Innovative Golf Putter Cody Jackson, Jeffrey Keenan, Corey Tillson, Victoria Thacher

Mentor: John Novotny Liaison: Tyler Sullivan

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Problem Statement

Improves consistency of short game performance Complies with USGA regulations Visual alignment cues Generates pleasant sound Generates pleasant feel Aesthetically pleasing Promotes smooth ball roll

-Topspin -Decreased ball loft

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Project Importance

Putting accounts for over half the shots taken

in a game of golf BombTech golf released their first club in 2012 Putter will be crucial in branding BombTech Ensure user enjoyment

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Objectives and Constraints

USGA Conforming

- Appendix II: Design of Clubs Improved performance Aesthetically pleasing Machinable Corrosion, temperature, and wear resistant BombTech color scheme

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Background Research

Examined all aspects of putter geometry Scholarly articles and research Looked at other top market putters USGA regulations Difficult to find competitors information

MOIz and center of mass were crucial Sound and feel hard to estimate in preliminary stages

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Background Research

Biomechanics of swings Alignment cues Psychological impacts of putting

Yips, nerves, and the average terrible golfer

High Contrast Alignment Cues

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Requirements

COM < 8mm above the club base COM > 15mm behind club face MOIz approaching 5900 g cm2

Majority weight positioned on outer 25% of club High contrast, distinctive alignment cues Heavy head > 400g Acceptable sound Acceptable feel Face angle 2°-3° degrees Comparable results with market putters

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Design Evolution Phase 1 (August – October)

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Design Evolution Phase 1 (August – October)

Phase 1 focused on Aluminum as primary material Aluminum considered for potential machining at UVM and lowered costs Considered using inserts in body and face Aluminum discarded in favor of carbon steel, which is a higher quality putter material

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Design Evolution Phase 2 (October – January)

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Design Evolution Phase 2 (October – January)

Phase 2 focused on carbon steel as primary material Inserts were discarded as a possibility in favor of a one-piece design Preferred design shown below Preferred design discarded due to high machining and production costs

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Design Evolution Phase 3 (January – May)

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Design Evolution Phase 3 (January – May)

Phase 3 focused on carbon steel as the primary material Designs were created with consideration for minimizing machining cost Distribution of weight to outer portions dominated design themes Final design chosen by client as design best suited for market and distribution

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Final Design Overview

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Final Design Overview

Precision CNC milled by Stephens Precision Inc. One-piece 12l14 Carbon Steel Head E-nickel plated Dot peen engraved logos

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z

y

x

Toe Side

Heel Side

50% of the club head weight is on the outer 25% of club geometry

Large MOIZ - 5850 g cm2 C.O.M. located at 0.4 cm above bottom and 1.7 cm behing the face

Increased sweetspot Mishit management

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z

y

x

Toe Side

Heel Side

Hole in which center mounted shaft is epoxied

Cut out added for weight reassignment and alignment assistance

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Face angle 2.5° Promotes topspin Reduces backspin Reduces skipping

Rounded bottom Helps with club lies when player rests it on the green Prevents digging

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Hand-painted, bright green alignment cues

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Analysis

Consistency Testing Initial Roll Characteristic Analysis Pilot/Qualitative Testing

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Consistency Tests

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Consistency Tests

Determined dispersion of putts hit off the center of the club, also known as the “sweetspot” Velocity on off center hits decreases due to energy loss as ball deviates from the center point on face Lose of energy leads to putts that stray away from desired target and travel shorter distances

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Consistency Tests

Consistent pendulum-style putting rig developed to produce constant, low error and bias putts at a fast rate Radial dispersion distances of shots varying from the clubface center compared to determined optimal distance on shots off the center of the face Three putters used for comparison – BombTech Grenade, Odyssey Rossie, TaylorMade Rossa

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Testing Rig

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Test Parameters

Three Putters

Control set as average distance and location on shots from sweetspot One cm variations off of the center: up to four cm toward heel and toe 20 trials per face location Results averaged and variance/standard deviation analyzed

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Consistency Results

BombTech Grenade (Sweetspot Distance: 360 inches)

Face Location (cm off face) Average Radial

Dispersion (in) Standard Deviation (in) RDispersion/DSweetSpot

Heel -- 4 37.250 8.447 0.104

Heel -- 3 26.850 10.577 0.075

Heel -- 2 16.813 10.130 0.047

Heel -- 1 16.200 3.918 0.045

Center -- 0 N/A N/A N/A

Toe -- 1 12.775 6.219 0.036

Toe -- 2 12.050 6.547 0.034

Toe -- 3 35.675 8.580 0.099

Toe -- 4 59.500 11.371 0.166

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Consistency Results

TaylorMade Rossa (Sweetspot Distance: 359 inches)

Face Location (cm off face) Average Radial

Dispersion (in) Standard Deviation (in) RDispersion/DSweetSpot

Heel -- 4 77.575 10.700 0.216

Heel -- 3 48.163 7.940 0.134

Heel -- 2 27.500 7.210 0.077

Heel -- 1 22.175 8.430 0.062

Center -- 0 N/A N/A N/A

Toe -- 1 18.145 10.630 0.051

Toe -- 2 28.100 7.870 0.078

Toe -- 3 54.815 9.670 0.153

Toe -- 4 100.588 12.130 0.280

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Consistency Results

Odyssey Rossie (Sweetspot Distance: 348 inches)

