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SkyTrak Distances vs Real Life

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  • Morini
    commented on 's reply
    Thanks for posting that GungHoGolf. The combination of higher launch and lower spin seems to give a flyer flight with 8 yards more carry, which would mostly explain Bogey Monsters extra carry. If this is the cause, you would have the same results from GC2, Quad, TM, FS and real life.

    I wonder if it is possible to develop a "normalization" algorithm that will put the spin & VLA back to what it would be off turf ... in order to equalize sim and real world numbers. Enter your mat model, and some basic swing tendencies, and let the algorithm take it from there.
    Last edited by Morini; 09-18-2019, 03:30 AM.

  • FaultyClubs
    commented on 's reply
    Distances match what would be expected from the measured ball parameters so flight algorithm seems fine.

    Ball speed of 131 mph on a 7 iron isn't believable though (lpga is 104mph and pga is 120mph) so something doesn't add up. What are your normal values for 7 iron?

  • Morini
    commented on 's reply
    AFAIK the ball flight model hasnt changed in a long long time, so that is unlikely. Coincidentally, both my kids started complaining that ST is coming up 10+ yards short. This started about two weeks ago. I haven't tried myself yet. My kids know their yardages very well, so I don't want to dismiss out of hand, but don't know what it could be.

  • GungHoGolf
    commented on 's reply
    Mats vs grass with 7-iron: https://blog.trackmangolf.com/mats-v...ts-difference/ - 2.7 deg higher launch and 25% less spin on mats compared to grass.

    In my opinion, this difference is due to the club moving through the ball at a shallower AoA, either from the player making a shallower pass on mats subconsciously to avoid hurting themselves, or the club physically being prevented from continuing down through impact, so it sort of slides/skips through more level through impact. One would think that mats accommodating "virtual" divots better (TrueStrike, DivotAction, Fiberbuilt, Magstrike) should minimize this effect.

  • Morini
    commented on 's reply
    Will double check with flightscope optimizer in a bit, but that seems to launch high and spin a bit low. That is very common with mats as there is not enough friction, so the ball slides up the face. Perhaps your swing and this particular mat combine in these particular lofts. The only way to know for sure is to take your mat to the range.

  • GungHoGolf
    replied
    For those of you with sudden changes of distance and/or spin numbers, it'd be nice to know what version of the SkyTrak app you're running, and what platform you're on (PC, iOS, etc.). Starting to wonder if there was some silent update of version on iOS or something.

    Leave a comment:


  • GungHoGolf
    commented on 's reply
    Ball logo towards cameras? This is so weird, with several people reporting sudden changes of distance and spin readings, both long and short. Would expect something like this with a software update, but there has been none (that we know of).

    Don't pay attention much to club speed. Has your ball speed changed, or just lower spin numbers?

  • BogeyMonster
    replied
    Originally posted by Morini View Post
    I am still interested in figuring out the cause of this. Would you mind sharing the ball data for say 6 iron.
    Here is some data from a few 6 iron shots from my CCE mat (no tee):

    6I
    CLUB BALL BACK SIDE CARRY TOTAL LAUNCH
    MPH MPH RPM RPM YARDS YARDS ANGLE
    84 122 5985 418 175 185 21
    85 124 5117 -583 183 197 20
    83 120 5200 -299 176 190 20
    84 123 6247 174 174 186 18

    For reference, in real life my 6 iron typically has a total distance of 170-175.

    Leave a comment:


  • OC_Mike
    replied
    I'm having the same problem with my Skytrak currently. It's always been spot on with my distances and now it's reading massively long. I get the same results and have tried: CCE mat, Fiberbuilt insert, garage lights on & off, changing balls, dark tarp behind me blocking out any reflections, raising and lowering the skytrak. In real life I hit my 7 iron 175, maybe 180 if I want to go after it. I'm frequently getting 200+ carry on the skytrak with ridiculously low spin numbers. Ball speed seems high for that swing speed? Here's a picture of a shot from last night. Any suggestions? I think I may need to send it in for repairs? Help!





    Leave a comment:


  • GungHoGolf
    commented on 's reply
    Your launch angles are all over the place, too - from 11 to 23 - leading me to think your face contact and perhaps AoA has a lot of variation, which could impact spin numbers. SkyTrak rarely misses getting the vertical launch angle correct, as that's a very easy thing to measure given two photos of a ball. Spin is a tougher thing to measure for SkyTrak - what helps the most is to always place the logo of the ball towards the cameras, and use white or otherwise solid-colored balls. I know some guys have success with Truvis, but I can't help but think all those hexagon blotches on the ball might confuse the computer vision algorithms when it's trying to pick out landmarks on the ball to measure the degrees of rotation.

    To better track your trends with your shot data, you might give our Advanced Analytics a try. It will show you your standard deviations for all data, and is the best way to look at trends over a period of time. Find the demo at https://gunghogolf.com/ron/analytics, and you can sign up during this beta period at https://gunghogolf.com/signup with invite code 2019-021.

