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Skytrak vs Trackman

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  • Skytrak vs Trackman

    I have managed to document part 1 of some recent testing.


    Thanks to TorchRedRob for help with some of the maths!
    I recently conducted some testing to compare my Skytrak to Trackman. I have read a number of comparisons (mainly by golf magazines etc) but ...

  • #2
    Wow, thanks James^2 for this! I suspected all along that the SkyTrak offline measurements were too punishing - and I think this proves it. I just read elsewhere about "spin decay" possibly being a factor that SkyTrak has not considered? My guess is that's the answer. I have a GCQuad on order and was going to do this same sort of comparison to my SkyTrak to see what gives?
    Last edited by rrobinson; 03-03-2017, 04:02 PM.

    Comment


    • #3
      Great write up and thanks for taking the time to compare.

      I saw you mention something about ball setting in trackman. " In Trackman ball conversion terms they are the equivalent of hard (reduced spin with short irons, elevated spin with long irons/woods)." Do you really need to do ball selection type there? This measures the entire flight outside correct, why would that matter? I might not understand the ball comment correctly.

      Ball speed, LA, Total Spin, Back Spin, Flight time all look very good.

      HLA, peak height look ok

      Side spin, spin axis, carry, not too good.

      2k vs 20+k, not too bad.

      Comment


      • James James
        James James commented
        Editing a comment
        Thats a good point. I can change the ball type to premium (so it doesnt perform ball conversion) and see what happens.

      • James James
        James James commented
        Editing a comment
        Normalised results (Player A):
        Club, ST Carry, TM Carry, ST Total, TM Total, ST Offline (yd), TM Offline (ft)
        Driver, 203, 203, 231, 229, -1.9, +7
        5 Iron, 166, 166, 188, 195, -12.25, -32
        PW, 119, 116, 124, 122, -5.5, +4

        I was impressed before the data was normalised!!!!!

      • SkyTrak_Seth
        SkyTrak_Seth commented
        Editing a comment
        Wow, pretty sweet.

    • #4
      Good to see the skytrak held is own. Given the cost compared to other like devices it is amazing.

      Comment


      • #5
        Yeah, if you have trackman using actual data, it will never line up if there is wind.

        Then again if you use normalize on trackman, you're basically just comparing flight algorithms assuming equivalent launch data is captured.

        Basically it's just real tough to compare apples to apples.

        Comment


        • James James
          James James commented
          Editing a comment
          Normalisation can also change the other parameters (ball speed, spin, launch etc) which would then give imply the ST was wrong when it was actually spot on.

        • James James
          James James commented
          Editing a comment
          This is also why people shouldn't read much into the calculated figures (carry, total etc) because that isnt a fair test. The parameters which interest me are the measured ones and not surprisingly the ST is near faultless.

        • jut111
          jut111 commented
          Editing a comment
          nice. good point. thanks for the work you clearly put into this.

      • #6
        Have added a part 2 which is shot by shot data graphs. I think these show the true (impressive) accuracy of the ST:
        Introduction After the first part I wanted to try and illustrate the data captured on a more blow by blow basis so this is that attempt; t...


        I think I have managed to explain most of the difference in the offline figure between ST and TM (an alignment difference of circa 1.5deg), but I dont think alignment plays any part on spin axis? What confuses me is the spin axis chart clearly shows the ST and TM tracking each other with an offset so the ST is measuring the spin axis reliably???

        Comment


        • #7
          Nice work, trying to digest it currently.

          Comment


          • #8
            yeah, this is good stuff, man!

            Comment


            • #9
              I'm guessing alignment does play a part on spin axis - if the ST unit is leaning towards the ball, or away from the ball, it might skew the spin axis. You might try leaning it 10 deg towards the ball, hit five or ten shots, then lean it 10 deg away from the ball, hit another five or ten, to verify that hypothesis.
              - Ron at GunghoGolf.com - we specialize in TrackMan, FlightScope, Foresight, Uneekor, SkyTrak, Garmin, Bushnell, TGC, and E6 Connect. 512-861-4151 or email hello AT gunghogolf.com.

              Comment


              • James James
                James James commented
                Editing a comment
                Good idea and easily tested.

                N.B. When we did our TM testing I made sure the ST was level (bubble and in-app).

