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ohplease
03-03-2005, 02:10 PM
How do I hit a heavy ball? Can lead tape help? How much weight should I add? Where should I put it?

I got tired of seeing these questions, so I'm providing a solution. First, some background: maximizing racket (or bat or golf club or even sword) impact is all about momentum transfer. Outside of strings or stiffness - for efficient energy transfer, you can either swing faster or swing more mass or both. Of course, for any given player, there will be an ideal racket mass such that they're still able to swing it at a speed that maximizes momentum transfer.

But what of the racket mass? Unless you strike exactly at the center of mass (or balance point), the amount of racket mass involved in the transfer will be some fraction less than the total. Call it the effective or apparent mass at contact. The closer the balance point or center of gravity is to the point of contact - the larger the fraction of total mass involved in the strike. Think hammer weighted frames. At their respective sweet spots, here are some of the frames with the most apparent mass at contact from the last few years: Aerotour Pro Ltd., M Fil 3 Hundred, Catapult 10, Aerotour Pro Ltd. +, Super Revelation 108, Pro Exreme FT, T Fight 315, 200G 95 (Tour Specification), 600G I.C.E., T Fight 325.

Ok, so other than maximizing power - what else do we want from a tennis racket? Well, we also want to make sure our arms don't fall off. That means that we want to minimize the amount of force pushing back into our arms at any given impact. In the same way that effective or apparent mass at contact is really about levers and fulcrums and mechanical advantage - the amount of shock at contact really depends on how far away the balance point is from our hand. Further away = more force (hammer weighting, bad), closer = less force (traditional head light balance). Here are some frames whose weighting minimizes shock: Liquidmetal Prestige Mid, Aeropro Control, Tour NXGraphite Mid, Pure Control Team, Tour NXGraphite OS, Hyper Pro Staff 5.0 Stretch MP, Pure Control + Team, Type C/93, Pure Control MP Team

Hm - a conundrum. We want to feel the sensation of a plowing ball strike, but at the same time we don't want cortisone shots. When we consider only weighting and balance, what are some frames that maximize effective mass while minimizing shock due to weighting and balance? Here are some: Aerotour Pro Ltd. +, Liquidmetal Prestige Mid, Tour NXGraphite Mid, Aeropro Control, M Fil 2 Hundred, Pure Control + Team, Aerotour Pro Ltd., Pure Control Team, Pro Staff 6.0 Original 85, Pro Staff Tour 90.

Say your racket isn't in any of those lists - is there a way to play with lead tape such that it could be? If so, maybe you don't want the swing weight or the balance to be any lower or higher than some numbers you have in mind. Maybe you don't want the total mass to be any greater than some target figure. Maybe you want to maximize the apparent mass to swing weight ratio. Maybe you only want lead tape at 3/9/12, or only at the throat, handle, and 10/2.

Before I send you to the tool, some notes: I'm not trying to horn in on the USRSA's action. They've got some great tools and are a fantastic resource - I just felt that none of their tools did quite what I wanted. Consequently, in deference to them, I'm not going to reveal either their (or my) shock or apparent mass formulas - though I will say that it's just simple mechanics and can easily be re-derived, especially if you spend some time reading about swords or baseball/softball bats. And levers - especially levers.

Anyway, here you go: http://specgeek.50megs.com/LeadTapeOptimizationApplet.html

Hopefully it will be useful to somebody out there.

Roforot
03-03-2005, 03:18 PM
A good intro and I'm curious, but I could not get anything out of the link. Just a blank page.

kv581
03-03-2005, 03:50 PM
A good intro and I'm curious, but I could not get anything out of the link. Just a blank page.
You need java installed on your computer.

nytennisplayer
03-03-2005, 05:26 PM
wow thats an awesome applet. kudos.

Kaptain Karl
03-03-2005, 10:51 PM
Okay, but how's your formula gonna "translate" into how it feels? Ya still gotta go out and hit with it to see if you like it.

- KK

ohplease
03-04-2005, 08:53 AM
wow thats an awesome applet. kudos.

Thanks man.

Okay, but how's your formula gonna "translate" into how it feels? Ya still gotta go out and hit with it to see if you like it.

- KK

In the few informal tests I've tried - let's just say that the number crunching's suggestions made a sub 300 gram tweener swing and strike more like the conventional midsized player's frame I used as a target than any of the guessing attempts I had previously tried. Did they "feel" the same? Of course not - totally different frames. Did they play similarly? Much more so than any of the previous attempts.

