10- Fly Fishing Rods: Design Over Time

I have long been interested in the sport of fly fishing. However, up until recently I have never realized the science and engineering that goes into the design of the fly rod and much of the other equipment used for the sport.

Fly rods have been hand crafted for hundreds of years, even before the craftsman understood the physics of obtaining the perfect cast. What the rod-smith would do is, using a piece of bamboo, would craft the rod to the customer’s certain specifications of length and flexibility. All that was known was generally how flexible a rod should be and generally the size of lour that would be fished with.

Fly fishing technology has since progressed and much more engineering design goes into the construction of fly fishing equipment. Physicists have derived numerous equations to formulate the exact tension a rod should put on the line as it casts the fly out on the water. The amount of variables taken into account while designing such a high performing rod is profound. Each rod is specifically designed to cast a certain thickness of line which has a certain ratio of taper to it which is designed to cast a certain size of fly in certain types of weather/geographic conditions. During the design process, engineers test different types of material such as graphite or bamboo which will give the ideal “fly presentation” meaning the fly will land gracefully and gently on the water simulating the real thing. During testing, designers determine the ideal material to use by measuring the line speed which means a farther/more efficient and controllable cast. Another thing taken into account is the taper of the line; meaning at the end of the line it is thinner in diameter than the butt of the line. This makes the line more aerodynamic and prevents it from coming down on the water with too much force which would scare a fish away.

It is clear that when variables are taken into account, it is always centered around 1 objective, catching a fish. Every bit of design comes from the certain behavior of the type of fish the rod is designed to catch. In order to design a fly rod, engineers first must know the exact behavior of the fish so they can design the rod to make the fly behave exactly like the fish wants it. Another example of the design process; this time in the sporting goods industry.

http://www.taipeitimes.com/News/feat/archives/2006/01/21/2003290123

http://www.ivanhoe.com/science/story/2011/04/847si.html

http://www.unc.edu/~blumensh/phys24physics.html

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