Flightscope xi indoor spin axis

[billydruce]

Hi guys been reading that the spin axis is not measured when the device is used indoors. I asked flightscope about this and they replied the below

"The spin and spin axis with FlightScope are directly measured, not calculated from other measurements. We also have a patent on our phase locked loop method for measuring spin. Here is some additional information:

http://flightscope.com/flightscope-patents-new-sports-ball-direct-spin-measuring-method/

As long as you have 13 feet of ball flight and 8-10 feet behind the player, we can guarantee our accuracy indoors"

I have emailed flightscope again to confirm that the spin axis is measured when using indoors.

[Brutaly]

Quote from Alex Trujillo

"Many different parameters are used as indoors is basically an entire calculation, with the exception of club data. The actually parameters that we use cannot be published."

Basically they wont tell us.

[Brutaly]

This pretty much means that spin axis means jack outdoors. If curvature is used to determine spin axis wind will absolutely remove any credibility.

Just imagine the difference in wind 25 yards from the ground compared to the tee.

[sorensen]

This pretty much means that spin axis means jack outdoors. If curvature is used to determine spin axis wind will absolutely remove any credibility.

Just imagine the difference in wind 25 yards from the ground compared to the tee.

it's probably a bit exaggerated to say it this way, if the curve is measured in the first part of the ball flight, and the rest of the flight is measured, then sidespin probably not so wrong

[Brutaly]

it's probably a bit exaggerated to say it this way, if the curve is measured in the first part of the ball flight, and the rest of the flight is measured, then sidespin probably not so wrong

Might be but if there is any wind from the side at ground level how can a correct spin axis be calculated if its curvature that determines spin axis? The curvature of the ball wont be "accurate" at any distance from the tee if there is any wind at the same height as the tee.
Add to that that the wind 10 meters from the ground seldom is the same as at ground level.

I just dont see it.

[sorensen]

Might be but if there is any wind from the side at ground level how can a correct spin axis be calculated if its curvature that determines spin axis? The curvature of the ball wont be "accurate" at any distance from the tee if there is any wind at the same height as the tee.
Add to that that the wind 10 meters from the ground seldom is the same as at ground level.

I just dont see it.

I would say that the wind does not move the ball significantly, in the first part of the flight. I must try to test the next time we have a strong crosswind in range, I'm quite good at work the ball both ways. but my guess is that the curve is measured in the first part of the flight. That said, I think from memory that I have often thought, sidespin figures were not consistent with the rest, including my feeling

[Bubba22]

So just as we thought, spin axis is calculated indoors. Billybruce, did you get anymore info from Flightscope? My feeling is tha who ever you were speaking to is not giving you the right information re spin axis measurement. Outdoors it should be more accurate. Did we not determine in the past that wind does not affect side spin or spin axis?

[billydruce]

The last reply I had from flightscope USA I post earlier, they confirmed it was measured however it looks like he doesn't know what he's talking about

[goatbarn]

Yes wind does not effect the number they report on spin axis. It is gather in the first 40 yards of flight. I have hit many times at the range where the ball is pushed to the right by the wind and the app reports a negative (left/draw bias) spin axis. It's very accurate outdoors.

Indoors though, I want more information.

The question I have is are they using any calculated parameters in their collision model to then calculate the spin axis when indoors.

I know face angle is calculated, but club path, AOA, and ball azimuth are measured. So, what's used?

[Skedaddle]

You should be able to work out the model FS uses by having the face, path and Vertical swing plane numbers. TM newslteers spell out but if the face is different to path by 2 on a 6i (60 degree Vplane) this will produce 4 spin axis. This is just an example but if the actuals marry up with your calculated you know gear effect is not taken into account, nor is the limited ball flight and spin axis just comes from known measured parameters.

I've done this with some of my numbers and am pretty comfortable is saying they are calculated from path and face indoors, with no gear effect

As I say the early TM newsletters give this in great detail especially the one where it runs through the parameters

[Brutaly]

One interesting thing is that one of the more active members in the group states that he done testing side by side with a gc2/hmt and got the exact same numbers with 9ft to the ball and 10ft to the screen. Aoa differed but also differed with the correct distances in the setup.

[goatbarn]

AOA is necessary to measure the "true" path of the club, so I wonder if AOA accuracy falters at less than 9' radar to ball, does that impact the spin axis calculation accuracy when used indoors?

