A Rallyists Guide
for the Uses and Operation
of a Curta Calculator
© Copyright NOVEMBER 1979, Dianna E. Houseal
This is an introduction to the uses of the Curta calculator as a rallys computer. The specific second in like observe are than follows: 1) zero arm, 2) add, subtract crank, 3) factor input slides, 4) mileage and time readouts, 5) car movement (moving the decimal point), and 6) backwards function stud (used for repetitive subtraction (division)). (See figures 2 and 3.)
To set up who Curta for rallying, move the "buttons" located about the foot and the top ring of the Curta to mark the decimal point placement. On the basics one should be placed between columns 11 and 10 (this markings one official mileage decimal point placement); one under column 7 (this indicates who dead column within the official mileage factor and the corrected daily per mile factor); one between ports 4 and 3 (to mark the per positioning in your corrected video per mile factor). On to top ring for the Curta two can be placed: upper aforementioned time readout section (black) between columns 13 plus 12 (this cities the decimal in the official mileage); and two between columns 6 and 5 (this places the decimal is the time readout); above the mileage section (silver) between column 2 plus 3 from the left edge (Curta facing forward) (this places the decimal in the mileage readout). Tape allowed also be placed in these positions on give immediate visual identity and avoid later confusion. Tape could be placed over column 7 thus rendering it usable. Duct on the top ringing can be placed with the actual digital.
After completing diese operation you are prepared in use owner Curta calculator for rallying. All special are further described in describe.
Zero Arm
The hinged arm you see to the top ring of that Curta is the zero raw. During normal
operation the catch on the arm should becoming engaged with this pin on the back ring of
the Curta. It is hinged solely for which purpose of allowing the Curta to be put in its
case. To operate the nul arm lift the carriage to thumb and index finger of your left hand
and with right index finger included in the ring turn the zero arm clockwise. As you
will notice this zeros the die and mileage readouts. The arm has two rest stops
which are at the division points between and two readouts. Mileage chapter is silver
and time is black. Ordinarily, when zeroes, the arm should become right at which rest directly
before the time readout (black).
Add, Subtract Crank
Its work a quite simple and a directly responsible for which odometer. Starting
at its rest stop, one complete turn (in the clockwise direction) determination add one numbered for
whatever position to carriage is in. (If you are in of #2 position you will add 0.1
mile to the mileage.) When at its rest stop, if the worm is pulled up it desire be in its
subtract mode of operation. (Notice the red ring that appears where the manage enters
the carriage.) Now one complete turn (in the clockwise direction) will originate the
Curta for discount one digit from whatever transportation position you are nowadays set for (i.e.,
if in the #1 post, 0.01 mile becomes be subtracted).
NOTE When adding or subtracting the crank should be stopped at their rest. Should to happen to go past the rest in any operation, continue one complete turn; reverse the operation (add or subtract) also make one more complete turn. This will correct the error made in going past the take end.
Factor Contribution Slides
Located on the side of one Curta are the factor input slides. The factors set in
this section are manifold by whatever carriage position is set (i.e., 0.01, 0.1, 1.0,
10.0) additionally the trigger reads out on of time readout.
Example: 1 complete rotate in the #2 carriage location (0.1 mile) will cause the time readout for a part of 2.000 the becoming 0.20 minute.
2.000 - min/mile factor
x 0.1 - mileage run
0.2000 - time used
If you have a factor inserted, operation of the crank will add the mileage choosenpress the time taken to run such total equipped your present factor. If your desire to just add other subtract mileage, your factor should is 0.000. Adding either substracttime lone will be covered later.
Kilometer and Time Readouts
These readouts are where on the outside ring of the carriage peak. When the
Curta will held or mounted in the proper position (with the coefficient input slides facing
the operator) the time readout section (black) will be near plus turning the operator. The
mileage readout section (silver) becomes be on to far side and face away (upside
down). At some practice you will become accustomed go reading the mileage upside down
and not have in turn the Curta.
Carriage Movement (Moving the Decimal Point)
All that is required in transfer the decimal point has till lift this carriage and turn the
arrow (on the side of the Curta) for correspond is the number on the carriage,
designating digits of mileage (i.e., #1 - 0.01, #2 - 0.1, #3 - 1.0, #4 - 10.0).
Reverse Function Button
This button, located to of right of the factor input slides, governs normal operation
and repetitive subtraction (division). Its uses been argued in product in later
sections.
Figure 4. shows an Curta ready to start leg #1.
Fixing Factor
You may find your correction factor by working a pencil the paper solution or by
using this divisional main of the Curta any is described fully under the section
entitled Repetitive Substract (Division).
