The speargun test tank (pool) is done.

I did some testing recently and found one very interesting thing. Flopper tuning can matter A LOT!!! I was shooting a gun from a maker who I respect greatly and couldn't understand why it was shooting so much worse than my other guns.

Let me back up. I started with one of the guns I shoot all the time, my hotdog bun gun, and found that I could hit 8 out of 10 shots within 2" of the bullseye at a distance of 20' from my hand. This gun was rigged with a 5/16" shaft, 1/16" cable and two 5/8" bands.

When I picked up the second gun, rigged with two 5/8" bands, mono and a 9/32" shaft, I fully expected similar results. My shots were consistently high and left by about 12 inches.

After much head scratching, I found that the end of the flopper had been bent down about 1/4" (to make sure it opened after passing through a fish). After removing the flopper it shot just as well, or better than the first gun.

I kept names out of this on purpose. In my experience, that leads nowhere good. I called the maker, who called the shaft maker and I'm sure the issue has been addressed.

My intention is to perform testing and to share the results.

While I "knew" intuitively that small things could throw off a shot, this was the first time that I was able to see how such a small thing could have such a big affect.

My explanation is that the bent portion of the flopper acted like a wedge at the front of the shaft, forcing in up and left as the shaft moved forward through the water.

Here are a few photos of the flopper. The last one shows it next to one that isn't bent away from the shaft.

Good post Chad! I agree, the little things can often times make the difference.

That's interesting. Not that I have been around the block for long, but I have seen a couple guns with the flopper end bent like that.

That just goes to show you that you can tune a flopper but you can't tunafish.
Thanks folks...I'll be here all night...please tip your waitresses.

Great post, Chad!

Chad,

When I was preparing my gun tank(pool), I noticed a shaft sliding hard to the side in the last few feet of a 20ft shot, single band freeshafting. I examined the set-up, and the leading edge of the flopper had a ding in it anterior to the pin on the side the shaft pulled to...and it pulled several feet to that side as the shaft slowed down.
I obviously used new shafts and bands for my test after that.

Any further gun testing will probably entail using the same flopperless shaft and the same band(s) if I compare similar guns again.


On another note, since I just had back surgery, I began making new bands for all of my guns (Kudana, Deathstick, Deathstick, Kahuna Stick, 54 SS Commercial Laminate(Miked's), and 52 SS Commercial Teak), and I was cutting off some old bands when I noticed some salty clear sludge in one band and sone sandy material in another. And the gun with the liquid in the band was definitely feeling weaker on 20ft+ shots.

Just a reminder to change bands more frequently and any time you feel less power or less accuracy with your weapon of choice. And the band looked brand new on the surface and felt normal resistance with loading.

Charlie

If you squeeze in a little silicone sealant when you put in your cord or even cable or solid wishbones, this water in the bands will not happen. Many years ago we used to call this boggy rubbers. When you take them apart after they obviously dont have the power they should, they always had water in them. I always use silicone sealant with any bands, as a lube, and mainly as a sealant. I put a glob on the knot and rub it around, making sure it is all coated, and I squeeze a little into the hole in the rubber. Then just push it in, tie it, and when both are tied, pull hard to seat them, and let it harden.

Chad,

I had that happen 2 weeks ago after I shot a big grouper. A good indication that it happens is that you cannot get the shaft out of the fish with a reverse bent flopper, even to a smaller degree than you showed in that picture. And I did notice a difference in accuracy after I did cut the shaft out of the grouper's head. Unfortunately, the flopper needed a good pounding with a hammer to re-bend it into a conformal shape with the shaft, so I had to wait to get home to do it.

Along those lines, I see a lot of people not put the ring on double-flopper shafts before shooting. Even though the floppers will fold back, then aren't as strealined as when they are retained.

Not only are they not as streamlined but you stand the chance of the ring holding the floppers open and not getting good penetration.

Water is nearly 800 times denser than air. For all of us swimming creatures, this fact wields a double-edged sword.

On the plus side, water being more buoyant than air, requires much less energy to prevent falling through it (what we terrestrial types call 'sinking or dropping'). Buoyancy also frees aquatic organisms from the need to support the body against collapsing under the force of gravity, which explains why the largest marine animals dwarf the largest found on land. On the other s of thew sword, water's density requires more effort to move it out of the way enroute to your target.

