Introduction

This was one of warm summer days some time in 2006 when I was wandering around the log cabin and had nothing better to do. I looked in my toolbox and found hundreds of lollypop sticks that had been collecting dust for a number of months, ready for something to make on the Kitchen table.

The girls were out in the garden and one asked what a catapult was. This was the inspiration required to make a mangonel, not any ordinary mangonel, but a desktop mangonel.

A Mangonel is defined as medieval artillery used during sieges; a heavy war engine for hurling large stones and other missiles

The Challenge

To be able to propel a mouse ball across the Magic Forest garden, the further the better.

Cost of build

£0.00

Items used

14 Lollypop sticks
2 foot of string
Culinary measuring spoon
Pipe cleaner
A Barbie® to operate and provide scale
Super Glue

Build Time

1 hour

Method

The secret is in laminating

The a little known secret in mangonel design is the fact that the energy that is required to fire a projectile is not in the cord but in the actual frame. The twisting of the cord puts enormous strain on the frame of the mangonel and therefore it has to be rigid and strong. A Single plank of lollypop stick wood was not sufficient so I decided to laminate it by glueing the planks together.

The main construction is loosely a 10 x 10 cm frame made from lollypop stcks that are 14cm in length . The top bar is constructed using 4 x 10cm lollypop sticks, glued together with 2 x 14cm sticks stuck either side to form a light but very strong laminated block of wood. The bottom bar is nmade from laminating 2 x 14cm sticks and fitted into the upward struts in a tenon join cut using a sharp craft knife.

The Stand

It has to be said now that this was a bit of a waste of time as the stands were just not long enough. These types of design faults are normally due tomy "design on the fly" approach. A G-clamp helped.

The image on the left shows a cut through of the stand design/ I wanted to make the legs to be 45 degress to the frame and so 12 cm length of lollypop stick and then glued two section, A and B to it. I had cut out a 90 degree "birds beak" out of the ends and then glued them with sufficient distance to allow another plank to be placed ( the sections in pink). There was no science to it jsut scratch, match, glue and cut off surplus. Once finished it was amazingly strong.

The photographic image below this shows the mangonel legs and the tenon joints where the base strut was glued in.

The mangonel's catapult arm was an old chopstick thatwas unearthed in the kitchen draw along with the culinary measuring spoon :-)

The catapult arm

Again there was no real calculation, measurement for this part of the design. My whole approach to this was just trial and error, have a go, if it works, do it, if not, change it.

I therefore got hold of the culinary measuring spoon, melted it with a match and bent it 45 degrees (longest trajectory possible).

Prior to adding this I got the string and made a loose circle and then wrapped it around the frame and placed the arm in to the loop and twisted. This was a bit fiddly but I was able to get about 3 twists in a triple thicknes length of string. I reaslised as I was doing this that this was about as much as the frame would take as there was a distinctive crackling noise. I reckoned this was the super glue complaining as it is not very flexible but also felt the wood giving way. I stopped at this point.

After this I attached the culinary measuring spoon using a pipe cleaner and marched, along with a mouse ball to the back garden and proceeded to test out the theory.

After about 10 shots, I was getting in the region of 25 - 35 foot shots down the garden..pretty pleasing considering there were no plans, designs or concept models made.....this knocked spots of the paper plane launcher

Magic Forest

The Desktop Mangonel