INTRODUZIONE

USO

Il programma è formato da tre tab ed un grafico.

Nel tab iniziale,  dopo aver inserito i dati del proiettile (peso, calibro e velocità) nei riquadri superiori, si preme il pulsante IMPOSTA e si ottiene l'energia del proiettile in kgm e in joule.

Si può poi passare ai riquadri centrali destinati a calcoli di balistica terminale:

Cliccando su LEGNO si ottiene la penetrazione nel legno di abete per la velocità impostata e il volume della cavità prodotta in un blocco di abete; questo volume è un ottimo indice del potere di arresto dei proiettili subsonici.

Cliccando su FERRO si ottiene la penetrazione in lastre di ferro in cm.

Cliccando su OSSO si ottiene la penetrazione nell'osso in cm.

Cliccando su TESSUTI CORPOREI si ottiene la penetrazione nel muscolo, e in genere in un corpo animale, in cm. Compare inoltre la velocità limite rispetto alla cute umana, in m/sec. Essa è la velocità al di sotto della quale il proiettile non riesce a forare al cute e la velocità che perde il proiettile nel perforarla. Sono state usate le formule di K. Sellier.

A destra, due caselle consentono di calcolare la velocità residua del proiettile dopo che esso ha perforato un determinato spessore di ferro o di legno di abete.

Il riquadro inferiore consente di calcolare la variazione della velocità di un proiettile al variare della lunghezza della canna. Per una maggior precisione la lunghezza della canna va misurata senza tener conto della lunghezza della camera di cartuccia.

Il secondo tab consente di calcolare tutti i dati per il tracciamento di una traiettoria. Come avviene per tutti i programmi di questo tipo, i valori sono sufficientemente esatti per gittate fino a 500 metri, ma possono fornire utili valori orientativi fino a 1000 metri. Il programma non è idoneo per il calcolo di tiri a lunga gittata con angolo di tiro superiore  a qualche grado.
Per prima cosa occorre inserire i dati relativi al proiettile per calcolare il coefficiente aerodinamico. Occorre inserire il peso e il calibro e poi la velocità iniziale e la velocità finale su di una tratta di determinata lunghezza. In genere si inserisce la velocità iniziale e poi quella a 100 metri, ricavabile dalle tabelle dei produttori. Cliccando su Calcola il coefficiente aerodinamico si ottiene il relativo valore  che il programma utilizzerà poi per il calcolo della traiettoria.
Dopo aver trovato o inserito il coefficiente aerodinamico si passa ad inserire i dati occorrenti per il calcolo della traiettoria:

• velocità iniziale del proiettile
  
  
• la distanza a cui l'arma è stata azzerata
  
  
• la distanza massima a cui si vuole calcolare la traiettoria (in genere sarà la distanza del bersaglio o la distanza massima a cui si ritiene che si avrà occasione di sparare)
  
  
• gli intervalli di spazio a cui calcolare i dati della traiettoria (di solito le tabelle commerciali dànno i dati a 50, 100, 150, 200, 250, 300 metri e per ottenere lo stesso risultato bisogna inserire il valore 50)
  
  
• velocità del vento laterale per calcolare lo scostamento del proiettile dalla linea di tiro per effetto del vento
  
  
• altezza dell'asse del cannocchiale rispetto all'asse della canna; in genere si calcola un'altezza di 50 mm.
  
  

Nel caso si voglia calcolare anche la correzione da apportare alla mira quando si spara con grande angolo di sito (cioè quando il bersaglio è sopra di noi sopra ad una ripida scarpata o sotto di noi, al fondo di essa), basta inserire nell'ultima casella il valore dell'angolo.

Se ora si clicca sul pulsante Calcola i dati della traiettoria, il terzo tab acquista il focus e si ottiene una tabella a dieci colonne con il seguente significato:

1)  La distanza impostata per i vari intervalli della traiettoria (ad es. di 50 in 50 metri)

2) La caduta del proiettile rispetto alla linea ideale di tiro (prolungamento della canna);
è un dato che non interessa il tiratore.

3) I valori della ordinata e cioè la distanza della traiettoria dalla linea orizzontale

4) La velocità residua alle varie distanze in m/sec

5) L'energia in joule

6)  La deviazione per effetto di un vento che soffia perpendicolare alla linea di tiro

7)  Il tempo di volo alle varie distanze

8) Lo scarto dalla linea di mira; questo è il valore concreto importante per il tiratore in quanto gli dice quanti cm il proiettile si viene a trovare sotto o sopra la linea di tiro prima di colpire il punto in bianco (quello a cui l'arma è stata azzerata)  o dopo averlo superato. Si ricorda che di regola le armi vengano azzerate in modo che il proiettile non passi mai a più di 4 cm al di sopra della linea di mira.

9)  Lo scarto dalla linea di mira nel caso in cui si spari con un grande angolo di sito

10) Lo scarto dalla linea di mira nel caso in cui si spari con un grande angolo di sito, ma tenendo conto anche del cosiddetto errore di prospettiva che si ha quando il bersaglio non si presenta perpendicolare alla linea di tiro ma è perpendicolare rispetto al terreno e viene visto come allungato; per un angolo di sito di 60° i valori di cui alla colonna 11 si raddoppiano!

Infine il programma, dopo aver ricordato i dati del proiettile, fornisce la distanza di azzeramento ottimale, quella cioè a cui di regola l'arma andrebbe azzerata se si usa quel proiettile con quella velocità iniziale.
La tabella creata può essere salvata su file di testo (*.txt).
Infine viene mostrato in grafico della traiettoria disegnato in base alle risultanze del calcolo della traiettoria (v. immagine).



