How do you input irons?

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nkent
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How do you input irons?

Post by nkent » Sun Aug 21, 2011 12:58 pm

I am using the software for seeing how changing the parameters effect the distance for irons, like 5i, 6i, 7i, 8i, 9i and PW.

I am using a clubhead speeds between 71-85 mph and I adjust dynamic loft for each iron. For testing, I leave AoA at 0.

Here is an example of what I entered for a 5i:

Clubhead speed - 75 mph
Dynamic loft - 25
AoA - 0

(5i static loft from the NicKent Golf site is 25 deg)

I get a carry distance of 118 yards.

Adding more clubhead speed does not increase distance by much, just the height of the shot.

I would think that the example above would produce at least a 170 to 180 yard shot, not 118.

I know I missing something here. But What? How should I set up the parameters for irons to get the correct value using the software?

Thanks for your help.

dtutelman
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Re: How do you input irons?

Post by dtutelman » Sun Aug 21, 2011 1:21 pm

nkent wrote:I know I missing something here. But What?
That's pretty easy to answer.

Did you notice the red warning message saying, "NOTE: The initial spin is outside the recommended range of 1000 to 4000rpm"? That's what you're missing.

TrajectoWare Drive loses accuracy for spin over 4000rpm. In particular, it overestimates the aerodynamic lift. The result is extreme ballooning. Way outside the constraints of reality. The reason is that the lift and drag coefficients change from our formula at high spin rates. We need to find a formula that covers a wider range of spin.

We hope to fix this in the next release, when we find time to do the next release. Until then, you're pretty much restricted to driver and 3w.

dtutelman
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Re: How do you input irons?

Post by dtutelman » Sun Aug 21, 2011 1:29 pm

dtutelman wrote:We need to find a formula that covers a wider range of spin.

We hope to fix this in the next release, when we find time to do the next release. Until then, you're pretty much restricted to driver and 3w.
Let me expand a bit on this.

Fairly early after the release of the current version, Frank came up with a modification to the formula that gave much more reasonable answers. But they seemed slightly "off". At the time, we didn't have the means to check the formula against real data, so we did not know whether it was accurate or not.

We were faced with a dilemma: leave it as it is, or modify it so it gives plausible but unverifiable answers. We decided on the former, so people would know not to trust the answers too closely. Nkent's experience validates that decision, IMHO.

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