yardhippie 0 #51 July 14, 2006 QuoteHow about some kind of dimpled balloon to reduce friction on the skin - like a golf ball? Therefore a smaller ballon to create the same speed? forgive me but im quite lacking on my fluid dynamics. My understanding of the dimples on a golf ball are for stability, not neccesarily for reduced friction. also as the surface area of the falling object gets smaller so does the pressure associated with said object upon impact with a stationary object. So am I right in saying that the more "aerodynamic", the more likely for injury or damage should the object make it to the ground and impact anything. Unless we can significantly reduce the mass associated with the object. I am NOT a physics professor, but I did stay at a holiday inn Express last night! Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
kmcguffee 0 #52 July 14, 2006 QuoteMy understanding of the dimples on a golf ball are for stability, not neccesarily for reduced friction. If I remember by aero classes right, the dimples on a golf ball should change the airflow from laminar to turbulent on the front and sides of the golfball while it is in flight. Turbulent flow causes less drag on the golfball at the same velocity. Friction is one of the components of drag on a flying body. "Any fool can criticize, condemn and complain and most fools do." Ben Franklin Quote Share this post Link to post Share on other sites
kallend 1,623 #53 July 14, 2006 QuoteQuote Both sniper and his target absorb same amount of kinetic energy in case of succesfull shoot (some times if bullet pass through the body and leave it carrying some emount of energy - target gets even less than sniper) but results are significant different NO, that is absolutely incorrect. They experience exactly the same change in momentum (m*v) but NOT kinetic energy (0.5*m*v^2. The faster object (the bullet) carries away the overwhelming majority of the KE on account of the v^2 term. The sniper experiences very little KE and his target gets a lot!... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites kallend 1,623 #54 July 14, 2006 QuoteQuoteMy understanding of the dimples on a golf ball are for stability, not neccesarily for reduced friction. If I remember by aero classes right, the dimples on a golf ball should change the airflow from laminar to turbulent on the front and sides of the golfball while it is in flight. Turbulent flow causes less drag on the golfball at the same velocity. Friction is one of the components of drag on a flying body. The turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. This is VERY sensitive to the shape of the object and really only works for spheres. They don't put dimples over car bodies or airplane fuselages, for example. Right, but the Reynolds numbers will be significantly different for a glof ball and water balloon.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites rehmwa 2 #55 July 14, 2006 Quote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Or are we comparing shuttlecocks to darts again? Edit: Oh, and I like "glof" balls. they're funny (I know I'm guilty of typing fast as much as anyone, but that's a funny word) ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites jeiber 0 #56 July 14, 2006 QuoteWe took out a plastic ball about the size of a baseball filled with water. It fell at freefall speeds, the problem wasn't fall rate, it was how erratic it would fly if it had any air in it at all. This is some good info. No air in the ball; maybe we can get away with no tail for stabilization. Baseball size is very practical as well. Were the freefall speeds bellyflying or freeflying? A baseball size object would be much more practical than the 8-10" initially mentioned. Using milk instead of water would increase the fallrate as well, but not sure by how much. Dimples is an interesting theory. Dimples might be tough to create on a water balloon, but what about 'bumps' on the outside - anybody know if it have the same effect as dimples?Shhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites jeiber 0 #57 July 14, 2006 Quoteif it had any air in it at all. Just thought of something else. When the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. Just another random thought to contribute! JeffShhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites jakee 1,254 #58 July 14, 2006 QuoteWhen the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. But it would get smaller near the ground and bigger at exit alt.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites yardhippie 0 #59 July 14, 2006 QuoteQuoteif it had any air in it at all. Just thought of something else. When the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. Just another random thought to contribute! Jeff taking this a bit further. if there were any air in the, balloon, then as you changed altitudes and air pressure the balloon would expand as you climb. so, would the difference in air pressures effect on the balloon size (assuming it had any air in it), adversely affect its fall rate at the associated air pressure at a given altude. so, would it speed up as it got closer to the ground (and smaller), or would the difference in size/pressure have no effect on overall fall rate?Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites kallend 1,623 #60 July 14, 2006 QuoteQuote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Or are we comparing shuttlecocks to darts again? Edit: Oh, and I like "glof" balls. they're funny (I know I'm guilty of typing fast as much as anyone, but that's a funny word) Glof - a stupid Scottish activity.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites kallend 1,623 #61 July 14, 2006 QuoteQuoteWhen the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. But it would get smaller near the ground and bigger at exit alt. Don't bother with physics here... