OMG. Almost forgot to mention a classic STOL aircraft that meets your requirements, plus the engine can burn diesel and land in a 300 foot (91m) clearing. The
Pilatus PC-6 Porter is a single-engined
STOL utility aircraft designed by
Pilatus Aircraft of Switzerland. First flown in 1959. It can fly in level flight as slow as a, well, let me just say the Pilatus Porter can fly really slow.