Face Location (cm off face) Average Radial

Dispersion (in) Standard Deviation (in) RDispersion/DSweetSpot

Heel -- 4 132.458 10.670 0.380

Heel -- 3 86.163 13.090 0.240

Heel -- 2 57.920 14.470 0.170

Heel -- 1 31.855 16.150 0.090

Center -- 0 N/A N/A N/A

Toe -- 1 17.030 8.490 0.050

Toe -- 2 22.798 15.150 0.070

Toe -- 3 64.053 18.980 0.180

Toe -- 4 110.588 17.110 0.320

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Consistency Results

One-way ANOVA used for analysis

Predetermined level of significance set at 5% Null Hypothesis: all mean dispersion ratios are statistically equal Alternate Hypothesis: The mean dispersion ratios statistically differ

Significant reduction in dispersion by Grenade compared to other tested putters (Except at 1 cm toward toe) Comparable precision compared to TaylorMade and increased precision compared to Odyssey

Analysis of Variance (One-Way ANOVA) of Normalized Consistency/Accuracy Test Data

BombTech Grenade TaylorMade Rossa Odyssey Rossie

Face Location

(cm off face) RDispersion/DSweetspot

Standard

Deviation RDispersion/DSweetspot

Standard

Deviation RDispersion/DSweetspot

Standard

Deviation

Level of

Significance

(α=0.05)

Heel -- 4 0.104 0.022 0.216 0.029 0.380 0.032 1.306*10-36

Heel -- 3 0.075 0.030 0.134 0.026 0.247 0.051 1.949*10-20

Heel -- 2 0.047 0.027 0.077 0.020 0.166 0.040 8.087*10-18

Heel -- 1 0.045 0.013 0.062 0.024 0.091 0.044 3.027*10-5

Center -- 0 N/A N/A N/A N/A N/A N/A N/A

Toe -- 1 0.036 0.017 0.051 0.027 0.049 0.026 0.103

Toe -- 2 0.034 0.020 0.078 0.024 0.065 0.042 5.379*10-5

Toe -- 3 0.099 0.027 0.153 0.026 0.184 0.056 2.949*10-8

Toe -- 4 0.166 0.036 0.280 0.032 0.317 0.047 1.276*10-17

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0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-4 -3 -2 -1 0 1 2 3 4

Rati

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f R

ad

ial

Dis

persio

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o I

deal D

ista

nce F

ro

m S

tarti

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P

oin

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Distance from Center of Club Face: Heel to Toe (cm)

Radial Dispersion Vs. Club Face Location

BombTech

Odyssey

TaylorMade

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Initial Roll Characteristic Analysis

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Test Parameters

Automated testing rig used for consistency/ accuracy tests used to ensure consistent trials 500 frames/second high-speed camera Three putters Five trials per putter First ¼ turn determined to be representation of pure roll Skipping, angular rotation, angular velocity, and translational velocity examined

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Initial Roll Characteristic Results Normalized Results

Lowest time ratio indicates that the Grenade achieves pure roll the quickest, while minimizing time spent skidding

Grenade, 0.19

Odyssey, 1.14

TaylorMade, 0.89

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Putter

t(skip

) /

t(1/4

turn

)

Comparison of Normalized Time Parameter

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Initial Roll Characteristic Results Normalized Results

Low velocity ratio indicates that the Grenade induced a lower rotational velocity on the ball, thus less skidding and over-rotation of the ball

Grenade, 2.23

Odyssey, 3.00

TaylorMade, 2.91

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

Putter

ω(1

/4)

/ V(1

/4)

Comparison of Normalized Velocity Parameter

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Initial Roll Characteristic Results High-Speed Footage

BombTech Golf Grenade Putter - Initial Roll Characteristics - High Speed Camera

https://www.youtube.com/watch?v=cyFuyrtW3ok

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Pilot/Qualitative Testing

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Test Parameters

Survey created to gather independent tester’s opinion on sound, feel, and appearance Portable putting mat set up in public space (between Davis Center and Bailey-Howe Library) to attract potential testers Three putters provided for comparison Project explained to tester’s, who were encouraged to give honest feedback Surveys taken by friends of team members and non-golfers discarded for accurate analysis

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Pilot/Qualitative Testing Results

Results of Head to Head User Testing (n=10)

(Rating out of 10)

BombTech Grenade TaylorMade Rossa Odyssey Rossie

Sound 8.28±0.29 7.00±1.67 7.50±1.38

Feel 8.50±0.53 7.00±1.41 6.86±1.57

Appearance 8.29±0.83 7.43±1.81 6.43±1.90

Not enough data points to perform full statistical analysis Low sample pool (10 golfers) does show initial opinion trends Sampling at a golf course would’ve been preferred, but local courses had yet to open at time of testing

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Issues With Testing

Unable to test with truly comparable CNC, high end putters due to monetary and availability constraints Would’ve preferred to test different parameters of putting – different impact points, shorter vs. longer putts, variable green speeds Testing occurred on carpet and synthetic putting mats due to poor conditions of local putting greens Difficult to accurately calculate roll ratio due to estimation of geometric parameters

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Conclusions

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Putter exceeded expectations in the consistency test

~50% reduction in radial dispersion Statistically conclusive data

Roll testing clearly showed quicker production of pure roll

~70% reduction in skipping Received nearly unanimous positive qualitative first impression feedback Putter entered the market April 28th

Looking Forward

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Current design could be modified to produce a blade style putter if BombTech desires The Grenade will be presented and used during “Demo Days” at local golf courses Upcoming independent reviews Possibly see it in the hands of a pro on the PGA Tour!

Acknowledgments and Thank You’s

BombTech Golf and Tyler “Sully” Sullivan John Novotny and Jeff Frolik Stephens Precision and Julian Stephens UVM FabLab and Hunter O’Folan UVM-CEMS Student Services Karen Bernard Catamount Country Club Gonzo’s HD Sports John Dow, GM of Golf & Ski Warehouse All of our friends and family and their support

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Questions?

#PullThePin

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