suspension systems

Horstman InArm®

InArm® has the lowest weight and space claim of all armoured vehicle suspension systems and provides a growth path to advanced variable damping, lock-out and ride height management systems.

The Horstman InArm® hydro-pneumatic suspension uses high-pressure nitrogen gas and an integral oil damper that are all contained within the road arm. As a consequence this reduces weight and space, compared to other hydro products, HSU or coil solutions. Designed as the most efficient packaging space solution, InArm® provides a growth path to advanced variable damping, lock-out and ride height management systems.

Developed by Horstman in the mid-1990s initially for the UK MODs Future Scout Cavalry System (FSCS) Tracer and US Army’s Future Combat System (FCS) programs, InArm® is designed to eliminate the need for torsion bars and to minimize or eliminate road arm penetration of the vehicle hull.

Benefits

Compact vehicle design, enhanced performance and survivability.

By removing the torsion bars and adopting an integrated system approach, we've not only saved mass but have also significantly enhanced the vehicle's operational capabilities. The external mounting of the independent suspension lowers the vehicle's profile, directly contributing to its survivability. Moreover, this setup provides a clear upgrade path for incorporating advanced suspension features and accessories, ensuring our vehicle remains at the cutting edge of military technology. This holistic approach exemplifies our commitment to innovation, performance, and the safety of those who operate our vehicles.

Additional space for equipment, ability to have a floor mounted emergency escape hatch
Reduced fragmentation effects from secondary projectiles from mine blast or IED blast

Integration of damper and gas spring inside road arm minimizes space claim
Simpler than a torsion bar system which needs separate road arms, bump stops, dampers, torsion bar attachments and protective tubes

Damaged units can be replaced more easily than bent or seized torsion bars
Reduced hull machining without precision alignment between left and right side of vehicle

Ability to lower the turret basket and reduce the height of the vehicle gives improved survivability (lower silhouette)
The saving of the hull side armour is typically 100-500kg

There is a upgrade path regarding ride height, lockout and semi active damping.