They had loads of torque and allowed fine control of speed
What’s your mental picture of a steam engine? Something big and heavy? Burns coal, spews clouds of black smoke, takes a lot of goading to speed up, and even then does not go very fast? You would probably put it at the head of an old train or above a flooded mine, or in the belly of a ship.
That’s an accurate picture, but not the only one in the steam engine album. What most of us do not know or remember is that steam engines were also used in cars. They were very popular till about a century ago, and they had qualities that made them suitable for not only pottering about streets but also serious adventuring. They could do what gasoline and electric vehicles couldn’t until the invention of four-wheel drive, and it would not be wrong to say that steam cars were the first SUVs without any of the complicated mechanicals that later vehicles of that class required.
Let us go back to our mental picture of a steam engine. Big and heavy? Look at these specifications of the entrants in a 100-mile endurance run organised by Automobile Club of America (ACA) on May 31, 1902. The cars had to drive from New York to Westport and back. Cars in the top half of the list had gasoline engines, and the heaviest weighed 2,600 pounds while the heaviest steam car weighed only 1,650 pounds (748 kg), which is lighter than a Suzuki Celerio sold in India.
Slow and lethargic? Here’s another list showing the results of ACA’s speed trials on Staten Island on the same day. The 10-HP Locomobile (steam engine) of S T Davis, Jr, covered a mile from a standing start in 1 minute and 12 seconds to finish a very close third. Notice that it was just a second behind the 24-HP gasoline Panhard.
Steam cars had excellent acceleration for that era because they delivered loads of torque from standstill. Check out this Jay Leno video of a 1925 model Doble E-20 that produces 1,000 foot-pounds (138 kg-m) of torque from rest. Bugatti Veyron Super Sport makes 1,500 Nm or 1,106 foot-pounds of torque at 3,000–5,000 rpm.
As for shovelling coal, steam engines made for cars were oil burners. Oil was light, could be carried in a tank, injected into the burner at high pressure for quick heating, and burnt (relatively) cleanly. The boiler in these cars was not a tank sitting on a flame but a very long coil of tube to maximise the surface area exposed to the flame.
How long was the tube? “The flash boiler, which in the 6-HP car is formed of 100 metres of tube of varying bore, is placed beneath the bonnet forward of the dashboard. The burner, which consumes ordinary paraffin, being contained within the asbestos lagged (insulated) metal case enclosing the boiler tubes.” That’s a description of the boiler used in a Miesse steam car.
Modern boilers could be retrofitted in old cars, as this 1902 ad promising 220 pounds of steam pressure in “2 minutes 15 seconds from cold water” shows.
How does all of this make the steam car an SUV? If you had to go off-roading in the early 1900s, some place where the slopes were steep, the soil loose or boggy, or a combination of both that might be called treacherous, you would want something that could progress really slowly without slithering at every turn. A steam car could do that better than the other automobiles of the day.
It was a time when American trendsetters were buying “secluded country estates…to cultivate hereafter the charm of a pastoral life, mitigated by the frequent use of automobiles for long excursions and touring.”
What they needed were cars that could tour over “rough country roads or virgin ground…where roads give out entirely, where gullies must be crossed or streams forded, or the path must be carefully picked between large boulders.”
Steam cars fit the bill because of the “infinite gradation of which steam power is capable… Few would venture to approach the edge of a precipice without having the assurance which steam affords, of ability to go as slowly as a snail, and of shutting the power off entirely at any second and without muscular effort or fear of a clutch seizing, or binding a trifle more than anticipated.”
Gasoline cars did not inspire the same confidence. “In crossing a Kansas ravine, how would the speediest and most perfectly obedient gasoline vehicle be situated after perhaps safely reaching the trough in the bottom, but then required to pick its way slowly up the slanting and rough incline on the opposite side?”
The writer was not blind to the advantages gasoline cars had over steam cars, “especially in fuel economy”, but if you had to go rough-roading on four wheels, only a steam car would do.
Here’s another great video of a steam car to help you chew over that.