There are just two top-rated commercial air shows in the world – Farnborough and Paris – and they take place in alternate years to avoid direct competition. 2015 being an odd-numbered year, aviation experts made their way to Le Bourget Airport, just north of Paris, to see and evaluate the latest developments.

Just for once, the ‘latest development’ in aeronautical engineering was not only striking in itself, but a substantial change from the Farnborough International show of 2014. I refer, of course, to additive manufacturing, 3D printing or its various other synonyms. The companies mentioned here are interesting examples of the new trend, though my selection is not claimed to be exhaustive.

Rolls-Royce had gained substantial publicity earlier in the year for what it claimed as the largest part ever made by ‘ALM’ (‘additive layer manufacturing’), its own, slightly more descriptive, term for additive manufacturing. The size of a tractor tyre, this titanium-alloy structure, 1.5 m in diameter and 0.5 m thick, is the front bearing housing of a Trent XWB-97 jet engine expected to fly late in 2015. But expectant visitors to the Paris Air Show had no chance of seeing it because, although Rolls had a substantial hospitality chalet, it had no direct presence in the exhibition halls.

Pratt & Whitney, Rolls-Royce's US rival, filled the gap, with an apparently similar AM product for its smaller PW1500G high-bypass jet engine (Fig. 1), as used in Bombardier's latest CSeries airliners. A tiny sign in the air inlet of the demo engine in our picture said ‘NO PHOTOGRAPHY’, but I was given special permission to take photographs provided I avoided a head-on position. From my angle, the engine can be seen to have about 18 integral vanes, less than half as many as Rolls’ much larger Trent demonstrator. Following rigorous testing, PW are already employing a host of AM parts in production jet engines and ancillaries, including critical parts of fuel injection nozzles (Figure 2 and Figure 3), compressor stators and synch ring brackets. The company is reported to have invested more than $4.5 million in The Pratt & Whitney Additive Manufacturing Innovation Centre at the University of Connecticut.

This article appeared in the Sept/Oct issue of Metal Powder Report.

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