Thanks! I was wondering why the Celera 500 airplane did not used dimples in the fuselage, since they’re aiming to minimize air drag. That could also explain why it worked in the myth busters car.
The aero design is clearly a natural laminar flow concept. Can tell clearly by how far back the maximum thickness location near is and the concave pressure recovery tail
Outstanding, however if one places dimps on the back ETA the disturbance mix flow the pressure conforms to give a greater positive squeeze back toward the front more than its smooth path let's see...just a widget thought in the case of the Russian Subroc torpedoes which uses it's soild or liquid spented exhaust gases to create the "Mass Disturbance" of air at front cone ports matching the same speed while submerged underwater as if were in air flight...then greater pressure follows the contours of the sphere and the bare proof is right in front of you, the key is the sphere, look at your sphere that's the key, however it clearly not be disregard... feedback responds welcome please
Have you guys looked at how much energy it would take to implement active boundary layer control - suck it down - to achieve more laminar flow? My guess would be the energy required to drive the boundary layer suction would be too much to justify the complexity, but I'm still curious what your thoughts are.
Zach Hazen Boundary layer control is a pretty hot topic, that I know nothing about :P. What I know that RC planes have been used as proof of concept for boundary layer plasma actuation, and that it worked really well at keeping the boundary layer attached. Any system we implement would need to be human powered. For this year, we did not bother even looking at it, there were a lot of places we could get easier performance out of the bike and rider. The University of Toronto human powered vehicle design team (which I used to lead) will probably look into it in one of their upcoming ASME bikes.
Hi, first off, very nice video. I finally got it:) Thank you for that. Here is a related question though...Taka .22LR bullet (5.6mm diameter, 2.6 grams, flat base, V_start=325(m/s)...strap on a boat tail to it, also have it at 2.6 grams and V_start=300m/s. When/what distance would you start to see the energies of both projectiles are equal? 100m? 200m? Or to make it more simple...if i were to put a boat tail on a .22LR (keep the same weight) how much will I gain? Also..do you think that it's possible to keep the flow at the nose of the bullet laminar at those speeds (325 m/s and 300m/s) or it's not even worth trying it'll go turbulent as soon as the air reaches the projectile?
In fact, the flow in the tube is always turbulent flow. So it is impossible to use theory to talk about turbulent flow and laminar. In addition, there must be increased kinetic energy for air to transport fuel and mix well. the velocity of air flow is also increased
This was actually very interesting! Would it make any sense to design a streamlined shape with a hole/canal going throug it from tip to tail? Sort of like an elongated donut. In order to avoid the stationary air cushions building up in front and behind the shape? (Given the fact that you don´t have to pierce this canal through the body of a rider sitting inside ...) Or it it just an error in reasoning becaus you would than have all the friction just on the inside? respectively you replace one tip by a new "tip" in a circular shape ...
possible...but yea, any area in contact with the air provides skin friction, and would be bad. Generally, if you have a big opening in your shape with a pipe going thru the interior, you could have made the whole thing smaller, and get rid some of skin friction. The high pressure areas in the front and low pressure in the back would now be a ring, instead of a circle. Somewhere the air has to be stationary.
The video seems like a well-reasoned argument for using smooth surfaces, that are also probably less complex/costly than dimpled. The bike is designed to sustain laminar flow for the greatest possible length along the body. The laminar flow is expected to become turbulent in the rear section of the body, can golf ball dimples from the turbulent point rearward provide less drag than a smooth surface? I didn't pick up on any evidence presented to show that dimples would hinder performance.
+Jeremy Priede dimple surfaces have greater surface area than smoother surfaces. As such, they got greater drag if the flow is attached. We are very confident our flow is attached over the whole bike, so there is no reason to use dimples. We are confident of this because our drag in real life is very close to the estimated drag (and we estimate no separation) and if there was any separation, our drag would be much higher, very noticeable so.
Thanks, I had thought that it was turbulence that caused drag, but as you point out - it is separation that causes drag. And turbulence can be used by a golf ball to decrease separation (and thus decrease drag).
+Jeremy Priede nope. I suggest you watch the video again. There are a number of causes for drag, such as skin friction and separation. We got no separation on the bike, so no golf ball dimples are necessary. Skin friction causes drag, and gold ball dimples make it worse. Not only golf ball dimples have more surface area, which causes more skin friction, but they also make the air more turbulent. More turbulent air means faster moving air molecules are able to get closer to the skin of the vehicle, thus increasing the skin drag. So gold ball dimples are always bad, unless you have separation, and are not able to get rid of separation any other way. They are a last resort for cases where the shape cannot be changed.
