Originally posted by Willymakit
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On your outside demo, you were using your iphone, so that's version 1.9.1 (not the PC APP). Issues with a "defective" unit were found on both irons and woods. Not just one or the other. Every person who says "my distances are short" is always with the woods.-
But I get the same distances inside when hooked up to the computer using the beta version.
Not sure if you can tell how frustrated I am with this unit at the moment. Obviously there's more then myself having the same issues and it's been dragging on far to long.
I watched a few videos on YouTube and not sure if they can hit it farther in what they show but I didn't see to many drives over 240.
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I also check my club strike with impact tape when practicing, so I fully understand the issues with using just club head speed. During the test, all comparisons were physically center hits. I have 11+ foot ceilings so it is a totally free and open swing, no restrictions. As stated my normal distance for the driver is 230+ carry.. At the range when using the Swingbyte, club head speed and the resulting actual distance all match-up. I will attempt to get to the range with the SW and also the ST, but the weather is already starting to turn and that may no longer be possible for this year. Also, I have a demo unit, really starting to think I should send it back for replacement....Comment
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There are some naive expectations for the advertised 2.0 iOS app when it comes to driver distance.
I believe Skytrak said. Minor tweaks. What that means remains to be seen. To claim with aggressive certainty that this will solve all problems is optimistic to put it politely.
For those that have not read the "ST vs. TM" thread, please do. I have no idea what the difference is between the range balls I used and a proper tour ball but I would expect that once the ball is air born. The diff is minimal. e.g. not 20y. When testing in door I can see some 20 -25 y diff between that range ball and a brand new ProV1 but that comes mainly from a lower spin and much higher ball speed.
So if the algorithm for calculating trajectory changes it might well mean that I will end up with a solution that shows excessive driver distance. I say might well mean because none of us has a clue what will change and when. Maybe the algorithm will be tweaked to only affect ball speed higher than 170MPH. In that case I am OK for now since I can't produce anything above 160MHP.
As for GC2 vs. ST. There is a lot of opinions flying around so I decided to buy both to test what is what. Will get the GC2 in 2 weeks so maybe in 4 weeks there will be one more opinion flying around :-)Comment
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Sounds like you've got a good idea what's going on. One problem you might have with that is the impact tape can really reduce the spin and the fact it's white in colour could also mess with the SkyTrack, confusing it with the ball which can possibly alter results.Originally posted by bbb287 View Post
I tried face tape and went from 6000rpm to 2000rpm with the 7i so it's a massive reduction, so need to take them results with a pinch of salt. That can vary my 7i carry by 20 yards. That's why I use a marker/ sharpie, as it doesn't effect the spin from the grooves etc.
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Hopefully this adds to the conversation...
For comparison purposes, and to learn a little about the ST algorithm vs ball speed, here is some actual data.
The following are driver shots made on my ST unit for three different ball speeds, and the Flightscope Traj. Optimizer output for the same launch conditions:
Ball ||| VLA ||| HLA ||| Spin |||| SpinAxis ||| Skytrak(Carry) ||| FTO(Carry)
184 ||| 16 ||||||| 9 ||||||||| 2917 ||| 31L |||||||||||||| 306 |||||||||||||||||||||||| 329
166 ||| 14 ||||||| 0 ||||||||| 2083 ||| 16L |||||||||||||| 279 |||||||||||||||||||||||| 286
148 ||| 18 ||||||| 0 ||||||||| 2024 ||| 0 ||||||||||||||||||| 257 |||||||||||||||||||||||| 254
You can see that at the higher 2 ball speeds, ST's carry is shorter than FTO's. At the lowest ball speed, ST is slightly longer compared to FTO. I'm guessing about 155-160 mph is the break point where ST starts looking short compared to FTO. That's not to say that FTO is the gold standard- just showing this for comparison purposes.
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This is why it's good to understand if it's an algorithm issue or a measurement issue. From above post, looks to be that the algorithm needs to be adjusted. This is easier than if it's not measuring correctlyl. I see why i don't have the issue, unfortunately, my ball speed isn't that high off the driver.Comment
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I guess that's why I see a difference with the driver but why not with the 3w and 5 hybrid I know my ball speed is around 165 with driver but I know it's not that high with the 3 wood and hybrid. So not sure why my distances with 3 wood and hybrid would be out then. I hit a 3wood between 250-260 and can barely get 210 on Skytrak. And hybrid I hit between 230-240 irl and last night at home I couldn't get the distance over 200. But when I use my 4 iron I can hit it 205 yards. Doesn't make sense. And I even set the sea level to 0 and up to 10,000 and never seen no distance increase/decrease All yardages stayed the same with each club.Originally posted by TorchRedRob View PostComment
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We have seen a couple of tweaks in ST's flight algorithm since their first release (short irons at first and then the mid irons if I recall correctly.). It is a good point that 155-160 might might be the break point. Also, it could be related to spin numbers. ST's algorithm seems to penalize higher spin numbers in terms of distance when spin numbers go above a certain break point in a certain range of ball speed. I am wondering what Willymakit's spin numbers are on his 3 wood shots. Willymakit? Can you please compare them to TorchRedRob's third number. I could be wrong, but my bet is that your spin numbers are a little higher than 2024. Probably 2400-2700rpm or higher.
