Skytrak alignment and misreads - BIG problem!! need help as close to giving up on it.

[Morini]

Well, it can only be one of two things, Either you create the side spin or the unit is faulty. Best to take it outside or. compare with Trackman to find out which it is.

If the unit does create false sidespin, I wonder what it would do for a lefty? Try placing the unit between you and the ball so you can "simulate" lefty shots while swinging right. If you now slice we know it is the unit. I may not be thinking straight due to all the turkey and other food I've gobbled down the last few days, but shouldnt miscalibration caused side spin be opposite if you swing opposite direction?

[SkyTrak_Seth]

From a side angle perspective, it looks like you've solved the alignment issue. It looks like your issue now is due to a heavy amount of hook spin, and it looks pretty consistent...if that's not your normal shot shape, then the most likely source is the mat (grabbing the club face and closing it down). There's not really a way for just side spin to be a problem with the hardware. What do your driver numbers look like?

[Gresh12]

Sorry I’m trying to help. The first shot could be a 7 iron or a driver based on launch angle and ball speed depending on your skill level. If it was a driver or 3-wood the backspin is in the ballpark but if it’s a 7 or 6 iron it looks to have the same issue as the shot I called out that I guessed was a wedge.

My typical 7 iron launches around 16* with low 120s ballspeed and about 6k backspin. When I catch it heavy the spin drops (granted it doesn’t drop in to the 3k range) and I can hook it as I described.

Try hitting irons off a low tee picking the ball clean to get the mat out of the equation with irons.

I will say I can easily produce the hooks your showing if I try to hit my hybrids in my 8 ft ceiling as I have to choke down to not hit ceiling height and I get tentative so super around. Like others have said the woods could be indoor swing for sure if you are at tight or not used to it.

[wbond]

Have you taken it outdoors to test? If not, i would suggest trying that and use something other than a range ball but ones you don't mind donating.

[David Williams 'Chips']

jtangm04 I do believe there's some truth in that. I am still getting used to swinging the club indoors and with the woods, I don't trust that I have plenty of space to swing and I hold back a little but this is not the case for my irons. I'm playing on the course tomorrow and will get some feedback to compare if there is a difference in my indoor and outdoor swing. I will get a pro to test it too as I'm not having much joy.

[Jtangm04]

Have you had a friend come over who you know is a scratch golfer and give it a try? If there numbers look great, then it would reassure you it's not the tool but the user (like 90% of us here). Indoor swing really does affect a lot of golfers.
For me, I have a golf buddy who is a 4-5 HCP golfer and easily drives it 270-280 straight in real life, but on the simulator will typically hit 220 yrd hooks cause he tightens up on the backswing.

[David Williams 'Chips']

Gresh12, you have focused on the only shot that was hit heavy. The others hit well, NOT heavy and the left spin is the area of concern. I hit wedges, 8i and rescue in the pics.

[Gresh12]

It may help us a bit if you select a club in Skytrak so we know what you are hitting. The spin seems all over the place (including backspin). You have one that launches at 24* with 90 mph ball speed and only 3400 rpms of back spin. I’m guessing that’s a wedge and my only thought on those numbers is it’s very fat causing the heel to stall and toe take over producing a huge hook. When I hit it fat on my mat I lose a ton of backspin and it’s often a big hook with the club flipping.

Can you produce big slices on purpose?

I can’t speak for your specific unit but mine has been to the range and also compared side-by-side with Trackman and shot shapes were very close on both comparisons.

[David Williams 'Chips']

Dave,

I’m a bit confused where you write that you align the SkyTrak between square and 10* closed. You should be aligning the SkyTrak very close to square, or exactly square. That’s the first thing.

Secondly, I notice that the SkyTrak is located within a recess. I guess it is possible that the second photo might be obscured because of this. It would be worth moving the Skytrak out of the recess, to make sure this isn’t an issue.

Once you’re happy that the side angle is close to being correct (by testing as previously advised), as you say the only things affecting the offline distance are side spin and the algorithm. The algorithm probably does over exaggerate the offline distance slightly, but by no more than say 3-4y on a 150y shot.

