On cars, old, new and future; science & technology; vintage airplanes, computer flight simulation of them; Sherlockiana; our English language; travel; and other stuff
RECENTLY IT was May 22, 1949, and I was listening to an ad for Ford Overdrive. (Such are the wonders of Sirius XM and its Radio Classics channel 82.) Despite six decades of age, this and other automotive ads from the period prove surprisingly timely in their technicalities and appeal.
To put things in perspective, the 1949 Ford was the biggest change to come out of Dearborn since 1927 when the Model A replaced the Model T. The ’49 model had “Hydra-Coil” independent front suspension (a first for Ford) and “Para-Flex” longitudinal leaf springs at the rear.
Engine choices were a 95-hp inline-6 or 100-hp flathead V-8. The only gearbox was a three-speed manual with column shift (“three on the tree,” as opposed to “four on the floor”). Ford’s first automatic transmission didn’t come until 1951.
Prices of ’49 Fords ranged from $1333 to $2199; in today’s dollars, $12,995 to $20,595. And, strictly speaking, the base three-speed wasn’t the only choice. For $97 (today’s $943), there was the optional Overdrive.
This Overdrive was an electrically actuated Borg-Warner planetary gearbox residing directly behind the three-speed transmission. At a car speed of 60 mph, Overdrive gearing gave engine speed of only 42 mph. Noted one ad, “It accents the new Ford ‘Feel’ while it saves you gas, saves your oil and saves your engine!”
The ad went on to describe Overdrive operation, albeit in rather exclamatory style: “Let up on the gas pedal above 27 miles per hour and a miracle happens! You’re in fourth gear for cruising! Engine speed drops 30% while the car speed remains unchanged! The Ford Overdrive seems to give your car wings, it’s so smooth, so quiet and so free of vibration!
“And should you require a burst of extra power, simply press through on the accelerator and you return to conventional third gear. Just as simple as that!”
There were technical aspects as well: “You’ll call it a ‘tip-toe miracle.’ Engineers call it a ‘simple automatic planetary transmission, combined with the regular three-speed transmission as a single unit.’ ”
Another feature of the Overdrive at speeds less than 28 mph was its lack of engine braking; that is, its freewheeling. Folklore had Overdrive coasting at higher speeds as well, but specialists say this didn’t occur in a properly functioning unit. The Borg-Warner Overdrive operated automatically, but also had a manual lockout by means of a cable-operated underdash control.
Ford and others continued offering overdrive options into the 1970s. By then, however, four- and five-speed manuals as well as automatic transmissions obviated the need for such auxiliary gearing.
A similar overdrive, the Laycock de Normanville unit, was offered on lots of the era’s British cars as well as on Volvos. Another planetary (also known as epicyclic) design, this one was devised by Edgar J. de Normanville, whose name conjures up a wonderful image of 1066 and the Conquest. ds
© Dennis Simanaitis, SimanaitisSays.com, 2012