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The Trebuchet Mystery Cache

This cache has been archived.

Touchstone: Thanks for all the great logs. Putting this one out to memory lane.

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Hidden : 6/8/2005
Difficulty:
3 out of 5
Terrain:
1.5 out of 5

Size: Size:   regular (regular)

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Geocache Description:

The cache is not located at the coordinates above.  To find the cache you must solve the projectile type problem explained below.

 


 

Trebuchet: An ancient siege engine used for hurling large rocks (and occasionally more macabre items like dead animals and POW's).  Invented in China around the 4th century B.C. and introduced to Europe around the 6th century A.D.  Considered the ultimate Weapon of Mass Destruction during its day, it was still in use up through the 16th century A.D.,  long after the introduction of gunpowder.

My son accompanied me to Roaring Camp in order to do a little research and some test firing for an upcoming Cache Event.  Things were going pretty well, and I had even included a .30 cal ammo box for a new cache for the Event.  Our little Trebuchet was performing admirably, but a few minor adjustments were still needed.  I left my son to stand watch over our belongings while a made a short run back to the car for some additional water balloon supplies.

When I returned to the launch site, I was horrified to see my son loading up the basket of the counterweight with every available stone, brick, and piece of heavy looking debris available on the ground.  I was just about ready to stop him when, to my surprise, he let loose on the trigger.  In a clean graceful arc, I could see a greenish black box hurtling through the air towards the dense trees in the distance.  It only took me a second to realize that what he had launched was the .30 cal ammo box that I had intended to hide for the Event.  I tried to follow the path of the ammo box's flight, but it soon receded into the distance.

My first thought was to run into the woods and see if I could find the box by just following the path of the flight, but my son suggested that I climb into the sling of the Trebuchet and follow the path in a more literal sense.  To humor him, I climbed aboard with a predictable disastrous conclusion.

A little shaken, but none the worse for wear, I hobbled my way back to the car to call my wife for help.  Now I must say at this point that anybody that has read my DNF's on Black Box will already know how inept I am at math.  My wife, on the other hand, is astonishingly good at it.  I figured that she would be able to find an elegant solution to the problem.  Sure enough, in a matter of minutes she had calculated the trajectory and I was able to map a projection on my GPS.  Below is a list of the information about the Trebuchet and the bearing that the ammo can took in its flight.

I eventually found the  ammo can, half submerged in the soft receiving earth.  I liked the area so much, that I left it where it was.  Hopefully you can find it too.

Trebuchet Construction:

Main launching arm is six feet in length and weighs five pounds.  The axis is five feet from the projectile side, and one foot from the counterweighted end.  A 440 lb. weight hangs down from the short end by a one foot length of metal on a pivot.   The sling that holds the projectile is four feet in length.  The ammo can weighs one pound.  The stand for the pivot arm is three feet high.

Release of the ammo can:

The projectile leaves at an angle with the ground = 43 deg .
It leaves the sling 0.7000 s after the trigger is pulled.  When last seen, the ammo can was heading on a bearing of 140 degrees from true North.

Brief Suspension of Reality:

There is no friction in the Trebuchet and the ammo can lands at the same elevation as the take off .  The ammo can miraculously has no air resistance, and does not roll, bounce or richocet when it lands.

Now a word from our sponsors:

The area in which you'll be searching for this cache has some fairly dense tree cover.  In other words, your GPS may act pretty flaky.  My best EPE was in the 20-30 foot range.  I'd just like to point out here that the cache is a couple of steps off of a trail.  There's no need to tear up the landscape, and in fact, if your calculations are within 100 ft of my calculations I'd just as soon give you more details about the hiding place than have the area trashed.  Feel free to email me with your best guess.

 

Additional Hints (No hints available.)