Mini KA


Type: King Arthur
CW: 3 1/2 pounds
Axle Height: 13 1/2"
Long Arm: 12 3/4"
Short Arm: Adjustable (4 1/4")
Sling: Adjustable (13 3/4")
Wheels: Yes!
Frame: 1 1/4 pounds (roughly)


Racket ball

Projectile: 1 1/4 ounces (roughly)
Range: 63'4"
RON: 0.983

Bouncy Ball

Projectile: ?? ounces (maybe .25, but I really have no idea)
Range: estimated 200 feet (easily landed on roof over 31 feet up and 124 feet away)
RON: Not enough data.

Testing and Construction

August 2, 2007: Mini KA day Two

Matt and I did some more testing with Mini KA today. We tried the racket ball with some more room and threw 63'4" and tested a smaller bouncy ball some where around a half ounce which got lost on top of a 31 foot high building 124 feet away. The throw would have gone about 200 feet. This shows that my Mini KA can be very efficient through a wide range of mass ratios through the adjustment of the arm ratio, secondary trigger, sling length, and pin angle.
Here is today's video. As you can see I'm getting better at video editing.

July 31, 2007

My Mini KA:

The day before yesterday I started making a small King Arthur inspired by the great CW I had laying around: A 3 1/4" long 2" diameter can filled with 3 1/2 pounds of solder. I grabbed a few pieces of 1/4" by 3/4" wood and started cutting with no real plan. A bit different from my normal computer modeling then building process. I finished the trebuchet yesterday and tested it today.


Test went well. Tuning was very good, but room was lacking. My joke desktop trebuchet with almost an equal sized counterweight and projectile, but 45:1 mass ratio, threw through part of a tree and uphill for a range of roughly 50 feet. I hope to do some testing with more room soon.
Frame seems quite strong (Took a few misfires and getting flipped) but the original axle bent, probably when the frame bounced; it gets about an 1 1/2" of air under the back wheels on a regular throw. New skinnier and stiffer axle works great.

Short Video

A single shot at real speed.

Long Video

Contains some pictures and slow motion.


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