Tying Parnell knots

[@cincotennisacademy]

Superv demonstration

[@Mr10sStringer]

Thank you

[@VeganO_MexicanO]

Nice 👍 What machine are you using in this one? And how many machines do you own? 😅✌️

[@Mr10sStringer]

I’m using a Tourna 700ES machine in this video. Presently I have 2 machines. The one in this video and a Gamma X-STRINGER. I have made videos with my Gamma 6004 with and without a Wise tension head and a Babolat Star 5, but I do not have the 6004 or Star 5 any more.

[@samharner2023]

Is poly string at 30lb still stiffer than natural gut at 60lbs?

[@Mr10sStringer]

I have no idea, but that’s a great question. To be sure you would need to measure the dynamic tension of the string bed. A stiff string like poly wil not stretch as much as a softer string like natural gut. So my gut feeling tells me gut would still be the easier string on the arm even is the DT value may be higher because it has less resistance to stretching. Once a stiff string is deflected from string to ball contact the tension going up until the string straightens back so so a stiff string, even at lower tension, gets dramatically higher at contact.

[@samharner2023]

Hey Irvine, so mgr/I is a real thing, yeah? What’s the point of it? Does it allow you to swing the racquet faster?

[@Mr10sStringer]

No. I don’t use it I go for Weight, balance, and SW.

[@samharner2023]

@@Mr10sStringer but is mgr/I real? Is it real physics though? could you tell me what it does?

[@samharner2023]

@@Mr10sStringer I think you did an experiment before where you put weight at 7” and you found it give quicker swing speed?

[@Mr10sStringer]

@@samharner2023 is it physics? No it is math. It gives you an overall idea of the ratio of torque (mass time balance) divided by inertia. Getting the right feel in your hand is determined by torgue or mass times balance. Too much inertia makes your racket too sluggish while not enough inertia makes the racket too fast and throws off you timing.

[@Mr10sStringer]

@@samharner2023 according to the laws of physics that is impossible. If you eliminate gravity by pivoting a racket on a horizontal plain as most SW machines do the slower a racket swing the higher the inertia of SW. SW has nothing to do with swinging a racket but everything to do with accelerating the racket. When you think of a tennis racket’s SW, don’t think swing, think snap or acceleration.

[@samharner2023]

Does weight under the buttcap make the racquet less powerful?

[@Mr10sStringer]

Yes it adds SW to the racket by a factor of mr^2. If you add 5 g u der the butt cap you add (.005*10*10) 0.5 kgcm^2 to the SW. as inertia or SW increases so does power.

[@samharner2023]

@@Mr10sStringer i don't understand. but why does the racquet seem less powerful when i add weight under the buttcap?

[@samharner2023]

@@Mr10sStringer also, how much SW is increase if I add lead tape to the throat of the racquet? I forgot the equation for it.

[@Mr10sStringer]

@@samharner2023 you can feel power all you feel is mass and balance. Lowering you balance will lower the Center of Percussion which is a sweet on the racket. Maybe you ball contact point is too far above the CoP. The farther away from the sweet spot you contact the ball the weaker your shots will be. Before removing weight try hitting for at least a week or so. You will adjust to the new sweet spot that way. The best way to just your rackets power is to hit with someone you normally hit with. They can tell you if you have more power or not.

[@Mr10sStringer]

@@samharner2023 the formula is mr^2 or mass in kg time the distance squared. You will have to measure the distance from the but cap to the point in the throat where the center of your mass is located. The pivot for SW is 10 cm up from the butt cap so subtract 10 from your measured distance. The mass must be in kg so divide weight in grams by 1,000. For example, if you add 2 g at 30 cm your SW increase is (2/1,000*(30-10)*(30-10) or 0.002*20*20) 0.8 kgcm^2.