The Henry System

Ernest Henry: The Grandfather of the Modern Competition Engine

Ernest Henry, sitting at his drafting table.
Ernest Henry, Swiss Engineer for Peugeot.

Ernest Henry was born in 1885.  Mechanically inclined, he studied at an applied school of mechanics in Geneva, Switzerland.  He graduated in 1906, at age 21.  Initially working on marine engines, he soon moved to Paris, France.  By 1911, he was picked up by Peugeot.  It was there that he would hook up with a few race drivers to create an engine that would have an everlasting impact on motorsport, and even cars in general.  The cars that he designed for Peugeot, Ballot, and Sunbeam achieved no more than moderate success; however, his influence on motorsport was (and remains) profound.

The Henry System.

Henry’s system, as it were, refers to the integration of several disparate concepts: (1) one or more overhead camshafts; (2) inclined overhead valves; (3) monoblock casting; and (4) central spark plug location.  Henry was not the creator of any of these particular concepts.  However, he was the first to shove all four into a single engine.  This combination of concepts indelibly stamped itself upon motorsport history.

The Henry System, as it became later known, first appeared in the three-liter 1912 Peugeot.  The 1912 Peugeot car was ahead of its time.  In fact, anytime you see “DOHC” (Dual OverHead Cams) stamped on a production car or its engine, be aware that the technology is over a century old.  It all began when three drivers, by the names of Zuccarrelli, Boillot, and Goux got together and conceived some ingenious ideas for a race car.  Ernest Henry, an enigmatic swiss draftsman, was tapped to force some big ideas into a single car.

The 1912 Peugeot was powered by a 7.6 liter inline four-cylinder engine with a bore of 110 mm. and a stroke of 200 mm.  This remarkably high bore to stroke ratio (1.82 : 1) allowed higher revolutions per minute than were previously possible.  In fact, the then high-revving car was capable of a whopping 2,200 RPMs (some accounts suggest 2,800 RPMs).  At this engine speed, Laurence Pomeroy estimated that the car would have conservatively put out around 130 brake horsepower (Peugeot claimed 175 bhp).  The car weighed a mere 3,100 pounds; it was rather nimble for its time.  Apparently, the designers made no effort to streamline the car; however, some streamlining was employed for record attempts at Brooklands in the spring of 1913.

The 1912 French Grand Prix.

The first major race that the 1912 Peugeot competed in, the French GP of the same year, was also one of the longest Grands Prix of all time.  It took place at the Dieppe Circuit, which was a triangular circuit between three cities totaling roughly 48 miles per lap.  The cars were to run 10 laps per day totaling a nearly 1,000 mile Grand Prix.  The only restriction for the Grand Prix cars was that they were limited to a width of 69 inches (1.75 meters).  In this era, the cars did not race head to head; rather, at this race, they were started in 30 second intervals.  Jules Goux, Georges Boillot, Zucarrelli, and Thomas comprised the Peugeot team.

Goux was the first Peugeot off the line at approximately 5:34 am.  He ran the first lap in 40:16; however, on time, he was ultimately slower than David Bruce-Brown (Fiat) at a blistering 37:18.  However, Boillot’s Peugeot was not much slower at 38:40.  Boillot made progress on Bruce-Brown on the second lap and Goux slotted into the third position.

Unfortunately, Peugeot’s fastest, Boillot had to stop on the third lap to repair a broken brake cable.  Goux also stopped, due to a hole in his fuel tank.  He refilled outside of the pits, and was consequently disqualified.  Boillot continued to struggle as he had to change both rear wheels mid-way through the fourth lap.  Zucarrelli, in the ‘third’ Peugeot, had to stop to replace a water house.  Overall, the engines themselves seem to have held up well through just shy of 200 miles of hard racing.

