Back motor arm is fine... It's the body portion that holds the arm in position when unfolded that has a hairline crack... The template is for a gusset to laminate on top of the cracked support surface. Gusset will be 1/16" Lexan, epoxy cemented to the support surface. I'll make two, one for each side. Alternative is a new body shell that would have the same poorly engineered support for the rear arms when extended...