The Pepperell range of model engines was among the very few such series produced in New Zealand. The only other commericially-produced engines from that country were the pre-WW2 Acme .99 cuin. spark ignition motor and the much-later Katipo models of somewhat dubious reputation. A full article on the Katipo range may be found through the link provided.
The Pepperell engines were constructed by the father-and-son team of Vern and Ira Pepperell, working from a home workshop in Onehunga near Auckland, New Zealand. Over the years betwen 1936 and 1952 the Pepperells managed to produce a amazingly wide range of different designs, many of which were "specials" or limited edition models. Their bread-and-butter offerings were their very well-executed crankshaft front rotary valve (FRV) diesels which were produced in some numbers over the years from 1945 through to 1952. Uniquely, these were identified by their bore dimensions rather than more conventionally by their displacements. They featured an unusual mixture adjustment arrangement in which the quantity of air was the metered component of the fuel mixture rathen than the amount of fuel.
A full review and test of the Pepperell Half-Inch model, together with a summary of the Perpperell range in general, may be found in Maris Disler's very informative article elsewhere on this website.