Wider body => stable through the contact

Discussion in 'Racquets' started by maxpotapov, Feb 3, 2014.

  1. maxpotapov

    maxpotapov Hall of Fame

    Joined:
    Feb 19, 2009
    Messages:
    2,523
    Location:
    Ukraine
    I played with 19-20 mm constant beam racquets all my life, but recently I experimented with some old Prince Shark MP, which has 26-22 mm "aerodynamic" frame. I modified it quite a bit, and it turned out headlight and polarized.

    What I found was much better stability through the contact compared to classic designs, and now I'm wondering what could be the reason.

    The racquet has ample swing weight and twist weight, thanks to those massive "shoulders". Clearly the tapered/aerodynamic frame really helps to fight twisting. But the most important thing is, such design forces me to hit a bit more through the ball, so that I don't frame it.

    I can still put a lot of action on the ball, but now I'm more cautious and calm (and relaxed too!) in how I brush it, which is exactly what I need to put more pressure on the ball.

    For everyone who thinks that wide beam can "get in the way" of how one can work the ball, this "obstacle" can be very beneficial as it will force some very good habits (such as hitting more through the ball).

    Now I can see how AeroPro/Pure Drive designs won such popularity as "tennis made easy" technologies.
     
    #1
  2. PMChambers

    PMChambers Professional

    Joined:
    Oct 16, 2013
    Messages:
    925
    Moment of Inertia is a function of the width cubed for hollow rectangular section. Therefore small changes in the width will amplify the resistance to bending significantly. Or simply wide body racquets are extremely rigid and resist bending. The negative is the impact angle of the racquet must be less to reduce framing, the current game tends towards heavy top spin and therefore this is an issue, therefore modern racquet use more rigid materials rather than structure to get their rigidity. If you hit relatively flat and require maximum power return from your efforts, wide body racquets are fine. However, if you are into reverse kick or slice on servers, heavy topspin or chop the ball then the width can be an issue. The use of graphene, liquid metal and other highly rigid materials make the requirement of wide body racquets obsolete. As a training device to force you to hit through the ball a smaller head has similar benifits.
     
    #2
  3. jackcrawford

    jackcrawford Professional

    Joined:
    Feb 19, 2004
    Messages:
    838
    Somebody forgot to tell Nadal and Gasquet and the many other ATP players who use widebody (> 22 mm at some point on beam) frames. Head has redesigned the Radical as a widebody, knowing that "Graphene" is not enough to increase plow on a light frame. It also changes feel, which some will not like.
     
    #3
  4. Winners or Errors

    Winners or Errors Hall of Fame

    Joined:
    Jul 16, 2008
    Messages:
    1,552
    Well, I have a wider body and I'm pretty stable through contact. ;-)
     
    #4
  5. NLBwell

    NLBwell Legend

    Joined:
    Jun 18, 2004
    Messages:
    7,156
    I have a narrow body and many people have criticized me for being unstable.
     
    #5
  6. PMChambers

    PMChambers Professional

    Joined:
    Oct 16, 2013
    Messages:
    925
    Nadal & Gasquet don't use wide body racquets, the wide body era was around Couriers time, era early 90's. Their racquets might be considered wide compared to the thin box beam of Federer, though I have not checked, wide body racquets in the 90's got to nearly 40-45mm wide.

    Plow is a none scientific/engineering term identifying the response to an action. Graphene increase the rigidity of a racquet which increases it's power, which was the point of wide body in the first place, hence material selection has reduce the requirement to increase width to the extremes of the wide body era. Plow is a function of many factors including mass and rigidity, graphene on it's own is very light and as such is only used as a "strengthening" material, the mass is determined my the resin and graphite composition. HEAD have used graphene to increase or retain power whilst allow a reduce mass allowing for greater head speed, which is used to add top spin. Though this is a bit mute on current pro's as they are strong enough to wield heavy racquets without issue.

    Back to the point, if you get a 18mm box frame and make it 36mm you don't double it's rigidity, you cube it's rigidity or increase by 4x. Hence small frame width increase = large increase rigidity.
     
    #6
  7. PMChambers

    PMChambers Professional

    Joined:
    Oct 16, 2013
    Messages:
    925
    Stability is a function of many factors such as rigidity, mass, contact point from racquets nodal point, etc. Their's nothing wrong with thin beam racquet however if you find you're stability is not enough adding mass will help as long as you can manage the increase weight. It's personal choice and preference. Personally I find nearly all the all my friends racquets unstable and low power, however, having picked up the coaches racquet last week I find his mass a little excessive. But he would have been touring pro 20 years ago when racquets where significantly heavier than today.
     
