Versions
The chassis was designed with a front mounted engine that still allowed a front entrance position suitable for one-person operation. In this sense there was a common goal with the earlier, unsuccessful, Guy Wulfrunian. The engine was the Volvo TD70, a compact turbocharged unit of 6.7-litres. The rest of the design was relatively simple, with beam axles and leaf springs. A Self-Changing Gears semi-automatic gearbox was used.
A prototype lowheight Ailsa, designated B55-20 (instead of the standard B55-10), was built for the Scottish Bus Group for operation in the Highlands with Highland Omnibuses. When SBG first looked at the prototype, they ran a mile, thus no more were built. Derby Borough Transport bought the bus in 1977. It remained a one-off and is now owned by WJC Coaches in Scotland.
In 1977 an improved MkII version appeared, with two transmission options offered - a Self-Changing Gears pneumocyclic unit and a Voith D851 with retarder. It was followed in 1980 by a MkIII version, for which the Ailsa name was dropped. This continued to use the Volvo TD70H turbocharged engine, and utilized a Volvo truck rear axle in place of the previous troublesome axle. Air suspension was also an available option.
In 1981, a 3-axle version of Ailsa B55 was developed to meet the demand of 3-axle buses in Hong Kong.
Read more about this topic: Volvo Ailsa B55
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“The assumption must be that those who can see value only in tradition, or versions of it, deny mans ability to adapt to changing circumstances.”
—Stephen Bayley (b. 1951)