01/31/2012. Remarks by Walter van Tilborg: "The F11/F12 series was derived by Chris Falconar from the two-seat Jodel D-11, changes including less dihedral on the outer wing panels, rounded wing tips and re-contoured tail surfaces, but also modifications to the fuel tanks and fuel system. The prototype F11 first flew in the early-1960s and several models became available for amateur construction.

F11. The basic model, which had a one-piece wing and it was mainly built with engines such as a 65 hp Continental A65, 75 hp Continental A75, 85 hp Continental C85, 90 hp Continental C90 or 100 hp Continental O-200-A. It retained the typical upwards canted outer wing panels of the Jodel D-11.

F11-3 Sporty. Also known as the F11A, the F11-3 had a modified three-piece wing, which was made foldable for easy hangar storage and road transport and this version was usually not fitted with the cranked Jodel tips. This version was suited for engines in the 65 to 100 hp range.

F11D. Based on the initial F11 model, but with a modified wing.

F11E. Version with a lighter construction, allowing engines in 50 to 100 hp range. By 1999 only one aircraft of this type had been completed.

F12. Based on the F11 airframe, but with heavier wing spars allowing an optional third seat and suited for engines up to 150 hp.

F12-3 Cruiser. Also known as the F12A, this was an improved version with the three-piece wing as used in the F11-3, but stressed for engines up to 150 hp such as the Continental O-320 series. It was introduced in 1966 and 25+ were completed, mainly in Canada.

The F11 and F12 were almost exclusively built in the USA and Canada, and an estimated 65+ were produced."