Se la traiettoria è troppo piatta per essere distinta, accanto alla traiettoria reale ne viene tracciata una fittizia enfatizzata in rosso. I numeri accanto alla traiettoria rappresentano il valore dell'ordinata espresso in cm. Il grafico può essere stampato, in orizzontale o verticale, in grigio o a colori, salvato in formato PostScript oppure Bitmap.

TODO

Il programma non è ancora terminato e alcune funzionalità di esso non ancora implementate (per lo più dovute a dimenticanze da parte del programmatore distratto!) verranno aggiunte nella prossima versione 0.2 :

1. Funzioni di stampa migliori;
   
2. Aggiunta nella tabella dei valori di velocità ed energia in Kgm e feet/sec;
   
3. Miglior disegno della traiettoria, che attualmente è molto primitivo;
   
4. Salvataggio dei dati della tabella in formato .sxc (foglio di calcolo Open Office.org)

COMPILAZIONE ED INSTALLAZIONE

Per ora non c'è configure. Per compilare Qtballit basta un:

[pippo@myhome qtballit] $ make

Per installare il programma, copiarlo in una directory nel proprio PATH.
Per ora è consigliabile copiare o creare dei collegamenti simbolici alle pagine .htm contenute nella directory di Qt ballit nella propria directory home. In tal modo è posibile accedere a questa guida (per il poco che serve) utilzzando i menu a tendina. Patetico, vero?
Ma non finisce qui, perchè nell'attesa di un convertitore java la voce di menu relativa alle conversioni per ora punta ad una smilza tabellina visibile qui.
Qt Ballit è stato sviluppato con le librerie Qt 3.3.1 , il Qt Toolkit, GCC 3.1, ln 4.1, sotto Linux (TM) 2.4.26.
Le librerie Qt sono disponibili sulla pagina web della Trolltech www.trolltech.com La versione utilizzata per realizzare Qtballit è stata scaricata all'indirizzo ftp://ftp.trolltech .com/qt/source/qt-x11-free-3.3.1.tar.bz2



Qt Ballit è stato compilato con successo su un Pentium 200 con Slackware linux 9.1. In questo caso è stato necessario aprire il progetto col comando
[pippo@myhome qtballit] $ designer

salvando i file di progetto nel formato delle librerie Qt installate, che in quella distribuzione sono più vecchie. In tal modo è possibile compilare il programma anche con versioni precedenti di Qt 3.

BUGS

Il programma considera come directory di lavoro la /home dell'utente. Quindi perchè il programma trovi i file di linguaggio (*.qm) e i file della guida (*.htm) è necessario copiarli o collegarli nella propria home directory oppure lanciare il programma da terminale posizionandosi nella directory che contiene il programma:

[pippo@myhome ~] $ cd qtballit
[pippo@myhome qtballit] $ ./Qtballit

LINGUA

Qtballit è sviluppato in italiano ma è possibile convertire l'interfaccia del programma per mezzo dei file  *.ts ; attualmente l'unico disponibile è "qtballit_de.ts" che fornisce la traduzione in lingua tedesca. Se Qt riconosce che la lingua locale è il tedesco caricherà automaticamente il file qtballit_de, in caso contrario si avvierà in italiano. Aggiungendo i nuovi file di linguaggio la traduzione nella lingua locale avverrà sempre automaticamente.
Se si intende forzare la traduzione in tedesco o altra lingua è possibile lanciare Qtballit con il parametro uguale al nome del file di linguaggio che si vuole caricare come argomento,quindi nel caso della lingua tedesca occorrerà digitare :

[pippo@myhome qtballit] $ ./Qtballit qtballit_de

Altri file di linguaggio potranno venire distribuiti in seguito.

LICENZA

Qtballit è sviluppato con Trolltech Qt. È distribuito sotto licenza GPL v2.

          -     Termini di Licenza    -

This program is distributed under the terms of the GPL v2.
            GNU GENERAL PUBLIC LICENSE
               Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
                          675 Mass Ave, Cambridge, MA 02139, USA
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                Preamble

  The licenses for most software are designed to take away your
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            GNU GENERAL PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
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Activities other than copying, distribution and modification are not
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is covered only if its contents constitute a work based on the
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Whether that is true depends on what the Program does.

  1. You may copy and distribute verbatim copies of the Program's
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You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.

  2. You may modify your copy or copies of the Program or any portion
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    a) You must cause the modified files to carry prominent notices
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    b) You must cause any work that you distribute or publish, that in
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    c) If the modified program normally reads commands interactively
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    does not normally print such an announcement, your work based on
    the Program is not required to print an announcement.)

These requirements apply to the modified work as a whole.  If
identifiable sections of that work are not derived from the Program,
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Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
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In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
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  3. You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:

    a) Accompany it with the complete corresponding machine-readable
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If distribution of executable or object code is made by offering
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  4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
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If any portion of this section is held invalid or unenforceable under
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It is not the purpose of this section to induce you to infringe any
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implemented by public license practices.  Many people have made
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This section is intended to make thoroughly clear what is believed to
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  8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
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may add an explicit geographical distribution limitation excluding
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  9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

Each version is given a distinguishing version number.  If the Program
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                NO WARRANTY

  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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             END OF TERMS AND CONDITIONS


        How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    < one line to give the program's name and a brief idea of what it does.>
    Copyright (C) 19yy  <name of author>
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

    Gnomovision version 69, Copyright (C) 19yy name of author
    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary.  Here is a sample; alter the names:
  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
  `Gnomovision' (which makes passes at compilers) written by James Hacker.

  < signature of Ty Coon > , 1 April 1989
  Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs.  If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library.  If this is what you want to do, use the GNU Library General
Public License instead of this License.