Author Topic: App development - Range Master - Need your input  (Read 4212 times)

Windmeister

  • Full Member
  • ***
  • Posts: 108
App development - Range Master - Need your input
« on: February 05, 2016, 11:40:45 AM »
Ok so I'll make this short and sweet.
We are a small group of designers and developers ios/android that have a long history of making games and apps. We are also into shooting various guns at the range.
Myself in particular like the benchrest competition variant, and that has lead us down the road of an a solid idea.

Facts are that it's hard to find good range masters or ranges that will coordinate/arrange matches for whatever you shooting, not only airguns.
So the idea for this app is simple but pretty darn deep. We want to set up a rugged system so anyone can initiate/participate (in) a match regardless of location. You can even setup a multi day match, options are endless. However, there are some things that need fleshing out, such as a handicap system based on weather/wind, since you can have a match where there will be blowing nails and in the other location it's featherly balmy.

The current handicap idea we have come up with is to run a system where you take the max potential score under perfect conditions, say 750 (typical for airgunning at 25m)
Instead of putting a reward on the handicapped person shooting in non optimal conditions, which could lead to over extending the max score, we suggest a system where we come up with a system where we ask the question, what would the top performer in the optimal conditions have shot in the worst condition, giving us a performance differential caused by the condition. This will render us factor that we then can multiply everyones score shooting in non optimal conditions to effectively eliminate conditional effects.

So statistics here we come:-)

Let's assume a top performer, shooting 750 on a regular basis on an indoor range, or outdoor in optimal conditions.
We've developed one version of this that gives you points back based on the difficulty of wind conditions. We've excluded pressure, humidity, and elevation, as those are expected variables you will have to be accounted for by the shooter no matter what.

Here is a screenshot of the excel doc, I've created which host a bunch of logic and math. It can never reward in such a way that anyone will be above the max score.
The wind conditions are calculated upon 2 factors, one is wind speed, the other is direction. wind from hard left or hard right is given a 1, or 100% wind factor. Wind from 0 degrees, head/tail is given the minimum of 0.25% or 25% wind factor. Which results in the overall Condition Factor.
For example a 5mph wind from 1:30 o'clock will result in a Condition of 2.5.
This is used to calculate the overall factor for each shooter. It does not award crappy shooting in bad conditions.
Nor does it award mediocre shooting in good to decent conditions.

« Last Edit: February 05, 2016, 12:40:39 PM by Windmeister »



rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #1 on: February 05, 2016, 12:02:45 PM »
Quote
For example a 5mph wind from 3 o'clock will result in a Condition of 2.5.

Don't you mean 5.0 ?.... that's what is shows in the table (bottom entry, shooter 8 ).... How do you arrive at the Wind Factors for angles between 12 and 3 o'clock, etc.?.... Do you use the sin of the angle to correct between 0.25 and 1.0?.... I'd like to see a table of "round the clock" corrections for the direction.... Does it take into account the Magnus effect raising and lowering the POI, or just the horizontal component?.... I know I have seen some interesting charts by Mike Niksch that shows that....

I think I understand the idea.... only using it and trying to find out if it over/under corrects will give you the answer to it's overall validity....

Bob
  • Coalmont, BC

Windmeister

  • Full Member
  • ***
  • Posts: 108
Re: App development - Range Master - Need your input
« Reply #2 on: February 05, 2016, 12:40:13 PM »
Shooter 8 have a condition of 1, so a full 5 for his base number.
So yes, you are correct, I was meaning to say 1:30.

I haven't decided on the non linear divider for the direction between 12 and 3(or 9)

Magnus effect and spin drift should be part of the shooters curriculum, just as pressure, humidity and elevation. Wind however is never predictable in real life as the other factors are.

Yes, I've been plugging at it for a while, and it returns good numbers across the board.
If you want to take it for a spin, to check my logic, I can send you the excel sheet.


rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #3 on: February 05, 2016, 01:26:14 PM »
So at the moment you are using an arbitrary correction for wind direction?.... eg. for 1:30 an arbitrary 0.5 x windspeed?.... I mentioned the Magnus effect because the rise and fall of the pellet as the windspeed and direction changes is quite significant, and should affect the correction factor for wind direction, no?.... IMO, what you are really after, in correcting for wind direction and speed is how far from the center would the pellet fall, in total distance, if not corrected for.... That is really the only reason and method I can see for making a correction at all....

If we were just dealing with the crosswind component, it would be relatively simple, you would use the sin of the angle times the windspeed.... as in this diagram for the Lateral Correction Factor (LCF)....



However, that would yield no correction for a headwind or tailwind (12 or 6 o'clock), and you wanted to use 0.25 for that.... In order to start at 0.25 and end up at 1.0, we would use a formula such as....

CF = 0.25 + (0.75 x LCF)

This would yield the following table....