According to David Hodges, one thing was clear at the first day’s halfway point: the Peugeots and Fiats were closely matched.  After five laps, the Fiats were first, third, and fifth overall.  However, Boillot kept on fighting maintaining second place.  The crowd, who only saw a given car pass every 40 minutes, was excited to see Bruce-Brown (first) and Boillot (second) stop at the same time.  Boillot struggled to drop his car into gear while Bruce-Brown raced away in the lead.  About a minute late, Boillot finally initiated his pursuit behind another Fiat driven by Wagner.  Some race accounts suggest that Boillot had better top speed; however, Bruce-Brown commanded superior acceleration.  Other reports suggest that Bruce-Brown’s flying kilometer was at times faster than Boillot’s.  One thing is certain, dueling down the long straights, if only by time and not by direct competition,  they traded places a couple times  between the fifth and eighth laps.  The first day concluded with Boillot trailing Bruce-Brown by a few ticks over two minutes.

Georges Boillot winning the 1912 French Grand ...
Georges Boillot winning the 1912 French Grand Prix in Dieppe, France (Photo credit: Wikipedia)

The weather was not so pleasant on the second day.  A soft drizzle turned into sharp cold rain on the second day.  The water seeped into the Peugeot’s trick spark plugs and required changing before Boillot could get away.  Boillot was determined and soon caught sight of Bruce-Brown’s leading Fiat.  According to Hodges, “Boillot passed while the American [Bruce-Brown] changed a tyre at Criel, Bruce-Brown repassed as Boillot refilled.  And then the Peugeot passed the stationary Fiat at the bottom of Sept-Meules hill.”  Bruce-Brown had run out of fuel from a fractured pipe.  He scrounged up some Petrol, but was later disqualified for receiving fuel outside of the pits.  Sadly, Bruce-Brown was killed later that year practicing for a race in Milwaukee.

Wagner was behind the Boillot, the new leader.  However, as hard as Wagner tried to catch Boillot, he was unable to make up the distance he was behind.  Finally, Boillot was triumphant winning his home Grand Prix.  Thus, the Henry system was victorious on its first outing.

The 1913 Indianapolis 500.

Jules Goux, Indianapolis 500 Winner, 1913
Jules Goux, Indianapolis 500 Winner, 1913 (Photo credit: Wikipedia)

Two of the 7.6 liter 1912 Peugeot’s, linered down to 7.4 liters each, were sent for the 1913 Indy 500.  One was to be driven by Zuccarrelli, who did not have much success at the race; the other was to be driven by Jules Goux.  Going into the third edition of the famous circle track race, Goux had an edge.  While most continental Europeans had little experience with this type of track, Goux had spent considerable time in a 1912 Peugeot at Brooklands earlier that year.  He also received advice from an American driver, Johnny Aitken.

According to William Court, “Goux apparently decided to use a tyre of half an inch less diameter on the left (inside) front wheel though this did not do him much good as is bursts of leadership in the early stages were interspersed with stops for tyres after which ‘he was out of pursuit of the field at a terrible speed.’  The race was one of attrition, and the Henry system was continuing to prove itself a reliable model of engine.

Popular lore suggests that Jules Goux drank upwards of six pints of champagne throughout the race.  William Court notes that some accounts, including that of W. F. Bradley deny this, suggesting he was drinking water out of champagne bottles.  However, in a letter to one Peter Helck, dated November 2, 1963, Goux himself swore it was champagne.  Goux, therefore, was the first European to win the Indy 500.  Having won the race, it was back to continental Europe for the French Grand Prix, later that summer.

The 1913 French Grand Prix.

In slightly smaller form, a set of similar 5.7 liter Peugeot’s turned up for the 1913 French GP.  Zucarelli had previously been killed testing the car when it struck a cart.  Georges Boillot noted, “we lost not only a close friend but an engineer of considerable ability.”  Boillot and Goux were both back to pilot Peugeot’s at a much shorter track for an also shorter Grand Prix.

