Reading the wind

[andyd1179]

You know you don’t have to go to the range every day and waste ammo in reading the wind, once you know the basics you can sit in your own garden and just spend time watching the flag and what is does to determine where you would aim on the target or maybe the case of not shooting.
I thought I would share my views on each picture and what I would do and maybe not do.

At time of pictures the wind condition was between 6mph and 15mph

Image 1
On this picture the wind is coming from the west and the strimmer is about 4 o’clock if you were looking at a dial, the propeller is about medium speed so on the target I would go 10 o’clock off the 10 ring.
If I was shooting straight and the bull this would land about 4 o’clock in the 9 ring, so I am compensating for this by going high and to the left.

Image 2
On this picture the wind has gone north, there is a bit of a swirl on the strimmer, in my view this is a difficult shot to take. With the swirl going on the bullet could go anywhere on the target, I may try a sighters on this one to see where it goes and if it was extreme then I would hold off till wind changed.

Image 3
On this picture you can see the wind is now coming back in from the west but the strimmer is now at 3 o’clock so I would go 9 o’clock on the target but more towards the 9 as the speed on the propeller is much faster than on image 1.

Image 4
This is an interesting one in that the propeller has stopped dead but the strimmer is at 4 o’clock but there is a slight swirl but I would go for more of the bull on this one.

Image 5
This one has everything going on as the wind comes in from the west but there is a bit of a flip in the strimmer that shows the wind pushing down but then bounces back up, so at this point I would hold off.

Image 6
This one you can see the wind id still coming in from the west but the wind has picked up a lot at this point but there is a draft pushing the flag upwards, if I was going to have ago at this one I would go 7 o’clock and into the 9 for this one and see where it lands.

Image 7
This is an interesting one in that the propeller has stopped but the srimmer is running wildly into the air, there is almost a funnel spin on it that again I would leave this one alone as it would be a wild card.

Image 8
This image shows the wind coming in from the east and the propeller is at a mild speed and the strimmer is running 7 o’clock so I would aim 1 o’clock on the 10 ring.

Image 9
The wind is coming in from the west but now the strimmer has gone wild with the strimmer heading for the skies, would I take the shot? The answer is no I wouldn’t I would wait for things to change.

Image 10
Now for a quick change the wind seems to be moving north but look at the stimmer, its dead in the water so I would go straight for the bull.

Image 11
The wind is still northerly but is picking up a bit, but I would not adjust on this one and still go for the bull depending on the last shot, if needs be maybe drop him down a bit off the bull.

Image 12
Even though still a northerly wind the speed has picked up, notice the loop in the strimmer, this would mean it would be extremely twitchy so I would hold off for a change.

Image 13
Here is a scenario for you.
It has only been a view seconds that have passed but look how extreme the up current has gone, would you take this shot, you would be more of a man than me. Think of it that you currently on a 249 and this is the last shot, where would you aim on the target, no time to go to a sighters and there is only 2 minutes left on the clock, do you take the shot or watch the clock to allow the change in the wind to your favour.
I would hold off even if this meant going down to the last 10 seconds till the wind changes in your favour, it’s a chance a chance worth taking as if you took the shot with the flags doing this it could go wild into the 7 or 8 which puts all that hard work before hand to waste.

Image 14
So over a minute has pass and what a change in the flag, it s dead in the water and you can go straight on the bull for your final shot. You have to think on the last shot of how important it can be even if at this stage you drop one point that is better than dropping 3 from the target before, if possible and most times it does happen I finish on a 10 and even with an x chucked in, it’s a good feeling to finish on a high.

There are a number of wind devices out there that you buy or make, but once you have got them spend time with them even if means in the garden, like I have said you don’t need to spend time at the range to read your flags all you need to do is put a flag up and watch or even like have for this exercise take pictures and then imaging a target and where you put the crosshair on the target.

If you have different thoughts on how I have read my flags then share with the rest of us.

AndyD

 

[Bulls-Eye]

Thanks...

Good thread!

 

[steyrl]

A really good posting.
The pictures help to understand what's going on!
Thanks very much for taking the time and effort.

 

[Brian_K]

Going to take you up on one Andy – Image number 8 – I would have gone for a 4 o’clock shot just on the edge on the 10 ring, working on the basis a right to left wind will make the bullet rise. Am I wrong?

