NavLog 1.1
Aircraft Navigation Aid



































(c) 1992 Scott MacLean
NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


Thank you for trying NavLog! This is the first aviation-related
program I have written, and if the response is generally good, it will
be the first in a series. I have written NavLog to be easy to use for
pilots, who are not necessarily computer experts. To this end, NavLog
utilizes a GUI (Graphical User Interface) and for that reason requires
that you have:

- A VGA card and monitor, either color or monochrome
- A Microsoft-compatible mouse

NavLog will refuse to run if either of these hardware items is
missing.


History Behind NavLog

When I began flight training, I was intrigued by the use of
analog "whiz wheel" E6B computers in solving time/speed/distance and
wind correction problems. I figured that anything an analog computer
could do, a digital computer could do better. I started making cross-
country flights, each one requiring a full navigation log. These logs
took a long time to calculate and fill out, and errors crept in very
easily. The same calculations were being done on each line, over and
over again. The complexity and repetition of the procedures caused
something to click in my mind: numbers, repetition - this task was
crying out for computer automation! I did some research and found a
book called "The Axioms of Flight," by James Embree. This excellent
book describes the formulae used in aviation, with full explanations
and developments for each one. This book helped me develop some of the
formulae used in NavLog. I also had some assistance from David
McKeehan. David is an engineer and a fellow aviation nut from Houston
Texas who helped me with some formulae and beta-testing.

NavLog began as a small character-driven program which allowed
you to input some numbers, and it would output some other numbers. It
soon became apparent that there just wasn't enough space on an 80 by
25 character screen to fit all the data that was required. The next
step was to utilize the high-resolution VGA screen, and the font
capability of Microsoft Basic 7.1 PDS. It only made sense at this
point to use the mouse as an input device, so mouse support was added
as well.

Once the basic version of NavLog was operational, I started ad-
ding other things. Calculation of pressure and density altitudes, cal-
culation of true and calibrated airspeed, and more. Time, speed and
distance to climb calculations were added from data gained from the
pilot's operating handbook of the Cessna 152 and Cessna 172. I will
add more airplanes to NavLog as I fly them!

Finally it was time to test NavLog and find the bugs. David
helped by running it on his Compaq laptop with a math coprocessor. (By
the way, NavLog WILL use the math coprocessor to speed up calculations
if one is installed.) When I was happy with NavLog, it was time to
release it, and that is what you are looking at right now!


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NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


Using NavLog

When you first start NavLog, you will be shown an introductory
page. When you have finished reading this page, NavLog will build it's
worksheet grid. You will notice that NavLog sets up the grid to look
just like a standard aviation navigation log. Notice that some boxes
are lighter than others. You are allowed to modify the numbers in the
light boxes, while NavLog calculates the numbers in the dark boxes.

To begin using NavLog, move the mouse pointer to the box which
you wish to alter. As you move the mouse, the mouse position indicator
on the right hand side of the screen will tell you the name of the box
that the pointer is on. For our example, we are going to create a log
for a fictional trip from Macon, Georgia to Dublin, Georgia. To begin,
point to the first "Checkpoint" box and click the mouse button. A cur-
sor will appear in the box, and you will be allowed to type whatever
you want. Type "Macon" in this box, and press RETURN to get the mouse
pointer back. In the second box, type "Top of Climb," in the third
type "Large Road" and in the fourth, type "Dublin Airport." The check-
point boxes do not have any effect on calculations (at this point,
anyway), so you may type anything you wish in them.

Next, we will need to know what altitude we will be flying at.
Move your pointer to the first altitudes box and press a mouse button.
On the right side of the screen, you will see NavLog asking you for an
indicated altitude. Type 3500 (this will be our cruising altitude),
but do NOT press RETURN. If you press RETURN at this point, the indi-
cated altitude of "3500" feet will be put into this box. Instead of
pressing RETURN, press and hold the "ALT" key, then press the "A" key
(for "All"). This will cause NavLog to insert "3500" into every al-
titude box downwards. This same "ALT-A" feature works for every box on
the screen except for the checkpoint box.

