▁comple ting ▁in ▁foreign ▁events , ▁after ▁the ▁war . ▁ ▁He ▁retained ▁his ▁German ▁Champion ▁title , ▁he ▁first ▁won ▁in ▁ 1 9 4 9 . ▁ ▁With ▁vict ories ▁at ▁H ock en heim , ▁the ▁Sch au ins land ▁Hill cl imb , ▁and ▁the ▁Gren z land ring , ▁Ul men ▁was ▁clear ▁champion ▁in ▁the ▁ 2 - lit re ▁Sports ▁Car ▁class . ▁He ▁participated ▁in ▁two ▁World ▁Championship ▁Gr ands ▁Prix ▁in ▁ 1 9 5 2 , ▁debut ing ▁on ▁ 1 8 ▁May ▁ 1 9 5 2 , ▁in ▁the ▁Groß er ▁P ries ▁der ▁Schweiz , ▁but ▁retired ▁due ▁to ▁fuel ▁tank ▁issues . ▁He ▁returned ▁for ▁the ▁Groß er ▁Preis ▁von ▁Deutschland , ▁where ▁despite ▁his ▁Ver itas ’ s ▁power ▁dis adv antage ▁compared ▁to ▁his ▁riv als , ▁his ▁finished ▁e ighth . ▁That ▁season ▁also ▁saw ▁Ul men ▁win ▁the ▁DM V ▁Gren aland ring ren nen ▁again . ▁During ▁the ▁season , ▁he ▁suffered ▁a ▁heavy ▁crash ▁during ▁a ▁pract ise ▁session ▁on ▁the ▁Sachsen ring ▁ ▁from ▁which ▁he ▁escaped ▁almost ▁un sc athed . ▁He ▁arrived ▁at ▁the ▁final ▁meeting ▁of ▁the ▁ 1 9 5 2 ▁season , ▁the ▁Av us ren nen , ▁as ▁leader ▁in ▁the ▁Formula ▁ 2 ▁class ▁and ▁ 2 - lit re ▁sport ▁cars . ▁On ▁the ▁AV US , ▁lost ▁a ▁dram atic ▁s lip stream ▁battle ▁with ▁fellow ▁Ver itas ▁driver , ▁Fritz ▁R ieß