Love this content. I completely Nerd out on ballistics for my handloading of gun cartridges, now I can start to do the same with archery. Keep up the awesome content. Thanks for sharing your knowledge!!
Lucas, thanks for your honest insight to arrow flight and sharing your ballistic calculator. Keep up your good work and looking forward to your next video.
I just found your site - thank you for the ambition to describe arrow flight and penetration in terms of physics that we can appreciate. As both a competitive target and a bow hunting recurve shooter, I understand that tuning an arrow is important for optimal arrow flight, but what really is the degree of flight and penetration deficency for a poorly tuned arrow? If the degree is less than 10 percent, is it really important (worth the effort) to tune an arrow? I say this after having spent considerable money over the past four years buying arrows of differing spine to tune my various recurve bow (and, now, longbow) systems. Small degrees may be scientifically measurable, but are they functionally significant? As well, when we agree that a poorly tuned arrow is energy inefficient, where is the lost energy going during arrow flight? if the energy is lost to heat, can we measure arrow temperature differences during flight to quantify degree of ineffciieny? There is lots more to this, but maybe these questions will start. Thank you.
Very good questions! So from the compound side there is a much greater benefit than a traditional bow. Compounds are able to shoot an arrow nearly perfect, while a traditional bow will have more shaft paradox as I am sure you know better than I. Shaft paradox or shaft flexing between bow and target changes the drag coefficient from 1.6 to 2.6. So there is double the drag on the shaft which is flexing nearly all the way to target, most traditional bows produces arrows that fly this way. A compound bow can shoot a stiff enough shaft and tune the bow to the arrow such that there is minimal shaft flexing from bow to target, because of this a compound can achieve as low as about a 1.6 drag coefficient. Now we will talk about a shaft that has an angle of attack, commonly known as planning/ untuned bow/arrow, this can increase the drag coefficient all the way up to 3.6 at only 3 degrees of attack angle, which would produce 3 times the drag. The increase in drag causes loss of energy as the drag is performing work on the arrow. The loss of energy would be proportional to the drag. If we achieve the drag of 1.6 that is about the best we can do on arrow performance. However, the biggest gain I think is going to come to penetration of the target/animal. This is something that is going to require more testing but, if the arrow hits sideways even a little the shaft buckling is greatly increased. As soon as the shaft buckles its ability to push forward/ penetrate is greatly reduced. Thank you for your comments I always appreciate answering the questions that I can. Lucas
Great job explaining it, Lucas. I greatly appreciate the hard work you put into this! Are you going to make the spreadsheet available to public (for a fee of course) ?
A couple of the ballistic calculators that I use, have a feature where you can calculate the BC of your arrow, based on two measured velocities and the distance between them. i.e. V(1) is 410 fps at muzzle, and V(2) is 382 fps at 40yds. I would be interested in the equation, and the math to solve this and other scenarios. Have you thought about incorporating something like this into your calculator?
