Does anyone not like to break, destroy and blow things up occasionally? I sure do! That’s why I’m really going to enjoy doing this testing. For a while I’ve been thinking of ways to build a database of arrow shafts to collects all the data in one place, data from the manufacturers as well as my testing results. For the impact strength testing I needed something that would be adjustable, repeatable and easy to use. Thus “Smasher” was born from aluminum, steel, screws, bolts, Teflon and a little bit of sweat.
The basic premise is that gravity is just about the most repeatable thing on earth. By using a pendulum, the impact force on the arrow shaft will be very consistent. Supports and guides for the pendulum are made of PTFE (Teflon) to minimize friction and increase repeatability. The pendulum body is threaded in the back to allow for varying amounts of weights to be added until the shaft fails. Each shaft type can be tested with a head-on impact as well as a sideways impact.
Probably the only bad part about this testing is that I will be destroying a lot of arrows (in the name of science of course!) I always cringe a little when one of my good arrows thwacks the steel target at our 3D leagues or sinks a little to deep in my target and crunches against the plywood barrier in the back.
Testing of arrow shafts will commence shortly with initial experimentation happening as this is written. I’ve contacted several arrow manufacturers and received some positive responses with hopefully more to follow in the near future. All data gathered from this testing will be made available along with the dimensional testing for spine, weight and straightness.
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Looks like a ballistic pendulum, the same thing scientist used when evaluating the effect of velocity and mass of rifle bullets. In the earlier versions, they used a piece of paper or cloth to record how far the pendulem was moved. Wondering if you be testing at various ranges and at a constant air temperature and density?
@Tim: This is different than a ballistic pendulum in that a sample portion of the shaft is held in the base and the pendulum arm lifted, the dropped to strike the shaft. The weight on on the pendulum will be increased until the shaft fails.
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