12:00/6:00 o'clock = 0.250
11:30/12:30/5:30/6:30 = 0.444
11:00/1:00/5:00/7:00 = 0.625
10:30/1:30/4:30/7:30 = 0.780
10:00/2:00/4:00/8:00 = 0.900
9:30/2:30/3:30/8:30 = 0.975

with  the number above to be multiplied by the windspeed, of course....

Other formulas could also be proposed, of course.... However, I don't think this is the whole story, as it doesn't take into account the Magnus effect.... Spin drift I agree should not be considered, because it is a constant for a given twist/velocity/distance combination, and in fact should be corrected for when sighting the rifle....

You can send me the Excel spreadsheet if you like to bob at mozey-on-inn dot com....

Bob
  • Coalmont, BC

Windmeister

  • Full Member
  • ***
  • Posts: 108
Re: App development - Range Master - Need your input
« Reply #4 on: February 05, 2016, 02:10:43 PM »
YGM

I love the way you process data Bob :-)


rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #5 on: February 05, 2016, 02:30:35 PM »
I am still looking for the post by Mike, which showed the results on a target, but here it is written out....

Quote
Left to right winds...

A left to right wind from 9:00 will move the pellet to the right and up at about a 30 degree angle.

A left to right wind from 7:30 will move the pellet to the right and up at almost a 45 degree angle.

A left to right wind from 10:30 will move the pellet to the right straight across.

Right to left winds...

A right to left wind from 3:00 will move the pellet to the left and down at about a 30 degree angle.

A right to left wind from 4:30 will move the pellet to the left straight across.

A right to left wind from 1:30 will move the pellet to the left and down at almost a 45 degree angle.

The up/down part is opposite of what is seen in rimfire.  Left to right wind will move a rimfire bullet to the right and down.

The best and fastest way to learn the wind is to zero your rifle indoors.....and then move outside and try to find an area to shoot that has unobstructed wind.....like an open field.  The patterns I have listed above will be readily apparent if you can do this.  I'm fortunate to have a 30 yard indoor range next to my outdoor range.  Once you know what the pellet should do.....it will be easier to recognize the source of the wind problems when the pellet doesn't go where it should have.

99% of shooters must zero their rifles outdoors, and therefore never really have a zero that will match an indoor zero.....especially if they are not even aware of the up/down characteristics.  Their rifles will exhibit extreme up/down surprises because they if they zero in a right to left wind......and then the next time they shoot its blowing left to right.....the pellet will go way higher than they expect.  You seem to be seeing the opposite, but it's probably still due to an outdoor zero that does not agree with an indoor zero.  You have to expect the up/down. It's there.

If you don't, first, learn what the pellet should do in a pure condition (like an open field)....it will be extremely confusing when you shoot in wind that is coming around and over obstructions. 

Because I have learned the way I described (indoor to outdoor).....I can now zero my rifles outdoors and usually be within 1 click of indoor zero, and that is something that keeps me from dropping unnecessary points in an outdoor match with switchy conditions.

Mike

What I need is to quantify those deflections to get a better feel for the magnitude of them as related to a 90* crosswind....

Bob
  • Coalmont, BC

rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #6 on: February 05, 2016, 03:01:57 PM »
I finally found it.... Here is the post that goes with it.....

Quote
Here is a chart based on PELLETS.  This is based on the international 25m target, LV power (12fpe), and a 3mph wind.

Note that the largest POI change occurs just before and after the 12:00 and 6:00 positions.  This is often the place that causes the most misses.  We often encounter this on our home range.  The wind is coming from the front, but shifts back and forth slightly to the left and right of the centerline.  You have to be very observant not to get caught with your pants down.  The effect is obviously magnified with more wind velocity.

The most favorable winds for a air rifle benchrest shooter are a L to R from 10:30, or a R to L from 4:30.  They will be straight lateral holdoffs with no vertical component.

Mike
and here is the chart, stolen from Mike's post above....



Now when you look at that chart, does it REALLY matter which direction the wind is coming from?.... In almost every case, with just a 3 mph wind, the pellet impacts in the 8 ring (but scores a 9).... Only with the wind at about 5:00 and 11:00 might you still hit the 10 (but not at 1:00 and 7:00).... and only with the wind at 3:00 and 9:00 would you miss the 9 (but as Mike says, you are more likely to correct for it properly.... I think Mike's comments about the largest POI shift occurring just either side of the 12:00 and 6:00 positions is particularly telling.... as that is the area you have weighted the least, at only 0.25.... I would tend to think that using a CONSTANT correction based ONLY on windspeed and not direction would more often than not be a better solution.... YMMV....

