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Drag coefficient of a shaved tennis ball?? ARG :(
Posted: Fri Nov 09, 2007 8:53 pm
by halfsquelch
I am trying to find the drag coefficient of a shaved tennis ball. The drag coefficient of a regular tennis ball is .55 but i cant figure it out for a shaved one.
Anyone please help!!!!!!!!!!!
I need to find this out for my MMAE class but have gotten stumped.
Thanks in advance to whoever helps!!
Posted: Fri Nov 09, 2007 9:02 pm
by Fnord
A perfectly smooth sphere is around .5, so I'm guessing that's the number you are looking for. If you have to figure this out by using a formula or something, I doubt I can help you.
Posted: Fri Nov 09, 2007 9:10 pm
by DYI
On the drag coef. topic, does anyone know the Cv. on a golfball? A throwing dart?
I thought a perfectly smooth sphere was .4, but I know very little about these things.
Posted: Fri Nov 09, 2007 9:22 pm
by halfsquelch
a golf ball should be Cv .52
the drag coefficient of the dart with no fins is Cv .2 but I have no idea what the Cv is with fins
and the drag coefficient of a sphere is .445
Posted: Fri Nov 09, 2007 9:44 pm
by POLAND_SPUD
as far as i know drag coef of perfectly smooth ball is 0.2 - 0.3
Posted: Fri Nov 09, 2007 9:45 pm
by halfsquelch
30 ppl in my MMAE class calculated it last week and we all got .445 which is what my prof said it should be, so I'm pretty sure its .445
Posted: Fri Nov 09, 2007 9:45 pm
by Fnord
Ok, we all have wildly different ideas here. Maybe someone should google it? (I would, but I'm leaving now).
Posted: Fri Nov 09, 2007 9:53 pm
by DYI
I somehow doubt that the drag coefficient of a golf ball is .52. I just don't believe that the people getting 250 yard drives are acclerating the ball to over 1200 feet per second.
Posted: Fri Nov 09, 2007 10:02 pm
by POLAND_SPUD
http://aerodyn.org/Drag/tables.html and
http://en.wikipedia.org/wiki/Drag_coefficient
DYI I hope u are going to fill tennis balls with something heavy. Light projectiles are not the best option for long range shooting
Posted: Fri Nov 09, 2007 10:23 pm
by DYI
I said golf balls, not tennis balls. And my main ammo is steel darts fired at short range and high velocity. Range shooting is useless when your cannon fires faster than most handguns.
Posted: Sat Nov 10, 2007 7:06 am
by POLAND_SPUD
ohh... sorry DYI....
It was writing it at 5 AM and....
I wasn't suggesting range shooting - I said that your spudgun would fire further when u use heavier projectile...
I assume that golfballs have better drag coef than 'normal' sphere - but anyway adding some weight would allow you to fire them further