Outboard Flywheel Technical Question

Outboard Flywheel Technical Question

Postby Johnny » Tue Jun 18, 2019 12:57 pm

I am thinking about adding a standalone flywheel to my second table and I have a simple questions.

The outboard motor will drive the flywheel and the flywheel will drive the platter. Does the diameter of the flywheel make any difference to the speed of the platter, therefore, allowing me to purchase any standalone flywheel or do I need to match the flywheel to the table?
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Re: Outboard Flywheel Technical Question

Postby Brf » Tue Jun 18, 2019 3:04 pm

Johnny, the simply answer is 'no' the size/diameter of the flywheel will not influence the platter speed. If you want to know the "why", please advise and I will elaborate.
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Re: Outboard Flywheel Technical Question

Postby elader » Mon Jun 24, 2019 9:06 am

BRF that seems superficially 'counter intuitive" (pun intended)

But I believe you of course.
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Re: Outboard Flywheel Technical Question

Postby Brf » Mon Jun 24, 2019 10:24 am

elader wrote:BRF that seems superficially 'counter intuitive" (pun intended)

But I believe you of course.

elader, you are not alone. People often relate to their bicycling experience whereby a large front sprocket will propel a bike to greater speeds when compared to a smaller sprocket. Although this is true, it is not a proper analogy to the VPI flywheel as the VPI flywheel is NOT the source of the drive output. The drive output is coming from the motor pulley.

It all has to do with surface speeds. The surface speed of the flywheel will be exactly the same as the surface speed of the motor pulley. Similarly, the surface speed of the platter will be exactly the same as the surface speed of the flywheel.

The vpi flywheel acts in the same manner as an idler wheel in that the gear ratio is determined by the output (drive pulley) and input (platter). Any pulley/gear that is placed between the main output and the target input will not affect platter speed (assuming that the flywheel’s input and output ratio is 1:1)

https://en.wikipedia.org/wiki/Idler-wheel
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Re: Outboard Flywheel Technical Question

Postby MMMC » Tue Jun 25, 2019 12:26 am

Johnny wrote:I am thinking about adding a standalone flywheel to my second table and I have a simple questions.

The outboard motor will drive the flywheel and the flywheel will drive the platter. Does the diameter of the flywheel make any difference to the speed of the platter, therefore, allowing me to purchase any standalone flywheel or do I need to match the flywheel to the table?


Johnny,

FWIW, In years past, I wanted to tweak the performance of my Aries I table, and I was lucky to find a used stand alone VPI flywheel, and added it to my Aries setup, and later to it's replacement, a VPI Extended Aries. The improvement is not Night vs Day, but it is an improvement. The difficult part is finding a standalone flywheel that is a direct plug and play dimension wise. Good luck locating a flywheel. I will look for a photo of that setup.

MMMC
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You can find a photo of my Extended Aries 2 setup in my old forum posts.
viewtopic.php?f=11&t=6592&p=15849&hilit=old+school+extended+Aries#p15849 (Sroll down 5 photos, then mouse click for this one to display propeprly)
"Old school-Extended Aries 2 with single Flywheel" is the title of the post.

Forum Member Pevo has a photo posted of his more modern VPI motor/flywheel unit also.
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Re: Outboard Flywheel Technical Question

Postby Votan » Tue Jun 25, 2019 8:05 am

Johnny wrote:I am thinking about adding a standalone flywheel to my second tables.

In the past I have used both, standalone flywheel (a well bearing, standard with my HR-V) as well later the Single Motor/ Flywheel Assembly (inverted bearing). When both were brand new, the sound improvement was significant comparing to the motor alone (but not Night vs Day, as MMMC mentioned above), but due to much greater added mass, I continuously was detecting a premature wear of belts due to much greater inertia during startup.
Some years later though, detecting a stealthy gradual degradation on sound quality, I compared the motor alone vs to the full SM/FWA. There I discovered that the sound of the full SM/FWA was inferior to the one of the motor alone, though maintenance (lubing, etc.) always was by the book. The reason, I think, was the significant wear of ball bearing (flat spotted) and of thrust plate. Using a stethoscope on flywheel’s casing I could easily detect a significant noise caused from its bearings which normally is an additional noise for TT.
My advice? If you already use a Periphery Outer Ring and/or the recent generation of VPI's heavier platters (which already give the added inertia for speed stability) don’t bother with an added flywheel, which, moreover, I think VPI has long abandoned even in their reference newer models.
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Re: Outboard Flywheel Technical Question

Postby Johnny » Tue Jun 25, 2019 9:03 am

Thanks everyone for both your insight and responses. In speaking with someone at VPI, I was told that one of the reasons that VPI has abandoned the flywheel drive systems is that US manufacturing cost have skyrocketed making flywheel drive systems almost cost prohibitive. In addition, finding an used single motor flywheel or a standalone flywheel is next to impossible, and when you do, the asking price is higher than the old MSRP.

Brf, I was speaking to one of my techie friends and he asserts that the flywheel size needs to be matched to the table and pulley. His argument is that when he added a rim drive to his table (basically an idler wheel) he had to change the pulley size to obtain the correct speed. This goes against what you stated above in that the pulley and platter size determine the speed and anything in between does not impact the table's speed. I am confused?
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Re: Outboard Flywheel Technical Question

Postby Votan » Tue Jun 25, 2019 9:08 am

Brf is correct. This is very simple mechanics…
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Re: Outboard Flywheel Technical Question

Postby Brf » Tue Jun 25, 2019 9:26 am

Johnny wrote:Brf, I was speaking to one of my techie friends and he asserts that the flywheel size needs to be matched to the table and pulley. His argument is that when he added a rim drive to his table (basically an idler wheel) he had to change the pulley size to obtain the correct speed. This goes against what you stated above in that the pulley and platter size determine the speed and anything in between does not impact the table's speed. I am confused?


Votan wrote:Brf is correct. This is very simple mechanics…


Thanks Votan

With a VPI rim drive, you have two surfaces mated together with different circumferences. The output of the pulley drives the rim drive’s smaller circumference input and the rims drive’s output is taken from the larger circumference rim drive. Since the two sections of the rim drive have the sale rotational speed and since their circumferences are different, their surface speeds are different.
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Re: Outboard Flywheel Technical Question

Postby Votan » Tue Jun 25, 2019 9:41 am

Johnny wrote: In speaking with someone at VPI, I was told that one of the reasons that VPI has abandoned the flywheel drive systems is that US manufacturing cost have skyrocketed making flywheel drive systems almost cost prohibitive.

On most VPI retailers, Single Motor/Flywheel Assembly is now sold for 999 USD and the Dual Motor/ Flywheel Assembly for 1.999 USD, when VPI’s periphery ring costs ~1.150 USD!! I don't think anyone would protest if VPI increased the M/F assemblies prices by say a 30% to cover their manufacturing costs, provided that the aforementioned units were long term worth their money.
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