The Strong 19 glow-plug motor is one of the great enigmas of the Japanese model engine manufacturing industry! This twin ball-race radially-ported glow-plug motor was introduced in 1964 at a time when no-one was developing radially-ported model engines any more. Apart from the performance limitations when compared with the far more fashionable cross-flow loop scavenging or the then-emerging Schnuerle porting system, the chosen design posed a considerable impediment to the increasingly-necessary use of a muffler. Although very well made indeed, the Strong 19 performed at very modest levels by comparison with its competitors, hence finding minimal market success and disappearing in 1966 as fast as it had arrived.
There were also a few Strong twin-cylinder designs, most notably a .45 cuin. in-line model. This latter engine was later (1974) re-developed into the Kamikaze 40 Twin of that year. For more complete information on the Strong engines, see my earlier article on MEN.