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Old 01-08-2013, 04:35 AM   #93
Technatic
Semi-Pro
 
Join Date: Oct 2009
Posts: 416
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Quote:
To give an example why this doesn't work lets consider three racquets, all 70 cm long and with a mass of 250 gram evenly distributed. Then:
to A: Add 50 g evenly distributed
to B: Add 50 g to the midpoint
to C: Add 25 g each to the top and bottom

You end up with three racquets that have that same mass (300 g) and the same balance point. So if you try to calculate the swing weight from these two values you will end up with the same swing weight, independent of which formula you use. With your method all three will be identical.
I misunderstood the matter at first:
If you add weights in one point you havd to add the Moment of inertia of that weight separately to get the right total SW.

meaning:
In case of adding 25 gram at both ends: a
The added SW with pivot point at 10 cm= 25*(10^2 + (Length - 10)^2 gr >>> 25 * Length^2
In case of the 50 gram in the center
The added SW = 50 * (bal-10)^2

If the balance point is at 35 cm and the length is 70 cm the added SW's are 90 and 31250 kgcm^2.
So this is the same difference as you mention between 350 and 290 kg cm

This is what the last section of the SW advisor calculates when you add weight.



We are testing this system and comparing it with actual SW tests on for quite some time now and we think that it is quite accurate.

Quote:
Hi Technatic - What is that 8 sided racquet? Is from late 80's? Any info would be appreciated! Thanks - Jack
It was a sample from a manufacturer, more than 20 years old, I don't think that it was ever produced.

Last edited by Technatic : 01-08-2013 at 06:59 AM.
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