements for a new gun would be:
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 FH77A could fire 4 rounds in 9 seconds, or 6 rounds in 25 seconds. In a sustained firing role, it could fire 6 rounds every two minutes for 20 minutes.
In order to use standard NATO ammunition, the FH77B was developed. While the sliding-block worked well with the cased charges acting as a seal, it was decided that bagged charges required an interrupted screw breech. This, combined with the slightly longer barrel, resulted in a slightly improved range but also a lower rate of fire. At the same time, the petrol-fueled APU was exchanged with a diesel-fueled one, allowing it to use the same fuel as the towing vehicle.

Driving and deploying

The dedicated towing vehicle for the FH77 was the Scania SBA111. The truck was 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.
The FH77 is manoeuvred by the gun layer, controlling the torque of the two main wheels through a joystick. Speed is regulated by changing the APU's RPM. The howitzer is deployed by spreading the trail legs, raising the castor wheels and driving the howitzer in reverse to anchor the recoil spades.

APU

The FH77 is powered by a Volvo B20 Auxiliary power unit, which gives the gun a top speed of 7 km/h. The engine is connected to three hydraulic pumps, of which two are linked to the wheels and one is used for a traverse, elevation, ramming and ammunition crane. The fuel tank could hold 40 litres, with two extra 20L jerry-cans as a reserve in front of the gun layer's position.

Crew

The crew consists of 10–14 men. The minimum crew setup would be 4 men; commander, gun layer, loader 1 and loader 2.
The FH77A uses the m/77 155mm HE shell combined with a plastic casing, containing six increments.
The FH77B uses standard NATO 155mm ammunition with bagged drive charges.
Both are able to use base bleed ammunition developed for the FH77B, as well as Bofors 155 Bonus and M982 Excalibur.

Controversy in India

The Bofors scandal was a major political scandal that occurred between Sweden and India during 1980s and 1990s, initiated by Congress politicians and implicating the Indian prime minister, Rajiv Gandhi, and several other members of the Swedish and Indian governments, who were accused of receiving kickbacks from Bofors AB for winning a bid to supply India's 155 mm field howitzer.
This resulted in India not exercising the option for 48 additional FH77B, instead these guns were acquired by the Swedish army and have now been converted into the Archer Artillery System.

Variants

Towed variant

Current operators