    #7
  8. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    37,137
    Location:
    East side of San Francisco Bay
    Lots of assumptions and flawed thinking by the above.
    1. NLBew is a 4.5 level player, able to play in Open events.
    2. He's joking.
    3. "all my friends racket's weak and unstable"....but they can beat you sometimes, so maybe it's not all the rackets.
    4. "20" years ago is around 1994. Average weight of rec rackets, around 11 oz, average weight of ATP pro rackets, around 12.8. Just like today.
     
    #8
  9. Winners or Errors

    Winners or Errors Hall of Fame

    Joined:
    Jul 16, 2008
    Messages:
    1,552
    Yes. I sometimes wonder if people read the posts around here. I can only assume that PMChambers is joking, but I'm not sure. He got me if he is...
     
    #9
  10. movdqa

    movdqa Legend

    Joined:
    Sep 19, 2006
    Messages:
    8,899
    I had an old Wimbledon Widebody - it was a Dunlop knockoff. RA was probably mid-1980s. It was a great frame - tons of power, could hit a lot of spin. Until one day, it killed my arm. I gave it to a friend that uses it and he doesn't have any problems with it. He has a very flat game.

    The modern stuff is narrow in comparison.
     
    #10
  11. PMChambers

    PMChambers Professional

    Joined:
    Oct 16, 2013
    Messages:
    925
    What point don't you understand, the effect wide body has? The physics and material science behind it? The point I explained in words rather than equations the effect increase body width had on stiffness and flexibility? The down side of increasing a racquets width excessively? The effect of increasing mass of a racquet? That pro racquets where heavier 20 years ago than current? Racquets where even heavier 40 years ago than current? That 20 years ago racquet companies where using "hammer" and "wide" body racquets to keep the mass down whilst increasing or maintaining power. "Wide" body racquets where really wide in 90's that 22mm would have been considered normal. That tennis is about personal preference and some people play better with light and other prefer heavy frames, some like stuff whilst other prefer flex, that all pro's don't use the same spec'd racquet because they have preferences to weight, weight distribution, stiffness, etc, that I find a light racquet uncomfortable though others find it adequate? That someone finds a light racquet comfortable and that is find and they should not be worried that others fiond it inadequate? That "plow" is not a scientific term, that represents an response many effects. That mass effects plow. That stiffness effects plow. The distance from the "nodal power point" effects plow.

    I think your arguing for the point of arguing. You could read the post and do some due diligence. Search for "Moment of Inertia" and review the effects of changing dimensions. Review Bending Beam equations and the effect "Moment of Inertia" has on deflection. Review material science and compare "E" - Young's modulus or Tensile modulus and it's effect on deflection. The original question was "I found was much better stability through the contact compared to classic designs, and now I'm wondering what could be the reason." The answer isn't magic it's based in material science. The racquet is acting similarly to a cantilever beam and therefore "I"- Moment of Inertia is heavily influenced by dimension parallel to the direction of force.

    Please find attached some basic Moment of Inertia tables for various shapes.
    http://chestofbooks.com/architecture/Cyclopedia-Carpentry-Building-1-3/Center-Of-Gravity-And-Moment-Of-Inertia-Part-4.html#.UvW6zfmSzE0

    In the example I assumed a box beam a it's a simple equation, but still identifies the importance of width, a hollow oval structure would have a much more complex formula.
     
    #11
  12. Winners or Errors

    Winners or Errors Hall of Fame

    Joined:
    Jul 16, 2008
    Messages:
    1,552
    Please re-read NLBwell's post. He and I were kidding around.
     
    #12
  13. droliver

    droliver Semi-Pro

    Joined:
    Aug 24, 2008
    Messages:
    703
    Location:
    Birmingham, AL U.S.A.
    The Babolats (pure drive and APD) ARE wide body frames by any definition as that get out to 26mm in width. They aren't wide like the original Wilson Profile, but they're very similar spec wise to the tapered beam widebody sticks from Prince (the CTS series), Head (the Ventoris) and Wilson (the Ultra line) that came out in 1989-90. Those racquets are very similar in performance to "modern" racquets and show that not much has really changed on the equipment side in a long time.

    Those early tapered widebody racquets didn't catch on the men's tour because they hadn't connected the dots with the polyester strings yet, which have also been around since the early 1980's BTW (the old Polystar strings)
     
    #13
  14. ChicagoJack

    ChicagoJack Hall of Fame

    Joined:
    Aug 11, 2005
    Messages:
    2,268
    No biggie, but I think the thread could use some clarification on this particular point.