ST's next release they promised would probably be a fix on distances in this range of speed and spin.Last edited by hks8888; 10-13-2015, 07:46 PM.Comment
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Yes I can tell you exactly what my spin rate is. But first. If you go back to my other post I made about a week ago or maybe two. I did mention that the spin rate was almost double on what i normally see from a simulator I'm around the 2500- 3300 rpm with driver tested on gc2 and HD golf but with Skytrak I was at 5500rpm I do believe. Skytak said there system was very accurate with the rpm. Which maybe with the irons they are but not the woods. My 3w and 5 hybrid were also around the 5000 rpm on Skytrak but never tested it on a different simulator.Comment
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Sorry, I didn't see your previous post. Anyway, 5000rpm on driver, 3w and 5 hybrid?? Wow..I assume that you use reasonably clean white balls. If so, I would start doubting on a defective unit. Consider asking for an exchange. Obviously, ST's algorithm is killing distances due to abnormally higher spin numbers.Originally posted by Willymakit View PostLast edited by hks8888; 10-13-2015, 08:18 PM.Comment
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Ball ||| VLA ||| HLA ||| Spin |||| SpinAxis ||| Skytrak(Carry) ||| FTO(Carry) ||| Optimal FlightOriginally posted by TorchRedRob View Post
184 ||| 16 ||||||| 9 ||||||||| 2917 ||| 31L |||||||||||||| 306 |||||||||||||||||||||||| 329 ||||||||||||||||| 304
166 ||| 14 ||||||| 0 ||||||||| 2083 ||| 16L |||||||||||||| 279 |||||||||||||||||||||||| 286 ||||||||||||||||| 280.6
148 ||| 18 ||||||| 0 ||||||||| 2024 ||| 0 ||||||||||||||||||| 257 |||||||||||||||||||||||| 254 ||||||||||||||||| 255.7
I ran the numbers in Optimal Flight which is another well known flight model. OF numbers are actually very close to Skytrak.
I was once told by the OF developer that FTO (web version) is not that sophisticated. It is his opinion, but good to know when we interpret numbers.
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Sweet! I was hoping someone with OF would back-check these for me. Thanks, hks!
Also, from what I've seen- GC2 algorithms will likely show a longer carry than ST for most driver shots. For example, if you watch any of Rick Shiels' videos, you'll see that he sometimes carries the ball 290+ with like a 158-162 ball speed.Last edited by TorchRedRob; 10-13-2015, 10:04 PM.
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Interesting comparison to the optimal flight. I've read elsewhere that many believe this is a very good algorithm to use.Comment
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I would say th Optimal Flight is the closest to the gold standard in flight algorithms.Comment
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I decide to add some actual GC2 data for comparison from Rick's recent videos. This could be a huge disclaimer, but I have no idea of the altitude settings on the GC2.
But, if we assume it's not jacked up to 6000 ft or something, then GC2 carry is certainly longer than SkyTrak and FTO. It would be interesting to see where OF puts these shots. HKS- a little help, please??
The two 166 mph shots are really interesting. Note that my shot and Rick's shot are nearly identical in terms of speed, launch angle, and spin. For Rick's shot, GC2 predicts 16 yds of additional carry compared to SkyTrak (295 vs 279). Again, I am assuming that there is not a huge elevation plugged into Rick's GC2, but we don't know.
Ball ||| VLA ||| HLA ||| Spin |||| SpinAxis ||| Skytrak(Carry) ||| GC2 ||| FTO(Carry) ||| Optimal Flight
184 ||| 16 ||||||| 9 ||||||||| 2917 ||| 31L |||||||||||||| 306 |||||||||||||||||||||||| N/A |||| 329 ||||||||||||||||| 304
166 ||| 14 ||||||| 0 ||||||||| 2083 ||| 16L |||||||||||||| 279 |||||||||||||||||||||||| N/A |||| 286 ||||||||||||||||| 280.6
148 ||| 18 ||||||| 0 ||||||||| 2024 ||| 0 ||||||||||||||||||| 257 |||||||||||||||||||||||| N/A |||| 254 ||||||||||||||||| 255.7
166 ||| 14 ||||||| 5 ||||||||| 2324 ||| 1L ||||||||||||||||| N/A |||||||||||||||||||||||| 295 |||| 288 ||||||||||||||||| ???
168 ||| 13 ||||||| 2 ||||||||| 2249 ||| 2L ||||||||||||||||| N/A |||||||||||||||||||||||| 299 |||| 289 ||||||||||||||||| ???
161 ||| 17 ||||||| 5 ||||||||| 2240 ||| 2L ||||||||||||||||| N/A |||||||||||||||||||||||| 290 |||| 283 ||||||||||||||||| ???
159 ||| 17 ||||||| 4 ||||||||| 2150 ||| 6L ||||||||||||||||| N/A |||||||||||||||||||||||| 286 |||| 278 ||||||||||||||||| ???
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yes, more of a glancing blow but not enough to account for significant yardage. For example, If I plug the launch conditions into FTO and change the axis from 16 to 0, carry goes from 286.4 to 287.7, so I'm only losing 1.7 yds... according to FTO, anyway. Similarly, if I change his shot from 1L to 16L, his carry only decreases from 288.2 to 287.0, or only 1.2 yds lost.
So, in the FTO model, spin axis is a small contributor from 0-16 degrees, but I'm curious to see what Optimal Flight says about it.
Also, for what it's worth, it's not way left at 16 degrees. If I had launched it only 2.5R, it would have come back to centerline when it landed.Last edited by TorchRedRob; 10-14-2015, 04:25 AM.
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I received my unit at the end of last week, and finally had a chance to set everything up last night.
I found the driver data to be accurate. My ball speeds on well struck shots were in the high 140s to low 150s with back spin in the mid to high 2000s. Carry distance was in the 240s to low 250s.
Those numbers were all very consistent with the numbers I was getting from Trackman during a fitting a few weeks ago, and are in line with what I see on the course.
The two numbers where I was seeing a significant difference to Trackman were launch angle and roll. On average, launch angle was 2* or 3* higher and roll was significantly shorter on Skytrak. The Skytrak numbers are more in line with what I see on the course - I hit a pretty high ball, and was a bit surprised that Trackman had me launching various head and shaft combos in the 11* to 13* range.
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