earliest references I have for the Howard Inline Twin engine is 1951,
first in ‘The Engineer’
“This engine has been built by Rotary Hoes, Ltd.”
[The Engineer. (England) Dec 14, 1951 p763]
next it is reported in the Howard mag:
“The new Series IV Model ‘Gem’, shown by Rotary Hoes for the first time at the 1951 Smithfield Show, offers
growers greater power and wider cultivation.
Although new to the home market, limited supplies of this model were sent during 1951 to Greece and
South Africa. … … The ‘Gem’ IV is powered by an engine of Rotary Hoes’ own design which develops
9.8 b.h.p. at 2,000 r.p.m. the maximum governed speed. The engine is an air-cooled twin-cylinder 4-stroke
with 3in. bore and 3 1⁄2 in. stroke and a capacity of 810 c.c.”
[Rotavator Pictorial, March 1952]
sorry i cant find this issue in my scanned docs, (another gunna-do job) it is the first one, i also have the second, then a big gap up to 1956. anybody have any more they can share?
my first reference to the 360 version is 1960, as per Brian Bells book, does anybody have Howard docs for earlier date? so yes your 1951 Gem has a later replacement engine, anybodies guess what motor it had originally, the Gem was available as both Series III and Series IV for several years. as well as the standard JAP 600 single, in the USA they also had Wisconsin singles and twins.
it is hard to imagine these machines being made by the thousands, it makes it more real to see those truckloads, thanks for great article Charlie. cheers Rod.