The KiraVan™ tractor is a modified Mercedes-Benz Unimog U500NA with a Mercedes Benz 6-cylinder in-line 260HP high-efficiency intercooled turbo-diesel engine providing 700ft-lb of torque. The chassis frame has been stretched and reinforced, a four-door composite crew cabin added, and an off-road articulating fifth-wheel trailer hitch attached.
While we had a very good experience with the Mercedes Benz Unimog chassis on the original MaxiMog project, the evaluation process was repeated for the KiraVan to see what new vehicle options were available, given the passage of time. While there were interesting new offerings, we ultimately decided to again use a Unimog chassis for the base vehicle for the following reasons:
- Proven extreme off-road capability for civilian and military users.
- Some recent models are now fully road-legal both in the United States and overseas, while capable of being effectively serviced and maintained anywhere.
- Excellent OEM configurability options with very well documented engineering design guides.
- Good factory support for technical information, global parts availability, and international service representation. (Although sadly, not currently in the United States).
- A network of people experienced with doing many of the Unimog modifications we required.
- Our past good experiences with Mercedes-Benz Unimog, established high quality supply-chain and technical support resources.
POWERTRAIN – The engine drives an 8-speed (6-reverse gears) electro-pneumatic shifted transmission and two power take-off units (PTO) that drive the hydraulics systems. An auxiliary gearbox, with both working and crawler reduction gears, in turn drives three differentials and portal axles. This combination provides extreme off- road power as well as the ability to cruise on-road at 70MPH maximum speed.
ALL-WHEEL DRIVE SYSTEMS – The KiraVan features permanent 4-wheel drive on the tractor, with 6-wheel drive at speeds up to 25mph using a Hydro-Drive system that powers the trailer axle.
TIRES AND WHEELS – The Michelin 395/85R20 XZL special service, steel belted, all-terrain radial tires are 46” in diameter and weigh 300lbs each. The light-alloy, bead-locking rims allow operation of the tires down to zero tire pressure. These wheels incorporate run-flat inserts for emergency use in the event of a major tire failure. A computerized Central Tire Inflation System (coupled with the hydraulically driven rotary-screw air compressor) allows all six tires to be refilled while on the move, in less than five minutes. Special Kevlar sidewall shields protect the sensitive parts of the tire from puncture by rocks and other foreign objects. Automatic tire chains may be deployed in low tractions conditions, such as ice and snow, at the flick of a switch, while in motion.
HYDRAULICS SYSTEMS – The tractor has three independent hydraulic systems. They are used to power the suspension system, remote controlled rescue winches (50,000lbs and dual 20,000lbs), trailer alternator, air compressors, high-pressure washer, Electro-Optical compartment ventilator, leveling legs, and portable hydraulic tools.
HYDRO-PNEUMATIC SUSPENSION SYSTEM – The portal type axles, which provide extreme torque and high ground clearance, are attached to a custom-built computer controlled nitrogen-over-oil active suspension system. This provides enhanced stability and continuously variable ride height and uses neither conventional springs nor shock absorbers.
OFF-ROAD FIFTH WHEEL – The light alloy, lubrication-free fifth wheel is connected to a two-axis articulated mount with hydraulic damping and locking.
TECHNICAL POWER SYSTEMS – A hushed 25kW diesel generator and one of the modular high-current battery banks with static inverters and UPS systems provide technical power. The battery charging system comprises one 570 amp and one 285 amp engine-driven alternator. The battery bank resides in a sealed stainless steel housing, with integrated charge state monitor and winter heater. There is an auto-ejecting shore power connection for use when external power is available.
GLASS COCKPIT SYSTEMS – Eleven display screens (6 are touch sensitive) form the user interface for the Glass Cockpit computer systems. These displays are deployed in a manner similar to that seen in aircraft. However, all software displayed is customized for the KiraVan, with human factors optimized for all-terrain land vehicle use. For reliability and survivability reasons, certain key functions (such as main power bus switching) do not run through the Glass Cockpit computers, but are monitored by them.