Wow, excellent response! A couple of us were worried that that we'd chilled people off with the pedantic technicality bashing, really glad we haven't. As to scoring over Goliath, now way, not thinking that way at all. If we get it right the results form this will be given to Goliath and the wiki. It's a hole which needs filling, the modern slinging distance records have helped to dispel the myth that most of the ancient authors exaggerated on range. If we can get the speeds figured that will help to sort out things like what slings could do against various types of armour.
Before replying to the points above I'm going to be lazy, it's late in the Uk and I've just got home, and quote myself from messages ( yes, that paranoid ) “...And very nice if it means that any slinger who can make a couple of recordings can use whatever method we come up with for an accurate ballistic analysis. If the pitch of the glans was constant only one recording would be needed, we know the start point, we know the time , Doppler shifts would give us relative motion and that's it. I think that the main problem is we need a solution which doesn't depend on constant pitch because barring throwing some gadget we simply cant have it. That's why I homed in on the distinctive pointy bits, try to make a solution out ot the problem itself. If we can use each dpb in the same way as the sheets of paper idea we've cracked it.”. And “Triangulation of the dpb's using a a timeline and knowing the speed of sound is the way to go. Certainly at first, when we have a few samples and some idea of what a particular glans design does THEN doppler will be very handy as it will allow some sort of single mic technique. Initially we will probably need at least two, maybe three ( which will be tricky at this end from a practical point of view ). That said we shouldn't write it off, the estimates for speed that I've seen knockiong around depend on quite a long section of flight average and slingers who had problems putting a stone through a 1 meter target at ten meters still got speeds only a little short of a handgun. As if what we're trying should be capable of plotting the projectile for any section of it's flight I think that we may see a pretty big shift in the initial part of it. It'll be on the recording anyway, might as well look at it.
I know some of that is a little out of context now but feel better for having pulled it out from under the rock, there is some good stuff I can't quote because it's not mine and it would be out of order. We honestly thought we were boreing the pants of you.
I know the sling you mean Matthias I thought it was great when I saw and especially heard it , the whipsling would be perfect for this. You're right, a single mic is enouth to get the average speed of glands to target, anywhere on the line. If by slinger then time from crack to hit minus the time the sound takes to get from the target to the mic is bang on. We are trying for a bit more detail. But yes agreed simple and something is better than clever nothing. I think this may best be done in easy stages, initially ignore the parabola and imagine straight line for example.
On a practical level I got some plastecine and some straws today and tomorow a mate and I will go and try out some prototype loud glans, ( just sling short range, modeling clay isn't gold but isn't free either, at a square of carpet and hope for loud flights. ) I've got a very low end still camera which has limited video capability, also a mini disc. Weather permiting, neither can handle damp, will record the tests.. If we get it right then solid ones based on what works and then we've got our sound source glans and ready to go. Trouble is we can only manage Fridays and maybe Sundays so it won't be until nest weekend that we can start producing data.
Unless one has a several tens of thousands of pounds worth of camera, frame rates are the problem when it comes to visual esimates, mine is only 20.020 ( strange eh?) so based only on that I'm only accurate to around 17 meters for distance estimates, okish for big shots into water but not really this. It's sound rate is also peculiar at around 10,000. Oh this is useful for trimming vids and exporting the sound track
http://www.virtualdub.org/ Mini disc 44.000. Which is why I'm going for sound.
That's a great vid tech stuff, nice shot. I can't download and play with it though. Any chance of uploading it here as a mpg or avi? Just a thought, maybe we should have a “raw data” thread for this, keep things tidy. Some day I will learn the art of the short post.