de Havilland DH.90 Dragonfly
Following on from the pressed plywood construction of the DH.88 Comet racers, DH designed their "executive" version of the Dragon family with this new construction technique.
The DH.90 Dragonfly adopted the two pilot layout of the DH.86, and the same ex-Tiger Moth engines as the DH.84, in two models; the DH.86 and DH.86A, differing only in their engine horsepower. In service use the differentiation was moot anyway, especially post-war, as even higher powered versions of the engines were sometimes fitted during overhauls.
With the fuselages being solid, there was little ability to add doors and windows as with previous Dragon designs, and the only factory modification made to new build aircraft was the potential to add a forward cargo hatch that also removed the starboard forward cabin window. During post-war rebuilds some aircraft had an additional passenger door retrofitted to this position.
de Havilland in Canada imported 7 airframes and assembled them for local use. All these aircraft were fitted with a standard DH seaplane-style fin, although only 1 aircraft appears to have ever been flown on floats.
Production ceased in 1938, but only as DH was committed to the production of so many other types. However the death knell further additional machines came with the use of the production jigs to form anti-invasion road blocks in 1940.
The prototype first flew in 1935, and performed well in the King's Cup air race in 1936.
A total of 67 aircraft were built, initially their high price led to their being only used as transports for high status individuals, however they soon found their way into air taxi work. With the coming of WWII their niche peformance meant there was little call to impress the Dragonflys.
They did however find their way into para-military roles in the UK, being used as express transports for vital companies. The DH.90 owned by the London Aeroplane Club found itself reverting to de Havilland's where in a camouflage colour scheme it served as a company communications aircraft.
Not suffering from war use, many DH.90's survived into civil service post-war, and with the plentiful supply of engines many continued on into the 1960's still in commercial use.
The 8th aircraft built spent most of its life in Australia, before returning to the UK as G-AEDT in 1963. In 1964 it was further flown to the US, making it probably the DH.90 that has conducted the longest flights. This aircraft is still flying in NZ.
The only other airworthy DH.90 is in the UK, after spent its life in Angola and South Africa.