These are some of a series of leaflets headed "Meccano Science Series", believed to have been produced in the late 1960s.

An article entitled "Energy Conversion" by Chris Jelley in the October 1968 Meccano Magazine shows three similar (but not identical) models. Also the December 1968 "Meccano Magazine Handbook, page56, states, "Meccano Ltd. ... are currently co-operating with the Nuffield Foundation in the development of a number of models that demonstrate various principles of science and mechanics." It is possible that these leaflets show some of the models resulting from that co-operation, but further research is needed to confirm that.