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[ortwin]

It's very dangerous to take aerodynamic strategies developed for bodies translating through the air and apply them to a top spinning in place without translation.

I would not call it "dangerous". There is not much lost in giving it a thought or try ! It might not work, or it might have a negative effect or it might indeed work for a completely different reason but we will not endanger anybody or lose big money. We invest our spare time and it can be frustrating when  we do not reach our goals, but we can enjoy our experiments and discussions anyhow.

[Jeremy McCreary]

Sorry, no offense meant. We've been struggling with top aerodynamics for a long time.

So let me put it another way: To make progress toward that goal, better to test the hypothesis that an aerodynamic theory or strategy developed for a body translating through the air also works for a top spinning in place than to assume it.

[Iacopo]

better to test the hypothesis that an aerodynamic theory or strategy developed for a body translating through the air also works for a top spinning in place than to assume it.

Did I affirm something different, Jeremy...?

[ortwin]

No offense taken at all Jeremy! You don't have to be sorry.
I guess I misunderstood your remark somewhat purposefully so I could make my point: "Let us allow our-self to think in all directions."And the way you put it in your last post is of course perfect. As non native English speaker I can understand it, but I could not come up with with a sentence like that.
 

[ortwin]

No go then, but rechecked just now. The starter here turns in both directions at 3,600 RPM with no top loaded. Chucking this top drops max speed to about 3,100 RPM.

Same 130 s spin time in both directions.

.

 If the ground clearance is large, more then 3mm, that is to be expected, everything quite symmetric. As you and Iacopo found out by experiment, the ground effect needs small spacings. If you could redo the experiment with that in mind it would be great.

Another thing to vary, is not the spacing to the base, but to cover the bottom end of the fan-top with a fairing. Again a check on spin-down  rate with different spin direction could be done.

[Jeremy McCreary]

Did I affirm something different, Jeremy...?

Sorry, not at all. Just got worried that we might be heading for some traps we've fallen into before.

[Jeremy McCreary]

Mistress von Karman says I'll have to be punished for overreacting. Yes, on my way to the dungeon now, Mistress. Oh no, Mistress! Not more spin time trials!

[Jeremy McCreary]

At ortwin's request in another thread...

"We proudly present: Mistress von Karmann and the fabulous  Poledancers!"

Here, the Poledancers are doing the supine kickline routine with Mistress von Karman dominating them at the center, as her contact of course demands.

[ortwin]

Great! And thank you.How many helping hands would you need, and how many microwave platters to get them dancing all at once for a video?

[Jeremy McCreary]

Great! And thank you.How many helping hands would you need, and how many microwave platters to get them dancing all at once for a video?

About as many of each as there are tops. With their max release speeds of 7,000 RPM or more,  the Poledancers can get quite energetic. And at large tilt angles, they cut a wide swath at high precesdion rates.

[ortwin]

"
About as many of each as there are tops. With their max release speeds of 7,000 RPM or more,  the Poledancers can get quite energetic. And at large tilt angles, they cut a wide swath at high precesdion rates. " 



So even that glass table below the microwave platter doesn't really take you anywhere. Maybe you can get a part of that VLT once they put it out of order.

[Joah]

Over in Spoke wheel performance, I suggested that ortwin dress his metal Spartan finger top in a skin-tight shiny black latex fairing -- strictly to reduce drag, of course. Also suggested he call it "Mistress von Karman".

Well, too slow, buddy. This isn't what I had in mind then, but Mistress von Karman is way too good a top name to go to waste...


(You know you're too far gone as a topmaker when you start giving your tops names.)

Wow that top looks deadly! Love it nice build!

[Jeremy McCreary]

Wow that top looks deadly! Love it nice build!

Mistress von Karman and I both say thanks, Joah!

Now that I look at Mistress von Karman again, wondering if there's a secure way to put in another layer of spikes upside down to give the spikes smooth surfaces above and below? Off to the workbench...

[Joah]

Wow that top looks deadly! Love it nice build!

Mistress von Karman and I both say thanks, Joah!

Now that I look at Mistress von Karman again, wondering if there's a secure way to put in another layer of spikes upside down to give the spikes smooth surfaces above and below? Off to the workbench...

Best of luck! That would be cool to see. Are the spikes secure enough to use in battle?

[Jeremy McCreary]

Wow that top looks deadly! Love it nice build!

Mistress von Karman and I both say thanks, Joah!

Now that I look at Mistress von Karman again, wondering if there's a secure way to put in another layer of spikes upside down to give the spikes smooth surfaces above and below? Off to the workbench...

Best of luck! That would be cool to see. Are the spikes secure enough to use in battle?

None of the spikes are going to come out in battle. The singles might get knocked out of radial alignment, but the doubles are locked down.