Reprinted With Permission From MotoHistory.net.
Erwin George “Cannonball” Baker, born in Indiana in 1882, became so renowned for his long-distance endurance and economy runs with both cars and motorcycles that relatively little has been written about his achievement as a machinist, designer, and inventor. According to published reports, Baker undertook over 140 timed long-distance record attempts during his career, 126 of which were cost-to-coast marathons across the continental United States. In 1911, he rode an Indian across the nation in 11 days, 12 hours, and 10 minutes, and in 1922 he reduced his time for that crossing to six days, 22 hours, and 52 minutes aboard a four-cylinder Ace. As reliability of both cars and motorcycles improved, manufacturers began to place more emphasis on efficiency, and Baker's cross-country jaunts became tests of fuel-economy rather than just speed and endurance.
Trained as a machinist from his teens, Baker learned about metallurgy by working in a foundry in Indianapolis, and he consolidated his technical knowledge and interests in vehicle performance and efficiency into a project to build a better engine, based on a revolutionary rotary-valve design. According to a report written by his nephew, Clarence, Baker began working on a single-cylinder, rotary-valve, air-cooled engine in 1929 (pictured here and below). The theory of a rotary valve is to achieve higher speed – thus, more power – by eliminating the reciprocating parts in the valve train. There are basically two types of rotary-valve designs that have been applied to four-stroke engines. One is the Aspen-type vertical valve, which is a rotating disc that sits atop the combustion chamber. As it turns, timed ports function as valves to introduce fuel and expel exhaust.
The other is the Cross-type horizontal valve, which is a cylinder or drum that sits horizontally across the top of the combustion chamber. It also contains ports that introduce and expel gasses as the cylinder turns, timed to the rising and falling piston. This design was developed by Roland Cross in Great Britain from 1920 to 1945. It was reported in The Motorcyclist in December, 1934 that Cross had perfected the design and it would appear on production motorcycles the following year. This, however, was an overly optimistic claim. When Cross entered two rotary-valve machines in the TT at the Isle of Man in 1935, one failed to qualify and the other retired with “spark plug trouble.” Cross's rotary-valve development came to an end when his company had to devote all of its resources to military production during the Second World War. Still, the design showed such promise that as late as the 1960s, Norton development engineer Joe Craig was working on a Cross-type rotary-valve head for the Manx engine. For more information about rotary valves, Cross, and the experimental Norton, and for excellent drawings of both vertical and horizontal valve designs, click here.
The “spark plug trouble” that Cross experienced at the Isle of Man is symptomatic of the Achilles Heel of the rotary valve design when the valve is integral with the combustion chamber on a four-stroke engine. The competing objectives of compression and friction are hard to overcome. Significant areas of metal against metal must be lubricated, and sealing for compression is complicated as metals expand and contract at different heat ranges. When one tries to overcome these problems with excessive lubrication, spark plug fouling is the result. How to keep the valve adequately lubricated without spilling too much oil into the combustion chamber is hard to do. Cross tried to place a cast steel valve in a bronze sleeve, using a spring-loaded scraper to reduce the amoung of oil spilling into the combustion chamber. The Isle of Man results and the failure to ever put a rotary-valve on a production motorcycle would suggest it did not work.
During more than a decade of development, Baker overcame this sealing/lubrication problem through extensive experimentation with the material used in his rotary valve. This was referred to in the undated report written by Clarence Baker sometime after 1941, and in an article by Chet Billings that appeared in The Motorcyclist in June, 1941. Billings stated that Baker overcame sealing and lubrication problems by using a “sintered material which was subjected to heat treating.” Clarence Baker reported that his uncle made the valve from “oil-impregnated graphite.” Baker's design took the form of a tall, finned cylinder head with a shaft and large sprocket on the right side, rotated by a chain driven from the crankshaft (pictured above). On the left side of the head is a round, finned, removable plate (shown here), presumably slightly larger than the valve itself. Baker mounted this upper end on the crankcase from a 21 cubic inch Harley-Davidson single, which was attached to an Indian primary drive cover, clutch, gearbox, and magneto drive. The whole package was mounted in an Indian Sport Scout frame. Billings reports, “Ready for the road the outfit weighed together with the rider a total of 725 pounds.” Since Baker was a big man, the motorcycle must have come in well under 500 pounds.
