Sorry, I don’t see how those three things are related.

IMO, feathers are hair adapted to form flying surfaces, but keeping the insulating properties by trapping air among fibers.

Riffling is not on the projectile, and its purpose is to create a gyroscopic effect that improves the trajectory of bullets.

Thank you, Banktoturn, your explanation is simple to understand.

Nature never created creatures or objects able to simultaneously roll and fly or swim efficiently.

When an aerodynamic shape is not possible, like for golf balls, the second best option to achieve efficient flight is to make the skin able to disrupt the airflow beyond laminar conditions.

arrows and bullets are projectiles the feathers on arrows help them fly straight. rifling is also used to make the bullet go straight and increase its range this is why there are dimples on golf balls. I was under the impression that was the question maybe I read it wrong.

Sorry psb667, I did not associate the feathers with arrows.[sm=52_52.gif]

I agree with you.

This type of shells use a gas generator system to help decrease the pressure differential. The range can be increased by as much as 30%.

The Mythbusters episode with the dimpled car is scheduled to be on again tonight at 8 PM EST

[link]http://wings.avkids.com/Book/Sports/instructor/golf-01.html[/link]

I think Pbs67 posted this link. It seems to support what I said about the golf ball. The travel distance/velocity is increased from reduced drag. Lift is created if a ball has back spin, otherwise lift will not effect foward motion asside from increasing the angle/altitude of the ball so it can stay in the air longer.

The effect of dimples on the submarine is a little different. The submarine is in water and does not experience exactly the same laminar separation and drag effects as the ball does in air. The pointed tail design does help reduce the effects of the low pressure area in the wake, but the benefits of dimples are due to reduction in friction against the bow and lateral surfaces of the hull.

<div style="margin: 0in 0in 0pt">Golf balls may be the only projectiles with dimples but they are not the only projectiles that benefits from having a rough surface. Any surface preparation that increases surface drag increases the Magnus effect such as dimples on a golf ball, fuzz on a tennis ball, threads on a baseball. Think of a spinning ball or cylinder as an air pump, the rougher the surface the more air the ball or cylinder can pump. A wing pushes (high pressure) and pulls (low pressure) air down to generate lift in the upward direction. A spinning ball or cylinder pumps air down by pulling on it to generate an upward force. This pulling is not characterized by low pressure it is more the result of the airs viscosity. So the wing and the spinning ball or cylinder can both do the same thing only one uses lift and the other uses viscous drag.A squirrel cage fan and a conventional house fan both do the same thing only one uses lift and the other uses drag. The paddle on a paddleboat and the propeller on a bass boat both generate thrust only one uses drag and the other uses lift. A round canopy and a square canopy parachute and a human body can all use still air to totally support their weight when dropped from height altitudes only two use drag and one uses lift and drag and one of em ain&rsquo;t going to make it. </div>

Goodness -you are going to upset the aeronautical terminology correctness control gruppe.
Lift is drag and drag is lift- is my take on it
But you must use the proper words .
These guys tend to get upset easily

<div style="margin: 0in 0in 0pt"><span style="font-size: 9pt">If you could be more specific about what aeronautic terminology that you think I have used incorrectly and what words I have used improperly maybe I would have a clue as to what you mean. The flight of a golf ball is more an aerodynamic phenomena as opposed to an aeronautical one. In controlled flight there is usually a pilot in charge of the controls. The pilot does not need to know the simple difference between lift and drag if he did there would be very few if any pilots. Lift is not drag but they are very similar. Lift and drag are infinite in direction, either one can cause the motion of an object or oppose motion in any direction. Lift and drag are the two aerodynamic forces that are inflicted on solid objects by relative airflow. By accurate definition the only difference between lift and drag is there direction in relation the relative airflow that caused them. Lift is perpendicular to the relative airflow that caused it and drag is in the direction of the relative airflow that caused it. Relative airflow does not require the motion of air around a solid object or the motion of an object through air (flight path) or the motion of an object while in the air (rotation) although any one or combination of any can make up the relative airflow that influences a solid object. </span></div><div style="margin: 0in 0in 0pt"></div><div style="margin: 0in 0in 0pt"><span style="font-size: 9pt">I am not going to intentionally be less than accurate to avoid upsetting some one with misconceptions about basic aerodynamics or someone with no misconceptions about bias aerodynamics. If every one agreed there would be little to discuss and if you don&rsquo;t be more specific there will also be little to discuss. </span></div>

[[i]quote]Lift and drag are infinite in direction, either one can cause the motion of an object or oppose motion in any direction[/quote]

Quote:

Lift is perpendicular to the relative airflow that caused it and drag is in the direction of the relative airflow that caused it

The first statement could be interpreted as contridictory to the second. The second statement is more accurate. Lift is created perpendicular to the direction of the object in motion. Lift is not created in front of the leading edge of a wing or in front of a golf ball and therefore is not "infinite in direction".

WoW
I simply noted that lift and drag are really in the eye of the beholder
You say banana
I say bahnahna
Lift and drag are like Yin and Yang
But The proper use of aerodynamic terms is nice - if gives people something to nit pick.
Like the blind men examining an elephant.

Golf ball that does not rotate creates even less drag...called a flyer.