Brian

by the way - good thread

 

[Bill Collaros]

I think u r closer to an X Brian, it's possible by image 8 Andy was either up to his 8th guiness or the local authorities had come to check on reports from neighbours about an ecentric nutter photographer taking shots of a flag & streamer in their neighbourhood.

But Andy I will say it is a good idea, sometimes you can try & teach people they dont get it, pictures say a thousand words, just dont forget so do sighters

 

[crb]

Andy,
You should try blackening one of the prop blades with a Magic Marker. What pitch prop are you using ?

 

[andyd1179]

Going to take you up on one Andy – Image number 8 – I would have gone for a 4 o’clock shot just on the edge on the 10 ring, working on the basis a right to left wind will make the bullet rise. Am I wrong?

Brian

by the way - good thread

Hya Mate,
I think 4 o'clock would be to low, going by the angle it gives the viex that the wind is pushing down, and on the basis of that i would go 1 o'clock off the 10. maybe the answer on this one would be to meet halfway and go 2 o'clock.

AndyD

 

[andyd1179]

Andy,
You should try blackening one of the prop blades with a Magic Marker. What pitch prop are you using ?

Hya CRB,

nit sure what pitch they are but i purrchass them from Dan Killough, they are great flags and very sensitive which is something worth looking at when purchasing wind flags.

AndyD

 

[Fred J]

Swirls and updrafts

It's doubtful, you will see these same conditions on your range. Houses and fence are causing these situations.

 

[Kent Owens]

Fred,
You beat me to it, I was thinking the same thing. The fence and surrounding buildings will make the wind and flags do some strange things as we all know.
That's what amkes one of the little wind and bullet drift charts useless on ranges with different obstacles and terrain.

 

[HuskerP7M8]

The vertical component acting on a rimfire bullet with a 1-5 o’clock or 7-11 o’clock crosswind is known as aerodynamic jump and in general it follows a 1:4 ratio for correction on the target. That means if you have to hold-off 1 inch horizontally on the target, you have to also add or subtract ¼ inch vertically to center your shot.

This is valid for 50yds/meters but may change at shorter or longer distances and it follows a linear progression, meaning the shape of your groups with no correction applied will be an ellipse with an approximate 10 o’clock to 4 o’clock slant that simply lengthens the major axis of the ellipse as the wind increases.

Turbulence in the flight path of a rimfire bullet needs to be explored in greater depth but I don’t believe thermals will ever affect the flight path at these short ranges and I would look to mirage as the culprit for unexplained vertical anomalies.

Here’s a test I did quite some time ago from a revolving bench and the wind logged with a Kestral wind meter showing an average of 13 mph for a direct crosswind at two 25yd targets.

And, here’s the formula for calculating vertical displacement from aerodynamic jump:


Dv = - (Ix/m*d2) * (Cla/Cmo) * (2*3.14/n) * (W/Vo) * R

Dv = Vertical deflection due to crosswind
Ix = Projectile axial moment of inertia
m = Projectile mass
d = Projectile reference diameter
Cla = Lift force coefficient
Cmo = Overturning moment coefficient
n = Rifling twist rate

 

[andyd1179]

Re Husker Last

WOW

Husker thank you for the data, but not sure how you would have the time to do the calculations in a match when you only have 30 minutes to shoot the card, but many thanks.

Yes i agree having fences around will give a different view of things, but the main thing that i was trying to explain that for people coming into the sport or trying to understand the flags can do this without shedding loads of ammo down the range.

if you know the basics of wind reading on the tartget then spend time watching the different combinations that you will get so that it becomes easier when actually shooting a match.

most people i know just spend time behind the rifle, but then its a small percent watching the flags, this was just an exercise which can be easily done anywhere.

AndyD

 

[wboonville]

thanks

Andy thats what we need to see to understand flags thanks for taking the time to do that

 

[Brian_K]

HuskerP7M8

All your calculations are very impressive, in an ideal world.

If you don’t think thermals affect a rimfire bullet, you should have been in Milan last year. With ground temperatures of well over 40c I assure you most of the competitors there thought it was thermals that were pushing their bullets into the 11 to 1 o’clock part of the black ring.

