Finned vs round canon ball

[Rain City]

That’s not how fluid dynamics work.

Long answer: Drag is a function of the variables Area x Velocity^2 x Drag coefficient and the fluid viscosity (which is constant). D = 1/2p*Cd*V^2*A Area does have an effect, but smaller surface area can be negated by a larger drag coefficient. The coefficient of drag is higher for a sphere because the turbulence that is created by the low pressure zone in the large wake of the sphere. An aero/hydrofoil has a higher surface area but much less drag due to the low coefficient of drag (Cd) resulting from the lack of wake an turbulence. A finned pancake DR weight is much closer in shape to a hydrofoil, and likely has a much lower Cd than a sphere.

The attached image shows that in 2 dimensions, the Cd of an aerodynamic shape is an order of magnitude lower than a cylinder.

All of that electrathon experience at play. That was you, right?

 

[Alex_c]

All of that electrathon experience at play. That was you, right?

Computer engineering, so completely unrelated aside from a handful of physics and mechanics classes lol. But I did pick up some pretty decent math and research skills.

 

[Rain City]

Computer engineering, so completely unrelated aside from a handful of physics and mechanics classes lol. But I did pick up some pretty decent math and research skills.

Ah, sorry. Another member in here was involved with the high school electrathon program, thought it was you. I'm the Canadian record holder. No big deal.

 

[onefish]

Your ball weight, rigger line choice, rod line choice, number of clips on one line, and flasher choice, will have far more impact on the "angle of the dangle" than "fin or no fin".
Want dimples, bang your leads on the bottom a few times.

 

[Fisher_dude]

I dimpled an 18 with a ball peen hammer before I did the research behind it. It works great on a golf ball but due to the denser water, you’re actually increasing the surface area of the ball with the dimples added which is going to create more drag. I ran it side by side with a normal 18 and it was further back but It wasn’t by much for me to care about it. Although I won’t get the time back that it took to dimple it.

 

[sly_karma]

I dimpled an 18 with a ball peen hammer before I did the research behind it. It works great on a golf ball but due to the denser water, you’re actually increasing the surface area of the ball with the dimples added which is going to create more drag. I ran it side by side with a normal 18 and it was further back but It wasn’t by much for me to care about it. Although I won’t get the time back that it took to dimple it.



View attachment 113712

Now we know. Thanks for your service.

 

[ab1752]

I bet the opposite is true. Someone smarter than me can chime in on that.

Haha we did an exact comparison yesterday. Same 18lb balls (if you can believe the stamping), same coating, same depth. The non finned had about 8 to 10 degrees more blowback, not an epic deal, but it was evident. Definitely not the results fit for a scientific journal, but I feel the fin does reduce drag notably.