Most people who want to perfect a new engine design would spend countless hours in the relatively safe and controlled environment of a test track, or perhaps on local roads. Not Baker! In typical fashion, he decided the best way to demonstrate the viability of his new engine was to ride it from coast to coast, which would test its durability and efficiency under all kinds of riding and weather conditions at altitudes from below sea level to 8,000 feet. This would be a feat for any test rider, but by this time Cannonball Baker was 60 yeas old. Chet Billings described his departure: “At 3:30 p.m. Friday, May 16 th , it was the old time Cannonball Baker who sat astride his motor at the city limits of Los Angeles and Alhambra . To see him off were AMA referee Al Koogler, west coast AMA representative Chet Billings, old-timer Fred Ludlow and Ed Farrand. At the tick of 3:30 Koogler waved him on, cameras clicked and a huge husky figure bent forward on the machine in the same position that it held years ago when many weary miles of bad weather and high speeds were ahead. Yes, Cannon Ball rode again.”
Clarence followed in a Chevrolet as his uncle made his way to Tucson, then Clovis, then Oklahoma City, then Carthage, Missouri; then on to Indianapolis, his home town. Billings reports, “He was brown as a berry, bewhiskered and tired. So, he treated himself to a bath, shave, some sleep and a good feed. He lost nine hours in all.” Continuing on, Baker passed through Illinois, Indiana, Ohio, Pennsylvania, and New Jersey, arriving at the Holland Tunnel in New York with an elapsed time of six days, six hours, and 25 minutes. Baker is pictured above after his arrival, with Indian dealer Ben Kasof. Though it had not been Baker's objective to beat his record set aboard the Ace when he was nearly 20 years younger, he did so, bettering that crossing by 16 hours. Rather, it was his intention to prove the reliability and economy of his rotary-valve prototype, which complete the coast-to-coast trip without mishap, averaging 57.2 miles per gallon on any type of pump gas that was available along the way, including the low-grade fuel that was known as “white gas” at the time.
Like Roland Cross in England, Baker had great hopes that his rotary-valve design would revolutionize the internal combustion engine. Not only did it offer a simpler, non-reciprocating valve train; he reckoned it would be cheaper to manufacturer and capable of greater horsepower without sacrificing reliability. For example, his transcontinental prototype, Billings reports, produced close to one horsepower per cubic inch. But it was not to be. Baker – an accomplished salesman and self-promoter – could not persuade investors to back his design, probably for the same reason that Cross ceased development in England in the mid-1940s. As nations prepared for war, few investors or governments were interested in funding novel or unproven ideas that did not involve weaponry or aeronautics.
Today, Cannonball Baker's rotary-valve prototype is owned by the Indianapolis Motor Speedway Hall of Fame Museum, and has recently been placed on display in a new motorcycle exhibit created to celebrate the fact that next year Indy will host a MotoGP. The motorcycle is original and unrestored, and its engine wears a patina of oily grime which may well be the very residue of its successful cross-country ride. Arguably, it carried rotary-valve development to a higher level of success than any other example, and it certainly proved that Cannonball Baker was a great deal more than a tough and stubborn man who could sit in a saddle for a week at a time. It is a tribute to a thoughtful and creative side of Cannonball Baker that has often been overlooked in the many stories of his feats of endurance.
To read Cannonball Baker's official Motorcycle Hall of Fame bio, click here. To reach the Indianapolis Motor Speedway Hall of Fame Museum web site, click here.
Picture of Baker aboard his rotary-valve prototype courtesy of Indianapolis Motor Speedway.
Thanks to Donald Davidson and Mary Ellen Loscar of the Indianapolis Motor Speedway Hall of Fame Museum for assistance with research for this article.
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