Figuring out the wind coming off buildings, trees, fences and not to mention 4 meter deep troughs in the range was something beyond me, but some managed to do it.

I agree with Kent, these charts are useless, on most of the ranges I’ve been to.

Brian

 

[andyd1179]

Re Husker Last

i would be intrested if HuskerP7M8 has a shorter version to work from or another way to apply this.

AndyD

 

[Kent Owens]

Andy,
Don't get me wrong, I think it's a great idea to watch flags and look for different conditions and wind patterns. If you'll watch and fire shots in certain conditions, most of the time you can find something you can shoot and have a good idea of where the bullet is going. Also if you'll fire sighters in some conditions you'll find a definite no-shoot condition. Whenever I go to a new range to shoot, that's the condition I hunt for, the one that will kill ya, and then you know to lay off that one at all cost, shoot anything but that one! All ranges have no shoot conditions you just have to hunt 'em out by shooting sighters over different flag patterns to find 'em. The no shoot condition can be an appearing dead calm, or a something else. Most folks do not shoot enough sighters, correctly. Sighters need to be shot with a purpose. and not just randomly. By purpose, watch the flag angle change and see what that does to your sighter shot. Sometimes a condition tha tlooks unshootable can be a great scoring condition, i, e. croossed up flags. Sometimes not. Also when your favored condition goes away, and then appears to return, shoot a sighter to confirm it's abck and doing the same thing as before, before going back to record bulls. It'll save a few points here and there. Best of luck in your shooting.

 

[andyd1179]

Thanks Kent,
I thiink you are right about the sighters, it is about using the wisely.

I think this is a good descussion as I have not seen anyone talk about wind flags in this way.

One thing i have done which was something somebody mentioned about was the propellers which is to break the colours up. What i have done is used a bright coilour on one propeller one one side and then the other one on the reverse side, this allows me to see clearly how fast the the propeller is travelling and then useing a electronic wind gage i make a mental note it the colour scheme that I see, i think it easier to have two speeds in your mind and use the sighters to get an idea of were the round is going to end up.

AndyD

 

[HuskerP7M8]

Andy & Brian,

It’s obvious that there’s no practical way at present to do the math during a match but if everyone keeps the 1:4 ratio in mind and doesn’t over emphasize the importance of a single shot or just a couple of shots on a sighter….their scores should improve.
You have to remember that even the most accurate rimfires won’t stack every bullet thru the same hole, so just a couple of shots on the sighter doesn’t necessarily mean you’ve found the prevailing wind condition because those shots may have been on the boundaries of what your rifle normally groups 25-50 shots into and the more inaccurate your rifle is the less credence you can place on a sighter shot. For many, maybe even the majority, the sighter targets could get you in more trouble than they’re worth. You might end up chasing your tail if you can’t get off enough shots under the same wind on the sighter to be valid.

Thermals. I know all about them from flying airplanes and gliders. In fact, I once lost control of a small aircraft when I foolishly flew thru a Nebraska “Dust Devil” that was almost the size of a small tornado.
Can you calculate the up-draft in ft/sec or meter/sec from a thermal layer that occurs as close to the ground as your target? If you can, I’ll bet it can’t be significant enough to move a flying projectile in 50 yds. Anyway, I’ll stand by mirage as the major factor.

Bear in mind that these are the thoughts of a “keyboard shooter” and no one takes us very seriously. Also, for those of you who have rifles that shoot every shot thru the same hole….you can disregard this post.

Landy

 

[andyd1179]

Re last Post

Thanks Landy,

I think that sighters do have there use in that you can choose a combination on the flags and see where on the target it will end up, then if you see the same combination again while doing the card you can go for it.

Is it a view that a target haveing a nough sighters on it for that match is just as important? I notice on another thread that the IR50/50 target only had 3 sighters, is this normal as we here in the UK have just introduce a new target 10 sighters or more.

AndyD

 

[Fred J]

Another method

The biggest problem, is what going on between the flags. Even when they are all saying the same thing, you will occassionally get that weird flier. Try setting your flags up around the perimeter of a swimming pool, with the pumps off. You can see the air flow over the water is telling you more than the flags. Problem is, you can't take the pool to the range, although it would be nice, to be able to throw the hot shooter in when he whoops up on everyone..