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SNAPSHOT 398: 1928 Coventry Eagle

This photograph from 1949 is not of the highest quality but is, we hope you will agree, worth showing for the remarkable situation and the unusual motorcycle.

It was found on the front cover of a 1992 magazine for vintage model aircraft enthusiasts and shows Brian Hewitt in 1949, ready to set off for the flying field with his radio-controlled “Mills powered” (more of this later) aeroplane strapped to his back. The large box on the rear carrier is the radio transmitter and just visible tied vertically to the front forks is the “Tx” (transmitter) aerial. Brian Hewitt’s mount is a 1928 Coventry-Eagle, bought in 1948 for £25, “being all Brian could afford on his de-mob pay”.

Founded by Edmund Mayo in 1890, the Coventry-Eagle factory made Royal Eagle bicycles in the 1890s and built their first JAP-powered motorised bicycle around the turn of the century, perhaps 1901. By 1903 they were making motorcycles and by 1916 they had produced a variety of machines assembled from mostly proprietary components. In 1921 they were producing 500cc singles and a JAP-powered 680cc V-Twin. In 1923 they introduced the 976cc Flying Eight, which competed in both speed and quality with Brough Superior. They continued to expand the range until the effects of the Depression were felt in 1929. Production continued until 1939.

The clues from our Snapshot point to a far more modest model than the Flying Eight: it is one of the smaller bikes with a pressed-steel frame and forks, visible in front of and behind the rider. It is powered by a single-cylinder two-stroke Villers engine coupled to an Albion gearbox with a hand-operated gearchange. It is a twin-port engine – hence the twin exhausts just visible in the photo. It could be a D21 (147cc, Albion 2-speed box), D23 (172cc, again 2-speed) or D25 (172cc, 3-speed). A curious feature is that the rear frame looks to be from around 1928 but the pressed-steel forks are from much later, perhaps 1935, when the pressing had no perforations. It seems that the bike may have had an accident and the forks had been replaced with the later type.

Coventry-Eagle were proud of the capabilities of their pressed-steel construction; here is a full-page advertisement from 1928 setting out its advantages over a tubular frame. The original 1928 perforated forks can be seen clearly.

And finally to the Mills model aero engine. This was a tiny diesel engine, first patented in 1946 and therefore quite possibly “the latest thing” for enthusiasts. The patent application claimed that “It has been found that by causing two or more streams of a fuel-air mixture to converge and meet within the cylinder such an efficient atomisation of the mixture is obtained that an efficient deflector plate on the piston does not chill the mixture sufficiently to prevent combustion”.

Apparently the ‘deflector plate’ is essentially a notch cut into the piston head. The patent further claims that this ensures that “the engine is easy to start”. Modern-day writers have supported this.

Images courtesy of The Richard Roberts Archive: www.richardrobertsarchive.org.uk


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