@@VRagusila I'd think that turbulent flow allows outside air to contact turbulent air instead of the skin itself. Air on air contact is much more frictionless than air on a solid
I would love to see some Monotracer type vehicles,except as a commuter type vehicle,single seat,low drag body,conventional door,light weight,small electric or 250 cc engine.Enclose a MP3,Yamaha Tricity parallel link type front end to eliminate out riggers,single wheel in rear.Why not a morphable surface,dimples at low speed only?
Hello Inagod. Such a monotracer would be fun. However, the gold ball dimples wouldnt make sense no matter the speed, unless the monotracer is forced to have a spherical or similar shape. Vision is one of the main issues of very low, aerodynamic shapes. It is both hard to see out of the vehicle, and it is very hard for anyone to see you. I believe vision and crash resistance are the main issues to deal with before such a vehicle can be a commuter.
I dont see why they would. They would increase skin drag, but I cant think of a mechanism that would result in more lift... Objects on underside of wings dont seem to affect the lift negatively too much either. All airplanes hang engines, rockets, missiles, fuel tanks, etc under the wing, keeping the top side as clean as possible, with the exception of turbulators.
dimples work for car-like object, or sphere like object. For an object with a tail that we can shape, it is not going to help. Not worth trying because we know the effects of even thicker tape on the back of the bike, which disturbs the airflow and causes higher drag. Dimples would add even more drag.
@@victorragusila7519 well, based on where the body seam is it's obvious why tape added would be a negative. The initial guess would be to put dimples on the rear surfaces of the body.
Well, the plot gets more density. Thickens is not a technical term :P Different air situations require different measures. If the manifold had any separation, dimples would definitely help. There might not be enough room to make the intake a shape that has no internal separation. The shape being fixed (or at least constrained) then the surface can be made to deal with some of the separated air. For us, we could make a shape with no separation quite easily. So no need to use surface features.
I work in very high end motorsports..( sorry not allowed to disclose where , so your guess where is pretty easy) and not used dimples to date. We say: its a solution for a problem created by yourselve....😄😄
@@appa609 Regardless with what contributes as a "small contribution," many small contributions create one big one. In theory, yes it will help. If you have the means to do it, do it.
Waylon Jeffery well it’s not clear it will be a net positive contribution. Dumpling the bat is also going to slightly decrease the stiffness if the bat. The overall restitution may go down. And it would certainly cost more. Even if it were right it would be tiny.
This does not make much sense to me.I say the turbulent air is slowed down so it can turn around the ball.The smooth fast non Dimple set up has the majority of the air go so fast momentum stops it going around the bend.
Unfortunately you are wrong. Aerodynamics is not really intuitive. It took me a while to understand why mixing fast and slow air, due to turbulence, can bent a curve better than slow air from the laminar air. The trick is to understand that the air right next to the object is perfectly still relative to the object. The goal is to keep the air moving against the object, and not make it move backwards. For example, www.researchgate.net/publication/327793049_The_Effects_of_Reynolds_Number_on_Flow_Separation_of_Naca_Aerofoil is a test showing that separation occurs at higher angles of attack for higher Reynolds numbers, which increase linearly with speed. So faster air can bend the curve better than slow air. My understanding is not perfect, and still trying to find the best way to explain it. Good luck trying to understand it better, it is not simple, nor easy.
@@victorragusila7519 The problem with Aerodynamics is we cant see it.I think we are always trying to understand it that's why I was watching your video after all.Because I did not understand your explanation I came up with my simpler explanation. Perhaps I am wrong.I guess I was just challenging your story on it.OK .I just looked at some other explanations on RUclips & have a important Question. Does the ball have to spin in flight.That could change everything.How important is the spin factor ?
