▁used ▁include ▁the ▁ ▁Rot ax ▁ 5 0 3 ▁and ▁the ▁ ▁Rot ax ▁ 5 8 2 ▁two - st ro kes ▁as ▁well ▁as ▁the ▁ ▁Rot ax ▁ 9 1 2 UL , ▁the ▁ ▁Rot ax ▁ 9 1 2 U LS , ▁ ▁J ab ir u ▁ 2 2 0 0 , ▁ ▁Sub aru ▁E A ▁engine , ▁ ▁Cont inental ▁C - 9 0 ▁and ▁the ▁ ▁Cont inental ▁O - 2 0 0 A ▁four - stroke ▁power pl ants . ▁ ▁In ▁ 1 9 8 8 ▁the ▁J 6 ▁design ▁was ▁adapted ▁to ▁the ▁Canadian ▁ul tr al ight ▁rules ▁as ▁the ▁Norman ▁A viation ▁J 6 ▁Kar ato o ▁and , ▁in ▁ 1 9 9 0 , ▁as ▁the ▁B uzz man ▁L ' il ▁B uzz ard . ▁ ▁Oper ational ▁history ▁In ▁August ▁ 2 0 1 2 ▁there ▁were ▁ 1 4 ▁J 6 ▁Kar ato os ▁registered ▁in ▁the ▁United ▁States ▁with ▁the ▁Federal ▁A viation ▁Administration ▁in ▁the ▁Ex perimental ▁- ▁Am ateur ▁Bu ilt ▁and ▁light - s port ▁categories . ▁ ▁Vari ants ▁J 6 A ▁Kar ato o ▁Initial ▁model ▁with ▁a ▁gross ▁weight ▁of ▁, ▁commonly ▁power ed ▁by ▁a ▁ ▁Rot ax ▁ 5 0 3 . ▁The ▁earliest ▁versions ▁had ▁a ▁solid ▁spr uce ▁main ▁sp ar ▁and ▁later ▁a ▁spr uce ▁I ▁beam ▁sp ar . ▁J 6 B ▁Australian ▁Kar ato o ▁Im pro ved ▁model