It took awhile to get here,  but we finally have some encouraging results from our first accuracy test of the Orsova reconstruction.  I spent most of the morning yesterday  balancing the rotational position of the washers so that both limbs were working in unison.  Initially, the best way to do this is by observing how closely the limb tips match up as they swing past the stock during the wind up process.  If one limb tip is drawn back further than the other, this indicates that the washers on that side need to be rotated to the next position to increase the torque in that bundle.  Ultimately the final adjustments are made by observing the bolt flight.   In the case of yesterday’s test,  the bolts kept shooting erratically and maybe a foot to the left,  relative to  where the bolt groove was aimed.     I tightened the washers on the left side to compensate,  and finally the bolt flew straight and true, shooting out of the machine directly in line with the bolt groove.    I decided to leave the sight alone and  just see if the machine would shoot some kind of a group on a new target.   The first shot hit about 4  inches  left of the bulls eye.  I took special care to sight the machine for the second shot, and then eased back the firing lever until the shot was released.   “Yes! Yes! Yes! Yes!”.   The second bolt had gone right through the hole made by the first shot.   When I finally got through dancing a jig and thanking the Catapult Gods for their mercy,   I pulled myself together and settled down to the serious work of sighting a third shot.   It went off without a hitch and again the bolt flew straight into the hole left by the previous two shots.   At this point I was beside myself with elation and Becky came out to see what all the fuss was about.  After a couple of minutes  of deep breathing I prepared for shot number four.  Now  my ever patient wife was looking on.   This time the bolt hit about 1 inch low and the hole in the target took on a more ragged appearance.  Shot five again followed the track of the first three shots and further validated that original group.  Shot six was a blow out because I screwed up the release.  In the photo below,  it is the lone hole close to the bulls eye.  Shot seven was a success and only slightly opened up the original group.   All seven shots were made with the same bolt to enhance consistency.  Here is what the target looked like as I wrapped it up for the day.


The range here is 50 yards.  The backstop is a 12″ deep wooden box, filled with sand.   The back wall of the box  is a 1/4″ steel plate covered with plywood.  The sand slows the bolt down to the point that when it hits the solid back wall,  no damage is  done to the projectile.  I elected not to set up the chronograph for these shots,  but the velocity appeared to be in the 350 fps range.

From my perspective,  this level of performance was essential for what comes next.   There are any number of improvements that need to be made yet,  but today’s performance vindicates all the work that has gone into this so far.   Right now,  more than anything,  I feel an overwhelming sense of relief.

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