@@lomasck The spin would definitely affect things, but I think that is a separate problem. Understanding it without spin is important to help understand it with spin later on. I looked for a few more videos to recommend for you, and because I need a refresher course in Aerodynamics, since i havent looked at it for a few years (off to a new obsession for now). I highly recommend this video, they explain boundary layer better than me, without going into Laminar VS turbulent discussion ruclips.net/video/5zLCofDSt_Q/видео.html The Wiki page on flow separation also has some good info .en.wikipedia.org/wiki/Flow_separation We actually can see aerodynamics. We need a wind tunnel or day with fog, but we can see (with the help of smoke) the way the air behaves. It was probably one of the main tools that helped develop airplanes around the two world wars. I am sure you can find some really good videos of flow around balls or wings. A few points that helped me understand aerodynamics: 1) dont think of air as small balls that move around a wing. A faster small ball is harder to turn, whereas a slow one can turn easily. I think that is why intuitively, it is easy to think that fast air separates easier. 2) Air works more like molasses, it has viscosity. Much smaller than molasses, but it still exists. There is friction between all layers of air, and between air and any object. 3) Separation means air moves backwards over a wing (if we think of the wing as 0 velocity). For a ball going thru the air, it means the air sticks to the ball and travels with it. That is generally BAD. You dont want your ball (or wing) to grab a bunch of air and take it along, that creates lots of drag. You want the air to stay exactly where it was before your wing or ball moved thru it. That would be 0 drag (and impossible). Good luck, it took me a while to find an explanation that made it click for me. I was lucky to have a few classmates that took a lot more aerodynamics courses than me, and were very good at explaining it. Once you understand the effects of boundary layer velocity on pressure and separation, you should be able to derive the effect of spin.
yes, people have tried dimples. It is also attempted on cars, bike helmets, etc. While my understanding might be faulty, none of the other teams that went fast in the last 20 years ever used dimples, and they all tried to achieve the smoothest possible shape. Some experienced racers, such as the world champion for 15 years, Sam Whittingham, can feel the difference between different waxes. The smooth ones are always faster.
Hi, so sorry, I am not saying you personally have a faulty understanding, but the general understanding of why dimples work, may be faulty. I was thinking about fish, such as tuna, and sharks, also sailfish are very fast, but have scales that may also act like the dimples. Perhaps if someone tries the dimples and it turns out to help, there will be more research in dimple shape and size. If you have access to a wind tunnel you will be able to measure and compare the drag forces between a dimpled & smooth shell. No need to go out on the field. May be able to also apply this technology to swimsuits for competitive swimming, if it works.
Sean Rhoades Aerodynamics have a bad habit of working very differently depending on the fluid (air or water), size of objects and speed at which they travel. In water some surface roughness or scales do seem to help in some respects. Swimsuit makers have looked into it, and it is a very active research topic. Small channels on the surface of jet engine cowling seem to work as well, and it is being experimented on by NASA. Unfortunately, our time and budget doesnt allow us to research too many topics simultaneously. Tires and wheel aerodynamics are now our main areas where we think we can get a big advantage. The surface of the bike is as good as we will get it without a big research effort, and all existing evidence points for the air, at the speeds we travel at, smooth surfaces are best.
quite likely on motorbike jackets, but I am not an expert. I find that a lot of new jackets use the back protection to change the shape of the rider, and provide a larger area of attached flow. Pretty neat trick.
it does on a car, because a car's exterior shape cannot be changed (much). If the shape is fixed (ball, car, truck) then surface aero devices, such as dimples, turbulators, etc, can help quite a bit. But for our bike we were able to use a nearly-perfect shape, so no need for those band-aid fixes. not sorry. :P
This was a great video, you are a good teacher!
This should have more views on it, you answered my question very well, thank you!
Thanks! I was wondering why the Celera 500 airplane did not used dimples in the fuselage, since they’re aiming to minimize air drag. That could also explain why it worked in the myth busters car.
Holy shit the video was informative, definetly giving a thumbs up for this
Aerodynamics of Spheres, and Rotating Spheres. (Golf Balls, Baseballs, Cricket Bowls.) Versus the theory of Laminar Surfaces. Nice job Victor.
The aero design is clearly a natural laminar flow concept. Can tell clearly by how far back the maximum thickness location near is and the concave pressure recovery tail
yup, correct
Shadowboost - not so, "UFO" are round.... As in a flat golf ball...
Outstanding, however if one places dimps on the back ETA the disturbance mix flow the pressure conforms to give a greater positive squeeze back toward the front more than its smooth path let's see...just a widget thought in the case of the Russian Subroc torpedoes which uses it's soild or liquid spented exhaust gases to create the "Mass Disturbance" of air at front cone ports matching the same speed while submerged underwater as if were in air flight...then greater pressure follows the contours of the sphere and the bare proof is right in front of you, the key is the sphere, look at your sphere that's the key, however it clearly not be disregard... feedback responds welcome please
Great explanation!
