Board Thread:General Nerf discussion/@comment-37882578-20190815144807/@comment-26431461-20190824091840

Thanks Elliott, the math may or may not check out, idk, but that's what fudge factors are for. I'm assuming this drum is simply just a circle with some sort of rotating mechanism, which opens at the top for feeding (no stick-mag thingy sticking out at the top like a regular clip-system drums, I'd say this is for the better).

My biggest issue is that during feeding, the shells will be rotated 180 degrees due to being dovetailed like that. I guess this can be remedied a bit with some clever engineering, where the bolt and extractor (ejecting part) would need to accept both a right-side up shell and an upside-down shell. The coolest part about this is that during firing the darts will alternate in different patterns between shells, which has some sort of charm to it.

Or, we can have a spiral-ramp thingy in the chamber that just corrects the shells to the upright position as they are pushed into the chamber. Might not be the most reliable of systems, but then again, we are talking about a drum-fed, automatic shell blaster.

So I was wondering how big a drum would be if the shells weren't in a compact dovetail configuration (which would be a larger drum than yours, but would also ensure that they are in the same orientation). Also, sorry, no diagrams.

Let's assume that the shells are configured in such a way that they form a 35-sided figure (also known as a triacontakaipentagon), with side length of 1.2 inches.

So, each interior angle of a regular triacontakaipentagon is ~169 degrees. We can find the radius (?) of the triacontakaipentagon by making an isosceles triangle with base 1.2 inches and base angles of 169/2 = 84.5 degrees each. The radius would be the equal sides.

Do some basic trigonometry, and you get a leg length of 6.26" (the drum's approximate radius). Multiply that by 2, and you get 12.52" (diameter). That's much larger than Elliott's design. Not looking good.

Now we need to account for fudge factors. We need to take in account mainly the thickness of the drum. I'd also assume that there would be space in between each shell to accomodate a carousel-like mechanism that is found on most drums to hold the ammunition in place (think of it like a rotating cylinder but not completely enclosed). The latter I won't take in account because Elliott didn't.

So I'd say with this drum, the diameter would be around ~13.52"? Sadly, larger than Elliott's drum design, but on the bright side it has all the shells in the same orientation.

Is it worth the extra 3 1/2 inches? Not sure.

Ok Elliott, this is the part where you make corrections to my math because you're the engineer.