Gabriel Voisin was a pioneer aircraft manufacturer and flyer. After World War 1 he left aviation behind to concentrate on car manufacture. His designs were pioneering and individualistic with so many ideas incorporated from his previous aircraft background, as one can see so clearly with his monocoque chassis Voisin C6 entry for the 1923 French GP! Most Voisin cars were fitted with the Knight sleeve valve engine. All Voisin models were prefixed with C, the last model C30 being at the insistence of his financiers for something less experimental and more traditional, built around the mechanicals of a Graham Paige but with a compressor added. If you are interested in Voisin the book on the subject written by Pascal Courteault is essential reading. After the war the Voisin business was nationalised. One of his employees Andre Lefebvre ended up working at Citroen designing the Traction Avant, 2CV and then postwar DS range, which embodies so much of what was Gabriel Voisin.