I needed exactly this explanation and its so good hahah
Have you guys looked at how much energy it would take to implement active boundary layer control - suck it down - to achieve more laminar flow? My guess would be the energy required to drive the boundary layer suction would be too much to justify the complexity, but I'm still curious what your thoughts are.
Zach Hazen Boundary layer control is a pretty hot topic, that I know nothing about :P. What I know that RC planes have been used as proof of concept for boundary layer plasma actuation, and that it worked really well at keeping the boundary layer attached.
Any system we implement would need to be human powered. For this year, we did not bother even looking at it, there were a lot of places we could get easier performance out of the bike and rider. The University of Toronto human powered vehicle design team (which I used to lead) will probably look into it in one of their upcoming ASME bikes.
It looks like it's going to become someone's Master's project.
Hi,
first off, very nice video. I finally got it:) Thank you for that. Here is a related question though...Taka .22LR bullet (5.6mm diameter, 2.6 grams, flat base, V_start=325(m/s)...strap on a boat tail to it, also have it at 2.6 grams and V_start=300m/s. When/what distance would you start to see the energies of both projectiles are equal? 100m? 200m?
Or to make it more simple...if i were to put a boat tail on a .22LR (keep the same weight) how much will I gain?
Also..do you think that it's possible to keep the flow at the nose of the bullet laminar at those speeds (325 m/s and 300m/s) or it's not even worth trying it'll go turbulent as soon as the air reaches the projectile?
not sure about projectiles at high speed. my guess is that there is a lot of research out there, that you can find for free.
That darned sticky air.......
In fact, the flow in the tube is always turbulent flow. So it is impossible to use theory to talk about turbulent flow and laminar. In addition, there must be increased kinetic energy for air to transport fuel and mix well. the velocity of air flow is also increased
what tube you talking about?
This was actually very interesting! Would it make any sense to design a streamlined shape with a hole/canal going throug it from tip to tail? Sort of like an elongated donut. In order to avoid the stationary air cushions building up in front and behind the shape? (Given the fact that you don´t have to pierce this canal through the body of a rider sitting inside ...) Or it it just an error in reasoning becaus you would than have all the friction just on the inside? respectively you replace one tip by a new "tip" in a circular shape ...
possible...but yea, any area in contact with the air provides skin friction, and would be bad. Generally, if you have a big opening in your shape with a pipe going thru the interior, you could have made the whole thing smaller, and get rid some of skin friction.
The high pressure areas in the front and low pressure in the back would now be a ring, instead of a circle. Somewhere the air has to be stationary.
The video seems like a well-reasoned argument for using smooth surfaces, that are also probably less complex/costly than dimpled. The bike is designed to sustain laminar flow for the greatest possible length along the body. The laminar flow is expected to become turbulent in the rear section of the body, can golf ball dimples from the turbulent point rearward provide less drag than a smooth surface? I didn't pick up on any evidence presented to show that dimples would hinder performance.
+Jeremy Priede dimple surfaces have greater surface area than smoother surfaces. As such, they got greater drag if the flow is attached. We are very confident our flow is attached over the whole bike, so there is no reason to use dimples. We are confident of this because our drag in real life is very close to the estimated drag (and we estimate no separation) and if there was any separation, our drag would be much higher, very noticeable so.
Thanks, I had thought that it was turbulence that caused drag, but as you point out - it is separation that causes drag. And turbulence can be used by a golf ball to decrease separation (and thus decrease drag).
+Jeremy Priede nope. I suggest you watch the video again. There are a number of causes for drag, such as skin friction and separation. We got no separation on the bike, so no golf ball dimples are necessary.
Skin friction causes drag, and gold ball dimples make it worse. Not only golf ball dimples have more surface area, which causes more skin friction, but they also make the air more turbulent. More turbulent air means faster moving air molecules are able to get closer to the skin of the vehicle, thus increasing the skin drag.
So gold ball dimples are always bad, unless you have separation, and are not able to get rid of separation any other way. They are a last resort for cases where the shape cannot be changed.
The myth busters tried this with a car and they were wrong! The dimples made the cars mpg increase
@@VRagusila I'd think that turbulent flow allows outside air to contact turbulent air instead of the skin itself. Air on air contact is much more frictionless than air on a solid
I would love to see some Monotracer type vehicles,except as a commuter type vehicle,single seat,low drag body,conventional door,light weight,small electric or 250 cc engine.Enclose a MP3,Yamaha Tricity parallel link type front end to eliminate out riggers,single wheel in rear.Why not a morphable surface,dimples at low speed only?
