                                                      May 3, 2000





Introduction
------------


This is a preliminary set of instructions for a first public
version of a balloon lift calculation program that has been in
use at SkyQuest for a number of years, but just now being
released for general circulation.

Much care has been paid to the accuracy of the internal modeling
algorithms in LIFTWIN to handle the physics of buoyancy and drag of
lighter-than-air balloons, with particular attention focused on
their compliance with the published characteristics of the Kaymont
company's latex balloons.

LIFTWIN does very well in tracking the Kaymont ascent rates and
burst altitudes.  In order to provide the very best in estimated
fill data, LIFTWIN accepts a range of site altitudes and temperatures,
since these qualities affect the lifting power and the atmospheric drag
of the balloon as it rises to burst altitude.

Primarily in order to duplicate the Kaymont charts, LIFTWIN accepts
hydrogen as an option for the fill gas, but it's not at all recommended
for amateur balloon launches.



Packing list for LIFTW-02.ZIP
----------------------------


liftw-02.exe           main program file
liftwin.txt           this instruction text
freelift.txt          table of freelift vs. release diameter

kay-am.txt            Kaymont type A data in metric units
kay-ae.txt            Kaymont type A data converted to english units

kay-cm.txt            Kaymont type C data in metric units
kay-ce.txt            Kaymont type C data converted to english units




Getting started
---------------


The exe file runs under any version of windows.  A setup program is
presently not available, so do your own installation of the small
exe file wherever you want it in your computer.  The VBRUN300 runtime
file must be available in your computer for LIFTWIN to operate.  VBRUN
is typically installed under the windows/system directory when operating
under WIN 3.x.

Since this is a comparatively compact program it should be handy for
use on older computers and laptops.

Selecting a balloon type from the menu bar will immediately provide
results for a range of typical values for diameter and payload weight.
Those values can be edited and new results immediately displayed by
clicking the CALC button.

Launch site temperature and altitude (as well as inflating gas type)
are selected from the SITE CONDTIONS menu bar, but the defaults of
0 feet altitude and 60 degrees Fahrenheit are automatically in effect
upon program startup.  Note that changes to site condition entries
initiate a recalculated display with a click of the CALC button.




Use of default switching for balloon comparison
-----------------------------------------------


This is a feature that may take a bit of practice to get used to in
order to realize its full utility.

With default values ON (enabled), *new* suggested balloon parameters
of minimum diameter, maximum diameter, and payload weight are
automatically updated for each new balloon selection.

If you want to compare the performance of two or more different size
balloons with the same payload weight, disable defaults (defaults OFF)
and then you are free to pick different balloon types without
disturbing the values in the editable uppper left hand data frame.

If at any time you'd like to temporarily revert to the suggested data
values for the presently selcted balloon type, just click the
RESTORE DEFAULT VALUES button.  If you'd like to *always* get the
suggested values in the data frame whenever changing balloon types,
just click the check box for DEFAULT VALUES so it shows ON.




Additional features planned
---------------------------


Printing of the display results.

A separate all metric version.

Accepting a user identified balloon type (weight and burst diameter).

Technical paper on the factors affecting lifting force, ascent rate,
and burst altitude; the importance of knowing the temperature and
altitude at the site.

Expanded user instructions.




Supplementary data
------------------


At the time of this writing I've discovered there are no less than
three different Kaymont tables with differences in some of the
bursting diameters which govern how high a balloon will rise for
a certain release diameter.

This release of LIFTWIN (v 0.2) includes the original table
from the old Kaymont website, and the table from the current
(May 1, 2000) Kaymont/Eastern Scientific catalog.  LIFTWIN at
present complies fairly well with the old table values.

I'm not sure what to do about the existence of the three sets of
values for Kaymont balloons.  My inclination is to make selection
of any of those tables an option on LIFTWIN, but for the moment
the program fits the old website table.

Text files included in the distribution are conversions of two of
the three Kaymont balloon characteristics tables to english units
of measurement.  If one uses this to test the accuracy of LIFTWIN,
note that the Kaymont data are for hydrogen fill, and apparently
for sea level altitude and an approximately 60 degree Fahrenheit
temperature.

The three tables are named as follows:

from old Kaymont website                        Type A
from new Kaymont website                        Type B
from Kaymont/Eastern Scientific catalog         Type C

Table file names:

Metric type A     kaya-m.txt
English type A    kaya-e.txt

Metric type C     kayc-m.txt
English type C    kayc-e.txt

I've also included a small table of balloon release diameters and
free lifts required to achieve an ascent rate of 1000 feet/minute for
release diameters from 3 to 8 feet.

There seems to be a popular notion that one pound of free lift will
achieve a desirable ascent rate.   Well, very roughly I guess that's
true, but one look at the table shows that towards the larger
end of the range of amateur balloon release diameters, one pound will
result in an ascent rate considerably under 1000 feet/minute.




Revision history
----------------


0.1     04/24/00

	Initial release


0.2     05/03/00

	Removed VBRUN300.dll from LIFTWIN.zip distribution (available
	separately at HABLIC website).

	Fixed error causing division by zero error and inaccurate results
        for Kaymont KCI 1200 balloon (1200 gram).

	Fixed minor cosmetic tint mismatching on display.

	Revised included text files to reflect two of the three types of
	Kaymont balloon characteristics tables.




Comments and questions
----------------------


I'd like to know your impressions of this software, and your reports
of any improper performance or results.  Email can be sent to

                    h1riley@umassd.edu

The latest version of this software will always be available at
the SkyQuest/HABLIC website:


     http://www.geocities.com/capecanaveral/3161/hablic.htm


LIFTWIN offers new enhancements and improved precision, but is based
on fundamental program methods first made available to amateur
ballooners by Bill Brown, WB8ELK.


Hank Riley, N1LTV
SkyQuest/HABLIC
