Lew Blackmore, Model Engineer

A pastoralist and pilot, Lew Blackmore was interested in all things mechanical and as a child had an extensive Meccano set. He then joined the RAAF during WW2 and trained as an Aircraft Fitter and was posted to RAAF Base Darwin during the Japanese bombing raids of 1942 and later to Adelaide Waters.

He inherited Gregory Downs from his great uncle Robert McGregor Watson, the last of the three Watson Bros who settled Gregory in 1877. In 1945 he married Louie Suttor from Ilford and they settled at “Rosedale” Kandos initially and later moved to “Chester” at Clandulla, next to his parents property “Mt View”.

He had a workshop with a lathe attached to his house as well as a shed with welders and other engineering machinery, and manufactured some of his own farm implements, including a forage harvester as well as a few models including a boat hull from brass plates and a small Kiwi engine.

Bentley BR2 Rotary Engine Model

After he retired to Buderim, Lew took up model engineering, as a full time hobby and constructed a number of old aero engine models.

Bentley BR2 Model

The most famous of these was the 1/4 scale working model of the Bentley DR2 Rotary engine that powered the Sopwith Snipes during WW1. The cylinders rotated around the crankshaft. (Later engines that remained static with a rotating crankshaft were called radial engines)

Bentley BR2 Model
The Sopwith Snipe powered by a Bentley BR2 Rotary Engine

In 1982, Lew entered his fully functional, one quarter scale model of the Bentley BR2 rotary engine in the British Model Engineer Exhibition, winning the Duke of Edinburgh Challenge Cup and becoming the first winner to take it from British soil.

The Model Engineer magazine later published a long series of articles by Lew, illustrated with drawings, plans and photographs, for others wanting to build their own BR2 model. Lew followed up in 1986 by refining and expanding his series into a hardbound book titled “Bentley BR2 WW1 Rotary Aero Engine”, which he self-published.

The Book

The book begins by describing the history of WO Bentley’s second engine design for the British Admiralty during World War One, showing a sectioned drawing of the BR2 and the Clerget rotary it was derived from. Subsequent chapters describe the research for the model and devote individual chapters to the components, including a working, scale oil pump and scale, but dummy, magnetos that hide the contact breaker system for a conventional coil ignition system. The book concludes with a reprint of the official BR2 Aero Engine handbook of 1925.

The Bentley BR2 model’s crankcase

This ¼ scale working replica of the Bentley BR.2 World War I rotary aero engine built by Lew is currently on display at the Bentley Memorial Building in Oxfordshire, UK. This was the first model built of this engine.

Bentley BR2 model on display behind vehicle
Bentley BR2 Model in corner at the Bentley Memorial Building, Oxfordshire, UK

Lew also constructed a model of the Gnome Rotary Monosoupape Aero Engine.

The Gnome Model
The Gnome Model

The first successful rotary engine is generally attributed to the American F.O. Farwell in 1896; but the French Gnome, developed by the Seguin brothers, was much more successful in bringing the rotary to a broad aviation market beginning in 1909. The original Gnome had two valves, with the inlet in the piston head and exhaust in the in the cylinder head. The monosoupape, as the name signifies, had only one valve in the cylinder head, eliminating a weak feature of the earlier design, and was the most numerous model during WW1. Used mainly on fighter aircraft where speed and maneuverability were especially important, rotary engines were light and compact for their power. However, excessive engine torque and gyroscopic forces made airplanes difficult to control, causing high oil and fuel consumption.

An incomplete model by Lew Blackmore was the Bristol Hercules.

Bristol Hercules Model
Bristol Hercules Timing Gears (full size engine)

The Bristol Hercules was a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the most numerous of their single sleeve valve designs, powering many aircraft in the mid-World War II timeframe.

Lew was also working in a model of the Napier Lion engine but this was also not completed.

The Napier Lion engine (full size)

With an industrial history dating to the early nineteenth century, D. Napier and Son began building aircraft engines in the World War I era. Napier began work on a remarkable new engine, the Lion, in 1916. Its three banks of four cylinders formed a “W” or “Broad Arrow” configuration. The arrangement provided a much shorter crankcase, a stiffer and simpler crankshaft, and a more compact engine than the 12-cylinder “V” construction of other high-performance engines of the period. Napier produced the reliable and widely used Lion series from 1917 until 1932 for military, commercial, and special-purpose racing aircraft. This photo of a full size engine is an early version of the Napier Lion is believed to be a Model II or IIB. Napier manufactured these models from 1918 through 1925 to power many British aircraft types, including the Handley Page H.P.15 V/1500 bomber, Supermarine Sea Lion I racer, and the Felixstowe F.5 flying boat. (Note: Photo is of a full size engine)

Lew also published another book about the life of Australian aviator Harry Hawker.

Lew passed away in 1995 before completing some of his model projects such as the Bristol Hercules and the Napier Lion mentioned above.

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