Aerospace Accuracy

Sponsored by: Swhacker Broadheads, C’Mere Deer & Atsko Products

By: bowhunting biologist Wade Nolan

Ever miss? If you’re a bowhunter, the answer is yes. We all occasionally miss. We miss because the arrow hits a branch, the string hits our sleeve or even because we flinched at the shot, but those misses are our fault. Do you ever wonder if your broadhead is flying true? I do and I’m working on some science that will reveal why some broadheads fly better than others.

I’m cooperating with a major university’s aerospace lab with rocket scientists who know what factors make a design fly. With missiles, it is important that they fly true. Some of them cost millions of dollars. That’s motivation with a dollar sign. To a bowhunter, a true flying broadhead is the difference between success and failure. Our research is the first and only aerodynamic testing regime done with broadhead prototypes.

This head may be the only broadhead to undergo aerospace lab testing. Here Wade Nolan discusses the testing regime and how to interpret the results.
A wind tunnel is powered by a jet engine and the wind speed is measured in hundreds of miles per hour.

We will be using a wind tunnel and a sophisticated water tunnel to conduct the tests. The water tunnel is preferred for aerodynamic testing because it offers a visual perspective. The wind tunnels operate at rocket speed. At 500 mph, things happen too fast to see. Sophisticated measuring devices alone tell the story at high speeds.

A water tunnel is an effective way to visually observe flow patterns over a wing design.

In a water tunnel, the visualization occurs because a fluorescent ultra-violet dye tracks the currents. This dye allows scientists to see wind convection patterns that feed back into design modifications. The big companies who design and produce passenger jets as well as our most stealthy bombers all spend much time in the lab before the engines are fired up.

This stealth delta wing design is very effective in directing wind vectors over its surface in a planned way to achieve lift. Although not a new design the long rising surfaces offer great lift and stability.

The water tunnel offers great visualization, which we were able to observe with the UV dye. The dye follows the current vectors and surprisingly the vectors are the same in water as in air. Math converts one to the other. Although the small size of the first test broadheads presented some challenges they yielded promising results. The prototypes that the lab typically use are 2-3 feet in length. This means the pressure sensors are recording larger numbers when the water pushed on the test rocket. All data is interpreted via a computer program.

Seeing is believing. Swhacker testing is going to make aerospace history this spring. As you see, there is a little math involved.

Our broadhead test prototypes will be large and made to exact specifications. The data gathered will be similar to the data retrieved on an authentic rocket test. Broadhead flight is not a product of luck. If it flies true, it is because of engineering…in this case aerospace engineering.

This Swhacker design looks simple. The magic is in the details.
After all, the goal is to put bucks into trucks.

For a broadhead to achieve stable flight, the same factors need to be in play as with a rocket. We will be investigating broadhead designs and revealing the results to you this spring. Leave it to Swhacker to do the science.

for more please go to: Swhacker Broadheads