  • kokoskorpen
    commented on 's reply
    I’m a total noob when it comes to ST, but can the mat you’re hitting from impact the spin numbers? I’m have the same issue, sometimes 10000 spin on a 7-iron on shots that feels good but are very short on ST. I’m hitting from a carpet in my livingroom.

  • MisterA
    replied
    For me, my carry and total numbers are all over the place. Below are some numbers of a recent practice session I did. I was hitting outside in a net, not in direct sunlight, using Bridgestone B RXS balls. I was hitting my 7 iron, on course I hit about 170m or 186yards. During lessons on the driving range I see that spin is in the 6000's (using trackman), and I hit my normal distance.

    What I notice in the numbers below: some shots come up short to my normal carry numbers, but most of the time my spin is above normal (8000 and above). On other occasions I supposedly hit +220yards with spin being only 2000-3000rpm. I understand that spin can explain the exagerated (both ways) carry numbers, the problem is that I don't havy any means to recalculate with a degree of certainty my 'true numbers'. In another thread I read that minimal side spin difference can already have a substantial impact on draw/fade numbers. So I wonder if my offline numbers are to be trusted either.

    It's also holding me off to buy TGC or something like that, it's no fun playing when your carry numbers are all over the place.

    I tried using different balls with extra markings on them for example, also Chromesoft Truvis balls (blue ones). But the number I get keep being erratic.
    BALL LAUNCH BACK SIDE CARRY TOTAL CLUB
    MPH DEG RPM RPM yards yards MPH
    124 19 8106 -1284 168.5 176.1 94
    123 16.2 2258 -1192 184.9 209.0 79
    114 18.5 4921 494 165.2 178.3 79
    128 18 6575 376 180.5 190.4 93
    119 18.6 8763 -1006 159.7 166.3 94
    125 18.2 5591 886 180.5 192.5 88
    125 18.5 11813 507 149.9 154.3 99
    126 23 5264 -150 186.0 198.0 88
    127 19.5 8131 -1051 172.9 180.5 96
    126 16.6 4692 336 189.3 203.5 86
    127 17.4 5792 1612 180.5 192.5 90
    129 18.3 6547 563 182.7 192.5 94
    124 14.6 6372 -1010 175.0 184.9 91
    121 12.7 2786 -818 176.1 198.0 78
    134 16.9 4892 -140 204.6 218.8 92
    131 17.5 2275 -704 215.5 240.7 84
    127 22.1 5680 -81 183.8 195.8 90
    132 17.9 3743 1336 202.4 219.9 88
    124 20.7 8383 -841 167.4 175.0 95
    122 17.7 7663 -438 169.6 176.1 95
    118 17.4 3720 922 176.1 193.6 79
    125 15.6 6537 374 176.1 186.0 92
    123 19.1 6979 100 169.6 177.2 92
    125 18.9 6973 499 171.8 180.5 93
    132 16.7 5357 77 198.0 210.0 92
    131 18.1 4260 -1120 199.1 214.4 88
    120 17.1 6282 -1367 167.4 177.2 88
    123 23.4 7978 -916 164.1 171.8 96
    125 11.4 5495 -2801 168.5 182.7 88
    132 20.5 4110 2170 195.8 213.3 89
    130 21.8 5208 598 193.6 206.8 90
    132 18.4 3974 341 205.7 222.1 88
    128 18.9 8356 -1080 175.0 182.7 98
    130 20.4 4834 207 196.9 211.1 89
    129 19.2 3206 -229 207.9 227.6 84
    120 16.1 5679 -149 159.7 173.9 85

    Leave a comment:


  • Morini
    commented on 's reply
    My guess is that in this particular situation, the ST is reading the ball data correctly. Thus a GC 2/trackman would have the exact same data.

  • FURY
    replied
    Hi All!

    I am contemplating the purchase of a ball, and maybe club tracking device. Have been reading about Skytrak, Gc2 amd Quad. Has anyone, who has had the above stated variance with the Skytrak compared with the Foresight or even Trackman offerings? If so, please comment/share results. It probably does not come up often, but my garage sapce will not allow driver to be used with impunity, as it "can" reach the ceiling on followthrough, so outdoor range protability of device is something I would like to have.

    Thank you very much

    FURY

    Leave a comment:


  • Morini
    replied
    I am still interested in figuring out the cause of this. Would you mind sharing the ball data for say 6 iron. For reference, there is 5 mph ball speed difference between irons (exception being 6 to 7 which is 7 mph) for PGA tour. You are pretty close to PGA tour numbers, so should be similar. For 5 to 9 iron, there is 2 degrees per club increase in launch angle. There is 800-900 increase in spin per club. Finally, landing angle goes from 49 degrees for 5 iron to 51 degrees for 9 iron.

    Since I doubt that the ball flight and roll out model is the culprit, there must be something whacked in your actual ball data. Most likely club mat interaction for selective lofts. Checking the "gapping" in terms of ball speed, launch angle, spin and landing angle (calculated obviously) may shed some light on what is going on.

    Leave a comment:

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