The coach parked here in front of the DAF Museum is a unicum, a Curbside Classic Sole Existing Exemplar. It’s a 1970 DAF SB200 bus chassis with a one-off body from the Belgian coachbuilder Jonckheere. Custom-built for Philips, the Dutch technology company.
The coach was specifically built to test a Philips-Stirling vehicle engine, mounted in the rear of the DAF chassis. On its roof the engine’s heat exchanger/cooling unit. The driving force behind the project was Frits Philips (1905-2005), the president of the company from 1961 to 1971.
Frits Philips was convinced that a Stirling engine eventually could become a real alternative to the internal combustion engine. Unfortunately, some major problems occurred during the field-tests.
The starting procedure turned out to be rather problematic. But above all, the Stirling engine didn’t have the qualities to run at variable speeds, which is of course an absolute necessity in any road vehicle.
Alas, the Philips-Stirling had to removed from the chassis and the coach was retrofitted with a trustworthy 6-cylinder DAF diesel to keep it on the road. Nevertheless, Philips-Stirling engines certainly functioned successfully as a stationary power unit. Highly efficient, very clean, no noise.
The Philips company worked on the Stirling engines from the late thirties to the late seventies and improved them significantly. They were good enough for the NASA, for example.
This is clearly a VIP-coach interior, equipped with all the luxury and goodies that were available when it was built. All in all, the coach is a great piece of industrial heritage, even without its original engine. And with that conclusion we end the 2016 DAF Museum Days Bus & Coach Tour.
(A more detailed read about the Philips-Stirling engines can be found here, included the Philips Type 4.235 Stirling vehicle engine)
1970 DAF-Jonckheere (the conventional coach)