I once had a 250 m ( 288 yards ) stroke with an i5 ( 10 years ago ).

<div style="margin: 0in 0in 0pt">Thank you for your comment and being more specific about what I have written that you do not agree with. The reason lift and drag are infinite in direction is that the relative airflow that they are determined by is infinite in direction. Only in certain circumstances is lift perpendicular to the direction of the object in motion but in every circumstance lift is perpendicular to the relative airflow that caused it. An example would be objects in wind tunnels that generate lift and drag on objects that are not in motion.If the definition of lift were determined by its direction in relation to the motion of objects, objects in wind tunnels would not generate lift because they are not in motion. As far as determining aerodynamic force is concerned the only motion that is relevant is the motion between the air and the solid object or relative airflow.Another example would be a sail boat, aerodynamic force is determined by a combination of the direction of the motion of the sail and the direction of the wind just like a sailplane that flies in to a strong updraft.</div><div style="margin: 0in 0in 0pt"></div><div style="margin: 0in 0in 0pt">You are so right lift is not created in front of the leading edge of a wing or in front of a golf ball this is why I specifically said aerodynamic force is inflected on solid objects and not in close proximity to solid objects. </div><div style="margin: 0in 0in 0pt"></div>

<div style="margin: 0in 0in 0pt"><span style="font-size: 9pt">_ Sorry (to all) I tend to get on a soapbox when I reply to a post. You could write a book on inaccurate definitions of aerodynamic force so you are right lift and drag appear to be in the eye of the beholder and this gives people a lot to nit pick about. It would make me so made when someone would say it&rsquo;s just a matter of semantics. Words are useless without meaning and the simpler more accurate less obscure the definition is the more useful the word and the less room for nit picking. So what I am trying to say in my soapbox kind of way is I agree the proper use of aerodynamic terms is nice.

</span></div>

Roy, how about a normal font?

Roy's font appears to be the result of a copy/paste. When you compose a text in another application and paste that result, with it's imbedded control characters and such, and there is no font parameter, the receiving application makes up for what's not imbedded or passed.

It is quite readable.

I just wanna add that my 250 m stroke had a touch and go at 200 m flight ( GIR ) but skidded of the green. Mike Austin is a legend of having hit a ball 515 yards of the tee. I hit mine from a position where the ball was lower than my shoe soles and at delofted club face angle ( loft i3 equivalent ) at very high speed at least 110 mph where the ball leaves the club face at 160 mph having 0.5 N of drag. I was also in slighty elevated postition in comparison to the green ( 5 meters / 15 ft ).

I was told it was a flyer..but maybe it only had less rotation than normally hit balls.

Hugger I'm very sorry , it finally dawned on me what you ment. Correct me if I am wrong. Because of my obscure wording you though I ment lift was infinite in direction in every instance. I should have said the potintial directions for lift are infinite. I will try and do better next time and you keep keeping me honest.

It's hard to go back and say what the original reason for dimples on golf balls was. But there's no doubt that they have a number of effects. One, as Sport Pilot said, is to aid in the generation of lift up or to the side through aiding the Coanda effect when a spin is imparted on the ball. However other factors weigh in as well such as the delay in airfow separation which is the real topic of this thread.

read and learn, (yes it is a cut and paste, but all this conjecture is driving us nuts) dimples are not there to keep them from rolling of gentle slopes either

Dimples first became a feature of golf balls when a certain Taylor patented a dimple design in 1908. Other types of patterned covers were in use at about the same time, including one called a "mesh" and another named the "bramble", but the dimple became the dominant design due to "the superiority of the dimpled cover in flight".[6]

Most golf balls on sale today have about 250 – 450 dimples, though there have been balls with more than 500 dimples. The record holder was a ball with 1,070 dimples — 414 larger ones (in four different sizes) and 656 pinhead-sized ones. All brands of balls, except one, have even-numbered dimples. The only odd-numbered ball on the market is a ball with 333 dimples, called the Srixon AD333.

Officially sanctioned balls are designed to be as symmetrical as possible. This symmetry is the result of a dispute that stemmed from the Polara, a ball sold in the late 1970s that had six rows of normal dimples on its equator but very shallow dimples elsewhere. This asymmetrical design helped the ball self-adjust its spin-axis during the flight. The USGA refused to sanction it for tournament play and, in 1981, changed the rules to ban aerodynamic asymmetrical balls. Polara's producer sued the USGA and the association paid US$1.375 million in a 1985 out-of-court settlement.

The United States Patent and Trademark Office's patent database is a good source of past dimple designs. Most designs are based on Platonic solids such as icosahedron.

Golf balls are usually white, but are available in other high visibility colors, which helps with finding the ball when lost or when playing in low-light or frosty conditions. As well as bearing the makers name or logo, balls are usually printed with numbers or other symbols to help players identify their ball.

My bad on calling the lift from the spin being due to the Coanda effect. It is the Magnus effect.

I'm getting my effects all mixed up....

Dimpled cars do get way better mileage. Trouble is you guys wont buy and drive them! LOL

only a golfer would know eh?.......having tried everything in sight, i can honestly say that the dimple count does make a difference.............some fly better in the wind than others.......some fly better in the heat..etc

I'd be afraid that it wouldn't go fast enough to outrun the guy chasing me with a pitching wedge....