When I decided to feature our rare Whittle aircraft engine in a recent blog post, I entered the term ‘Whittle’ in our database. Data on the engine appeared, along with a photo. Another object also popped up, with little data and no image. Intrigued, I had to check out this ‘early experimental Whittle turbine blade with fir tree base’.
I’d seen turbine blades before, but none as small as this, just three inches (75 mm) long and one inch (25 mm) wide. I didn’t have a clue about the fir tree base, but I did know it couldn’t be made of timber! And I wanted to know more about the donor, Mr C A Saxby, and whether the Whittle attribution was true; if it was, the object could connect us directly with an important and contentious research program, Frank Whittle’s development of the jet engine during World War II.
Whittle’s autobiography (Jet: the story of a pioneer) explained that the fir tree base was developed by his team to overcome the problem of wobbly blades. A turbine has a large number of blades attached to a fast-spinning rotor, and vibration at the attachment points reduces both efficiency and lifespan. Whittle’s earliest experiments used the established ‘bulb root’ design, a cylindrical base that fits in a matching slot; in cross-section, this resembles a plant bulb in a round hole. The fir tree base, which has a series of steps that lock the blade into the rotor more effectively, is the standard design today.
But who was Mr Saxby, and how did he come to have the blade? Exam results in Trove gave me his Christian names, Colin Ambrose. A 1935 article turned up a grainy photo of him; the caption placed Saxby as one of a select group to graduate from Sydney University that year with honours in electrical and mechanical engineering.
So Saxby was a bright young engineering graduate at the time Whittle began his research. Did he travel to England and work with Whittle? One of our archivists searched for correspondence related to the object – and scotched that theory. The real story was that Saxby was the Acting Advisory and Inspecting Engineer to the NSW Government and was sent to England to tour various engineering works soon after the war ended. When he was at the Vickers works, an employee offered him the turbine blade. As Vickers made jet engines during the war, with advice from Whittle, it is highly likely that the story of the blade is true.
Curators must be sceptical about provenance because apocryphal stories can develop around objects, often linking them to famous people or events. However, provenance is not the only story. One object can tell many stories, and in this case they include: a problem to be solved; engineers striving to find a solution; the technology this contributed to; use of that technology in warfare and later in civilian aviation; technology transfer from Whittle to Vickers; and the story of Colin Saxby, his contribution to engineering in NSW, and his decision to donate this interesting souvenir to the Museum, to inspire future generations.