Ryszard Bartel's
...that Ryszard Bartel's design, the Bartel BM-4, was Poland's first own aircraft built in series?
...that <b id="mwAug"><a href="./Ryszard_Bartel" id="mwAuk" rel="mw:WikiLink" title="Ryszard Bartel">Ryszard Bartel</a>'s</b> design, the <a class="mw-redirect" href="./Bartel_BM-4" id="mwAuo" rel="mw:WikiLink" title="Bartel BM-4">Bartel BM-4</a>, was Poland's first own aircraft built in series?