Downwind - Knocking the Ball Out of the Air

[HanNL]

Maybe this helps

http://blog.trackmangolf.com/headwind-vs-tailwind/

Basically, the amount of spin needed to still create lift in a tailwind is higher than in a headwind. (because of the ball's relative forward velocity). When the tailwind 'catches up' with the ball, there can be no lift (ball not moving relatively vs the wind, no amount of spin will help now), thus, it falls out of the sky. In higher windspeeds: this happens sooner. Of course, the distance is helped a bit by the relative reduction of drag and increase of velocity because of the tailwind.

Vice versa, the amount of spin to create lift in a headwind is lower than in a tailwind. Too much spin will cause the ball to balloon (too much lift) and thus lose a lot of distance. Of course this is combined with the extra drag and consequent loss of velocity due to the wind direction.

To clarify: lift is created by two different airspeeds that work on the ball: lower speed on the bottom of the ball (actually on the bottom of the spin axis) and higher speed on the top of the ball (top of the spin axis). This creates less pressure on the top and the ball will move up. (relative to the spin axis).

[boogielicious]

Maybe this helps

http://blog.trackmangolf.com/headwind-vs-tailwind/

Basically, the amount of spin needed to still create lift in a tailwind is higher than in a headwind. (because of the ball's relative forward velocity). When the tailwind 'catches up' with the ball, there can be no lift (ball not moving relatively vs the wind, no amount of spin will help now), thus, it falls out of the sky. In higher windspeeds: this happens sooner. Of course, the distance is helped a bit by the relative reduction of drag and increase of velocity because of the tailwind.

Vice versa, the amount of spin to create lift in a headwind is lower than in a tailwind. Too much spin will cause the ball to balloon (too much lift) and thus lose a lot of distance. Of course this is combined with the extra drag and consequent loss of velocity due to the wind direction.

To clarify: lift is created by two different airspeeds that work on the ball: lower speed on the bottom of the ball (actually on the bottom of the spin axis) and higher speed on the top of the ball (top of the spin axis). This creates less pressure on the top and the ball will move up. (relative to the spin axis).

Excellent post.  To summarize: When the ball slows down to the point of being equal to the wind speed, lift created by ball spin is disrupted. The ball is now just a falling object being pushed by a tailwind.  JAMO was on to this as well.

[iacas]

Maybe this helps

http://blog.trackmangolf.com/headwind-vs-tailwind/

Basically, the amount of spin needed to still create lift in a tailwind is higher than in a headwind. (because of the ball's relative forward velocity). When the tailwind 'catches up' with the ball, there can be no lift (ball not moving relatively vs the wind, no amount of spin will help now), thus, it falls out of the sky. In higher windspeeds: this happens sooner. Of course, the distance is helped a bit by the relative reduction of drag and increase of velocity because of the tailwind.

Vice versa, the amount of spin to create lift in a headwind is lower than in a tailwind. Too much spin will cause the ball to balloon (too much lift) and thus lose a lot of distance. Of course this is combined with the extra drag and consequent loss of velocity due to the wind direction.

To clarify: lift is created by two different airspeeds that work on the ball: lower speed on the bottom of the ball (actually on the bottom of the spin axis) and higher speed on the top of the ball (top of the spin axis). This creates less pressure on the top and the ball will move up. (relative to the spin axis).

Yes, that's what I'm trying to discuss here.

I'm a bit dismayed at my lousy communication on this one. I must not have taken the time to communicate it clearly. I know all the stuff you posted there - basic physics… what I was trying to create was a discussion of when/how that happens? You only ever really hear about it happening with a wedge, but clearly if the winds are strong enough it can affect the latter stages of some longer clubs.

Wedges are affected more so because they spin more and rely a bit more on lift, but at the same time get LESS lift because their linear ball speed is slower than every other club.

I wanted to discuss the ranges and concepts there… what ball speed and spin rate (both decayed from initial launch) versus what wind speed is likely to result in a net loss of distance by the two factors: wind pushing the ball and reducing drag versus wind decreasing lift.

[David in FL]

I wanted to discuss the ranges and concepts there… what ball speed and spin rate (both decayed from initial launch) versus what wind speed is likely to result in a net loss of distance by the two factors: wind pushing the ball and reducing drag versus wind decreasing lift.

I'm anxiously waiting to hear some thoughts too, because I don't have any answers, and it's a very real, frustrating problem. I find it much easier to be consistent when playing most approaches into a strongish breeze (10mph+) than downwind.

[HanNL]

Yes, that's what I'm trying to discuss here.

I'm a bit dismayed at my lousy communication on this one. I must not have taken the time to communicate it clearly. I know all the stuff you posted there - basic physics… what I was trying to create was a discussion of when/how that happens? You only ever really hear about it happening with a wedge, but clearly if the winds are strong enough it can affect the latter stages of some longer clubs.

Wedges are affected more so because they spin more and rely a bit more on lift, but at the same time get LESS lift because their linear ball speed is slower than every other club.

I wanted to discuss the ranges and concepts there… what ball speed and spin rate (both decayed from initial launch) versus what wind speed is likely to result in a net loss of distance by the two factors: wind pushing the ball and reducing drag versus wind decreasing lift.

