Wheels

Intended for use in areas where there is a risk from explosive devices, LOCOSTRA wheels are designed to withstand the detonation of 200g TNT without damage that would halt operations. The same blast resistant wheels are mounted at the front and rear.

These large wheels are heavily braced dishes with a tread attached and a large solid rubber wheel in the hub. Designed to allow blast-ventilation and prevent shock transfer to the bearings and chassis, these wheels are original and shockingly robust. On soft ground, it is anticipated that the tread on these wheels may need to be replaced after five blasts. On hard ground, the loss of the tread should not have any great affect on mobility. 

Between May and June 2010 we tested four different wheel designs developed with the very important help of Andy Vian Smith and Ed Pennington Ridge.

Apart from one, fully made of steel, the other three wheels are made of a combination of a rubber tire and an outer part of steel.

Out of all wheels the one embedding a solid rubber tire performed better both on the ballistic pendulum and on the tractor. 

Compromising between weight, ventilation and a threat that will usually be “low”, the armouring of Locostra is quite simple. The suggested armouring is not intended to provide protection in all possible fragmentation scenarios. It is accepted that this would be impractical on a lightweight air-cooled vehicle.

The armouring comprises:        

1.     Blast resistant wheels able to vent and absorb shock waves

2.     Deflection plates, 3mm thick, made out of mild steel. Empirical evidence suggests that this will be able to stop fragments from common fragmentation mines at ranges over three metres and may deflect those from closer detonations;

3.      Kevlar/aramid coverings for exposed hydraulic linkages and hoses that are not vulnerable to blast directly from beneath the wheels - so protected against deflected blast, ricocheting ground fragments and direct fragments from fragmentation mines at a distance of several metres;

4.      Flexible Kevlar/aramid curtain to attach to and hang from the three point linkage between the tractor and any toll that may be attached. 

In order to avoid predictable weak points where stresses might accumulate, axles of the tractor originally made out of spherical cast iron, were changed into new thicker ones made out of mild steel. New axles are rounded and have are 25mm thick.