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites kallend 1,623 #62 July 14, 2006 QuoteQuote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Those are usually present to delay the stall by energizing the boundary layer and keeping it attached. There's actually a small drag penalty in most cases.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites rehmwa 2 #63 July 14, 2006 QuoteThose are usually present to delay the stall by energizing the boundary layer and keeping it attached. There's actually a small drag penalty in most cases. I know how it works, and the penalty for the separation of the boundary layer (plus the loss of lift) is worth the small drag penalty. Turbulent flow ROCKS!! But I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball and causing it to pressurize irradically also giving it more randomness to the flight path. By using dimples to trip the flow from laminar to turbulent, the flow would stay attached and the net effect is the ball flyies farther and straighter. ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites jeiber 0 #64 July 14, 2006 QuoteDon't bother with physics here Oooops, that's right... rafts explode at altitude! Ha ha. Typing that message was the only separating work from vacation! Not gonna even try to defend that screw up! LOLShhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites jeiber 0 #65 July 14, 2006 QuoteBut it would get smaller near the ground and bigger at exit alt. You're right, I screwed the pooch on that one. Don't know where my head was at. Obviously not on physics! LOL! Shhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites jakee 1,254 #66 July 14, 2006 QuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites rehmwa 2 #67 July 14, 2006 QuoteQuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. well, that settles that then Now, if you throw a glof ball out of an otter and wait for it to get to 45 degree before exiting, would you then let the swoopers out before the freeflyers to avoid freefall collisions? ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites jakee 1,254 #68 July 14, 2006 Celcius or Farenheit?Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites kallend 1,623 #69 July 14, 2006 QuoteQuoteQuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. well, that settles that then Now, if you throw a glof ball out of an otter and wait for it to get to 45 degree before exiting, would you then let the swoopers out before the freeflyers to avoid freefall collisions? You keep your glof blals out of my Ottel. editled to collect the sperring.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites BASE1036 0 #70 August 14, 2006 Has anyone thought of filling the balloon with jello? HMMM? ____________________________________________________Daniel Protect Yourself and Your Loved Ones Tasers - Pepper Spray - Stun Guns and more! www.dallassecuritysupply.com Quote Share this post Link to post Share on other sites Paige 0 #71 August 14, 2006 QuoteHas anyone thought of filling the balloon with jello? HMMM? ____________________________________________________ In hopes that in crashes near some girls who just started a cat fight?!?!?! That would be a sight if physics didn't apply and everyone was safe after the balloon bust.Tunnel Pink Mafia Delegate www.TunnelPinkMafia.com Quote Share this post Link to post Share on other sites Prev 1 2 3 Next Page 3 of 3 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. 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kallend 1,623 #54 July 14, 2006 QuoteQuoteMy understanding of the dimples on a golf ball are for stability, not neccesarily for reduced friction. If I remember by aero classes right, the dimples on a golf ball should change the airflow from laminar to turbulent on the front and sides of the golfball while it is in flight. Turbulent flow causes less drag on the golfball at the same velocity. Friction is one of the components of drag on a flying body. The turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. This is VERY sensitive to the shape of the object and really only works for spheres. They don't put dimples over car bodies or airplane fuselages, for example. Right, but the Reynolds numbers will be significantly different for a glof ball and water balloon.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
rehmwa 2 #55 July 14, 2006 Quote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Or are we comparing shuttlecocks to darts again? Edit: Oh, and I like "glof" balls. they're funny (I know I'm guilty of typing fast as much as anyone, but that's a funny word) ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
jeiber 0 #56 July 14, 2006 QuoteWe took out a plastic ball about the size of a baseball filled with water. It fell at freefall speeds, the problem wasn't fall rate, it was how erratic it would fly if it had any air in it at all. This is some good info. No air in the ball; maybe we can get away with no tail for stabilization. Baseball size is very practical as well. Were the freefall speeds bellyflying or freeflying? A baseball size object would be much more practical than the 8-10" initially mentioned. Using milk instead of water would increase the fallrate as well, but not sure by how much. Dimples is an interesting theory. Dimples might be tough to create on a water balloon, but what about 'bumps' on the outside - anybody know if it have the same effect as dimples?Shhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites
jeiber 0 #57 July 14, 2006 Quoteif it had any air in it at all. Just thought of something else. When the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. Just another random thought to contribute! JeffShhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites
jakee 1,254 #58 July 14, 2006 QuoteWhen the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. But it would get smaller near the ground and bigger at exit alt.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
yardhippie 0 #59 July 14, 2006 QuoteQuoteif it had any air in it at all. Just thought of something else. When the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. Just another random thought to contribute! Jeff taking this a bit further. if there were any air in the, balloon, then as you changed altitudes and air pressure the balloon would expand as you climb. so, would the difference in air pressures effect on the balloon size (assuming it had any air in it), adversely affect its fall rate at the associated air pressure at a given altude. so, would it speed up as it got closer to the ground (and smaller), or would the difference in size/pressure have no effect on overall fall rate?Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
kallend 1,623 #60 July 14, 2006 QuoteQuote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Or are we comparing shuttlecocks to darts again? Edit: Oh, and I like "glof" balls. they're funny (I know I'm guilty of typing fast as much as anyone, but that's a funny word) Glof - a stupid Scottish activity.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 1,623 #61 July 14, 2006 QuoteQuoteWhen the air expands, the water balloon would gain surface area, thereby slowing it down a little before impact. But it would get smaller near the ground and bigger at exit alt. Don't bother with physics here... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 1,623 #62 July 14, 2006 QuoteQuote They don't put dimples over car bodies or airplane fuselages, for example. Wouldn't the analogy on an airplane wing be turbulent flow LE trip features or air hockey-like blowers? Not so much for drag reduction but to keep the flow from detaching. (Although separated flow does have a drag effect). And not that I don't like laminar flow, but it can be touchy at times...... Those are usually present to delay the stall by energizing the boundary layer and keeping it attached. There's actually a small drag penalty in most cases.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
rehmwa 2 #63 July 14, 2006 QuoteThose are usually present to delay the stall by energizing the boundary layer and keeping it attached. There's actually a small drag penalty in most cases. I know how it works, and the penalty for the separation of the boundary layer (plus the loss of lift) is worth the small drag penalty. Turbulent flow ROCKS!! But I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball and causing it to pressurize irradically also giving it more randomness to the flight path. By using dimples to trip the flow from laminar to turbulent, the flow would stay attached and the net effect is the ball flyies farther and straighter. ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
jeiber 0 #64 July 14, 2006 QuoteDon't bother with physics here Oooops, that's right... rafts explode at altitude! Ha ha. Typing that message was the only separating work from vacation! Not gonna even try to defend that screw up! LOLShhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites
jeiber 0 #65 July 14, 2006 QuoteBut it would get smaller near the ground and bigger at exit alt. You're right, I screwed the pooch on that one. Don't know where my head was at. Obviously not on physics! LOL! Shhh... you hear that sound? That's the sound of nobody caring! Quote Share this post Link to post Share on other sites
jakee 1,254 #66 July 14, 2006 QuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
rehmwa 2 #67 July 14, 2006 QuoteQuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. well, that settles that then Now, if you throw a glof ball out of an otter and wait for it to get to 45 degree before exiting, would you then let the swoopers out before the freeflyers to avoid freefall collisions? ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
jakee 1,254 #68 July 14, 2006 Celcius or Farenheit?Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
kallend 1,623 #69 July 14, 2006 QuoteQuoteQuoteBut I was wondering if that's the same principle behind the glof ball dimples or if the glof balls have some other purpose. Figured you knew or could make a good guess on that. I'm thinking a smooth glof ball would shed separation of flow about the ball and cause bunch of drag, thus slowing down the ball I think Kallend already said that was the reason in his first post about glof ballsQuoteThe turbulent flow is inherently more draggy, but on a sphere the turbulent flow stays attached longer, which reduces drag overall. well, that settles that then Now, if you throw a glof ball out of an otter and wait for it to get to 45 degree before exiting, would you then let the swoopers out before the freeflyers to avoid freefall collisions? You keep your glof blals out of my Ottel. editled to collect the sperring.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
BASE1036 0 #70 August 14, 2006 Has anyone thought of filling the balloon with jello? HMMM? ____________________________________________________Daniel Protect Yourself and Your Loved Ones Tasers - Pepper Spray - Stun Guns and more! www.dallassecuritysupply.com Quote Share this post Link to post Share on other sites
Paige 0 #71 August 14, 2006 QuoteHas anyone thought of filling the balloon with jello? HMMM? ____________________________________________________ In hopes that in crashes near some girls who just started a cat fight?!?!?! That would be a sight if physics didn't apply and everyone was safe after the balloon bust.Tunnel Pink Mafia Delegate www.TunnelPinkMafia.com Quote Share this post Link to post Share on other sites
