PZL SM-4 Łątka
... that the PZL SM-4 Łątka never flew, because its engine was not approved for use in flight?
... that the <b id="mwCVk"><a href="./PZL_SM-4_Łątka" id="mwCVo" rel="mw:WikiLink" title="PZL SM-4 Łątka">PZL SM-4 Łątka</a></b> never flew, because its engine was not approved for use in flight?