Hello Inagod. Such a monotracer would be fun. However, the gold ball dimples wouldnt make sense no matter the speed, unless the monotracer is forced to have a spherical or similar shape.
Vision is one of the main issues of very low, aerodynamic shapes. It is both hard to see out of the vehicle, and it is very hard for anyone to see you. I believe vision and crash resistance are the main issues to deal with before such a vehicle can be a commuter.
Would dimples on under side of wings increase lift?
I dont see why they would. They would increase skin drag, but I cant think of a mechanism that would result in more lift...
Objects on underside of wings dont seem to affect the lift negatively too much either. All airplanes hang engines, rockets, missiles, fuel tanks, etc under the wing, keeping the top side as clean as possible, with the exception of turbulators.
What about inside tubes?
Good explanation ! It is quite amazing tghat your streamlined bike shell has no need of VGs...
Thing is, you are probably wrong. Mythbuster did a dimple car test and it was more fuel efficient. Why not try?
dimples work for car-like object, or sphere like object. For an object with a tail that we can shape, it is not going to help. Not worth trying because we know the effects of even thicker tape on the back of the bike, which disturbs the airflow and causes higher drag. Dimples would add even more drag.
@@victorragusila7519 well, based on where the body seam is it's obvious why tape added would be a negative. The initial guess would be to put dimples on the rear surfaces of the body.
at the front tip of a super sonic plane. high speed , high friction ,hi heat. with dimples, hi speed ,less friction, less heat.
The plot thickens: However intake manifold of a 600Hp engine gained 23 hp wit dimples.
Well, the plot gets more density. Thickens is not a technical term :P
Different air situations require different measures. If the manifold had any separation, dimples would definitely help. There might not be enough room to make the intake a shape that has no internal separation. The shape being fixed (or at least constrained) then the surface can be made to deal with some of the separated air.
For us, we could make a shape with no separation quite easily. So no need to use surface features.
I work in very high end motorsports..( sorry not allowed to disclose where , so your guess where is pretty easy) and not used dimples to date. We say: its a solution for a problem created by yourselve....😄😄
Very well explained, thank you
Sorry just read the comments, looks as though Sean Rhoades asked a similar thing already
What about dimpling a baseball bat? Would that result in the possibility for a faster swing?
+John Hogue Drag forces are a small contribution to the energy of a baseball bat.
@@appa609 Regardless with what contributes as a "small contribution," many small contributions create one big one. In theory, yes it will help. If you have the means to do it, do it.
Waylon Jeffery well it’s not clear it will be a net positive contribution. Dumpling the bat is also going to slightly decrease the stiffness if the bat. The overall restitution may go down. And it would certainly cost more. Even if it were right it would be tiny.
Well and, if the ball contacts a dimple it's not going to go where the batter wanted it to
More dots, 50 dkp MINUS!
This does not make much sense to me.I say the turbulent air is slowed down so it can turn around the ball.The smooth fast non Dimple set up has the majority of the air go so fast momentum stops it going around the bend.
Unfortunately you are wrong. Aerodynamics is not really intuitive. It took me a while to understand why mixing fast and slow air, due to turbulence, can bent a curve better than slow air from the laminar air. The trick is to understand that the air right next to the object is perfectly still relative to the object. The goal is to keep the air moving against the object, and not make it move backwards.
For example, www.researchgate.net/publication/327793049_The_Effects_of_Reynolds_Number_on_Flow_Separation_of_Naca_Aerofoil is a test showing that separation occurs at higher angles of attack for higher Reynolds numbers, which increase linearly with speed. So faster air can bend the curve better than slow air.
My understanding is not perfect, and still trying to find the best way to explain it. Good luck trying to understand it better, it is not simple, nor easy.
@@victorragusila7519 Unfortunately you are wrong.
@@lomasck care to elaborate? I always want to learn more about aerodynamics.
@@victorragusila7519 The problem with Aerodynamics is we cant see it.I think we are always trying to understand it that's why I was watching your video after all.Because I did not understand your explanation I came up with my simpler explanation. Perhaps I am wrong.I guess I was just challenging your story on it.OK .I just looked at some other explanations on RUclips & have a important Question. Does the ball have to spin in flight.That could change everything.How important is the spin factor ?
@@lomasck The spin would definitely affect things, but I think that is a separate problem. Understanding it without spin is important to help understand it with spin later on.
