Strange Variation in Powerballs

[Syed769]

I have a Blue 250hz pro and my friend has one also. After using mine he said that mine felt heavier than his. I didnt think it was possible, but after using his I felt that it is definitely a bit lighter.

We decided to open both the powerballs up and look inside for any variation and surprisingly we found one big difference that perhaps shouldnt be there. The yellow sphere has metal on the inside lining the inner track, this is what gives the powerball it's weight. I noticed that mine has one "hole" in the metal parts on each side, making a total of two "holes." They aren't really holes, but it looks as though someone has drilled into those areas, thus removing some of the metal part. They arent placed in the same places on each side either. My friends however, has a total of 4 drilled areas, 2 on each side. That's why mine feels heavier because his has more metal drilled out. Also, one of the drill holes in his has also shaved away a little of the plastic "cross" in the sphere.

I don't really know what to think of this, but im wondering whether all powerballs have these "drill holes" and why mine has 2 and my friends has 4. I'm also wondering if this has some negative effect on performance because the holes are not places symmetrically.

[Adrena1in]

I asked this when I first discovered those drill-holes. They're just there to give the rotor it's unequalled balance, ensuring it's smooth and vibration-free right up through the rev-range.

I've also noticed that some Powerballs have more drill-holes than others. However, it's such a small hole I'm sure you wouldn't really be able to notice the difference just by holding them...or perhaps you can. Have you actually weighed them to see what the difference is?

Mind you, I've got two old 250Hz Powerballs and two new ones, and the new ones are definitely a little bit heavier because they have that cylindrical counter-weight on one side of the axle, whereas the old ones don't. I think this reduced weight does make me think the older ones are quicker, (even though they do really appear to be.)

I'll get some electronic scales soon and weigh all my Powerballs to see how they vary.

[Dennis]

Hi Syed769,

I don't really know what to think of this, but im wondering whether all powerballs have these "drill holes" and why mine has 2 and my friends has 4. I'm also wondering if this has some negative effect on performance because the holes are not places symmetrically.

On the contrary! The holes are especially drilled to accurately correct the balance of the rotor! This ensures that, even at high speeds (i.e. 15000 rpm), the rotor doesn't vibrate so hard that you can't keep it under control. You can imagine the rotor's are fabricated automatically; thus, there is a difference in each rotor's weight distribution due to minor variances during production. This is analyzed by a computer and corrected by drilling holes (that's why it says "Balance corrected by computer..." on the box). It is like balancing the wheels of a car after the tires have been replaced by attaching little weights on the rim.

Notably, this is one of the major differences between a genuine NSD PowerBall and a cheap imitation. The latter of which will never reach those increadibly high speeds!

Still, I think you might be right that, depending on the number and depth of the holes, the rotor's total weight may differ from others. I'm not an expert, but I'd say that Newton was right when he found out that mass is slow. Thus, it'll take a little more effort to start up a heavy rotor compared with a lighter rotor. Don't know if this effect can be detected at these weights and speeds, though...

Hope this helps... If anybody thinks I'm wrong, don't hesitate to correct me!

Kind regards,
Dennis

[Dennis]

Geez, Adrena1in. You're fast! ;)

[Syed769]

wow, extremely fast replies, thanks.

After checking again, turns out that he has a total of 6 holes, 3 on each side. I guess thats why we can feel the weight difference. How about it shaving a little of the plastic part off as well? Could that reduce its strength and possibly cause it to break some time in the future?

It's not like his powerball works any better or anything like that, in fact, mine is a little smoother and quiter, but it was still something we were curious about.

[Adrena1in]

(Keep seeing your Avatar figure rising Syed...you'll be overtaking me soon too!) :(

I don't think a little bit of plastic shaved off is going to be a problem. The size and position of the holes are probably all a part of the balancing process, and this does happen sometimes.

Six holes though?! I think I've seen a maximum of three or four on my Powerballs...didn't check last night. I'm sure I've seen them with only one or two holes. I suppose a difference of 4 might be noticeable.

As for what Dennis said about heavier ones being harder to get going, I wonder if this extra weight will be a benefit at high speed, with the increased momentum (or inertia?) helping the Powerball go quicker.

Another question is, because heavier gyroscopes generate more torque, will a very slightly heavier rotor in one 250Hz be harder to get to speed than a slightly lighter rotor in another 250Hz. (Perhaps this is why I've always felt the older 250Hz Powerballs are quicker.)

[Syed769]

You have no idea what happened to me, after about 2 weeks of not seeing any increases in my high score, I put on a rubber surgical glove and decided to go all out. I could tell I had broken my old record just by the way it felt. I got 13,671, a modest 300rpm increase, but I was really happy because I had been stuck for a while.

Anyway, I went to my friends house to take a picture because my camera is broken and he decided to try out my powerball. After he used it, I asked him to give it back so I could take the picture and update my avatar. I looked at the counter and it said "0". He DELETED my new high score, I got really angry for a second, yelled at him for like 5 minutes, but then cooled off and decided to try again. I could only get around 13,560, which is an improvement, but I just wish I had taken the picture of my higher score before I let him use it. Oh well.

Now i'm just waiting for him to email me the picture, so i can cut it up and update my avatar.

About it being harder to get the heavier ones going. I don't notice any real difference, but my friends says that he has trouble getting my heavier powerball started. He says that his is much easier for him.

[Syed769]

13,677

Rubber gloves really help

[donkapone]

good job :) i believe Tim is about to cry now :D

[Syed769]

It's weird though, I hadnt been improving for the past few weeks and suddenly something just clicked, I think it was a slight change in grip and I just felt like my technique would be better if I slighty changed my movement. Since this morning, i've been consistently getting over 13,000. I definitely wasn't able to do this before. Feel great though and I hope I can break 14,000 within the next month

[Adrena1in]

i believe Tim is about to cry now
:mad: :(

:rolleyes:

No...I'm just not going to approve his score, that's all. :p