IMPA Tu-Sa / LF-1
The IMPA Tu-Sa, (IMPA - Industrias Metalúrgicas y Plasticas Argentinas S.A.), or Impa Tu-Sa-O, was a civil trainer developed in Argentina in the 1940s for aeroclub use. It was a conventional, low-wing monoplane with wide-track fixed tailwheel undercarriage. Frst flown on 17 April 1943, approximately 25 were built as LF-1 during 1943-1944. Derived directly from the RR-11, the Tu-Sa (or Tu-Sa-O) initially had the same 65hp Lycoming O-145-B2 engine but that was later upgraded to a 80hp Continental.
In service, the aircraft demonstrated a number of serious and fundamental design flaws that led to a series of accidents and pilots joking that Tu-Sa stood for Todo Un Sarcófago Aéreo ("Altogether an aerial coffin"). When it became apparent that the defects could not be corrected without a complete redesign of the aircraft, they were withdrawn from use.