Post some shot data so we can see what we’re dealing with. Really, the easiest way to test your SkyTrak is to hit balls in real life, and observe. Many / most amateurs aim right of target (without realising) and pull the ball back online, so if you’re in a controlled environment and aiming straight in your sim, your normal shot will be a pull. Obviously, just speculation.

Skytrak in general is accurate, as verified by tens of thousands of users. It is possible, I suppose, that your unit isn’t, but really you need to test it against real flight. Otherwise, we’re just speculating.

Dan

Another frustrating session in which I experimented a bit but didn't really learn anything new. See pics attached:

[sdavidow]

Oh Boy...this is interesting!
A few weeks on my ST and a week or 2 with TGC.
Seeing the same thing...hitting way more left than I think I am/was/should be.
I'm not good enough of a golfer to know what my ball should be doing (or did) just from the swing...WHICH IS WHY I BOUGHT A SIMULATOR!
So I really have to eyeball the alignment? I'm guessing I need to find my local rep and get him out to help me with it as it seems like there should be SOME sort of easy alignment process that doesn't rely on me hitting a ball.

I may take it out to the range and try to see how "accurate" my hitting is vs. the ST.
Anyway...glad I found this post.

[David Williams 'Chips']

Dave,

I’m a bit confused where you write that you align the SkyTrak between square and 10* closed. You should be aligning the SkyTrak very close to square, or exactly square. That’s the first thing.

Secondly, I notice that the SkyTrak is located within a recess. I guess it is possible that the second photo might be obscured because of this. It would be worth moving the Skytrak out of the recess, to make sure this isn’t an issue.

Once you’re happy that the side angle is close to being correct (by testing as previously advised), as you say the only things affecting the offline distance are side spin and the algorithm. The algorithm probably does over exaggerate the offline distance slightly, but by no more than say 3-4y on a 150y shot.

Post some shot data so we can see what we’re dealing with. Really, the easiest way to test your SkyTrak is to hit balls in real life, and observe. Many / most amateurs aim right of target (without realising) and pull the ball back online, so if you’re in a controlled environment and aiming straight in your sim, your normal shot will be a pull. Obviously, just speculation.

Skytrak in general is accurate, as verified by tens of thousands of users. It is possible, I suppose, that your unit isn’t, but really you need to test it against real flight. Otherwise, we’re just speculating.

Dan

Hi Dan, I followed Morini's advice and hit 20 yard straight shots with a 7i to get side angle close to 0 to determine how to align the unit and it was close to square to target. The MAJOR problem I have to somehow overcome is the crazy amount of left spin the ST is reading. I have always played with a slight fade and sometimes a slight pull. The straight pull is caused by the face and path being equal and minimal spin on the ball. When a ball curves violently, there has to be a big disparity between path and face. I am physically unable (and I don't want to be able) to generate so much side spin on the ball making the ball curve so much on the golf course. It's in the recess as it needs to be to hit driver, otherwise I'd be swinging too close to the left wall on follow through. This however, makes no difference to the spin generated as numbers are the same when I take it out of there. I'll post some pics up later for you to have a browse. I'll hit a few different clubs too. Thanks Dave

[DannyMRICS]

Dave,

I’m a bit confused where you write that you align the SkyTrak between square and 10* closed. You should be aligning the SkyTrak very close to square, or exactly square. That’s the first thing.

Secondly, I notice that the SkyTrak is located within a recess. I guess it is possible that the second photo might be obscured because of this. It would be worth moving the Skytrak out of the recess, to make sure this isn’t an issue.

Once you’re happy that the side angle is close to being correct (by testing as previously advised), as you say the only things affecting the offline distance are side spin and the algorithm. The algorithm probably does over exaggerate the offline distance slightly, but by no more than say 3-4y on a 150y shot.