    1. "Plow" (short for plowthrough), IS a very straight forward measurement, and the word is rooted in observational science.

    2. There is much confusion about this, and I'll hazard a guess on the source. Chris Edwards is an extremely likeable guy and popular play tester with great insights. But he seems to use this word at least a 3-4 times in every TW playtest video review, for every racquet ever made. (eye roll) Many here have picked up on the phrase and it's become slang for a vague sensation of putting some mean wallop on the ball. It sort of gets the idea across, but one can come away with the concept that it's a "non scientific term" of vague origin or nebulous meaning in the process.

    3. The phrase was intitialy coined by Physicist and Tennis Researcher Crawford Lindsey. He tested hundreds of different racquets, and noted ball impacts at 13 separate locations on the racquet face for each, then created a searchable index. Plowthrough is the percentage of racquet velocity after impact. If the number is very low, or even negative digits, this means the racquet has slowed considerably or is moving backwards during the 5 millisecond impact. If the number is higher, this means the racquet "plows through" the ball with out slowing down as much.

    4. If you spend any time at all studying the index, (or play testing for that matter) you'll quickly see that overall weight and swingweight are the much larger factors regarding plowthrough, with stiffness/beam width being of minor importance with miss-hits near the outer edges. Not saying that stiffness/beam thickness does not matter, tennis is a game of inches and little things add up.

    Quote: "Plowthrough Index: The percentage of racquet velocity at the impact location remaining after impact. The lower the number, the more velocity is lost, which means the racquet head (and your arm) experiences a larger deceleration during the 5ms of impact. The higher the number, the more the racquet "plows through" the ball without slowing down as much. A negative number means the racquet location is for a brief instant actually going backwards (due to twist, recoil, rotation), not just going slower! (SEE SUMMARY BELOW) More weight will increase Plowthrough and lower racquet speed lost (i.e., less shock). Adding racquet speed increases Plowthrough but also increases speed lost (i.e., more shock) "

    Plowthrough Index
    Tennis Warehouse University
    http://twu.tennis-warehouse.com/cgi-bin/plowthrough.cgi

    [​IMG]

    -Jack
     
    Last edited: Feb 22, 2014
    #14
  15. Power Player

    Power Player Talk Tennis Guru

    Joined:
    Sep 2, 2008
    Messages:
    20,199
    Location:
    On my iPhone
    I would agree with Jack - the more weight, the more plow. I usually get that feel once I get the stick to around 335 grams and a SW around 330. If I go even bigger, the result is more plow. It can be addicting, so you have to test out the racquet in match play, and not just hitting around.
     
    #15
  16. ChicagoJack

    ChicagoJack Hall of Fame

    Joined:
    Aug 11, 2005
    Messages:
    2,268
    Yeah, I'm with you on that one. Just hitting balls leisurely for grins and giggles, I find a pretty sweet impact sensation at around 13 ounces and sw 365. But that SW just doesn't work for me in competitive play.
     
    Last edited: Feb 22, 2014
    #16
  17. Sparky

    Sparky Semi-Pro

    Joined:
    Dec 25, 2013
    Messages:
    575
    Yeah, you and me both. :twisted:
     
    #17
  18. TennisCJC

    TennisCJC Legend

    Joined:
    Apr 20, 2010
    Messages:
    5,498
    There's a lot wrong with your statement above. The "hammers" and "wide bodies" were not widely used by atp pros 20 years ago. Sampras, Courier, Chang, Agassi, Stich, Becker, Edberg, Rafter, and Guga all used thin beam rackets.

    You are correct static weight has gone down a bit but actual ATP pros still play with heavy rackets. An Analysis of 45 recent ATP pros shows the average strung weight is 12.6 oz which is still heavy. Yes, there are some around 12 and a wee bit under 12 oz, but Nestor, Monaco, Blake, Wawrika, Mirnyi, and Seppi are a few over 13 oz. Gasquet, Chela, Volandri, and Federer are all near 12.75 to 13 oz.

    The only pros who used the hammers/wider rackets were recently retired pros who Wilson payed to use them. They would have used a broomstick for the right amount of money.

    Even pros with low static weights like Rafa who is reported to be just under 12 oz to right at 12 oz in static weight have high SW. Rafa's SW is reported to be around 355-360 which is roughly the same as Federer's 12.8 oz racket.

    Also, stiffness does very little to increase power when compared to mass. Adding weight at 3/9 o'c will increase twist weight and stability dramatically even on a flexible racket. Mass also has a much bigger impact on power than stiffness. Stiffness or flex has more to do with feel and control in my view and makes a very minor contribution to power and stability.
     