            • #10
              Amazing analysis James James. Your are clearly our resident sim PhD =)

              As for comments on your analysis:
              - I tend to draw the ball so sometimes think that ST over-exaggerates the side RPM and spin axis to the left so sometimes turning draws into hooks. But I really wonder if this is true on fades and slices? In part 2 of your analysis, you said: "I think this chart clearly shows the Skytrak is measuring Spin axis (I would even say accurately) but for this player it is predominantly skewed in a negative direction. For myself (Player B) I am pretty sure we will see the reverse (skewed positively) because our shot shapes are opposing." Do you have the data from Player B showing this reverse skew in positive (instead of negative) direction?
              - Also what happened w Player A's 3 wood? This is the only club where ST shows a less negative side RPM and spin axis than Trackman.

              Again, thanks for the great analysis. Super helpful to me, and I'm sure to all.

              Comment


              • #11
                Preparing the data is time consuming but here is a glimpse of the Spin Axis chart for myself (Player B) and I think it confirms my suspicion:

                Player A is r/h and hits a natural hook.
                Player B (me) is l/h and I also hit a natural hook.

                Because we hit from opposite sides the ST was aligned (and levelled) twice (once for him, once for me).

                Comment


                • doublebogey
                  doublebogey commented
                  Editing a comment
                  Hmmm... I'm wondering if a right-hander has natural slice will have same reverse skew in positive direction? I would think should be same...

              • #12
                The side spin number are very interesting. Over the past month or so (I can't remember exactly how long), the side spin seems to have increased significantly on my Skytrak. Up till now, I thought it was my swing but now I'm questioning my Skytrak or at least the software. Did re-installing the software have any impact? I also see higher side spin numbers when I'm playing sim software so I'm not sure if the increase is related to my swing, Skytrak hardware, Skytrak firmware, or other software.

                Comment


                • #13
                  I have been looking through my data today and I am not happy with it so don't feel it is worth publishing in the same way. During my part of the testing Trackman missed a couple of shots and ST missed 1. I therefore have some offsets in the shot-by-shot analysis that I cannot reliably eliminate (you can kind of see it in the chart above) so I would rather rerun my part of the testing at some point in the future than publish questionable data.

                  I might well publish the summarised data if I am confident the quality isnt affected.

                  Comment


                  • #14
                    James, that's some really great data and write-ups there ! (I think I've finally found someone more analytical and geeky than myself on golf...)

                    I've had my unit over 2 years now and hit regularly on TM and FS, as well as used to hit on GC2 quite often. I know my numbers pretty well.

                    I've long held the opinion that the raw speed and spin data was extremely accurate on the Skytrak, but the ball curvature of the flight model over exaggerated shape. I have an almost dead straight flight on the range and on course, but have always seen a consistently wider dispersion pattern on the Skytrak range.

                    Your suggestion that Spin axis is somehow over calculated makes total sense to me; I sometimes struggle to believe the spin axis readings I get on Skytrak.

                    Having said that, I'd rather have the error be that way and be straighter on the course than I am when practicing, than the other way round...

                    Comment


                    • SkyTrak_Seth
                      SkyTrak_Seth commented
                      Editing a comment
                      But we don't calculate spin axis. It is a measured parameter. It's effect on curvature lines up extremely close to Optimal Flight and other flight models. It is odd though looking at James's analysis that the measured axis is that much more extreme. Still makes me wonder about wind though. I know wind is super-temperamental with our robot testing with Trackman.

                    • James James
                      James James commented
                      Editing a comment
                      SkyTrak_Seth In your experience are there any things which can affect the measurement of Spin Axis that we should be mindful of? The bit I struggle with is the accuracy with which total spin and launch direction are measured suggests the spin axis should also be spot on?

                  • #15
                    James James , yeah definitely. If you are doing this sort of detailed testing, always make sure that a clear black mark (line is best) is facing the SkyTrak unit. Especially outdoors, the dimples can get washed out pretty easily making it much harder for us to track the spin.

                    Comment


                    • Igor-247-golf
                      Igor-247-golf commented
                      Editing a comment
                      May be doing indoor comparison with metal dots on the ball (for trackman to track actual spin) may give more accurate comparison numberS?
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