Tracing it origins back to the British Nieuport Nighthawk fighter, the Grouse sesquiplane led to the Grebe fighter. The sole Grouse, G-EAYN, was converted to a two-seat trainer and sold to Sweden in December 1925 where it was designated Ö3 as an 'exercise' (advanced trainer) type aircraft. It was withdrawn from use in 1929. Photo by: Karl Johan Stenhardt / Östergötlands Museum