Y A C S    2 . 0
Yet Another Curta Simulator 2.0

SIMULATION

Background color

Cover type

Cover mode

Exploded view

Show or Hide Parts
Toggle









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OPERATION

Cranking

Carriage position

Adder mode


Turns Counter mode


Clearing



ABOUT YACS

Help and Information




Comments and Suggestions

info@satadorus.eu

Contributions via Paypal
VIEWING  YACS

Rotate
Drag with mouse button pressed
Pan
Drag with center mouse button pressed
Zoom
Use mouse scroll wheel
Zoom in to inspect a part
Double-click on it
keep Double-clicking it to get closer
View preset Viewpoints
Right-Click in the 3D window and select Viewpoints
Use Page-Up / Page-Down keys
Home-key selects first viewpoint
End-key selects last viewpoint
Run the Simulator
Click the Buttons or
use keyboard Shortcuts
More information
Hover the mouse over the controls in the panels for pop-up hints
Right-click in the 3D window for a pop-up menu
USING  YACS

Operating the Curta Simulator

Setting a number
Setters
Drag the slider up or down with mouse button pressed.
Here 163 is entered on the setters.
Turning the crank
Crank handle
Click the crank handle to start a crank cycle.

The higher you click on the handle the faster the turn.

Speeds are 1, 3, 9 and 27 s


Extending the clearing Lever
Clearing Lever
For easy use the clearing lever can be extended.
Click any part of the lever to extend it.
Folding the clearing Lever
Clearing Lever Position Plunjer
The clearing lever must be folded to store the Curta in the storage container.
Click the clearing lever position plunger to fold the lever.
Clearing CCW Very Slow
Clearing CCW Very Slow
Click on any of the 4 colored section of the clearing lever ring to start a clearing action
Here we start a Very Slow Clearing Counter Clockwise (CCW))
Clearing CCW Very Fast
Clearing CCW Very Slow
Click on any of the 4 colored section of the clearing lever ring to start a clearing action
Here we start a Very Fast Clearing Counter Clockwise (CCW))
Toggle the main mode between Addition and Subtraction
Adder mode is ADD
Click the Crank handle to toggle the adder mode between Addition and Subtraction.
Here the adder mode is Addition
Toggle the main mode between Addition and Subtraction
Adder mode is SUB
Click the Crank handle to toggle the adder mode between Addition and Subtraction.
Here the adder mode is Subtraction.
Note the red ring under the crank handle to indicate Subtraction mode.
Set Turns Counter mode to Increment
Turns Counter mode is Increment
Drag the Reversing Lever up for Increment mode.
Set Turns Counter mode to Decrement
Turns Counter mode is Decrement
Drag the Reversing Lever down for Decrement mode.

Rotating the Carriage with the cover visible
Carriage rotation with Cover Visible
Click on the digits 1..6 on the underside of the carriage.

Rotating the Carriage with the cover removed
Carriage rotation with Cover Removed
Click on the shaft to rotate it to the x 1 position.
Calculating 12345 x 298

Calulated as: 12345 x 298 = 12345 x 300 - 12345 x 2
This way only 5 crank turns are required.
Set 12345 on the Setters

Set the carriage to the x 100 position


Crank 3 times to caluclate 12345 x 300

Set the carriage to the x 1 position

Set the Adder mode to Subtraction

Crank 2 times to caluclate 12345 x 298
Done...


12345 x


298


= 3678810


ABOUT  YACS

Current Version
VRML: loading...

Why did I do it

For two main reasons:

My first exposure to the Curta was when a teacher showed us a Curta in our classroom.
It really was an amazing little machine. We were each allowed to do one easy calculation on the Curta.

That was early 1964, not long after JFK was killed in Dallas. The Royal Dutch Air Force crashed an F 104 Starfighter every few months and there was Robot Archie, a fictional comic character known in the Netherlands as Archie de Man van Staal.

Yes:

In the past everything was better... even the future.

...
>> Fast Forward 44 years >>
...

After searching the Internet for a while I discovered that it was called a Curta.
The good thing is that there is plenty of information on the Curta.
The bad thing is that they are now collectable.

Not willing to spend 1000+ dollars on the real thing I decided to build my own.

Because I do not like to get tired or dirty I soon settled for a virtual one.

I already did a few things in VRML, so it was a logical choice to use it for the Curta.
VRML 2.0 allows for basic animations, and for more complex things you can use JavaScript Nodes.

All you need is a PC, and a little time :-)


How Was It Done - The YACS Classic edition for BS Contact - 2008

To get things done I decided not to

but

and

At first I used a lot of information from the Internet and a set of drawing of the outside of a Curta I from Rick Furr.
A lot of information came from the Curta Disassembly.

When I had the basics in place I mailed Rick Furr the owner of The Calculator Reference a splendid website with a large section on the Curta with a request for some measurements.
Over the next months I received every measurement I asked for and lots of suggestions too.
Rick measured many of his Curta parts and also sent photographs of all the details.

From then on it was a matter of stepwise refinement

and the result is


How Was It Done - The version for X_ITE - 2020

Now that the BS Contact viewer is no longer available for free download it was time to move to another viewer. The X_ITE viewer works with WebGL and works on most modern browsers.
It is free, there is no flying saucer and it doesn't expire.

Best of all there is nothing to download and install.


Thanks and Curta links

Rick Furr is the owner of The Calculator Reference a splendid website with a large section on the Curta.
He measured a lot of Curta parts, tested the model and mailed a lot of suggestions and photos.

The Posters you can order on his page are a must have for every Curta Collector.

For my daily reminder that a Curta simulation is a completely pointless exercise.
No better motivation to continue!
Imagine that it was a real project... With meetings, a plan, reviews and a boss...

But to be fair, he certainly had a few perfect suggestions. When I find time...

For proof reading everything and finding 28 errors in 8 files.
Build your own

Over the years I received several mails requesting to use the files of YACS for 3D printing projects.
There are several reasons why the YACS files are NOT a good starting point for a 3D Curta project.
The original Engineering Drawings

A full set of the original engineering drawings for the Curta Calculators is available thanks to the curator of the MuseumMura in Mauren, Liechtenstein.

To download the drawings


Comments and Suggestions

info@satadorus.eu

Contributions via Paypal
ABOUT  THE  CURTA

For a splendid explaination of the inner workings of the Curta watch this video