Additionally, something I forgot to mention: consider racquet research's tailweighted hammer 6.2

mass length balance sw recoil effective mass
mod 394 28 28.58 390 254 137
stock 258 27 39.37 334 111 172

The tailweighted delivers way less shock - but it also brings less mass to bear at contact. So, despite the added leverage from the handle extension, the increased static and swing weights, and in spite of the increased comfort due to weighting - we're now probably hitting a less penetrating ball.

tom-selleck
03-04-2005, 10:49 AM
thanks for the applet and the writeup!!! much appreciated.

but i can't interpret the output.... i assume it works because it spits out alot of numbers.

how much lead tape can you add to a low swing weight racquet, before you get to the point where you're better to start with a more appropriate racquet....

ohplease
03-04-2005, 11:30 AM
thanks for the applet and the writeup!!! much appreciated.

but i can't interpret the output.... i assume it works because it spits out alot of numbers.

how much lead tape can you add to a low swing weight racquet, before you get to the point where you're better to start with a more appropriate racquet....

Sorry - with the default values (adding 15 grams to the pure drive standard, maximizing effective mass), the top row is the best value. That adds 5 grams an 2.54 cm up from the butt, 9 grams in the throat at 34 cm up, and 1 gram split between 3/9 at 52 cm up. That results in an effective mass of around 175 grams.

Note that rackets considered to have that plow through sensation (volkl c10 pro tour, yonex rd-7) have effective masses around 180-190 grams. The trick is to keep that number high while also minimizing shock (ie. - maximizing recoil weight).

As far as the point where you're better off just getting a new racket? I have no idea - though I tend to think that such a point probably doesn't really exist. Unless, of course, you just want to buy a new racket.

Gaines Hillix
03-04-2005, 02:11 PM
ohplease, how does the POG OS fare with your algorithum? BTW, I'm using FireFox and have Java and Java Script enabled and I still just come up with a blank page when I try to open your applet. :-(

ohplease
03-04-2005, 02:39 PM
ohplease, how does the POG OS fare with your algorithum? BTW, I'm using FireFox and have Java and Java Script enabled and I still just come up with a blank page when I try to open your applet. :-(

You need to install the java plugin. For firefox, as per the instructions here: http://www.mozilla.org/support/firefox/faq.html#q2.2 Otherwise, get the JRE here: http://java.sun.com/j2se/1.4.2/download.html

In the "least shock list" I mentioned - the best was the LM Prestige Mid at 172 kg*cm^2 - POGO is at 184 kg*cm^2 - so it's still the best. However, it also doesn't hit that heavy a ball - only 156 grams apparent mass. From just fiddling with the specs, it appears the choice really is comfort or putting some beef on the ball - POGO happens to be a comfort choice, Hammers are a momentum choice, and sticks like the LMPM and Aeropro Control seem to strike a nice balance between the two - at least in terms of weighting only - not in terms of string pattern, stiffness, etc. Interestingly, classically weighted player's frames seem to also emphasize momentum over comfort. For example, like the RD-7 and C10PT, the PSC 6.1, anecdotally and apparently numerically is just a bludgeon.

Also, it's not "my" algorithm - it's standard mechanics. The USRSA's recoil calculator will give you the same numbers, as will any number of versions of the formula mentioned by various softball/baseball bat or sword enthusiasts websites (btw. tennis players ain't got nothing on those people in terms of spec obsession - not by a long shot).

Kaptain Karl
03-04-2005, 10:17 PM
... formula mentioned by various softball/baseball bat or sword enthusiasts websites (btw. tennis players ain't got nothing on those people in terms of spec obsession - not by a long shot).
That is a truly scary thing to read...!

- KK

aj_m2009
03-06-2005, 01:41 AM
How do you get it to work? I put in all of the stuff and I pushed the button but it doesn't do anything. Can someone please help me?

gmlasam
03-06-2005, 07:29 AM
Nice work ohplease. I have it bookmarked.

raftermania
03-06-2005, 08:51 AM
Hey Ohplease, great article on customizing. I'm anxious to get this applet of yours in gear but I get a blank page too. I'm running IE 6 and I do have Java runtime installed (For playing Yahoo! Pool/Chess), will that not do the trick?

Thx,

ohplease
03-07-2005, 08:13 AM
Hey Ohplease, great article on customizing. I'm anxious to get this applet of yours in gear but I get a blank page too. I'm running IE 6 and I do have Java runtime installed (For playing Yahoo! Pool/Chess), will that not do the trick?

Thx,

That should do it. I really don't have any guesses as to what else might be wrong.

ohplease
03-18-2005, 01:02 PM
Updated - will now actually tell you if your desired specs can't be achieved.

ohplease
01-06-2006, 02:29 PM
Updated, replaced 10&2 weighting option with top of handle in response to the johncauthen threads.

jonolau
01-07-2006, 12:28 AM
This is a truly awesome site, thanks for the tip!

meh
01-07-2006, 12:34 AM
ohplease, did you design the app?

timmyboy
01-07-2006, 01:13 AM
that's an interesting read. I don't find that lead tape does too much. I like the added weight, but i don't think i'd play signifigantly worse without it.