Post some shot data so we can see what we’re dealing with. Really, the easiest way to test your SkyTrak is to hit balls in real life, and observe. Many / most amateurs aim right of target (without realising) and pull the ball back online, so if you’re in a controlled environment and aiming straight in your sim, your normal shot will be a pull. Obviously, just speculation.

Skytrak in general is accurate, as verified by tens of thousands of users. It is possible, I suppose, that your unit isn’t, but really you need to test it against real flight. Otherwise, we’re just speculating.

Dan

[David Williams 'Chips']

Just to add to what I posted earlier. Here is my understanding of how the ST algorithm calculates spin axis.

1. Ball passes later curtain. The refracted light is used to determine when the ball passes the sensor.
2 .An IR strobe fires twice, capturing two images of the ball.
3 .Those images are transferred to your device.
4. Your device processes the image to locate the two ball images.
5. The algorithm flattens the balls into two 2d images.
6. The common areas of two images are compared relative to center of ball and are used to determine degrees of rotation in backspin and sidespin direction.
7. Since time difference between the two images is known, rotation is converted to respective rpm, which is then used to calculate spin axis.

On a related note, the center of the ball images are compared to determine ball speed and VLA. The size difference between images is used to calculate HLA.

I could be off on some of the details. The point is that if HLA is accurate, spin axis is accurate. You are in all likelihood hooking the ball. The ST algorithm does not account for the spin dropping over time and will exaggerate a bad hook.

Thanks Morini, very grateful for your response as always, this is very informative and relevant and I will try some of your tips. I have to disagree with you that there is not an issue with skytrak. I do have a tendency to sometimes hit left on the course but we're talking 20 yards max and only sometimes. The skytrak is exaggerating this, turning 20 yard left into a 60 yard left and doing it consistently and I believe turning a relatively straight shot into a 20 yard left shot. If I hit a 7i on the course, I tend to hit the green or miss it left and usually not far off the green. On the skytrak, i'm hitting it sweet but nothing in going at my target of 150 to 160 yards, a crazy and exaggerated amount of spin is being calculated and sending the ball 40-60 yards left of my target. The only way I have found to combat this so far is to close my unit 30 degrees, watch the ball start out right and it bend back into my target. I agree my swing can be improved but the skytrak is making me look worse than what I am and I think you'd agree that having spent $2k on it, I shouldn't have to compromise on the setup to get it to give a more expected outcome. A problem I have with closing the unit say 30 degrees for a full 7i is that if I keep it closed 30 degrees for example for a 50 yard half wedge, the ball will start right, come in a bit but miss my target right. I would therefore have to constantly keep adjusting the amount it's closed to target for every club. I will keep experimenting and looking for answers but I'm really not confident I will get the unit performing like a GC2. Two of my mates have used it and I play with them on the course and know where they tend to hit the ball and they too are generating a lot of left spin and sending the ball out to the left.

[maine skytrak]

mine must need to be recalibrated... ST parallel to target line 20 yard "straight" shots show up 6 degrees to right with 100 to 200 of side spin in both directions. Does anyone know a tilt or lean formula to help this issue? Really don't feel like sending it in for repair....I use it to much lol.

[Morini]

Just to add to what I posted earlier. Here is my understanding of how the ST algorithm calculates spin axis.

1. Ball passes later curtain. The refracted light is used to determine when the ball passes the sensor.
2 .An IR strobe fires twice, capturing two images of the ball.
3 .Those images are transferred to your device.
4. Your device processes the image to locate the two ball images.
5. The algorithm flattens the balls into two 2d images.
6. The common areas of two images are compared relative to center of ball and are used to determine degrees of rotation in backspin and sidespin direction.
7. Since time difference between the two images is known, rotation is converted to respective rpm, which is then used to calculate spin axis.

On a related note, the center of the ball images are compared to determine ball speed and VLA. The size difference between images is used to calculate HLA.

I could be off on some of the details. The point is that if HLA is accurate, spin axis is accurate. You are in all likelihood hooking the ball. The ST algorithm does not account for the spin dropping over time and will exaggerate a bad hook.