A less turbulent Druine aircraft…..


Roger Druine was a French flying instructor in the 1950s with several aircraft designs already to his credit, including an attractive little single-seater known as the D.31 Turbulent. He realised that there would also be a ready market for a simple-to-construct two seater, which could act as a club aircraft and an economical tourer; the result was the Druine D.5 Turbi.

The structure of this French-designed classic was primarily wood, with a simple, parallel-chord wing (with slotted ailerons) built up around a wooden, laminated box spar. To make for better controllability, with a single occupant, the aircraft is usually flown from the rear of the two open cockpits. Power came, initially from a Beaussier-converted Citroen car engine, producing about 50hp. This gave a top speed close to 90 mph, and the generous wing surface ensured that the stalling speed was only 34mph!

Converted car engines were often used by early lightplane designs due to cheapness and availability. Aircraft fitted with such units include the Pietenpol Aircamper and the Chilton Aircraft D.W.1. Indeed, the modern Flitzer Biplane design still uses a converted air-cooled flat four engine, from Volkswagen.

The Turbi was greeted with acclaim by home-constructors everywhere – the first British example being built by a Popular Flying Association group in Hatfield, Hertfordshire in 1955. Two years later, in Glasgow, a Mr Francis Roche conceived of the idea of building a Turbi, and in 1960, G-APBO took to the air. Powered by a Continental Motors Corporation C-75-12 air-cooled engine of 75 hp, ‘Bravo Oscar’ gave excellent service to many owners, finally ending up with Mr Rupert Hibberd of Wiltshire.

Here you can see ‘Bravo Oscar’, one of only two British aircraft still active, at the Great Vintage Flying Weekend, at Keevil Airfield. A regular GVFWE visitor, she also appeared at the Hullavington and Kemble shows. This very attractive green/white paint scheme was seen on the aircraft in 2004; other colour schemes in which the aircraft has appeared include blue and white in 1981, and a rather florid scarlet, silver and yellow paint job in 1960!

Chris Falconar, a Canadian Ontario-based engineer, modified the Druine design to have a sliding cockpit canopy. This had been done much earlier with by De Havilland Canada, wit their DH Tiger Moths, due to the brutal Canadian winter weather! Following Falconar’s death in September 2018, the company’s designs were taken over by a number of other aviation concerns, but it appears that no Canadian company wanted the Druine Turbi. Fortunately, Manna Aviation in Australia continue to offer a set of plans for the Turbi to home-builders for $444 (Aus).

The original design was a dual windshield open cockpit, but available plans from the Australian company show open cockpits with dual controls that can be flown solo from either the front or back seat. Early Turbi’s built in England were powered with the De Havilland Gipsy Minor engine, a now-rare, pre-World War 2 powerplant.  The 4 cylinder 65hp Czech Walter LOM II AE has a dry weight of only 132 lbs – which is a similar configuration to the Gipsy Minor and is a perfect substitute for the de Havilland engine.  Other popular engines which can be fitted include Continental or Lycoming units of between 65 to 115 HP. 

Recently updated plans and kits for this light 2-seater tandem sportplane now include an enclosed cockpit with single curvature windows, or a vacuum-formed bubble canopy.

The beauty of this lovely French design is that, being built of wood, it has no fatigue life, unlike contemporary metal monocoque lightplanes.

The Druine Turbi – simple, yet effective.

bit.ly/TPMShop

http://peoplesmosquito.org.uk

https://www.picfair.com/shortfinals

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