You will notice that there are actually three altitudes: Indi-
cated, Pressure and Density. You are always typing in the Indicated
altitude. NavLog will automatically calculate the Pressure and Density
altitudes according to the temperature and altimeter settings you have
entered. Enter the temperature in FAHRENHEIT only, in the "WIND"
column. The altimeter setting for each line is in the third column
from the right, under the "estimated groundspeed" boxes.

Next, we need to enter the wind direction and velocity. Typi-
cally, this will be taken from a DUAT or other aviation weather
report. On the first line, enter the SURFACE winds for your departure
airport. In the remaining wind boxes, enter the "Winds Aloft" data for
your cruising altitude. Similarly, the temperature in the first line
should be the airport's surface temperature, and the remaining tem-
peratures should be the winds aloft temperatures.

The CAS/TAS column has an automatic calculation feature. If you
enter a CAS value, NavLog will calculate the TAS value, and vice
versa. This feature only works properly if you have already entered a
proper altitude, temperature and altimeter setting for that line.



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NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


The next column is "TC," for True Course. Enter the course you
plotted on your sectional chart here. For our example, the course is
103. Notice that NavLog will automatically calculate the wind correc-
tion angle to get your "TH," or True Heading. Next you need to enter
your magnetic variation. Remember, East is Least and West is Best.
This means if you are entering an east deviation, enter a negative
number, and if you are entering a west deviation, enter a positive
number. NavLog will calculate your "MH" from this, or Magnetic Head-
ing. Lastly, enter your compass deviation. This is taken from the com-
pass correction card in your airplane. It will be added or subtracted
(depending on whether you enter a positive or negative number) from
your MH to get your "CH," or course heading. This is the number that
you will actually steer in your airplane when flying the trip.

In the next column, you will see the "Distance" entries. Enter
the distance between checkpoints in each applicable box. NavLog will
calculate the total distance, and the remaining distance after each
checkpoint. If you have entered a TAS or CAS, NavLog will have calcu-
lated an estimated groundspeed. If you have entered winds and courses,
NavLog takes these into account when calculating the estimated
groundspeed. If NavLog has calculated a groundspeed, it will also have
calculated an estimated time enroute value. This time is in hours and
minutes, and is the time estimated for each leg. At the bottom of this
column is a total time value, which is also shown in hours and
minutes.

Lastly, we move onto the fuel column. At the top of the column,
enter the number of gallons your aircraft burns each hour at cruise
setting. At the very bottom of this column is the total usable fuel
your aircraft is loaded with, in gallons. (Obviously if you are carry-
ing less fuel due to weight restrictions, enter the actual amount of
fuel on board here.) Once these values are entered, NavLog will calcu-
late the amount of fuel used in each leg, and the amount of fuel
remaining at the end of each leg. If your trip uses more fuel than you
are carrying, NavLog will show NEGATIVE fuel remaining, flagged with
small asterisks (**).


NavLog Functions

On the far right hand side of the screen are seven functions.
These functions are activated by moving the mouse pointer on top of
them and pressing the mouse button.

SAVE/LOAD

SAVE and LOAD are fairly obvious - they simply save and load your
current worksheet. Standard eight character filenames are used. A good
idea is to use airport identifiers. For instance, for a trip from
Macon to Dublin, you could call the file "MAC-DBN" or something
similar.





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NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


PRINT

NavLog will print your navigation worksheet on any Epson com-
patible printer. No fancy high-density, high-resolution graphics are
used, just the basic EPSON graphics commands. This should make NavLog
compatible with most printers on the market. To abort printing, press
the ESC key.

INFO

Info displays a small screen with some extra information on the
program, as well as some credits. Press any key (or a mouse button) to
return to your worksheet when finished.

CALC

You may turn the auto-calculation functions of NavLog on and off.
This applies only to horizontal calculation. Vertical calculation
(such as calculating total fuel remaining) is still done. Remember!
Whenever the CALC flag is dark, no calculation is being done! For nor-
mal usage, this flag should be on.

TYPE

This button is covered in the next section.

