So, when I started my introduction thread I asked which forum would be best to ask questions about making a slingshot crossbow, and I was told that the general forum was fine. If I made this topic in the wrong place, please move it. Because I have so many questions about designing a slingshot crossbow I decided to divide my questions into 2 topics: 1 on the physics/limits/potential of Theraband (mostly on theraband gold), and the other on designing a slingshot crossbow in terms of body design, materials to use, etc.<br><br>My questions on Theraband Gold:<br><br>I plan to use a pulley method (like Joerg's bullpup crossbow) so that the bands do not smack the frame.<br>*1. So I have to ask about firing ammo lighter/heavier than the crossbow is capable of: if I were to fire light ammo, would it cause a "dry firing" effect that would damage the bands? Conversely, if I were to fire ammo too heavy for the bands would it cause strain?<br>2. How much (if at all) can the bands withstand slight prestretching in order to hold them in place across the pulleys? Will there be a noticeable loss in band life?<br><br>Now on to more theoretical questions about bands:<br><br>3. Because Energy= .5 X Mass X Velocity X Velocity, I want to know what the maximum contraction speed of Theraband Gold is, in order to understand the maximum possible velocity. I know that because of tapering/stretch/band width the absolute number is not known, but any information you have regarding a range, either from Joerg's videos or your own knowledge would be valuable.<br><br>*4. On Joerg's band calculator there are settings for the amount of stretch, and the amount of tapering for bands, rated from longest life to maximum power. I was wondering how many shots you could get out of a band at what ratings. Say for example, a set of bands at 5 and 5, a set of bands at 1 and 1, and a set of bands at 9 and 9. Please post what band dimensions you use and at what ratings in these numbers if you don't have a clear number.<br><br>5. While on the issue of the band calculator, when it comes to stretch length, how do each of the numbers measure to the % in which the band is being stretched. For example: would a 1 on the scale be 400% while a 9 would be 600%? (I am just wildly guessing on those numbers and have no confidence in them, they are just examples of what sort of info I am asking)<br><br>6. Do other colors of theraband have a faster contraction speed? or is Gold the fastest?<br><br>7. If I were to set up a set of bands of another color of theraband at the same draw weight and tapering as a set of theraband gold bands, would it launch the same projectile at the same speed and power?<br>8. If so, would it be more durable or just as durable as the theraband gold?<br><br>*9. A basic physics question that I honestly do not know the answer to: if 2 objects of different mass (that have equal air resistance) are dropped, while they both fall at the same rate of 9.8 Meters/second, do they fall at the same speed? or does the heavier object fall at a faster speed x the rate of gravity?<br><br>There are multiple factors to the amount of energy imparted from a band to a projectile. The following questions are about what role each plays:<br><br>10. Is it correct to assume that the amount at which a band is stretched and the amount of tapering of a band is essentially the same force? That is, both factors on the band cause the band to extend more and therefore contract faster and contribute more strain?<br><br>11. What is the relationship between the number of bands to the speed/energy of a projectile? Let me take away a few variables to make this question easier to answer: Let's assume that Y is the energy released from a specific shape/length of band. if another band is added, does the energy released become 2Y? By adding a 3rd band does it increase to 3Y? Will the energy imparted by the bands increase by 1Y until the projectile reaches a point where the projectile accelerates to the speed at which the bands contract? Or by adding more bands will the energy imparted increase only a fraction more for each band added?<br><br>12. What is the relationship between the draw distance and the speed/energy of a projectile? Let's say that I were to make 2 sets of bands, both the same width, with no tapering, and both with lengths that if they were stretched to their draw distance they would be 1's on the calculator for length. Would these bands fire the same projectile at the same speed? If not, then:<br><br>13. How much more energy is put into a projectile by a longer draw length? theoretically would a draw length of 36 inches be greater than 24? would a draw length of 48 inches be greater than 36?