BombTech Golf Releases the World's First Dual Cavity Golf Driver; This Innovative Design Was Co-Engineered With the University of Vermont and Hand Assembled in USA

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It was this unique partnership that has lead to the engineering of an original designed custom golf driver, the Grenade. Each golf club is built by hand to offer golfers guaranteed performance and the unique opportunity to customize their golf clubs if desired.

BombTech Golf launches their own brand of custom golf drivers. The golf drivers are hand assembled in South Burlington, VT and shipped direct to their consumers. The innovative technology, now called DUAL CAVITY DESIGN was co-engineered with the University of Vermont and proves to have significant improvement over current golf driver designs.

How it all started.
As told by Founder Tyler “Sully” Sullivan...

"BombTech golf was founded in 2011 out of necessity. I broke 7 drivers in 2 months…It was at that point that I threw my hands in the air and said 'Enough!' I decided it was time to make a better driver.

"I began building golf clubs, specifically drivers. Growing up playing competitive golf, I had always desired to find the best equipment on the market. Unfortunately, I continuously found myself unsatisfied. It was this desire that made me want to start my own original designed golf driver line.

"I already had knowledge of the production process and what metals would perform well. However, I knew that I needed a partner in design. I decided to reach out to my alma mater, the University of Vermont. It was there that I started working hand in hand with four senior engineering students on the design that now would be called the Grenade. This pure engineering approach allowed us to focus on the design and not on the marketing. This design was then optimized using premium materials and the best 2 piece production process available on the market. This pure engineering approach created the innovative Dual Cavity design. This unique design combined with high end materials allows us to compete and win against the biggest names in golf." Tyler Sullivan

Design Process - As told by the A Team (Engineering Students)

"We began by creating a problem statement to give our team a focused goal of what a successful design consisted of for this project and to provide guidance.

The problem statement: BombTech Golf wants a radically new golf driver head to be sold to the public. The driver head must adhere to USGA standards and must not infringe on any existing patents. It should have a loft of 10.5 degrees, be compatible with common shaft sizes, and should be designed with the average golfers’ ability in mind. Wind-tunnel testing and CFD modeling should prove that this new head is aerodynamic while offering a large sweet spot. The driver head design will be manufactured out of a Ti-1188 titanium. Samples will be tested to provide physical data as well as user tested and graded to insure that a high quality club has been created.

To gain some general ideas and a starting point, we researched patents and prior art for “aerodynamic” woods that had already been designed. This led us to club heads with dimples, channels, and grooves. We realized that a club head with a feature that reduced drag such as a cavity, such as these patents, would be more innovative and visually appealing than simply creating the most sleek club head possible.

We researched cars, boats, and trucks to see how they tried be more aerodynamic. We found our answer with trucks. A truck, like a golf club, has a large front surface that increases drag and cannot be streamlined like a small sports car. Everyone has heard the myth that you get better gas mileage with your tailgate up. This has been proven by different entities, most popularly Mythbusters. The tailgate creates a pocket of air to form in the bed of the truck which lets the oncoming air to travel over it instead of diving into the bed of the truck creating drag. We believed we could do something similar with a golf club head by making cavities in the sole of the club.

It was decided that two cavities was best to keep the center of mass directly behind the center of the club face. We created a 3-D model of a club head in SolidWorks, a Computer Aided Drafting (CAD) program. In this program we were able to use a Computational Fluid Dynamics (CFD) simulation to test different shaped cavities. We performed some simplified calculations to get a rough number for what our drag force should equal to prove the CFD models were accurate. We then began running dozens of tests to find which shape, depth, and angles of the triangles created the least amount of drag.

In order to make certain that our CDF simulations were accurate we analyzed the drag force on the club using the following equation:

F d = CDp1/2V2A
F d = Drag Force
C D = Drag Coefficient
p = Density of air at STP
A = Projected club area
V = Club Velocity
Fd = 7.21N

The density of air is known. The drag coefficient is based on a geometrical assumption and therefore also a known constant of 1.17. Since the density of air and the drag coefficient are intrinsically predetermined, we wanted to be very precise with the projected area. Using the maximum allowable face dimensions, we arrived at an area of 0.0070939047m2. It is important to have this many decimal places, as it is a multiplier of the entire equation. We also decided on a club velocity of an average amateur golfer (85mph). This is an arbitrary number as long as we use this value for all testing, both physical and computational.

This value served two purposes. It gave us a reference number allowing us to be certain that our simulations were accurate. 7.21 Newtons also served as a target maximum. Since the projected area was exaggerated our drag values at 85mph should fall below this mark. We were pleased when our simulations of our most aerodynamic design (now the GRENADE) was returning drag values of just above 5 N, well below our calculated maximum of 7.21 N.

Design Details
The basic shape of the club head was created to be a streamlined shape that was similar to current drivers on the market. The innovative feature is the Dual Cavity Design. Using CFD modeling on dozens of different designs, the optimum shape and depth of the cavities was found. The current triangular shape of the cavities with an angle of 55.8 degrees and a depth of 1 inch is shown in figure E1.

Figure E1: Dimensioned Drawing of the Grenade Dual Cavity Design.

As shown by the CFD modeling the cavities create a vortex behind the club-head to decrease drag. This vortex allows air to flow over it instead of the club head, decreasing friction and therefore drag. The decreased drag allows the player to achieve higher club-head speed with the same amount of energy put into the swing. A higher club swing correlates to a greater driving distance.

Drag Reduction was measured in a wind tunnel at 84 mph and showed a 48% reduction in drag versus a traditional shaped golf driver. Further tweaking of the design such as perfectly rounding the crown and slightly altering the depth and orientation of the cavities resulted in better and better aerodynamics according to our simulations. We knew we had the right design, it was original, sleek, and high performing.

Beyond Aerodynamics
The Dual Cavity Grenade golf driver was originally designed to reduce drag. The engineered design actually raises the center of gravity on the Grenade club head. The higher center of gravity reduces spin and creates a more penetrating ball flight. The COG reduces the "ballooning" effect that is common with many golf drivers on the market today. Reduced spin and penetrating ball flight allows more golfers to hit longer drives with more carry.

More Fairways
Since the launch of the Grenade golf driver. User testing has reported increased accuracy on mis-hits. Further research and testing has shown that the Grenade is more accurate on mis-hits. The mis-hit management or "self-correcting" technology is due to the airflow over the club head shape. The natural position for the Grenade golf driver head during a golfer's swing is square at impact. This tendency to square itself up at impact is helping golfers keep more golf balls in the fairway!

The GRENADE is truly a golf driver engineered by golfers, for golfers." UVM Engineering Students

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Tyler "Sully" Sullivan
BombTech Golf
+1 (802) 448-2094
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since: 11/2011
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