The HFC17 Basic roof truss teaching equipment is a benchtop setup designed for the study of co-planar forces. It is used for the evaluation of co-planar forces in the struts and tie of a basic roof truss with theoretical predictions. The equipment comprises two rafters or struts joined at an apex and a restraining tie with variable length. With adjustable length, the trainer unit allows students to observe the effect of changing the tie bar length. With the help of a full set of weights and hanger supplied, the training equipment allows direct force measurement in Newton's.