The Daimler Freeline is an underfloor-engined bus chassis built by Daimler between 1951 and 1964. It was a very poor seller in the UK market for an underfloor-engined bus and coach chassis, but became a substantial export success.
It was the first of only three Daimler PSV models to have a name, as well as an alphanumeric identity. The others were the Daimler Fleetline and the Daimler Roadliner.
The first underfloor-engined bus and coach chassis in Britain were built by Leyland Motors, Tilling-Stevens and the Associated Equipment Company in the years immediately prior to World War II. During wartime, the BMMO (Midland Red) company built prototypes for a substantial fleet of buses to this layout, which they built from 1946 for their own use: over 400 were in service by 1952.
The first manufacturer to offer this new, and more economic design, for general sale was Sentinel of Shrewsbury, from 1947, their models being of integral construction, as was the Leyland-MCW Olympic which followed, in 1948. In 1949, the Associated Equipment Company launched its Regal IV chassis. In 1950, Leyland Motors introduced the Leyland Royal Tiger, also a separate chassis.
The previous Daimler CVD6 half-cab single decker had sold well immediately after the war, particularly to coach operators and independent bus operators, neither of whom were previously core Daimler customers. When, in 1950, the permitted length of single deckers was relaxed, to a new maximum of 30 feet, the CVD6 was offered in a version for long bodies, but half-cabs were becoming obsolete on the home market.
In April 1950, Daimler announced that it would build an underfloor-engined bus and coach chassis. This was the Freeline. The first two were demonstrators. Chassis 25000 was a D650HS sent from Coventry to H. V. Burlingham for bodying to the Seagull coach style, in March 1951. It was later registered LKV218. The second demonstrator, chassis 25001 was sent to Duple Coachbuilders in Hendon and received a B30D+30 (standing) bus body. It was registered LRW377 and exhibited on the Daimler stand at the 1951 Scottish Motor Show at the Kelvin Hall in Glasgow, in the livery of Edinburgh Corporation, whose general manager was eager to trial standee single deckers on busier routes.
Like its Leyland and AEC rivals, the Freeline had a high, straight ladder frame, made of substantial steel channel section, with an optional rear drop-frame extension for luggage boots on coaches, or standee platforms for urban buses.
Three power units were offered:
The 5HLW and 6HLW from L Gardner and Sons were also used in equivalent chassis by Guy Motors, Bristol Commercial Vehicles, and Atkinson Vehicles and in an integral by Saunders-Roe. The 5HLW five-cylinder 7-litre engine developed 87 bhp, later uprated to 94 bhp, and the 6HLW 8.4-litre six-cylinder produced 102 bhp, later uprated to 112.
Models with these engines were coded G5HS and G6HS respectively.
Daimler also offered a purpose-built own-make engine for this model. This engine was called the D650H and was derived from the D650 engine used in the rare post-war CD650 double-decker. Swept volume was 10.6 litres, and the major difference from the vertical version of the engine was the sump casting. Parts commonality was such that CD650 operators could, and did, use the 'top end' of the horizontal engine when they could not get spares for the vertical version. Output was originally 125 bhp @ 1,650 rpm but this was soon raised to 150 bhp @ 2,000 rpm, which was class-leading power in 1953. The model code for this version was D650HS.
The axles was similar to those of the CD650, the rear axle being a substantial underslung worm unit, with the differential offset to the left.
Braking was originally full-power hydraulic on the controversial Lockheed Automotive Products continuous flow system, as employed on the CD650 and, as with that chassis, hydraulic-assistance could also be applied to the steering and the gear-selection pedal. The hydraulic system was unpopular with operators and air braking was 'quietly introduced' as an option in 1952. For the home market, only one wheelbase was offered: 16 ft 4ins for 30 ft by 8 ft bodywork. For export markets, a longer 17 ft 6in wheelbase (for 33 ft bodies) was standard, with a 20 ft 4ins version for 36 ft bodies introduced for markets where that length was permitted, in 1954.
Originally, the transmission was a Daimler five-speed preselector type (either overdrive-top or close-ratio with direct top, with four-speed optional) but, from 1957, the Daimatic direct operating semi-automatic transmission was available, with four forward speeds and this, with either electro-pneumatic or direct-air change-speed mechanism, soon became standard. Drive in both cases came from the engine, through a remotely mounted fluid flywheel.
The radiator was mounted vertically, directly behind the front wheels, and the semi-elliptic leaf springs were of substantial construction.
It soon became clear that the Freeline, like the Regal IV, Royal Tiger and Guy Arab UF, was over-engineered for UK operating conditions. A typical bodied 39-seat coach could weigh more than a 60-seat half-cab double-decker bus. Leyland, AEC and Guy developed lightweight chassis for the home market, but there was not to be a Daimler equivalent to the Leyland Tiger Cub, AEC Reliance or Guy Arab LUF. Geoffrey Hillditch, a well-known and respected passenger transport manager, who ordered the last Freelines built, expressed regret that Daimler did not build such a vehicle.
Due to heavy weight of the Freeline, its sales in home market were disappointing. In Daimler’s core market, in the British municipal sector, sales were little short of disastrous.
The Corporation fleets who purchased the Freeline were:
Total: 19 chassis.
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