The Sesqui 1.5 cc diesel of 1982 was the brainchild of the legendary Australian model engine enthusiast Ivor F (no period - F is his legal "surname"!). It was designed by Ivor's good mate Gordon Burford of Taipan fame, who also produced the production tooling and investment castings. Most of the production work was carried out by Ivor in his own home workshop, although Gordon may have done some of the final fitting. 

The Sesqui displays an unusually complex design arrangement for a 1.5 cc motor. It has such advanced features as twin ball bearings, three-port Schnuerle scavenging, a rear rotary drum valve and a rear exhaust. Bore and stroke are 12.2 mm and 12.5 mm respectively for a displacement of 1.46 cc. The Seqsui has an extremely high performance for its displacement - Peter Chinn estimated that a good example might develop around 0.34 BHP @ 17,800 RPM. 

The engine appears to have been developed as a 1.5 cc unit in the expectation that the FAI might reduce the engine displacement for F2C (control-line team racing) from 2.5 cc to 1.5 cc. In the event, this change did not materialize, leaving the Sesqui as a competition diesel without a class in which to compete. Consequently, no more than 350 examples ended up being produced. The engine is a prized collector's item today.