Calculating length of tapered bore

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Matt NQ
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Calculating length of tapered bore

Post by Matt NQ »

Calculators don't seem to help with the length of a tapered bore (if there is one please point me that way!) I imagine the maths is fiendish, especially as you have a (usually) straight head bore before the tapered body bore. I'm wondering if there are some general, approximate principles here to get me started, so I don't chew up too many trees with trial and error :) ?

Which of these would get me the closest:

1) Calculate approximate length using the head bore before the taper (widest section)?
2) Calculate approximate length using the end bore after the taper (narrowest section)?
3) Calculate approximate length using the average bore (midway between widest and narrowest)?
4) Calculate approximate length using a weighted average bore skewed to take into account the longer maximum width section in the head bore (closer to widest than 3)?

4 seems the most logical to my simple mind, but I'm aware that acoustics can be surprising (as with the endless mystical wiggliness of bore "perturbations"...).

If you think I'm being lazy and I should just "suck it and see", please bear in mind that trial and error with the length of a tapered bore is much more difficult than with cylindrical whistles, as chopping a bit off the end changes the bore, and you have to bore another body with a different taper angle to get back to your originally designed start and end bores... (or so it seems).

Any thoughts at all, from mathematic, acoustic or practical experience perspectives would be very helpful!
Tunborough
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Re: Calculating length of tapered bore

Post by Tunborough »

Matt NQ wrote:Calculators don't seem to help with the length of a tapered bore (if there is one please point me that way!)
You may have seen me mention WIDesigner before: https://github.com/edwardkort/WWIDesign ... WIDesigner. Handles as many different changes of bore as you care to supply it with, and even helps you optimize the bore to get the best tuning.
Matt NQ
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Re: Calculating length of tapered bore

Post by Matt NQ »

Thanks again Tunborough! Just checked out github.com, and indeed I remembered briefly visiting there before - probably because you mentioned it. I was looking for something simpler then, and didn't explore much, and forgot about it. Thanks for pointing out its relevance to my question - it looks like it does indeed help with calculating tapered bores, which is great! And about $10 a month (Aus) is fine for the extra it offers compared to the free calculators if it can deliver what it seems to. I'm looking forward to exploring it :)
Tunborough
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Re: Calculating length of tapered bore

Post by Tunborough »

Matt NQ wrote:And about $10 a month (Aus) is fine for the extra it offers compared to the free calculators if it can deliver what it seems to.
Eh?! I don't know who's charging you 10 AUD a month, but it isn't WIDesigner. WIDesigner is open-source software, free to download and use; no costs or subscriptions.

(Although I do accept finders fees, generally in the form of high-proof chocolate. :D )
Matt NQ
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Re: Calculating length of tapered bore

Post by Matt NQ »

Tunborough wrote:Eh?! I don't know who's charging you 10 AUD a month, but it isn't WIDesigner. WIDesigner is open-source software, free to download and use; no costs or subscriptions.
Ah! My hasty skimming of it all misled me. There's no obvious download button on the page you sent me to, so I clicked on "Pricing" at the bottom of the page. Reading the fine print now on the Pricing page, it's about developers joining, rather than users.

On closer inspection, there's a text link to download WIDesigner about halfway down the page you linked me to, so all good now, I can start playing with it :)

Many thanks again.
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