I looked for a few more videos to recommend for you, and because I need a refresher course in Aerodynamics, since i havent looked at it for a few years (off to a new obsession for now).
I highly recommend this video, they explain boundary layer better than me, without going into Laminar VS turbulent discussion ruclips.net/video/5zLCofDSt_Q/видео.html
The Wiki page on flow separation also has some good info .en.wikipedia.org/wiki/Flow_separation
We actually can see aerodynamics. We need a wind tunnel or day with fog, but we can see (with the help of smoke) the way the air behaves. It was probably one of the main tools that helped develop airplanes around the two world wars. I am sure you can find some really good videos of flow around balls or wings.
A few points that helped me understand aerodynamics:
1) dont think of air as small balls that move around a wing. A faster small ball is harder to turn, whereas a slow one can turn easily. I think that is why intuitively, it is easy to think that fast air separates easier.
2) Air works more like molasses, it has viscosity. Much smaller than molasses, but it still exists. There is friction between all layers of air, and between air and any object.
3) Separation means air moves backwards over a wing (if we think of the wing as 0 velocity). For a ball going thru the air, it means the air sticks to the ball and travels with it. That is generally BAD. You dont want your ball (or wing) to grab a bunch of air and take it along, that creates lots of drag. You want the air to stay exactly where it was before your wing or ball moved thru it. That would be 0 drag (and impossible).
Good luck, it took me a while to find an explanation that made it click for me. I was lucky to have a few classmates that took a lot more aerodynamics courses than me, and were very good at explaining it. Once you understand the effects of boundary layer velocity on pressure and separation, you should be able to derive the effect of spin.
Has anyone tried the dimples any why, perhaps your understanding is faulty?
yes, people have tried dimples. It is also attempted on cars, bike helmets, etc. While my understanding might be faulty, none of the other teams that went fast in the last 20 years ever used dimples, and they all tried to achieve the smoothest possible shape. Some experienced racers, such as the world champion for 15 years, Sam Whittingham, can feel the difference between different waxes. The smooth ones are always faster.
Hi, so sorry, I am not saying you personally have a faulty understanding, but the general understanding of why dimples work, may be faulty. I was thinking about fish, such as tuna, and sharks, also sailfish are very fast, but have scales that may also act like the dimples. Perhaps if someone tries the dimples and it turns out to help, there will be more research in dimple shape and size. If you have access to a wind tunnel you will be able to measure and compare the drag forces between a dimpled & smooth shell. No need to go out on the field. May be able to also apply this technology to swimsuits for competitive swimming, if it works.
Sean Rhoades Aerodynamics have a bad habit of working very differently depending on the fluid (air or water), size of objects and speed at which they travel.
In water some surface roughness or scales do seem to help in some respects. Swimsuit makers have looked into it, and it is a very active research topic.
Small channels on the surface of jet engine cowling seem to work as well, and it is being experimented on by NASA. Unfortunately, our time and budget doesnt allow us to research too many topics simultaneously. Tires and wheel aerodynamics are now our main areas where we think we can get a big advantage.
The surface of the bike is as good as we will get it without a big research effort, and all existing evidence points for the air, at the speeds we travel at, smooth surfaces are best.
VRagusila I hope some golf ball company CEO sees these posts and helps your team with some more funds. It could happen!
I'm not interested in the bike but thanks for a good explanation.
Wise guy!
nice explanation
Looks like Remi Malek
thanks! :)
thanks man. and if anyone needs a youge freddy murcury look alike here he is
ty, i understand. quite easy to see now :)
so it would work on a motorbike jacket or shuriken....well, sounds fun :D
quite likely on motorbike jackets, but I am not an expert. I find that a lot of new jackets use the back protection to change the shape of the rider, and provide a larger area of attached flow. Pretty neat trick.
The ball is spinning; the bike is not.
Mengapa bola golf berlesung ?
ruclips.net/video/3M6Kalar4W8/видео.html
Hence the mythbuster result was flawed and incorrect.
nah. They tested it on a car. which has a boxy shape. For that, dimples work. For our shape, since we can make it streamlined, it is not necessary.
Mythbusters Golf Ball Car, already proved it improved MPG. sorry
it does on a car, because a car's exterior shape cannot be changed (much). If the shape is fixed (ball, car, truck) then surface aero devices, such as dimples, turbulators, etc, can help quite a bit. But for our bike we were able to use a nearly-perfect shape, so no need for those band-aid fixes. not sorry. :P