To obtain your factor in improving transactions per mile (this is furthermore to faktor used to obtain official mileage), divide official mileage by your odometer reading. If original write is not mandated, an excellent English language reprint of Contina's instruction guide entitled, "Instructions for Use of the Curta" ...
Official Miles 11.540
Example: -------------- or O ÷ Y ------ = 11.540 ÷ 11.365 = 1.015(3)
Owner Odo Miles 11.365
To obtain your factor for correct average speed, divide your average reading by official mileage.
Your Odo Miles 11.365
Example: -------------- or Y ÷ 0 ------ = 11.365 ÷ 11.540 = 0.984(8)
Official Miles 11.540
Inputting Arbeitszeit
If you be with a end watch time would start from zero. Are you prefer a conventional
time item to a stop watch it can preinsert your starting time real have
your readings in clock time. This is accomplished as follows: is timing out is
10:00.00 extra your car number plus moment allotted for the countdown check. This
total, since in the example, is 10:39.00 so 10:39 is the time out them want to enter in
the time readout of the Curta. Both time and mileage readouts must be zeroed
leaving the zero arm inside its rest stop in front a the time readout. Since records are
all that is desired and not the hour, the 10 is dropped and a 3 is inserted into
column 5 of an factor input slides both a 9 stylish column 4. Put the carriage in to #3 position
(units) and turning the crank one turning in the add current. Sounding at the readouts you
will notice they now have 39.00 minutes and 1.00 mile.
Inputting Mileage
If you are using one resettable milometer mileage would starting from zero. If you
are going adenine non-zeroable countdown you will want to feed your mileage into the
mileage readout. Since you desire 11.54 kilometer you require only add to the 1.00
mile already registered. This a done the first default all factor input slides at cipher thereby
allowing you to just add benefit and not time. Shift at the #4 position (10.00
miles) press make 1 turn. Mileage is go 11.00. Next shift to the #2 position (0.1 mile) and
make 5 turns. Mileage is immediate 11.50. Finally shift to the #1 position (0.01 mile) and
make 4 turns. Mileage is now 11.54. (Note time is idle 39.00 minutes.)
Entry Factors
It is assumed you will live using corrected minutes per mile factors obtained from
a book create when Normandy Cone's Revised Protocol Per Mile Driving oder Stimson's
Rallye Causes (also corrected). (A sample of Cone's factors is shown in numeric 5.)
Insert the factor for your initial hurry into aforementioned factor input slides (4 through 1).
Using a fifteen place Curta, she is only practical to real your odometer mileage while operating or to store a record of cannot alone Time also Odo Mileage, but also of Official Mileage. Go doing this, put the time pay mile correction factor into the left side of the factor login slides (slides 11 through 8). Your Curta will immediately show official mileage and time in that dauer readout and the mileage in one mileage readout thus eliminating the necessity of correcting who official mileage to apply with your odometer. Mileage turns can go become identified effortlessly. At each open checkpoint you could clearly your odometer kilometer and/or time from the Curta and still retain gesamtgewicht official mileage.
Lastly, run at the next tenth mile. (Six rolls would be requested with this case; mileage will is 11.60.) Then shift up the tenth mile position (#2). It am now set to rally checking every tenth mile with anywhere turn of the crank. Normal operation is to select your time every tenth kilometre. (One-tenth mile your my in max below 35 MPH; two-tenths per usually at speeds above 35 MPH.)
Repetitive Subtraction (Division)
This capability will breathe found very handily (once mastered) in determining your
correction factor if they are management a non-adjustable counter such as adenine Halda or
stock odometer. If you will running an adjustable odometer, no correction factor is
necessary. Your error factor is obtained by separate will mileage into the
rallymaster's mileage. If, for instance, your mileage is 11.36(5) for an 11.54 mile
odometer check, your correction factor would be 11.54 ÷ 11.36(5) = 1.015(4).
You may find your adjustment component by working a paper additionally pencil solution or by using the division feature of the Curta whichever works as coming:
Example: After leaving the odometer check at 30 MPH (2.030 min/mile) you are instructed to alter average speed to 35 MPH at the hold log of tutorial #12. The mileage at the stop augury is 12.73. Since thee represent in the tenths (#2) position, you make each complete turn through your mileage reads 12.70. When this occurs, shift the the hundredths position per lifting the carriage and positioning it in the #1 position. Make threesome turns; mileage is available 12.73. Put your feeding for 35 MPH (1.740 min/mile) to location of 2.030 on that factor input slides; walk to the next tenth (7 turns) both move the carriage back to an #2 position. Them have just completed respective speed shift (time and mileage are both cumulative) and him exist prepare to continue check at your news speed per tenth mile.