    #18
  19. julian

    julian Hall of Fame

    Joined:
    Dec 20, 2006
    Messages:
    3,325
    Location:
    Bedford,Massachusetts,US
    A trick question

    Is plow index by a very definition smaller or equal than 100 percents?
    If yes is it obvious or is it implied by some laws of physics?
    If a tennis coach says "accelerate through the contact"
    is the coach implying to negate some laws of physics?
     
    #19
  20. ChicagoJack

    ChicagoJack Hall of Fame

    Joined:
    Aug 11, 2005
    Messages:
    2,268
    Hi Julian,

    The Plowthrough index is a collection of measurements which can be expressed as the percentage of total racquet velocity (tip speed) remaining after ball impact. If the racquet slows down just a little bit, you'll see a higher number. If the racquet stops moving entirely, (zero) then recoils backwards for a brief instant, this will be expressed as negative values. The figure of 100 (percent) has no other meaning in this context other than it represents the original racquet tip speed. The index has data points for 7 tip speeds: 15, 40, 50, 65, 75, 80 and 135 MPH.

    Hmm. If the answer is yes? You didn't ask a yes or no question. You asked if the plowthrough index was "smaller or equal than 100 percents". However, I'm going to guess that you continue to have issue with what is seen as an arbitrarily assigned value of 100? Again, this simply represents the original racquet head speed (tip speed) the moment before impact. Noting this is important, because unless it's noted, the speed of the racquet after impact has no real meaning.

    1. There is swing dynamics, then there is impact dynamics. These are inter-related, but let's unravel the two concepts for a moment.

    2. Ball impacts occur with time frames that are almost incomprehensible. To put this into proper context, the blink of a human eye takes place in the time span of 300 to 400 milliseconds, or 3/10ths - to 4/10th of a second. Ball impacts take place within time frames much smaller than this, about 3-5 milliseconds. On time scales of this magnitude, at the exact moment of impact, there's quite a bit going on that the player isn't even aware of, and quite a bit that he's not able to control. The racquet spins like a top, twists like a twizzler, flexes backwards, then overshoots center on the rebound (vibration) translates backwards, and wobbles like a bowl of jello.

    3. A faster swing will create more plowthrough, but also increases the ratio of speed that is lost due to increased shock. Adding more mass will also increase plowthrough (and decrease shock) but might also slow down swingwspeed. Where the rubber meets the road is that nobody wants to play with a racquet that gets beat up by the ball. We'd rather have the racquet exert some authority in the impact. As it turns out, there's not much in the way of a free lunch here. Plow turns out to be mostly a matter of swing speed and racquet mass, with stiffness/beam width making a little bit of difference in the off center hits at the edges. The index is simply a way to sort out which racquets do this better and which don't.

    4. This all makes complete sense if you realize that when you hit center, we all know the feeling. The impact sensation is really sweet. That's because the frame isn't bending, which is why vibration is minimal. When the impact is already close to 100% efficient, (no loss of power due to frame bending) then there's not much room for improvement in terms of materials, or clever design. But when you mishit near the tip, or at the edges of 3-9, there is a whole lot of bending (vibration) and frame materials, stiffness/beam width, and overall design matter a bit more.

    -Jack
     
    Last edited: Feb 23, 2014
    #20
  21. julian

    julian Hall of Fame

    Joined:
    Dec 20, 2006
    Messages:
    3,325
    Location:
    Bedford,Massachusetts,US
    I blew it

    I did not ask a right question.
    My real interest is in motion sensors.
    One of them is supposed to measure a racket head speed.
    Now a question is:
    Is it a speed of a tip of a racket before a contact?
     
    #21
  22. ChicagoJack

    ChicagoJack Hall of Fame

    Joined:
    Aug 11, 2005
    Messages:
    2,268
    I'd love to assist, but I have no expertise whatsoever regarding motion sensors. All I can tell you for sure is that rackets are (aside from volleys) swung in an arc, so location does matter in terms of racquet head speed. For instance, in a forehand stroke, if the tip of the frame is traveling at 80 mph, then the center of the strings is traveling at around 64 mph, and the throat is traveling at around 52 mph.
     
    Last edited: Feb 23, 2014
    #22
  23. julian

    julian Hall of Fame

    Joined:
    Dec 20, 2006
    Messages:
    3,325
    Location:
    Bedford,Massachusetts,US
    Numbers

    I was wondering about a source of numbers,please
     
    #23
  24. ChicagoJack

    ChicagoJack Hall of Fame

    Joined:
    Aug 11, 2005
    Messages:
    2,268
    Last edited: Feb 23, 2014
    #24

Share This Page