where did these popular aeroplanes - pratt & whitney r-2180-e twin wasp e and allison model 250 originate ?
SELECT DISTINCT var_uri where brack_open dbr_Pratt_&_Whitney_R-2180-E_Twin_Wasp_E dbp_nationalOrigin var_uri sep_dot dbr_Allison_Model_250 dbp_nationalOrigin var_uri brack_close