Cargo Storage and Load Distribution

Category	Typical Mass Range (kg)	Dimensions	Securing Requirement	Sensitivity
Dense/Compact	5–150	Small volume, high density	Rigid mount (bolted)	Vibration-resistant; mounting points must distribute load
Fragile/Sensitive	0.5–20	Variable; often modular	Vibration isolation + rigid restraint	Shock and continuous vibration; optics and sensor arrays require dampening
Bulk	10–200	Large volume, lower density	Strap restraint or drawer system	Moderate; volume-limited by platform capacity
Fluid	10–500	Sealed containers; variable dimensions	Baffled containment + rigid mount	High; center of gravity shifts during traverse; spill risk

Five primary mounting positions are available on documented traverse platforms. Each configuration presents trade-offs between center of gravity impact, load capacity, accessibility, and environmental exposure.

Configuration	CG Height Impact	Max Load (kg)	Access During Traverse	Exposure Level
Bed-Mount	Minimal (0–150 mm above datum)	400–600	Limited; requires stop	Low; protected by platform sides
Rack-Mount	Moderate (300–500 mm above datum)	100–250	High; accessible without stop	High; wind and vegetation exposure
Frame-Mount	Low (100–250 mm above datum)	150–300	Low; between-axle location	Very low; protected by platform geometry
External (Roof/Side)	High (600–900 mm above datum)	50–150	Very limited; fixed load only	Very high; full environmental exposure

Bed-mount is the preferred configuration for dense, high-mass cargo. Lowest center of gravity, excellent stability. Requires secure fastening to platform frame at load-rated anchor points.

Rack-mount systems increase accessible storage but raise CG and expose cargo to wind shear on exposed terrain. Best for bulk, lower-density items that remain static.

Frame-mount (axle-bridge placement) offers a compromise: protected location with moderate mass capacity. Suitable for fragile sensor arrays requiring isolation from ground vibration.

External mounting (roof bars, side racks) should be reserved for low-mass, low-sensitivity cargo. Impact on CG and lateral stability is severe. Bulky, low-density items (spare panels, netting, structural replacements) are candidates.

Placement of cargo directly affects clearance margins, breakover angles, and stability on camber. Optimal distribution requires simultaneous consideration of vertical CG height and lateral balance.

Vertical Center of Gravity

Higher CG increases rollover risk, particularly on high-camber terrain. Each 100 mm rise in CG reduces safe lateral acceleration by approximately 15–20%. On routes with documented camber angles exceeding 20°, maintain CG height below 400 mm from platform datum to preserve stability margin.

Lateral Stability

Uneven load distribution shifts CG laterally. Platform axle track width and suspension geometry set hard limits on safe imbalance. Maintain load symmetry within ±50 mm of platform centerline. Asymmetric cargo (tall items, irregular geometry) should be mounted as low as possible and secured against differential motion.

Longitudinal Distribution

Forward-biased loads improve traction during climb but increase braking forces during descent. Rear-biased loads reduce nose-down attitude in soft terrain but increase rear-wheel slip during accelerated traverse. Optimal balance places CG slightly forward of platform geometric center (approximately 150–250 mm forward). Extreme imbalances (forward >400 mm, rear >300 mm) degrade handling and increase risk of breakover failure on steep terrain.

Clearance and Breakover

Maximum static clearance (ground to lowest cargo point) must exceed documented minimum ground clearance for the route. Each 50 mm of CG height increase reduces breakover angle margin by approximately 0.5°. On routes with breakover angles below 20°, maintain cargo clearance minimum of 300 mm.

Acceleration forces during traverse demand restraint sufficient to withstand dynamic loading. Four primary securing methods are documented, each suited to specific load types and terrain conditions.

Securing Methods

Rigid Mount (Bolted Frame)

Direct bolted connection to frame via load-rated anchor points. Suitable for dense, vibration-resistant cargo. Requires load-rated fasteners (minimum grade 8.8, torque to specification). Best for tools, materials, repair components. Static load capacity: up to 300 kg per mount point.

Strap Restraint (Rated Tension)

High-tension webbing with buckle systems. Tension rating must withstand expected lateral/longitudinal acceleration with safety margin. Inspection required after every high-severity traverse (gradients >20°, rough terrain). Acceptable for bulk cargo, spare components, consumables. Typical capacity per strap: 500–1000 kg breaking load, secured at minimum 50% of rated tension.