Wouldn't the ratio between linear ball speed and spin be the deciding factor? Wedges have less ball speed but a lot more spin, low irons less spin, but more ball speed.

Less forward motion (in the direction of the wind) for wedges means that the wind catches up earlier. More forward motion for low irons implies that the wind catches up later and the ball keeps its lift longer.

A factor could also be that you notice the steep drop for wedges more than for low irons (because of the distance between you and the ball).

I realise I'm still talking in concepts, and not in actual numbers, simply because I don't have them :)

[iacas]

Wouldn't the ratio between linear ball speed and spin be the deciding factor? Wedges have less ball speed but a lot more spin, low irons less spin, but more ball speed.

It's likely a bit more complex than that. Remember, a tail wind is also pushing the ball. There's a reduction in drag to go along with the reduction in lift. It's a multi-variate problem that involves:

• Lift
• Drag
• Dimple Design
• Speed decay
• Spin decay

I'm simply posing the question because I'm looking for a reasonable explanation for the 6-iron shot I hit. I've only ever really heard of the wind knocking the ball out of the air with short irons. Outside of a tornado, is it possible with long-irons and mid-irons too?

A factor could also be that you notice the steep drop for wedges more than for low irons (because of the distance between you and the ball).

It's possible, but at the same time, we'd have people "noticing" their long irons and mid-irons coming up short, and I don't know that such observations are being made very often.

[dkolo]

I wonder if this is a phenomenon that would be accurately represented in a golf simulator. That would be a good way to get more data points if it did.

[trickyputt]

Maybe this helps [URL=http://blog.trackmangolf.com/headwind-vs-tailwind/]http://blog.trackmangolf.com/headwind-vs-tailwind/[/URL] Basically, the amount of spin needed to still create lift in a tailwind is higher than in a headwind. (because of the ball's relative forward velocity). When the tailwind 'catches up' with the ball, there can be no lift (ball not moving relatively vs the wind, no amount of spin will help now), thus, it falls out of the sky. In higher windspeeds: this happens sooner. Of course, the distance is helped a bit by the relative reduction of drag and increase of velocity because of the tailwind.  Vice versa, the amount of spin to create lift in a headwind is lower than in a tailwind. Too much spin will cause the ball to balloon (too much lift) and thus lose a lot of distance. Of course this is combined with the extra drag and consequent loss of velocity due to the wind direction.  To clarify: lift is created by two different airspeeds that work on the ball: lower speed on the bottom of the ball (actually on the bottom of the spin axis) and higher speed on the top of the ball (top of the spin axis). This creates less pressure on the top and the ball will move up. (relative to the spin axis).

So 25% of the time I need higher backspin to compensate when the wind is from the rear, not front or either side. Or do I club up into a trailing wind? That will be hard for me mentally.

[HanNL]

So 25% of the time I need higher backspin to compensate when the wind is from the rear, not front or either side. Or do I club up into a trailing wind? That will be hard for me mentally.

You could probably do with less spin in a headwind, but you have to have enough ballspeed (or less loft) to compensate the increase in drag. (thus: in a breeze, swing with ease). Clubbing up in a tailwind: I wouldn't do it, but it might work :).

It's likely a bit more complex than that. Remember, a tail wind is also pushing the ball. There's a reduction in drag to go along with the reduction in lift. It's a multi-variate problem that involves:

Lift

Drag

Dimple Design

Speed decay

Spin decay

I'm simply posing the question because I'm looking for a reasonable explanation for the 6-iron shot I hit. I've only ever really heard of the wind knocking the ball out of the air with short irons. Outside of a tornado, is it possible with long-irons and mid-irons too?

Of course ratio between ball speed and spin is not the only factor that is relevant, but in similar conditions (same ball, same wind), I would pose that that ratio would decide if your ball drops out of the sky or has a 'normal' ball flight.

I just thought of this: could it be that there was a wind sheer of a kind in your situation, or maybe different layers of air that move at different speeds (trees, hills)?

I wonder if this is a phenomenon that would be accurately represented in a golf simulator. That would be a good way to get more data points if it did.

I don't think any simulator would accurately show this effect. (it might be possible though, if the simulator calculates drag etc differently if there is wind).

[chris3putt]

Quote:

It's likely a bit more complex than that. Remember, a tail wind is also pushing the ball. There's a reduction in drag to go along with the reduction in lift. It's a multi-variate problem that involves:

• Lift
• Drag
• Dimple Design
• Speed decay
• Spin decay

I'm simply posing the question because I'm looking for a reasonable explanation for the 6-iron shot I hit. I've only ever really heard of the wind knocking the ball out of the air with short irons. Outside of a tornado, is it possible with long-irons and mid-irons too?

The reasonable answer is that with long and mid irons, it probably isn't something that you can reliably factor for.

As you point out, the physics is complicated. All we have to go on is experience, and because it happens infrequently, with mixed results, that experience is limited.

[Gunther]

No one is buying my gusts theory or variable wind speeds up where our ball travels? I'm no scientist but not many have played in as much wind as I. I don't discount drag, spin, etc., but I truly believe it's the variability that is the biggest culprit. Mother Nature is cruel.