Bob

  • Coalmont, BC

Motorhead

  • Sr. Member
  • ****
  • Posts: 438
  • Older & Slower ... Field Target Shooter
Re: App development - Range Master - Need your input
« Reply #7 on: February 05, 2016, 03:59:50 PM »
Bob,
On that chart are we assuming shooter is in the 6 o'clock position shooting at 12 o'clock ?
  • Old Hangtown ... California
"Home of Motorheads Air Gun Tuning Service"
    ***** Airguns need love too !! *****

oldpro

  • Guest
Re: App development - Range Master - Need your input
« Reply #8 on: February 05, 2016, 04:04:54 PM »
Id think at 6 shooting center no?

rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #9 on: February 05, 2016, 06:36:13 PM »
6'o'clock is behind you, 12 o'clock is straight ahead of you, in the direction of the target.... The POA is at the center of each target, and the black dot is where the pellet will hit, relative to that target, with a 3 mph wind, from the direction of the small arrow beside the target.... The range is 25m, and the rifle is 12 FPE, using pellets, which knowing Mike are likely 15.9 gr. AA's.... There are 16 wind directions shown, each 22.5* from the next....

The interesting thing (to me) is that with no hold-off to correct for the wind, the average shot would score a nine, landing mostly in the 8 ring, in only a 3 mph wind.... two 10's, twelve 9's and two 8's....

Bob
« Last Edit: February 05, 2016, 06:38:55 PM by rsterne »
  • Coalmont, BC

oldpro

  • Guest
Re: App development - Range Master - Need your input
« Reply #10 on: February 05, 2016, 07:09:13 PM »
Ok but this may seem weird but if the target was in the center of all those targets and the wind direction coming from the arrows wouldnt the results from each target be the same?

rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #11 on: February 05, 2016, 07:46:27 PM »
I think you may be looking at the diagram wrong, Travis.... Look at the target on the extreme right, where 3 o'clock would be.... Forget all the other targets and arrows.... You are aiming at the small circle in the center of that target, which is the 10 ring.... The arrow is the wind direction, from your right at 3 o'clock.... The pellet will hit to the left and a bit low, just missing the 9 ring and scoring an eight.... It hits left because of the crosswind, and low because of the Magnus effect of the crosswind on the spinning pellet, causing it to drop....

If you look at the target at the top, the wind is coming straight towards you from 12 o'clock, ie from the target towards you.... Your pellet hits low, scoring a 9, because this is a headwind, slowing the pellet and allowing gravity longer to pull it downwards....

Half way between those, there is a target at 1:30, and the wind is coming from 1:30 o'clock, ie a 45* angle towards you.... so it is equal parts headwind and crosswind.... The pellet hits low and left, barely touching the 9 ring.... It is low because of the headwind component (and the Magnus effect) and left because of the crosswind component....

Half way between that target and the one at the top, the wind is coming from slightly less than 1:00 o'clock.... so mostly headwind with a little wind from the right.... As expected, the pellet hits low and slightly left.... However, due to the Magnus effect, it hits lower than it did on the 12 o'clock target, because of the Magnus effect.... and again scores a nine....

The really interesting one is the target just the other side of the top, at just past 11 o'clock.... Again, mostly headwind with a little wind from the left this time.... You might expect it to mirror the last one, but it doesn't, it is much higher.... It is only slightly low, and slightly to the right.... and close enough that it scores a ten.... That is because the Magnus effect is now lifting the pellet instead of pushing it down.... If it were not for the Magnus effect, the diagram would be a perfect mirror image, left to right, but it is not.... On the left side, the pellets hit higher, and on the right side they hit lower.... This is because the spin of the pellet causes it to lift in a crosswind from the left, and drop in a crosswind from the right....

HTHs.....

Bob
  • Coalmont, BC

oldpro

  • Guest
Re: App development - Range Master - Need your input
« Reply #12 on: February 05, 2016, 08:06:12 PM »
 Ok got it. Now on another note will pellet rotational speed effect magnus effect?

rsterne

  • Member 2000+fps Club
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 1855
  • Mozey-On-Inn and see what Coalmont has to offer!
    • Mozey-On-Inn
Re: App development - Range Master - Need your input
« Reply #13 on: February 05, 2016, 08:25:12 PM »
Yep, and to a certain degree surface roughness, for example those grooved skirt some pellets have (RWS I think uses those, and some H&N).... Faster twist and rougher surfaces (like the dimples on a golf ball) increase the Magnus effect.... Even the rifling marks will have an effect (smoother is better), which may be one reason the FX Smooth Twist barrels work as well as they do.... With the pellet going flat out when it hits the short bit of rifling at the muzzle it "strips" through it, leaving the outside slightly smaller in diameter, and with no visible rifling marks.... Smaller and smoother = higher BC as well.... However, there was a thread a while ago on the GTA where a guy was finding them starting to tumble at over 250 yards.... spinning too slow, I guess....

Bob
  • Coalmont, BC

oldpro

  • Guest
Re: App development - Range Master - Need your input
« Reply #14 on: February 05, 2016, 08:43:21 PM »
My reason is this often I will see two seperate but very accurate patterns on a tune . One 6 hole tight group at 880 fps then a seperate also very tight group at 920fps I have seen it so often im beginning to susspect magnus effect moving pellet at different rotational speeds