Drawer System (Latched, Vibration-Resistant)

Enclosed compartments with mechanical latches and dampening. Protects contents from environmental exposure and provides passive vibration isolation. Suitable for fragile sensor arrays, optics, electronics. Maximum load limited by drawer structure and latch mechanism (typically 50–150 kg per unit). Latch wear inspection required every 20–30 traverse hours on high-severity terrain.

Net Containment

Elastic netting with multiple anchor points. Used for bulk, low-density cargo (spare panels, netting, structural items, consumables). Provides secondary restraint in combination with other methods. Not suitable as primary restraint for high-mass items. Tension maintenance critical; slack netting fails under acceleration.

Expected Acceleration Forces by Terrain

Terrain Type	Lateral Acceleration	Longitudinal Acceleration	Required Securing Method
Flat gravel	0.3 G	0.2 G	Basic strap or net (safety margin minimum 1.5×)
Rolling terrain, light camber	0.4 G	0.3 G	Strap restraint or rigid mount
Switchback (15°–20° camber)	0.5 G	0.4 G	Strap restraint or rigid mount (safety margin 2.0×)
Steep descent with braking (>20° grade)	0.4 G	0.8 G	Rigid mount (bolted); safety margin 2.5×

All securing methods must withstand the stated acceleration values with a minimum safety margin of 1.5× (lightweight cargo, favorable terrain) to 2.5× (steep, severe conditions). Actual acceleration measured on instrumented platforms during documented route traversals.

Securing Procedure

• Measure cargo mass and verify against mount capacity.
• Select appropriate securing method for cargo category and terrain route.
• Apply restraint with tension/torque to specification. Do not over-tension (risks fastener fatigue and structural damage); do not under-tension (restraint failure under acceleration).
• Verify load symmetry (±50 mm lateral balance) and CG height against route constraints.
• Conduct visual inspection before traverse initiation.

Securing hardware fatigue under repeated acceleration cycles is inevitable. Planned inspection and replacement maintain platform integrity and cargo safety.

Inspection Intervals

Terrain Severity	Inspection Interval	Focus Areas
Flat, stable terrain	Every 40–50 traverse hours	Strap tension, minor corrosion
Rolling, moderate camber (<15°)	Every 20–30 traverse hours	Strap fraying, mount bolt loosening, drawer latch function
High-severity terrain (>15° camber, steep grades)	Every 8–12 traverse hours	All fasteners, strap condition, latch wear, vibration-isolation mounting condition

Signs of Failure

• Strap fraying: Web separation, loose fibers, or color fading indicates UV degradation and loss of tensile strength. Replacement threshold: visible fraying on >10% of webbing surface or >5 mm edge separation.
• Mount bolt loosening: Visual play at fastener or audible rattle during traverse. Check torque specification immediately. If torque cannot be maintained after two re-tensioning cycles, fastener or mounting point is compromised; replace.
• Drawer latch wear: Hesitation, incomplete engagement, or excessive play. Latch should close with firm, distinct click. Loose latch risks drawer opening during traverse.
• Vibration-isolation dampening failure: Increased vibration transmission or visible cracking in isolation material (rubber, foam). Compromised isolation allows cargo shock damage.
• Corrosion on fasteners: Surface rust acceptable if no pitting or structural loss. Deep pitting, flaking, or structural corrosion (>25% section loss) requires replacement.

Replacement Thresholds

• Straps: Replace when fraying reaches threshold or after 5+ re-tensioning cycles in a single maintenance interval (indicates micro-damage).
• Bolts and fasteners: Replace if torque cannot be maintained, if corrosion pitting is visible, or if fastener shows plastic deformation (unable to retighten to specification).
• Drawer latches: Replace if engagement is inconsistent or latch does not hold cargo against 0.5 G lateral acceleration test.
• Vibration-isolation mounts: Replace if cracking is visible, if isolation thickness is reduced >20% from nominal, or if cargo vibration amplitude increases >50% from baseline.

Record Keeping

Maintain inspection log with date, terrain route, hours since last inspection, fastener torque values, and any repairs made. Track strap re-tensioning cycles. Patterns in fastener loosening or latch wear indicate systemic issues (incorrect specification, installation error, overload condition) and warrant design review.

Load distribution effects measured on instrumented platforms. Acceleration values recorded during traverse of documented route segments. Securing methods tested to the stated force values. All specifications reflect field data from multiple platform configurations across diverse terrain.