Scottish gears raise the Marines` big guns

A Scottish company has been chosen to supply the gearboxes for a new generation of lightweight Howitzer field guns for the US Marines. Neeter Drives - part of the Power Jacks group - will supply three gearboxes for each M777 Ultra lightweight Field Howitzer (UFH).

Neeter has developed the boxes in collaboration with BAE Systems (VSEL) which won the contract to supply the guns in 1997 (as Vickers Shipbuilding and Engineering). Three years of development were followed by five years of testing and trials. After an initial contract in 2002 to deliver 94 pre-production Howitzers, BAE has recently won a production order worth $834m for 495 of the new guns.

The 155mm guns (shown in action above) are designed to be carried to the battlefield slung under a helicopter, or air-dropped from a C-130. They make extensive use of lightweight materials such as titanium and aluminium, and are 3,175kg lighter than the previous towed Howitzers that they will replace. They incorporate a digital fire control system that uses a combination of inertial navigation, GPS and motion sensors to locate and point the gun accurately.

Neeter was chosen to supply the Howitzer gearboxes following the success of its boxes on an earlier BAE gun, the AS90. Each of the new Howitzers has three gearboxes - two power-driven, and the third hand-wound - which are used to elevate the gun, before it is fired.

The gearboxes had to be light, compact and able to operate in arduous climates. Their housings and covers are made of aluminium and they have special coatings and shafts. Two of the boxes are based on Neeter`s standard N35 range, while the third is a bespoke design. Many prototypes were built and tested before the final design was agreed.

The M777 guns are being assembled by BAE in the US.