Water is 55 +or- times more viscous (resistant to flow and fresh\salt is relative factor) than air. As a result, water does not move easily around a moving body with tanks (let alone doubles and deep water gear.)

Drag is an unavoidable consequence of living in a material world, and may be defined as resistance to moving through a fluid.

A layer of fluid - called the boundary layer - 'sticks' to and is carried along with the surface of a moving body creating drag. Those of us that play golf understand this with our purchase of golf balls.

Drag increases with speed, fluid density (salt\fresh water obviously effects hydrodynamics) and object size. In aquatic animals, boundary layer drag (whilst the Blasius boundary layer refers to the well-known similarity solution for the steady boundary layer attached to a flat plate held in an oncoming unidirectional flow.

When a fluid rotates, viscous forces may be balanced by the Coriolis effect, rather than convective inertia, leading to the formation of an Ekman layer.) is ultimately due to the stickiness of water: not only does a swimming organism have to carry a mass of water along with it, but - more significantly - this mass of water adheres to the inert surrounding water, further increasing drag.

A key element to understanding drag is the distinction between turbulent versus laminar flow. Turbulence is a form of fluid flow in which the molecules of the fluid move over a surface in irregular paths, resulting in the exchange of momentum from one portion of the fluid to another. Laminar means 'in layers', referring to fluid flow in which the molecules of a fluid move over a surface in discrete layers without fluctuations, so that successive particles passing the same point have the same velocity. In energy terms, a smooth laminar flow is more efficient than - and thus preferable to - a turbulent flow.

The simplest way to achieve minimum drag is through streamlining. A streamlined shape is longest in the direction of travel and tapered on both ends. But optimizing laminar flow is not as simple as one might imagine especially with dive gear.

Theoretically, the optimal shape has its maximum diameter at the anterior third of the object, with ratio of length to width of 4.5. Among fishes, many of the tunas come closest to this hydrodynamic ideal. Such specifications work fine for rigid-hulled craft such as submarines, but for flexible-bodied swimming creatures the situation is rather more complex. For a flexible form, the optimal hydrodynamic shape also features reversal of planes, in which the plane of the flattened forward portion is at right angles to the plane of the flattened rearward portion.

Bernoulli's Principle states that a foil with a curved upper surface moving through a fluid medium causes the fluid to move faster over the upper surface than the lower; this greater speed creates a negative pressure ('suction') above the foil. The plane of a foil relative to the long axis of the body to which it is attached is called the angle of attack. The greater the angle of attack, the more both lift and drag (which operate at right angles to one another) increase. Stalling occurs when laminar flow separates from the surface of a foil. The speed at which this occurs is called the stalling speed and varies with the size and shape of foil.

Planing surfaces allow control of yaw, pitch, and roll, but also increase drag. Turbulent flow at the distal tips of wings or fins - called wing- or fin-tip vortices - increases drag with increasing speed. Larger foils can carry greater weights, but also experience greater drag. A foil's ratio of length to width is termed its aspect ratio; a foil with a high aspect ratio affords a lot of lift relative to drag - which allows a shallower gliding angle and a higher stalling speed than low aspect ratio foils. In the case of an oscillating foil, in the form of a caudal fin or pair of flukes, a high aspect ratio tail provides maximum thrust with minimum drag.

Thrust results when a propeller or tail pushes fluid backward; the fluid pushes the body forward with the same force. In practice, velocity is dependent upon forward thrust minus rearward drag. The more drag can be reduced, the faster and more efficiently a body can move through a fluid.

The course of a body through a fluid can be adjusted by changing either body shape or lift and drag characteristics of foils.

Changing body shape by bending to the left or right will change course in the respective direction.

By adjusting the lift and drag characteristics, a moving body can achieve fine control over its course through a fluid.

As quoting RW " the absolute “laws of physics” CAN’T apply because of inherent imperfections. A “perfect” gun would have to made by a “perfect person” using a “perfect machine” and “perfect materials.”

So, My point is, with some tweaking to all shafts and spearguns; they can shoot quieter, further, safer and be much easier to use overall providing a higher level of satisfaction! Proof in the freezer if measured by some with the amount of fish you have... Others by the experience or the adventure...

Personally, if you research, tweak and find what works best for you producing memories, full freezers and good friends along the journey; it's all good at the end of the day!!!

you must have a very short torso if your ass is towards the front 1/3 while swimming forwards

:rofl::rofl::rofl::rofl: