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James Parks Programm
Verfasst: 16. Dez 2023, 19:36
von jos
Hallo zusammen,
in mehreren Beiträgen ist das Programm von James Park erwähnt bzw. Bilder davon zu sehen.
Kann jemand sagen wo das Programmm erhältlich ist bzw. einen Downloadlink nennen.
Habe schon etliche Suchanfragen per google versucht und auch das Forum dursucht, leider ohne Erfolg.
Vielen Dank schonmal für sämtliche Infos
Gruß Joachim
Re: James Parks Programm
Verfasst: 18. Dez 2023, 13:30
von b_der_k_te
Hallo Joachim,
Ich kann natürlich nicht sagen woher Sebastian bzw. Florian das Programm haben.
Ich habe es erstmals im australischen Forum kennen gelernt. Dort hat James Park selbst aktiv mitgeschrieben und hat da auch die Programmdateien frei zur Verfügung gestellt. Damals auch schon mit dem eindeutigen Hinweis das es für das Programm kein Service gibt. Er hat es für sich selbst geschrieben, dementsprechend sind auch nur bestimmte Pfeilsorten mit bestimmten Spinewerten darin auswählbar. (Es ist auch nur eine Auszugskurve hinterlegt - die man beim alten Programm aber mittels Parameter anpassen konnte.)
Leider ist das australische Forum vor ein paar Jahren offline gegangen...
Doch dann habe ich einen Artikel auf der Webseite des Magazins "bow international" entdeckt in der Park einen Screenshot von seinem Programm eingebunden hat. Mir sind ein paar kleine Änderungen aufgefallen, womit mir klar war das er weiter daran gearbeitet hat. Besonders ist nun das Logo eines befreundeten australischen Bogenshops zu sehen und ich dachte, naiv wie ich bin, das Programm sei jetzt käuflich zu erwerben. (Park hat nämlich tatsächlich ein Visierskalenprogramm welches man u.a. über diesen Shop kaufen kann.) Auch habe ich damals Parks Buch über diesen Shop bestellt.
Naja, ich habe den Shop angemailt, die haben von nichts gewusst aber meine Anfrage gleich direkt an Park weitergeleitet.
Ein paar Mails später hat er mir das neue Programm zugeschickt. Es beinhaltet nun ein paar Pfeiltypen und Spinewerte mehr.
Wenn ich nicht vergesse werde ich Dir heute Abend eine PN schreiben. Darüber werden wir alles Weitere klären können.
schöne Grüße
Re: James Parks Programm
Verfasst: 24. Dez 2023, 10:32
von JamesPark
I assume you are referring to my program showing arrow behavior during the power stroke of a recurve bow? (I have a few other programs as well - all part of my research).
If that is the one, yes, I have made it freely available.
It covers a good range of arrows, but not all arrows - just the ones that interested me. Many of the Easton arrows are included.
The arrows have been modelled in detail - quite a lot of work.
In the program you can change just about every parameter of the arrow and of the bow. For example, you can do things such as examine the effect of cutting arrows from the rear or varying the point mass.
I have used it both in my research and from time to time to optimize arrows for various archers. For example, a few years ago Taylor Worth won the bronze medal at the World Indoor - I modelled his arrows for that event. I also modelled the arrow behavior for the 2016 Australian team that won the bronze medal in Rio.
It works best with a high-resolution screen but will work with lower resolution.
I cannot always email it to people - for example Gmail blocks me sending an application.
However, I am happy for others to share it and I can use Dropbox.
Re: James Parks Programm
Verfasst: 26. Dez 2023, 13:24
von rstoll
Hello James,
thanks for your offer to join this program for free!
Some questions:
1) Would it be possible to share any link to the dropbox or is there anything special necessary?
2) Is it a great problem to expand your diagram for a "few more meters". Especially (for me
) concerning the papertest-thread (part) here (
viewtopic.php?f=22&t=498&start=50) this would be very interesting.
3) What parameters are necessary to include other arrows? Do you see any chance to involve the community? For me as a youth coach (always changing Size/draw length/draw force) this would be very interesting
yours
Ralf
Re: James Parks Programm
Verfasst: 27. Dez 2023, 09:41
von JamesPark
Ralf,
I guess Dropbox would work.
In modelling arrows, we need to calculate the mass, diameter and stiffness along the shaft.
I have found the manufacturer's stated mass and diameter specifications are usually not of sufficient accuracy.
I measure the outside diameter - and you can do that with good accuracy.
The internal diameter is also needed, and that is difficult to measure accurately.
Those two diameters let us calculate the second moment of area, I, along the shaft.
We also need E, the Young's Modulus of the material - which is not easy to measure.
For a shaft of uniform diameter, we can use the formula for the deflection of a beam with simple support at each end and a force in the centre (as in a spine test).
That is:
Deflection = Force * Length^3 / 48EI
As we know the specified spine, we can hence calculate E.
As well as all-carbon shafts or all-aluminium shafts, we also need to be able to model shafts with a combination of carbon and aluminium (such as X10s). That just means we need to allow for both materials in calculating the second moment of area.
We also need to be able to deal with shafts of varying diameter (such as X10s).
To deal with those shafts, we need to integrate along the shaft for the deflection.
We then assume densities for the various materials and calculate the mass of the shaft and compare that with the manufacturer's specifications.
I have an application that does all of that very well, including for tapered and barreled shafts, and I am very confident in the modelling that I have done.
That is, including other arrow shafts is possible, it just takes time. The first need is a table of inner and outer diameters and mass per unit length for each arrow spine. If the shaft is tapered or barreled, we need the profile the whole way along the shaft (much more work - but I have done all the Easton tapered and barreled shafts already).
Interestingly, having done all that modelling, I am sure I now have full engineering details for all the arrow shafts I have modelled.
Re: James Parks Programm
Verfasst: 15. Jan 2024, 13:15
von ChristianG
Hello James,
I am a German archer, trainer, and mathematician seeking to utilize your program to analyze the "arrow behavior during the power stroke of a recurve bow." This will help me understand and address peculiar arrow interactions with the bow, a concern observed among some of our young archers.
Could you also provide a link to the program on Dropbox?
Sincerely
Christian