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TK3 Model Trebuchet, Hobbyist Version

Perfect for your next science project!

Designed and made in the USA for
better quality, better performance!

The TK3 Trebuchet Model Kit is an ideal science project machine! Use the hanging counterweight bucket for variable weights, or convert it to a fixed counterweight machine, wheels, or no wheels. The choice is yours!

The TK3 model trebuchet can demonstrate all the principles of the trebuchet as either a hanging counterweight machine, or quickly convert it to a wheeled fixed counterweight machine (and back again!) Which is better? Which one is more efficient? More accurate? More fun? Now you can be the judge!

This professionally engineered model requires only two or three hours and a little glue to assemble. The only tools you'll need are a pair of scissors and (optionally) a utility knife. It has a 15 inch throwing arm, is 18 inches from front to back, 9 inches wide and 13 inches tall at the axle. This is a working model capable of tossing the included wooden missiles over 40 feet!

Precision cut from high quality solid hardwood, the kit includes everything you need to build a working model!*

The detailed instructions are complete with diagrams, photos, tuning tips, and even efficiency equations for calculating your maximum theoretical range! All parts are pre-cut, pre-drilled and can be assembled to a finished model in one evening (plus glue drying time).

The trebuchet is a fantastic demonstration in physics and dynamics. One of the big debates in recent years among historians is whether trebuchets in history used wheels to increase their efficiency and make them more portable, or if they were built on-site without wheels and with counterweights hanging from the end of the arm. This debate was even explored in a TV documentary (NOVA, Secrets of Lost Empires: Medieval Siege).

We've put a lot of time and effort into making this kit as easy and complete as possible. It's a fun way to learn about science and history!

* The counterweight box is supplied, but you'll need to supply the counterweight material to fill the box. For best performance, we recommend using 360 pennies for counterweight and/or two 1.25 lb. barbell weights (barbell mounting inserts also included). These barbell weights can be found at sporting goods stores or on our website.

Tools required:
Scissors, Glue, Ruler, and a utility knife. Sandpaper is optional.

Assembly time:
For a Master carpenter doing a sloppy job: about 2 hours.
A person with no kit building experience being extremely meticulous: about six hours.
The model in these photos was built by Ron Toms in about three hours.

Assembled Size:
- Height: 13" at the main axle, 24" to the tip of the arm.
- Length: 18"
- Width: 9"

Additional Counterweight Required: 360 pennies recommended
(Or loose nuts and bolts, other coins, rocks, anything that
can fit into the 2" x 2" x 3" counterweight box.) and/or two 1.25 barbell weights (barbell weight mounting inserts are included, but not the weights.)

- 20 to 40 feet with the included wooden ball projectiles.
(Optimal range assumes a well tuned machine)

Shipping weight: 2.5 lbs.
Box dimensions: 20" x 12" x 4"

Quantity pricing info:
0 to 4 kits, standard price.
5 to 9 kits, 10% off
10 or more kits, 15% off

Orders of $200 or more qualify for FREE ground shipping!

For more discount pricing info, please visit

WARNING! This is a functional model intended for display and/or educational demonstrations of physics. It contains a fast moving arm and projectile that can cause injury if you make contact when firing. Use only under strict, competent adult supervision.

* The counterweight box is supplied, but you'll need to supply the counterweight material to fill the box. For best performance, we recommend using 360 pennies for counterweight and/or two 1.25 lb. barbel weights (barbel mounting inserts are included).

* Can throw 40 feet when properly constructed and tuned with sufficient counterweights. Your performance may vary.

* TK3 Trebuchet is a trademark of RLT Industries.

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    Price: $79.00
    Minimum age: 10
    Availability: out of stock

    Item code: 10401

So, why do my kids
need this stuff?

Seriously, get some toys, go outside and play. It's good for you. Spend some quality time with your kids, your buddies or just get away from the TV and computer long enough for a good dose of sunshine.

Learn a new skill. Get some exercise. Make someone happy. Make yourself happy. Set-up some cans and knock them down, just to see if you can.

Teach your kids something about safety, posture, focus and concentration. It's easy if they have something fun to do while they're learning it.

The science of Physics was founded on the principles of ballistic motion. What better way to develop an interest in physics than to play with ballistic toys? And you know where that leads... First, physics, then math, engineering and economics. Next thing you know, he'll be studying medicine with plans to become a ridiculously high paid sports doctor with a keen knack for investing, all because someone bought him a projectile shooting toy gun as a kid. How's that for a reason?

Here's an even better reason- kids like to play with their parents and they like to compete. Do some target practice with your kids in the backyard. It's far better than watching re-runs of some lame TV show or turning into a video game zombie! Parents and kids need to interact. It's our goal to provide the toys that make it easy. We're doing our part, now you need to do yours.

So, one more time, get some toys and go outside and play!