This stalwart group of time travelers has just braved wind and cold and bumpy roads to witness this Sunday’s ballistic recreation from the Fourth Century.    On the left is George Baumgardner, on the right is Dr. Walter Henze, and in the middle, our beloved and intrepid lab assistant: the Rebecca.   Richard Rough, who has been out on these jaunts with us before, was also present to observe our attempt to poke holes in the sky and bring home some fresh data.

The small size of this group of shots is remarkable.   They were all fired consecutively from a carefully positioned 44 degree launch angle.  George and Walter’s bolts are only 13 feet apart, while the average range for these  shots is  790 yards.    So at this range Firefly is tossin’ them into a 20 minute of angle group.  This is exactly the kind of performance I’ve been dreaming about these last four years.  To the gunnies out there, 20 MOA at 800 yards is pretty lame to be sure, but I don’t recall anyone recording that kind of performance from a modern reconstructed ballista before.

Before we get to the data, here is the only video we could get of the parabolic flight path of a 521 gram heavy bolt.  I believe it is that same bolt that Walter is standing next to.  The footage shows only the first two seconds of it’s ten second journey, so it takes some pretty quick eyeballs to see it at all .   Click for video:  20121104130331(1).

Here is a snapshot of the three types of bolts we tested today.  The red one weighs 521 grams and is 36″ long.  The blue is 340 grams and 29 1/2″ long.  The orange is 276 grams and 21 1/2″ long.

Here is a scale chart showing an overview of all the shots in today’s shooting.  Click to enlarge.

And here is a closer look at the actual landing zone for the three different types of bolts we were testing today.

The reds, on the left, are the “heavies” we’ve been testing over these last few postings.  They form themselves into two distinct groups.  Numbers 1, 2 & 3 were fired at the beginning of the session when we had a 6 mph tail wind; while shot numbers 4, 5  & 6 were  fired at the end of the session when the tail wind had dropped to 3 mph.  This latter group is the one seen in the above photo that fell inside a 13 foot diameter circle.   It makes sense that the higher wind speed caused the greater dispersion of shots 1, 2 & 3.  Average velocity for the “reds” was 315 fps.

The oranges, on the right,  are the same orange bolts we used on the last field trip and can be considered functional duplicates of the famous Dura Europos bolt from the Third Century.  What caused them to string out in such an even fashion is unknown.  We’ll blame the wind.  I suppose, to a certain extent, we should also thank the wind for helping give us the longest shot Firefly has made to date:  947 yards.  It looks like it is going to take either a hefty gale from the south, or at least some more innovation, to get us striking beyond the 1,000 yard mark.   (Which, of course, is a meaningless,  arbitrary goal we probably shouldn’t be spending too much time on…. more — blah, blah, blah.)  Average velocity for the “oranges” was 360 fps.

The blues, in the middle, are something new.  They are the same as the orange Dura Europos bolt, except 6″ longer, and with heavier heads that boosts their weight to 340 grams.   They very neatly dropped themselves into a 20 foot diameter circle at an average range of 934 yards.  Not bad for the new kid on the block.  Average velocity for the “blues” was 348 fps.

Also of interest is the increased depth of penetration now that the ground has been thoroughly soaked with rain.

This heavy “red” bolt  has an overall length of 36″ and  has buried itself  to a depth of 18″.  When the ground was dried out over the summer these same bolts penetrated 10″ on average.  It should be noted that the ground on our firing range has a uniquely homogeneous consistency with no rocks or other anomalies.  It is some pretty fine grained stuff and, now that it has been wetted down, the bolts show amazing consistency in how far they penetrate.  The “blues” penetrated 15″ , and the “oranges” did 14″.   I am not sure what any of that means, but we record the fine quality of our target medium in deference to the large amounts of “moondust” we all must eat when the roads around here get dried out and driven over by big trucks with lumpy tires.   More yum than you can possibly imagine!

And, finally,  some photos to brighten up the page.

A “blue” looking pretty for the camera at the 895 yard mark.

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And demonstrating the dispersion of the three shots in the “blue” group,  in the foreground we see George standing next to a bolt at the 904 yard mark,  while Walter and  myself are standing by ones back at the 896 yard mark.

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And here the humanoids mark  the longitudinal positions of those lightweight orange bolts, the furthest of which made it out to 947 yards.

(Sorry! No photo of you Richard.  Are you camera shy?)

 

 

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