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FrozenGate by Avery

Supersonic ping pong ball

B

BrainEater

New member
Joined
May 20, 2022
Messages
20
Points
3
Happy Friday everyone !

I know some of you know what I'm up to.
I want to make a ping pong ball go so fast it melts when it hits air.
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For those that don't :
In 2013 a paper was published by Purdue university about making a ping pong ball go faster than sound.
This paper : (see PDF)
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I have made a proper testbed for supersonic and maybe hypersonic ping pong balls.

I have pics.


overview2.jpg

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I have to do some resizing for the rest of the pics.
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Here's the rundown :

I had 2 test fires of 99% subsonic (750 MPH or so).
But not one iota faster....I was not getting the pressure required for supersonic flow.
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I'll get more pics up in a bit !

:D
 

Attachments






The current world record for this is 976 M/s or Mach 2.8

I've designed this cannon for 100 PSi/100 C helium. Using that gas, the math says exit velocity of 4470 MPH/Mach 5.6/ 2 kilometers per second !
here's a pic of the pressure assembly :

tank2.jpg

The tank is heated, and rated to 150PSi/100C.
That ASCO solenoid is what replaces the laser I wanted.....
 
Hehe !

I should update this.
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869898_ss1.jpg

That's Mach 1.07 (Measured)
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I've just started playing around with the Helium.
Here's Mach 1.25 :

h2.jpg

Take a look at that red oval. The backdrop is 1/2 inch plywood.

h3.jpg

The back :

h4.jpg
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It's worth mentioning that as it turns out, I don't need a popper, laser or otherwise.
Proper Mylar sizing will allow it to burst itself no problem.

(y)
 
Here's a pic of the Helium test setup.

h6b.jpg
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I'm currently reshaping the rocket nozzle.

More to come, (after ski season probably)

:cool:
 
While I don't allow people in front of the muzzle,
The ball only goes about 60 feet, all corkscrew.

The terminal velocity of a ping pong ball is only 32 M/S.
At 428 M/S it slows down fast, and does weird things.
Hypersonic ( 1700+ M/S) the ball might just melt after 10 feet of air.

Only dangerous for 10-15 feet mebbie.

(y)
 
I seem remember a Mythbusters episode on a high powered
Air Canon shooting ping pong balls. But they only used Air.

Jerry
 
Why waste helium instead of using hydrogen? Bonus points for higher velocity/pressure
 
You know the Challenger spacecraft was brought down by some debris off the underside that was going thousands of miles/ hour. Many didn't think it was dense enough, but they should have remembered their early physics classes. Density doesn't matter. BTW, helium is much rarer than hydrogen. That's why the Graff Zeppelins used hydrogen. Unfortunately for them.
 
paul1598419 said:
You know the Challenger spacecraft was brought down by some debris off the underside that was going thousands of miles/ hour. Many didn't think it was dense enough, but they should have remembered their early physics classes. Density doesn't matter. BTW, helium is much rarer than hydrogen. That's why the Graff Zeppelins used hydrogen. Unfortunately for them.
Click to expand...

That's wrong.

The Challenger spacecraft broke apart 73 seconds into it's flight due to the failure of the primary and secondary redundant O-ring seals in a joint in the shuttle's right solid rocket booster.

Maybe you meant to say the spacecraft Columbia .......

But even then you are still wrong.

At T+81.9 seconds, insulating foam that had broken loose struck the reinforced carbon-carbon (RCC) panels on Columbia's left wing at relative velocity 426 to 573 miles per hour which is 625 to 840 feet per second.
 
Yeah, I meant the Columbia spacecraft. The point was that many felt that the density of the underlying debris was not sufficiently dense enough to cause the damage. They were wrong. This has been documented sufficiently to prove my point.
 
You said thousands of miles/ hour....... that is wrong.

The other interesting part of the story is the insulating foam struck at subsonic speed..... not 1000's of miles per hour.
 
The spacecraft was going at that speed. Now the debris may have not been going at that speed relative to the Columbia, but that was what the speed of the spacecraft was. My point was that many felt, engineers, that the debris wasn't dense enough to cause this damage, but they were wrong.
 
You were commenting in a thread about supersonic ping pong balls and you related a story about a spacecraft, of which you got the name wrong and the insulating foam was NOT moving at 1000's of miles per hour as you said it was.

You have a bad habit of thinking you know what you're talking about, then refusing to admit you were wrong when called out..... yes things moving at speed carry more energy than things at rest, but your example was not supersonic ( 1000's of miles /hour ) it was subsonic in relative impact speed.

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EDIT:
Also the shuttle Columbia was traveling at about 1570 MPH ( which isn't even 1000's of miles /hour ) when the foam broke loose, but because the foam lacked density it decelerated in the air stream quickly striking at a relative velocity of 530 MPH, if the foam had been heavier per it's volume it would have decelerated more slowly thus striking at a lower relative velocity, that said neither the shuttle nor the foam were traveling at 1000's of miles /hour as you stated.

Now the piece of foam would have been traveling at approximately 1040 MPH ( in the same direction as the shuttle which was going 1570 ) when it hit..... rather the shuttle hit the now slower moving piece of foam at a difference of 530 MPH .... subsonic collision speed/differential and neither foam nor shuttle was going 1000's of miles /hour, nor had they been..... Your 1000's of miles /hour statement was - see video below.

 
Last edited:
paul1598419 said:
You know the Challenger spacecraft was brought down by some debris off the underside that was going thousands of miles/ hour. Many didn't think it was dense enough, but they should have remembered their early physics classes. Density doesn't matter. BTW, helium is much rarer than hydrogen. That's why the Graff Zeppelins used hydrogen. Unfortunately for them.
Click to expand...
Actually the Germans used Hydrogen because the US would not sell
them Helium...

Jerry
 
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