The M4 Sherman medium tank was a real workhorse of the American army. Its M4A3E8 modification, nicknamed "Easy Eight" by the tankers, was the pinnacle of this family of tanks.
The creator of the tank was the talented, but largely unknown engineer Harry Oxford Knox. His vehicles dominated in American tank development for over ten years! Who was he, and what did he contribute to the American tank school of thought?
Before the Tank
Harry Knox was born on January 19th, 1875, next to Westfield, Massachusetts. He graduated from the Springfield Technical Institute in 1894. Knox was obsessed with cars, and built his first gasoline engine in that year. Initially, Harry worked at the Overman Bicycle Company, where he made engines for three-wheeled cars. Later, he decided to start his own business.
In 1900, the Knox Automobile Company was formed. At first, Knox made three-wheelers, but later he switched to four wheel cars. From 1906, his company also produced fire trucks. The company made passenger cars until 1914. The production of trucks lasted much longer, until 1927, when the company ceased to exist. Some of its products survived to this day.
Car to Tank
Some sources mention that Harry Knox took up tank design, but few mention how deeply he delved into it. His work for the military began in 1924. At the time, the American Ordnance Department burned its bridges with John Walther Christie, another tank designer that rose from the car business.
Unlike Christie, who was difficult to work with and frequently drew the attention of the press to himself and his vehicles, Harry Knox was not a public man. As mentioned above, even some tank historians have not heard his name. Nevertheless, this unknown car designer was a key figure in American tank building.
His influence can be seen by looking at the patent bureau archives. The famous rubber-metallic track link, a suspension using volute springs, a single block front transmission used on American tanks for over 10 years, all of these things were thought up by Harry Knox. He had nearly a hundred inventions to his name which were used in American tanks and half-tracks.
Knox didn't just patent components, but entire tanks. For instance, Knox was the author and owner of the T1 Cunningham patent. Cunningham was just a subcontractor of the Ordnance Department. Christie looks like a nobody next to Knox and his inventions.
Left in Shadow
Why is this man unknown? This question is answered by any of Knox's patents. They all begin with the disclaimer that the invention is created for the government, and can be used with no limitations. Knox was left in the shadow of his patrons in the Ordnance Department.
The inventor had a sufficient salary, plus he likely received generous bonuses. On the other hand, the Ordnance Department was rid of the headaches that come with invention due to a "court" inventor that, unlike Christie, didn't hound them for royalties. By the way, one of Knox's patrons was John Christmas, a man that played a key role in the exile of Christie and his tanks from the American army in the early 30s. Christmas is even listed as a co-author in several of Knox's patents.
Having such powerful patrons, the inventor didn't need to worry about competition. Yes, Knox's T1 tank and the T2 medium built on its basis lost to Christie's M1928 on all fronts, which appeared at the worst possible time. Christie's tank ruined the planned purchase of 250 T1s, and Knox had to radically redesign his vehicles. This resulted in light T2 and T5 tanks, which became the basis of nearly all American tank development from 1935 to 1945.
Light M2, M3, M5, medium M2, M3, M4, M7, the heavy M6, and even the superheavy T28, all of these tanks were made with suspensions and other components designed by Knox. His idea of a bogey with a rubber-metallic track was used on American halftracks. Knox's designs were also used by the Marmon-Herrington company, including the M22 Locust.
Knox's fame started to wane in the middle of the 1940s, when it was clear that his designs were obsolete. Torsion bars replaced springs, the transmission was moved to the rear of the tank. This change was partially influenced by the KV-1 tank, which was sent to the US in the fall of 1942 for trials. Knox's last patent is dated 1951.
The star of American tank building died in 1957, leaving his mark in history as only the creator of one of many car companies. Harry Knox's tank legacy awaits its researchers...
Article author: Yuri Pasholok
Yuri Pasholok is a historian, a specialist in the area of WWII armoured vehicles. He is the author of countless articles in various publications related to tanks, as well as the books Panzerkampfwagen Maus and Stalin's Steel Balls. He is also a historical consultant for World of Tanks.