The most frequent question asked by new catapult users is which bands should I use.
Many new catapult shooters are tempted to go for the most “powerful” catapult they can get, a frequent question being “what is the most powerful catapult you sell?” Or “what's the strongest bands you do?”
Before deciding how powerful you want your catapult to be it is wise to consider what you will be using it for. And remember if you cant hold the frame steady at full draw you will not be accurate. If you are shooting paper targets at ten metres you wont need bands that can launch a cannon ball. However if you are hunting you will need a set up that can propel a .44” lead ball at a decent pace.
The “power” of a catapult is dependant on two factors; the speed of the ammo and its weight. And it is the bands (through the shooters muscles) that provide the energy. So some facts to consider:
Thinner bands accelerate faster than thicker bands, if maximum velocity is required multiple thin bands are faster than a single thick band.
A longer draw gives the ammo more distance to accelerate and is therefore faster.
Drawing the bands close to their maximum stretch will result in greater velocity.
Using more rubber will not necessarily increase the velocity but it will carry heavier ammunition.
Tapered bands are usually faster than straight bands with the same average dimension.
Most methods of increasing the velocity decrease the lifespan of the bands.
All bands are less efficient in colder weather
As it is not easy to compare the amount of rubber in a set of bands I have made a table showing the cross sectional area of all the rubber I sell. This is just a guide, as stated above there are many other factors which will influence the performance of a catapult. Also there are variations in the thickness of bands and tubes due to the manufacturing process so sizes are averages rather than exact.
In general the heavier the ammo being used the greater the cross sectional area of rubber will be needed to propel it, either by using thicker bands or multiple bands. But the fine tuning of which bands, the draw length and ranges at which they are shot are down to individual preferences.
|Brand||Tube / Flat||Name||Thick||Width||Size||ID||ED||xSection Area|
|TheraBand||Flat||Black 20||0.38||20||Black 20||7.6|
|TheraBand||Flat||Black 25||0.38||25||Black 25||9.5|
|TheraBand||Flat||Silver 20||0.54||20||Silver 20||10.8|
|TheraBand||Flat||Silver 25||0.54||25||Silver 25||13.5|
|TheraBand||Flat||Gold 20||0.64||20||Gold 20||12.8|
|TheraBand||Flat||Gold 25||0.64||25||Gold 25||16.0|