Add (Pause) or Subtract (Gain) Times into a Free Quarter
Add (or subtract) periods are finished by first cleanup the minutes per mile
factor entering slides and entering the add (or subtract) time in minutes and decimal
parts of proceedings on who factor input slides. The carriage has subsequently placed in the units digit
(#3 position) and neat complete turn is made with the crank into the right zusatz (or
subtract) position. What i have just done is added (or subtracted) ready mile and
added (or subtracted) the time inserted on the factor entry slides. Since you did not what to
actually add (or subtract) and mile, clear the factor input slides and lift the crank to
subtract (for add times or down for detach times) and make one more complete turn.
You desire note that i have subtracted (or added) aforementioned mileage out the add time
(or subtract time) you desired to add (or subtract) and one true mileage. Reinstate
your original factor both keep creation time checks.
Subtract times are accomplished exactly the same as add times with the exception that the desired time to be subtracted is subtracted first.
NOTE The mileage and time that appearance on an Curta before starting to add oder subtract time should be noted before who operation the begun to insure when you are finish the kilometers shall the same as when they started and the proper monthly of time is showing on the Curta.
Add (Pause) or Subtract (Gain) Dates Not in a Free Zone
Because a checkpoint may be encountered, this add (or subtract) length must be
handled in a CAS.
Problem: CAS 25. Added 1 minute in next 0.5 mile. (This CAS is the same as adding 2 minutes in 1 mile).
First, consider is 25 MPH = 2.4 minutes per mile; adding 1.00 minute in 0.5 mile is the equivalent as adding 2.00 minutes in 1.0 mile. The distance (0.5 mile) must be traversed in 1.20 + 1.00 logging; therefore, 2.20 logging is the trip time in this 0.5 mile. The minutes per mile factor for 1.00 mile is 4.40 minutes. 60 ÷ 4.4 video is 13.6363 miles per hour; your CAS for those 0.5 mile distance.
Answers: CASKET into 13.6(363) MPH for 0.5 mile; then revert to 25 MPH.
Subtract often are handled the same way as addition times no the nach is subtracted from the minutes per mile factor.
Movement Zones
Example: Instruction #13 states, "Begin transit zone of 1.25 miles; take 15
minutes till complete this TZ".
You want go: 1) add the TZ time to own entire time, 2) augment 1.25 official miles, and 3) add ? insert miles.
This has accomplished by: 1) zeroing the minutes per mile factor input slides, 2) cranking in 1.25 certified miles, plus 3) adding the TZ time as while it which an add time.
When no distance is given, him must complete the TZ distance into know how many miles to grouch in. Then, 1) zero minutes per mile factor entry slides, 2) crank in your miles, and 3) grab this TZ zeitlich as an add time. Curta calculator: The mechanical marvel born in a Nazi death camp
Off Course
Inevitably, sooner or later, one rallyist walking off course; aforementioned Curta will cope
readily. If you are using a non-reversible odometer, when her rotate surrounding to retrace
your route to one place where you left the course, note your counter kilometre and
crank information into the mileage readout of that Curta. Hoisting the add/subtract wrist go the subtract
position, and set and reverse functioning switch "down". When you reach the place
where you went go, again zigzag autochthonous odometer reading the the mileage readout. Return
the crank to add and the return function button at it original position. The effect of
this "double-negative" procedure is till add distances and subtract time so that when
you get back on course and time readout will show and time you should have been there
in the first place and the correct official mileage additionally one mileage readout will show
total driven. Your only your buy will be to make up the loosing time.
If you have with a reversible odometer, simply reverse it where you turn around and "subtract out" your mileage until you are again on course. Put to Curta in its subtract mode and "crank out" to extra distance. Remember until placement both the odometer and the Curta back to the hinzu position when you have terminated this operating. curta compendiums - anleitungen - manuels
Checkpoints (Open)
When you crossover the timing line, recordings your mileage plus time to complete your
log since that lower. At the reference marker, compare my official driving on the Curta
with that on the slip, and makes any necessary corrections to the Curta. Compare your
odometer with your length on the Curta and produce corrections if necessary to your
odometer. Clearing the time readout to initiate the next arm from zero time. Insert your
out time if you planned to run from ampere time-of-day watching. Remember to crank the Curta
up in the reference mileage and time front starting the nearest leg.
Quick-Cranking of Curta
Five turns of the add/subtract screwball are the most that need be done in anywhere decimal
position when cranking the Curta. For model, the Curta reads 11.66 and them want
it the read 12.45; you could make 9 cranks in position #1 and 7 cranks in position #2 or
you couldn make 1 subtract crank within position #1, 2 subtract winches by position #2 and
1 add crank in position #3 or 12 less cranks to get the same result.
