Backspin Rate Research Articles

Effect of 3-Piece Golf Ball with Difference Structures on Golf Ball Performance according to Driver and 52 Degree Wedge Shot

[Purpose] This study aims to demonstrate how, in 3-piece golf balls, the structure difference between dual core with single cover (DSB) and single core with dual cover (SDB) balls can affect the performance of drive shots and 52 degree wedge shots. [Method] The differences between the two ball types were determined by conducting drive shots at 80, 90, and 100 mph swing speeds along with 52-degree wedge shots at 70 mph. [Result] No significant differences were observed between the two balls in the drive shot performance at 80 mph swing speed. In contrast to 80 mph, better performances in DSB were observed in the distance to maximal height (p=0.005), carry distance (p=0.001), and total distance (p=0.027) at 90 mph swing speed. At 90 mph, spin rate (p=0.007), maximal height (p=0.032), carry distance (p=0.006), and flight time (p=0.041) in DSB were observed better performance compare with SDB. Launch angle (p<0.001), back spin rate (p<0.001), total spin rate (p<0.001), height, and decent angle (p<0.001) at wedge test were significantly difference between DSB and SDB. The maximal height (p=0.032), backspin rate(p=0.007), carry distance(p=0.006), and flight time(p=0.041) were also significantly difference between DSB and SDB. [Conclusion] These results demonstrated that DSB would be the more favorable option than SDB for golfers or coaches trying to improve their drive distance and shot preciseness.

The relationship between foot-ball impact and flight characteristics in punt kicking

In football kicking, a player imparts the initial flight characteristics by impacting the ball with his foot. Imparting the correct combination of flight characteristics is the basis of a successful kick. However, examination of the relationship between foot-ball impact and flight characteristics for a non-spherical ball, the ball shape in Australian football and rugby, has been limited to ball velocity. Consequently, little is known of the relationship with other flight characteristics of ball trajectory and spin. The aim of this study was to determine the relationship between impact and initial ball flight characteristics. A mechanical limb, designed to replicate the impact phase of Australian football, performed punt kicks. Four impact characteristics were systematically examined to determine their influence on flight characteristics: foot velocity, medial–lateral impact location, proximal–distal impact location and ball orientation. This study identified each flight characteristic (ball velocity, elevation angle, azimuth angle and spin rate) were influenced by multiple impact characteristics (foot velocity, ball orientation and/or impact location). For example, elevation angle was increased by foot velocity, relative foot-ball orientation and proximal–distal impact location on the foot. Foot velocity had the largest influence on ball velocity (linear slope = 1.43). Medial–lateral impact location had the largest influence on azimuth angle (linear slope = 2.73). Ball orientation had the largest influence on elevation angle and back-spin rate, both measures were sine dependent (elevation angle curve amplitude = 19.4°; back-spin rate curve amplitude = 2754°/s). Players must control all impact characteristics to successfully kick to their desired destination.

Effect of string bed pattern on ball spin generation from a tennis racket

Topspin has become a vital component of modern day tennis. Ball-to-string bed and inter-string friction coefficients can affect topspin generation from a racket. The aim of this research was to determine the effect of string bed pattern on topspin generation. Tennis balls were projected onto nine head-clamped rackets with different string bed patterns. The balls were fired at 24 m/s, at an angle of 26° to the string bed normal with a backspin rate of 218 rad/s and outbound velocity, spin and angle were measured. Outbound velocity was shown to be independent of string bed pattern. Outbound angle increased with the number of cross strings, while outbound topspin decreased. In the most extreme case, decreasing the number of cross strings from 19 to 13 increased rebound topspin from 117 to 170 rad/s.

The Effect of Fastball Backspin Rate on Baseball Hitting Accuracy

The effectiveness of fastballs of equivalent speed can differ; for example, one element of this difference could be due to the effect of rate and orientation of ball spin on launched ball trajectory. In the present experiment, baseball batters' accuracy in hitting fastballs with different backspin rates at a constant ball velocity of 36 m/s was examined. Thirteen skilled baseball players (professionals, semiprofessionals, and college varsity players) participated in the study. The movements of bat and ball were recorded using two synchronized high-speed video cameras. The Pearson product-moment correlation coefficient (r) was calculated and used to analyze the relationship between ball backspin rate and the vertical distance between ball center and sweet spot at the moment of ball-bat impact. Ball backspin rate was positively correlated with increases in the distance from the optimal contact point of the swung bat (sweet spot) to the actual point of contact (r = .38, P < .001). Batters were most effective at the usual backspin rate for the ball velocity used. The decrease in accuracy of the batter's swing that was observed when the fastball's backspin deviated from the usual rate likely occurred because experienced batters predict ball trajectory from perceived ball speed.

선 충격량과 공의 회전 속도와의 상관관계

Golf ball spin rate after impact with club is created by the contact force, which is greatly influenced by ball and club mass, material, impact speed, and club loft angle. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of the ball, and the tangential force creates the spin. Especially, the tangential force takes either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail. It is shown in this work that the linear impulse of the tangential force is directly related to generation of back spin rate of golf ball. The linear impulse can be calculated from the tangential force, which depends upon many factors such as ball and club mass, material, impact speed, and club loft angle. In this research, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and the contact time at impact between golf club head and ball are computed using FEM.

골프 공의 충돌 시 스핀 생성 원리 연구

It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and force. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail in the literature. In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.

Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.

Material and surface effects on the spin and launch angle generated from a wedge/ball interaction in golf

Backspin rate and friction coefficients have been studied for a range of commercially available wedges and multi-piece golf balls using a mechanical golfer and a modified pin-on-disc tester. Analysis of shot characteristics for wedges with three different surface roughness values and two golf ball types (two-piece ionomer covered and three-piece polyurethane covered) was carried out using the mechanical golfer, whilst pin-on-disc testing was performed to determine the friction coefficient between the different golf ball covers (with a range of hardness values) and steel discs with a range of surface roughness values seen for different wedges. It was found that the polyurethane covered balls (lower hardness) showed greater backspin than the ionomer covered balls (higher hardness), and showed higher friction values during the pin-ondisc testing.

Some additional CFD flow field and pressure solution results for dimpled golf ball with backspin rate of 2,000 rpm

Some additional CFD flow field and pressure solution results for dimpled golf ball with backspin rate of 2,000 rpm

Numerical analysis of golf club head and ball at various impact points

This paper investigates how the physical characteristics of a golf club head affect its performance, with the aim of developing a superior club head. The physical characteristics investigated were the magnitude of the moment of inertia and the location of the centre of gravity. The performances were classified as the release velocity, the spin rate of the ball and the size of the uniform restitution area. In the numerical analysis, several kinds of club head were modelled with different moments of inertia and different locations of the centre of gravity. For every club head model, the ball was hit at various impact points and the release velocity, spin rate and size of the uniform restitution area were calculated. The results are as follows. The bigger the moment of inertia Izz about the vertical axis or the shallower the depth of the centre of gravity, the less side spin rate caused. Izz has more influence on the side spin rate than the depth of the centre of gravity. The shallower the depth of the centre of gravity, the more back spin rate caused. The size of the uniform restitution area increases in proportion to the increase in Izz, or in proportion to the decrease of the depth of the centre of gravity.