Anyone used a Curta?

Oh, boy, does that name bring back memories. I used one in sports car rallies during the '60s. Most clubs had a separate class for people who used Curtas. They were considered to be an unfair advantage against those who didn't have them.

Ed Huntress

My brother bought one to go with his Porshe 914 and it's sitting on the bookshelf next to me. I traded him something for it after the cheap 4-function calcs came out in the mid 70's. Even though they are fetching about $700 on ebay, I can't bring myself to part with it. A very cleverly designed and implemented device.

Heck, I still have one. If I turn my head about 45 degrees to the left, it is sitting right there in its case. I bought it from a rallie nut who upgraded to the larger one. I used it in control system labs at MSU to supplement the sliderule. With all the arithmetic it took to get those labs running, I needed the additional digits to keep round off error from driving me nuts. Nedra remembers when we bought it, it was a "major" purchase in those days of me being a starving student with a wife and two kids.

They are about the best built article I ever owned.

Fitch

You aren't one of those guys who used to quick-draw their sliderules in Anthony Hall around 1966, are you? If so, you contributed to my changing my major from engineering.

Ed Huntress

Never used one but use to "drool" over the pix and articles about them when I was into Sports Car Rallys. In the late 50s and 60s. I just used a home made .001 mile odometer and stop watches with a circular slide rule. Those were the days. Sighhhh. :-) ...lew...

I've still got a "small" Curta from my sports car rallying days. (I sold the "big one" I also had when I got bored with rallying.) I built a "Curta cranker" around 1960. The cranker had a small dc motor in it with a single stage worm gear reducer, a cam operated microswitch and a latching relay It was triggered every hundreth of a mile by one of those speedo cable mounted cam/microswitch units some folks used to run 12 volt Veeder Root counters as odometers reading to the hundreths of a mile.

The cranker zipped the Curta around one turn every hundreth of a mile, It has an overunning roller clutch in it which let me crank the Curta by hand without removing it from the cranker.

Setting into the Curta the right "factor" (minutes per hundreth of a mile) for the average speed you were trying to hold caused it's "display" to display the correct elapsed time for the distance traveled. I got pretty good at comparing that reading to a stopwatch and telling my first SWMBO (the driver) whether to speed up or slow down. Woudja believe the "sports car" we rallied in was a big assed red '55 Chrysler convertible? But, I've still got a boxfull of trophies somewhere in the basement as evidence that you didn't need to drive an MGA, a

I just grabbed my old Curta off the bedroom closet shelf and struggled to open the screw top of its two piece case for about 30 seconds before I remembered that the damned thing had left hand threads, so you wouldn't accidently drag the Curta's crank forward when opening the case. Other than a 3/4" hole in it's bottom plate through which my cranker twirled its guts, The Curta still looks and works like new.

Thanks for the memories.

Jeff

I do remember those from when I was in High School. They were the absolute top of the line mechanical calculators around, and probably still are today. No better mechanical calculator was ever made. We would drool over them, but could never afford one. The best I ever had in high school was a slide rule.

The Curtas now fetch over $600 on eBay.

I had the same experience not 20 seconds ago!

Fitch

You guys are really dating yourselves here! And I thought I was old at 51!

Lane

There is one just finishing up on Ebay for $1700, comes with a Floyd's Factors book also. Greg

Not in this group, dude. Remember, the average age of a tool and diemaker in the US is now 58, and climbing fast.

Ed Huntress

Jeff Wisnia wrote: (clip) Woudja believe the "sports car" we rallied in was a big assed red '55 Chrysler convertible? But, I've still got a boxfull of trophies somewhere in the basement as evidence that you didn't need to drive an MGA, a 190SL or an XK6 to win rallies.(clip) ^^^^^^^^^^^^ Those were the days. I used to do pretty well driving a VW bug with a Judson blower, and one Michelin X tire on the left front (the odometer drive wheel.) In those days steel belted radials were not the norm, and without them, your measurements were subject to an additional correction for tire expansion.

We had a big binder full of computer generated tables of "minutes per mile" for every conceivable "odometer correction factor." Do you remember that? The rallymaster would lay out about a ten mile odometer calibration leg at the start of the rally, and each car would have to allow for any difference in tire circumferemce from the rallymaster's.

And, do you remember all the trick instructions which were designed to lure you into a trap and make you late (or early?)

Reminds me of Boris Hagelin's M-209 code machine (called here Converter M-209). Beautiful stuff.

Regards,

Marv

Karl Pears> This month's Scientific American has a great article about the Curta

Of course, that number will start to go down again, at some point. :(

Jim

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Yes - but they'll all be Asian.

Regards,

Marv

jim rozen wrote:

Probably not for a while. With the number of new young T&D men entering the field being less than replacement, the average age for the group could continue to increase until the group size reaches zero.

Gary

But as long as there is one young buck out there, the

Jim

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IIRC we used a purchased book of tables, I think it wuz titled, "Floyd's Factors"

Yep..

Remember 'em? Heck, the then SWMBO and I burned up lots of midnight oil trying to think them up whenever we got tasked with being "rallymasters".

The only one like that I can still remember was an instruction we put in near the end of a rally wherein we told the navigators to change to a new speed and then exponentially increase that speed so that by the time they had gone some specified distance they would be traveling at a higher specified speed. We had people sweating and busting their nuts trying to figure that one out all through the rally. When they got to the next to last checkpoint, which was just prior to that instruction, they were handed a note reading, "Disregard Instruction No. xxx."

Jeff

-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."

Ah, the old "pepper-mill" rallye calculator!! Many of the crews I ran against worked the Curta - but my brother and navigator had an HP programmable calculator that made life a LOT easier.