Simanaitis Says
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JAGUAR XK-120—LEAPING BEYOND 120 MPH
THE 1948 EARLS COURT Automobile Show was Britain’s first after World War II. The country had yet to evolve from wartime austerity: Cars were fueled by 70-octane “Pool petrol.” Chocolate was still rationed. But the 1948 motor show was filled with new designs, many styled after and with aspirations for the American market.
The star of Earls Court was the Jaguar XK-120, the company’s first sports car since prewar discontinuation of the SS Jaguar 100. The SS moniker traced back to the company’s origin in 1922 as Swallow Sidecar.
The XK-120’s designation identified its show car nature, introducing the company’s all-new double-overhead-camshaft inline-six, and the car’s capability of reaching 120 mph when many cars topped out at little more than half that.
An XK-120 Time Capsule. Here are tidbits from R&T, September 1961, when the magazine abstracted material from its 1951 assessment of the Jaguar XK-120.
This and other images from R&T, September 1961.
“The Jaguar XK-120,” R&T wrote, “has proven to be extremely popular in the U.S., but there are those who have questioned its high-speed ability. For this reason, we were particularly anxious to obtain an accurate top-speed figure.”
Jabbeke Highway, 1949. Indeed, back in 1949, Jaguar took the second XK-120 built, a white left-hand-drive version, to the Belgian autoroute between Jabbeke and Aalter, closed for the occasion. Wikipedia writes, “With hood and sidescreens erected, and the airflow under the car improved by the addition of a full-length aluminum undertray, the Jaguar was timed through the flying mile by the Royal Automobile Club of Belgium at 126.448 mph.”
The Jaguar XK-120, chassis 670002, at Jabbeke Highway, May 30, 1949. Image from stevemckelvie.wordpress.com.
Wikipedia continues, “With hood, sidescreens and windscreen removed, a metal airflow deflector fitted in front of the driver, and a tonneau cover fastened over the passenger side of the cockpit, the speed improved to 132.596 mph. The Observer’s Book of Automobiles said it was the fastest production car in the world.”
R&T’s Desert Test, 1951. “Our test car was completely stock,” R&T reported in 1951, “with no engine alterations, underpan or tonneau cover, and used the standard 3.64:1 rear axle ratio. However, we did remove the windshield and fitted an ‘aero screen’ (optional extra), a concession to performance which resulted in both the driver and photographer turning a deep blue in the morning desert cold. It was necessary to make numerous runs to obtain the figure we felt was optimum for the car.”
And you thought R&T testing was all beer and skittles.
R&T wrote, “At 123 mph (there were two men in the car during the runs), the Jaguar had a steadiness usually associated only with race cars, and occasional gusts of wind had very little effect on its stability.”
It can be added that R&T testers upped the top-speed ante considerably in 1956 with another Jaguar, the D-Type. It was closer to home, 162 mph on a two-lane road through an orange grove in, appropriately enough, Orange County. ds
© Dennis Simanaitis, SimanaitisSays.com, 2020
Simanaitis Says 
I assume that the 120+ mph performance was achieved with better than 70 octane fuel, or otherwise that performance would be all the more remarkable.
Later in the piece where you mention that cross winds had little effect on stability reminds me of a “communications” person hired by my previous employer who had difficulty with choosing effect/affect appropriately. She wrote an article in the monthly newsletter about some new cost saving procedure where the hours spent for a given deliverable were reduced significantly, and she concluded the article with something like “and this new procedure is executed without effecting quality”. Sort of the opposite of what she was trying to say.
I was not suggesting that your usage was incorrect, just that the word “effect”, correctly used, reminded me of the communications person, who didn’t know the difference despite her professional title.
That is, “Eschew being affective about one’s effectiveness.”
No roll bar? I bet the R&T test people were shaking with fear as well as blue with cold. Beautiful car, though.