April 2001
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One of the most versatile tools used by rallyists in the 1950s and 1960s was the Curta Calculator. Often called "The Peppermill" due to it's cylindrical shape and the crank on the top, this mechanical device had the advantage of being quite portable, and accurate to several decimal places. Before the dawn of the portable electronic calculator in the early 1970s, all serious rallyists used a Curta in conjunction with a 1/100th reading odometer such as a Halda Twinmaster or Tripmaster.
Curta Type II. Ray traced image by John Cherry. The Curta Calculator was invented by Curt Herzstark, an Austrian whose family business was the manufacture of calculating machines under license. He received the original patents in 1938, but manufacture did not begin until after WWII, in 1947. It was built by Contina Ltd., of Vaduz, Liechtenstein. The larger Type II went into production in 1954.
There were two versions of the Curta Calculator, known simply as the Type I and Type II. The Type I, the smaller of the two, has an 8-place setting register, a 6-place indicating dial, and an 11-place answering dial; the corresponding capacities of the Type II are 11, 8, and 15.
The Curta came in a special shock-resistant carrying case, originally made of stamped metal. Later versions had a plastic case. Both opened with a clockwise twist, the reverse of opening jars and most other cylindrical containers. The reason had to do with protection of the crank mechanism. Consequently the opening instructions were printed on the outside of the case.
With the growing popularity of Vintage Rallying, the Curta is again in demand. They may often be found on eBay, generally selling for about $600 to $700, though prices vary depending on condition and associated goodies such as the original box and literature. A very early Type I in excellent condition recently went for over $1300.00.
Listed below are links to several pages on how to rally with a Curta. There are also links to the online Museum of HP Calculators and The Curta Calculator Page and Registry.
- The Curta and You by David Hebb & Arthur Peck
- Rallying with the Curta Calculator from Stimson's Rally Factors
- A Review of CURTA Techniques for the Rallyist - Peppermill Potpourri by John B. Burns
(as published in Sports Car magazine, February, 1961).- The Curta Mechanical Calculator by Jim Bianchi
(as published in rallye magazine, March, 1976).- The Museum of HP Calculators - Significant non-HP calculators.
- Curta Calculator Site and Registry - The best source of information on the Curta and its inventor Curt Herzstark. Includes a Registry of Curta owners around the world.
- A Rallyists Guide to use of a Curta by Diane Houseal