supersonic ping pong ball

http://www.youtube.com/watch?v=I9zBGgpzl0I&feature=youtube_gdata_player

Hey Freb, I know what we're gonna to do today.

http://www.youtube.com/watch?v=djm4h7nv2oI

I am so going to build one of those at home.

I was thinking that you could put a quick valve on the tank side instead of tape and get more pressure.

mrhappy wrote: I was thinking that you could put a quick valve on the tank side instead of tape and get more pressure.

... and a rather large surge tank

I can hear the EMS dispatch now. One male patient struck by ping pong ball, through and through, patient had been drinking previous to injury

I want to know what the pingpong ball looked like after going through the paddle

In reply to mad_machine:

Confetti?

aight, who wants to play beer pong?

Talk is cheap; less theory, more application....

Bring on the (fake) Lee: http://www.youtube.com/watch?v=SncapPrTusA

Is there any science to the pinched section? I mean any specific entrance and exit angles and opening size that must be adhered to to get that boost of power?

Too much Poindexter lecturing, not enough Ping-Pong balls going through paddles and other things.

I've met that guy, he is worse in person lecturing........

If you could get it going past 1500fps, you might be able to trip low velocity tannerite for a nice explosion.

carguy123 wrote: Is there any science to the pinched section? I mean any specific entrance and exit angles and opening size that must be adhered to to get that boost of power?

Absolutely, look up convergent-divergent nozzle. The basics are that there is a critical area with smooth entrance and exit to get the air to accelerate past the speed of sound. It is affected by the pressure of the system and the other abmient values (temp etc). If the throat of the nozzle is too large you don't get super-sonic, if too small yo uget choked flow and no super-sonic flow.
The best application data for this is rocket nozzles.

Wear safety goggle so the paramedics know you took some precautions...

SCIENCE!

I will not try this at home.

So what about at work ? They better keep me busy or a trip to Lowes and Dicks will be in order.

I used to build wind tunnels for a living, that's a pretty good demonstration of how they work (except we used a really fast opening valve instead of packing tape.)

I'll start w/ subsonic and work my way up