A good test would be to go outside, set the unit to indoor, and hit shots trying to curve the ball. See if you can get one to curve one way in real life, and show up as opposite curve on the app.

Of course you'd need center contact (to avoid major gearing) and no wind.

Then play with distances from radar to ball until you get inaccurate ball flights shown on the app.

[Skedaddle]

I've found that outside with indoor mode on my out to in driver swing shows a cut even though I mostly hit it off the toe, hence showing a straight or drawn ball flight. This kinda proves the parameters are being used to derive spin axis on indoor mode

Also the below shows my attempts to calculate spin axis based on path and face difference. It's pretty close and was done using TM's newsletter notes. These numbers are from indoor

																				Face to	Spin Axis
																				path	Calc	Actual
	carry	landing	cs	bs		time	spin	spin axis	la	horiz launch	descent	height	aoa	face angle	dl	path	vert swing	swing dir
1	137	18	80.3	103.6	1.29	6.4	6556	6.3	31.2	6.1	54	121.9	-6.8	8.2	50	1.9	60	-2.1		6.3	9.45	6.3
2	137	-22	77	102	1.32	5.1	6149	-17	18	-5.4	41	64	-8	-9	30	61	-1.7			-70
3	139	9	77	102	1.32	5.8	6166	0.6	25	3.8	49	94	-7.8	4	41.8	3	66		49.6	1	1.5	0.6
4	139	-14	80.5	102.4	1.27	5.7	6074	-10	24	-3.4	48	90	-9	-6.4	41	2.5	58	-3.1	50	-8.9	-13.35	-10
5	130	-5	75.4	97	1.29	5.6	6549	-5	26	-0.8	48.5	88	-1.5	-2	38.8	1.8	60	1	40.3	-3.8	-5.7	-5
6	134	-13	78.5	100	1.27	5.5	5190	-12	23.7	-3.2	46.7	82	-4	-5.8	36.5	2.5	65	0.6	40.5	-8.3	-12.45	-12
7	137	-11	80	101	1.26	5.6	6096	-8.7	23.7	-2.6	47	85	-5.6	-4.8	38	1.9	63	-1	43.6	-6.7	-10.05	-8.7
8	125	11	77	92	1.19	5.2	6788	5.5	24.6	3.9	45.6	74.8	-2.9	5	37	1.2	66		39.9	3.8	5.7	5.5
9	137	15	77	103	1.34	6.4	6596	8.1	31	4	54	120	-3.7	6.4	48.6	-1	65	-2.7	52.3	7.4	11.1	8.1
10	130	-7	78.2	97.7	1.25	5.7	6573	-1.8	26.8	-2.7	49	91	-3.5	-3.2	41.9	-1.7	62.7	-3.5	45.4	-1.5	-2.25	-1.8
11	124	5	75	94.5	1.26	5.7	7467	-0.6	26.7	2.5	48.2	87	-2.2	2.3	40.5	2.8	67.2	1.9	42.7	-0.5	-0.75	-0.6
12	133	-13	75.9	99	1.30	5.3	6095	-7.2	22	-4.2	44.9	75	-3	-5.5	32.5	-1.1	64	-2.4	35.5	-4.4	-6.6	-7.2
13	123	-11	78	93.8	1.20	5.3	6711	-13	25	-2.2	46.6	78	2.9	-4	33	2.9	73	3.8	30.1	-6.9	-13.8	-13
14	123	-1.5	73	94	1.29	5.4	6725	-5.7	25	0.6	46.8	79	-2	-0.6	37.8	3.4	73	2.8	39.8	-4	-6	-5.7
15	122	3.6	76	93	1.22	5.3	6704	2.6	24.6	1.1	45.8	76	-2.6	1.6	36.7	-0.1	66	-1.3	39.3	1.7	2.55	2.6
16	134	-7.8	76	99	1.30	5.4	6148	-7.8	23	-1.6	45.9	79	-3.3	-3.1	34	2	69.8	0.8	37.3	-5.1	-7.65	-7.8
17	124	2.5	77	95	1.23	5.8	6977	1.5	28.9	0.8	50	93	-3.8	1.2	45		66	-1.7	48.8	1.2	1.8	1.5
	131	-2	77.2	98.2	1.27	5.6	6445	-3.8	25.2	-0.2	47.7	87	-3.9	-0.9	39.0	4.9	61	-0.4