▁He ▁began ▁development ▁of ▁the ▁engine ▁at ▁NS U ▁Mot oren werke ▁AG , ▁leading ▁to ▁the ▁first ▁running ▁prototype ▁on ▁ 1 ▁February ▁ 1 9 5 7 . ▁Un like ▁modern ▁W ank el ▁engines , ▁this ▁ 2 1 ▁horse power ▁version ▁had ▁both ▁the ▁rot or ▁and ▁housing ▁rot ating . ▁His ▁engine ▁design ▁was ▁first ▁lic ensed ▁by ▁Curt iss - W right ▁in ▁New ▁Jersey , ▁United ▁States . ▁ ▁On ▁ 1 9 ▁January ▁ 1 9 6 0 ▁the ▁rot ary ▁engine ▁was ▁presented ▁for ▁the ▁first ▁time ▁to ▁special ists ▁and ▁the ▁press ▁in ▁a ▁meeting ▁of ▁the ▁German ▁Engine ers ' ▁Union ▁at ▁the ▁Deutsch es ▁Museum ▁in ▁Mun ich . ▁ ▁In ▁the ▁same ▁year , ▁with ▁the ▁K K M ▁ 2 5 0 , ▁the ▁first ▁practical ▁rot ary ▁engine ▁was ▁presented ▁in ▁a ▁converted ▁NS U ▁Prin z . ▁At ▁this ▁time ▁the ▁" W ank el ▁engine " ▁became ▁syn onymous ▁with ▁the ▁rot ary ▁engine , ▁whereas ▁previously ▁it ▁was ▁called ▁the ▁" M ot or ▁nach ▁System ▁NS U / W ank el ". ▁At ▁the ▁ 1 9 6 3 ▁I AA , ▁the ▁NS U ▁company ▁presented ▁the ▁NS U ▁W ank el - Sp ider , ▁the ▁first ▁consumer ▁vehicle , ▁which ▁went ▁into ▁production ▁in ▁ 1 9 6 4 . ▁Great ▁attention ▁was ▁received ▁by ▁the ▁NS U ▁in ▁August ▁ 1 9 6 7 ▁for ▁the ▁very ▁modern ▁NS U