The Payen Pa 49 Katy was a small experimental French turbojet powered tailless aircraft, designed by Nicolas Roland Payen, and first flown in 1954. It was the first French aircraft of this kind and the smallest jet aircraft of its day.
The all-wood Katy was a tailless aircraft, having no separate horizontal stabiliser. The wing leading edge was swept at about 55° but, unlike the classic delta with its straight trailing edge, the Katy's was swept at about 30° with each trailing edge carrying full span control surfaces, elevators inboard and ailerons outboard.
At its root, the wing merged gently into the fuselage with small air intakes for the 1.47 kN (330 lbf) Turbomeca Palas engine built into the leading edge. The cockpit was placed just aft of the intakes and the long straight-edged fin, swept at about 75° and initially as wide as the cockpit, began immediately behind it, narrowing to a slightly swept trailing edge carrying a full depth rudder. Images recorded before the first flight show the Katy with a low bicycle undercarriage with wing tip skids, but, by the time of the flight itself, this was replaced by a fixed, un-faired tricycle undercarriage.
First flight 22 January 1954; Retired 1958; Number built 1.