FRONTLINE
Page 52
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FIRE FIG114TER
Not only is the Marlin three-axled all-wheel-drive fire tender cheaper than its continental competitors, it also has a number of strong selling points.
• A new generation of rapid intervention vehicles has just gone into service at Manchester airport.
The 33-tonne, three-axled all-wheeldrive Marlin is built by Fire Trucks of Mitchelden, Gloucestershire, on a Reynolds Boughton, Griffin chassis. It is designed to meet the requirement for lighter, more powerful first-line airfield crash tenders as older models become obsolete.
Its rear-mounted vee-12 two-stroke 18.1-litre Detroit Diesel engine develops 566kW (761hp) at 2,300rpm with 2,760Nm (2,0351b1t) of torque at 1,400rpm — that's about 50% more power than is available with equipment in current use. It drives through a German Renk 227 seven-speed automatic transmission incorporating the transfer box; a hydrodynamic torque converter, and a locking differential. A single control is used to engage all cross-aide and interaxle differentials.
The Renk transmission and 3.5m-wide Kessler axles are a new departure for Reynolds Boughton, but it has retained Kirkstall rear suspension.
Renk, an autonomous company within the MAN group, is best known for its military and off-road construction-industry transmissions for power outputs over 336kW (450hp).
PLANETARY
The transmission features planetary gear trains actuated by oil pressure-controlled multi-disc clutches; the electronic control incorporates a fault diagnosis system, and provides for hold-down in the lower ratios. Helped by this, acceleration is impressive, with a 0-801on/h possible in less than 25 seconds. Top speed is 108km/h (67mph), and maximum claimed gradability is SO% (1-in-2).
An airfield crash tender must be able to travel to all parts of an airfield, irrespective of the terrain or ground conditions. Large (24.00x20) Michelin X tyres give good floatation and grip on soft going. That, combined with its power, under-axle clearance of 334mm, approach and departure angles of 30° and cross axle articulation of 380mm, means there are few places it will not go.
A low overall height of 3.5m and the full-width 14,000-litre GRP water tank, built integrally with a 1,680-litre foam liquid tank, gets the centre of gravity down to allow a side tilt angle of 28°. Internal baffles are included to prevent surge under braking and cornering.
TRANSMISSION
Disc brakes with anti-lock on all wheels are operated via an air/hydraulic system with separate reservoirs for each hydraulic cylinder at individual wheel stations. A transmission disc brake, controlled by a hand valve, looks after parking-brake requirements.
Fire Truck's three-part modular body construction separates cab. tanks and engine comparment: the suspended four-man crew-cab, made of GRP and aluminium panels over a steel frame. allows good all round visibility with a degree of styling.
The rounded front is complemented by a flat safety-glass side section. Wide front hinged doors allow fast entry, and a sliding hatch gives further access to the roofmounted monitor. The driver's seat is located centrally, and twin power assistance makes light of the steering — but a 27m turning circle will hardly help to improve the Marlin's manoeuvrability.
A rear engine cover slides clear to give good access for servicing.
Other equipment includes a Godiva 6,500 light alloy pump with a rated capacity of 7,2001ft/rain at 15bar, and a foam system supplying a Chubb FB-6000 dualoutput, monitor with a 6,000litimin discharge rate.
Hauliers might be taken aback at the Marlin's £360,000 price tag, but in fact this is one of its selling points — some of the continental opposition costs at least ,M0,000 more.
LI by Bill Brock