QUIT

Quit means what it says: Quit to DOS. To ensure that it isn't
selected in error, you must press BOTH mouse buttons simultaneously
while selecting QUIT, otherwise it will not work.


Time/Fuel/Distance to Climb

The last, and most useful function of NavLog is its ability to
calculate the time, fuel and distance required to climb to cruise al-
titude from takeoff. Because this involves complex calculations and
interpolation based on specific data obtained from an aircraft's POH,
each aircraft has to be specifically written into the program. At this
time, NavLog supports the Cessna 152, 172, Piper Arrow III and Semi-
nole.

To switch between the different aircraft datasets, select the
"TYPE" button on the right hand side. You will notice that the
aircraft identifier on the bottom of the screen will switch from one
identifier to the next and back again each time you select "TYPE."

To activate the time/fuel/distance to climb function, we have to
alter the name of the first checkpoint. First, we must know the field
elevation of the departing airport. Enter this elevation between two
slashes, followed by the airport name. For instance, Macon is at 463
feet. Therefore, it would be entered as "/463/Macon." When NavLog sees
that the first checkpoint consists of a number enclosed by slashes, it
will recalculate the first line automatically, based on a climb from

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NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


field elevation to cruising altitude. It will calculate the time re-
quired, distance travelled and fuel consumed (including manufacturer
recommended values for run-up and taxi). See the bottom of this docu-
ment for technical information relating to these values.


Files

This is a listing of the files which are supplied with NavLog,
and what each one does:

NAVLOG.DOC This file
NAVLOG.EXE The NAVLOG program itself
HELVE.FON Font file for NAVLOG
TMSRE.FON Font file for NAVLOG
CLEAR.CP "CLEAR" worksheet
CLEAR.NVG "CLEAR" worksheet

Both .FON files must be present in order for NAVLOG to run. When-
ever a worksheet is saved, two files are created: a .CP file and a
.NVG file. The .CP file is 607 bytes long, and the .NVG file is 1111
bytes long. Both files are required in order to load the worksheet
again. The "CLEAR" worksheet which is supplied is simply a blank
worksheet which can be loaded to clear out any existing worksheet.


Conclusion

Used properly, NavLog can replace the tedious job of calculating
navigation logs by hand, using primitive analog computers, and follow-
ing hard-to-read charts in the POH. I have worked steadily for just
over a month on this program, and sincerely hope it will help you as
much as it has helped me. I have shown the output of NavLog to an FAA
examiner, and even used it for one of my checkrides. In every case,
the numbers put out by NavLog have been within one to two percent of
the actual values experienced in flight.

In releasing this program to the public, I hope that those people
who find it useful, and who use it on a regular basis will see fit to
compensate me in some way. Be it a letter with five bucks in it and
some suggestions, a program you have written yourself, or perhaps a
job offer flying your corporation's Lear jet. The amount of response I
get from this program will determine how hard I will work towards
writing more aviation-related programs.

I can be contacted at:

Scott MacLean
6 Marilyn Crescent
Georgetown, Ontario, Canada
L7G 1K4

AMEX BBS: (416) 631-6073

Thank you for your support, and thank you for using NavLog.

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NavLog 1.1 Aircraft Navigation Aid (c) 1992 Scott MacLean


Technical Documentation

The following information is how the manufacturer specifies the
aircraft must be configured in order for the fuel/time/distance to
climb values inside this program to be accurate.

Cessna 152: Added December, 1991
From 1980 POH

Flaps up
Full throttle
Mixture leaned above 3000 feet for maximum RPM

Cessna 172: Added December, 1991
From 1981 POH
Flaps up
Full throttle
Mixture leaned above 3000 feet for maximum RPM

Piper Arrow III: Added February, 1992
(PA-28R-201) From 1976 POH
Flaps up
Gear up
Power - 2700 RPM, full throttle
Climb speed - 90 KIAS
2750 lbs gross weight

Piper Seminole: Added February, 1992
(PA-44-180) Flaps up
Gear up
Cowl flaps open
Power - 2700 RPM, full throttle, both engines
Climb speed - 88 KIAS
























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