The 5.7 liter incarnation of the Henry system was consistent with the general trend of the day.  The huge displacement titans had become dinosaurs and were disappearing in favor of smaller, nimbler cars.  Yet, engineering such as that by Ernest Henry ensured rising power in spite of falling displacement.  In any event, the success of the Henry system at the 1912 French Grand Prix resulted in a substantially similar, albeit smaller, engine for the 1913 races.

The 1913 French Grand Prix instituted a new formula.  In a parallel to the current 2015 rules, the 1913 French Grand Prix race sought to slow the cars by limiting fuel consumption.  Fuel consumption was limited to 20 liters of petrol per 100 kilometers.  This required each car to run at least 14.12 miles per gallon.  Cars also had to weigh between 1,763 pounds (800 kg) and 2,425 pounds (1,100 kg) ‘dry.’

There were three early morning practice sessions.  These were largely devoting to fuel testing by the various entrants.  On race days, dense crowds were ready for the race at 5:00 am; however, the fog was even denser and caused the race to be delayed by a half-hour or so.  According to David Hodges, “At 5:30 visibility had improved somewhat, although the ‘yellow advertising balloons presented mere dim outlines in the sky,’ and the race was started.

After the first lap, Boillot was fastest and Goux was second fastest.  The gaps between the first three were increased during the second lap.  On the third lap, Boillot had to stop to fix a broken ignition wire.  This allowed Goux, in his Peugeot, to take over first place.  However, Boillot immediately put in the fastest lap of the race, thus far, at 16:15.  The fog began to clear and the morning progressed and lap times dropped consistently.  It soon became clear that only the Delages and Sunbeams could compete with the Henry-designed Peugeots.

By lap 12, Boillot had moved into second place, in spite of a stop for his riding mechanic to repair a “lubricant sight-feed” according to Hodges.  Just beyond half-distance, the order was Guyot (4:02:32); Boillot (4:03:51); and Goux (4:05:09).  However, on the next lap, Guyot gave the race over to the Peugeot’s when he ran over his mechanic.  According to Hodges, the mechanic had jumped out while the car was still moving.  However, the car was moving faster than he expected.  He was knocked down and run over.  “No bones were broken but Guyot had to lift him into the cockpit once he had changed the wheel and slowly complete that lap.”

Thereafter, there were essentially no changes to the order and Boillot won the French Grand Prix for France for the second year in the row.  Boillot had averaged 72.12 miles per hour over the course of the race.  His win made him a national hero of the day.  Goux came in a strong second.  Thus, the Henry designed inline four cylinder again proved its relative dominance over the large displacement titans that had come before.

In Conclusion.

Peugeot’s success with these cars was modest, as compared to the sheer magnitude of Ernest Henry’s impact on overall modern engine design.  It was Ernest Henry who proved that a smaller, more efficient engine could beat the huge-engined chain-driven titans that came before.   As just one example, the Offenhauser engine that was so dominant in American racing owes its fundamental design principles to those employed in the Henry system.  We may never know whether Ernest Henry was a mere draftsman or the driving force for the ideas.  However, before the age of 30, Ernest Henry forever altered the direction of motorsport engineering.

 

Works Relied Upon.

Court, William, Power and Glory: The History of Grand Prix Motor Racing, Vol. 1: 1906-1951 (1988).

Fox, Jack, The Indianapolis 500: A Pictorial History of the Greatest Spectacle in Automobile Racing (1967).

The Henry Affair, Motor Sport Magazine, 38 (July 1974).

Hodges, David, The French Grand Prix: 1906 – 1966 (Temple Press Books 1967)

Racing Car Evolution, Motor Sport Magazine, 3 (September 1942).

Wikipedia, Ernest Henry (engineer), https://en.m.wikipedia.org/wiki/Ernest_Henry_(engineer) (accessed November 5, 2015) (establishing the basic biographical details of Ernest Henry’s life.  This resource was used cautiously, and only in the absence of other sources, to identify the basic timeline of Mr. Henry’s life).

Pomeroy, Laurence. The Grand Prix Car Vol 1. S.l.: Motor Racing Publications (1954).