Balancing Wind Flags

KEITH MYERS

KEITH MYERS

New member
I have a set of double vain flags that I removed the daisy wheels. I then replaced the daisy wheels with painted wood balls. My question is the flag supposed to be balanced so at the pivot point both ends weigh the same? I was thinking (Again) that if one end was lighter than the other the flag would be more responsive to subtle changes.
 
Keith,
Make the vane side or backside just a little heavier. It will do what you say and minimize the windshield wiper effect.
Butch
 
What Butch is suggesting may be true for some flag designs. (and maybe yours, I don’t know) Suggest you try them different ways and observe them.

Since I’ve been asked about this many times, I would like to take this opportunity to say that Graham flags should not be balanced with the tail end heavier. It is my opinion that if you need to have your flag out of balance to remove the “windshield wiper effect” that is a poor flag design. That problem was designed out of Graham flags many years ago so keep them well balanced including the tail to get the most out of them.

Rick Graham
 
RJG said:
What Butch is suggesting may be true for some flag designs. (and maybe yours, I don’t know) Suggest you try them different ways and observe them.

Since I’ve been asked about this many times, I would like to take this opportunity to say that Graham flags should not be balanced with the tail end heavier. It is my opinion that if you need to have your flag out of balance to remove the “windshield wiper effect” that is a poor flag design. That problem was designed out of Graham flags many years ago so keep them well balanced including the tail to get the most out of them.

Rick Graham
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I agree Rick. The center of pressure must be behind the center of gravity to be stable. If daisys or pinwheels are to be used, they should be as light as possible. Therein lies another interesting area of flag design. The pinwheel can't simply be sized down to decrease weight, without adding pitch...or else the pinwheel itself is less responsive, and won't turn as easily. I'm no aeronautical engineer, but I did and still do seek the advice of a friend that is one, in the design of my Neon Wind Flags. They are the best flag that I have seen at any price, and are made in USA(sorry Butch:p). They are now made pretty much entirely of fiberglass, carbon fiber and teflon, and use high visibility vinyl for the colors. You do have to be secure in your manlihood to shoot with pink flags, but you don't have to have 20/20 vision to see them though.:D. I just introduced them in March of this year.--Mike Ezell
An older pic below.
IMAG0141.jpg
 
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IMO the thing that lures wind flag builders into a position where they have to use out of balance to create friction in the pivot to counter the windshield wiper effect is the desire to make their flag as light as possible. To accomplish this they extend the front counterweight and or propeller too far forward, which although it lowers that amount of weight required to balance the flag, creates excessive polar momentum, or flywheel effect if you will. By moving the counterweight or combination of propeller and counterweight closer to the pivot it has to be heavier to work, but the windshield wiper effect is conquered, and the additional weight, while increasing the down force on the pivot, should not be a problem with the materials commonly in use. A steady breeze, that has a stable direction does not show the problem. Wind that changes angle rapidly, and continues to do so is a better test. Another issue that can slow response is too close "sail areas" of what is in front of the pivot, and what is behind it. Putting the propeller close to the pivot helps deal with this problem, when the areas are close, because it gives a leverage advantage to the vane. Or I could be wrong about all of this.:D
 
Boyd Allen said:
IMO the thing that lures wind flag builders into a position where they have to use out of balance to create friction in the pivot to counter the windshield wiper effect is the desire to make their flag as light as possible. To accomplish this they extend the front counterweight and or propeller too far forward, which although it lowers that amount of weight required to balance the flag, creates excessive polar momentum, or flywheel effect if you will. By moving the counterweight or combination of propeller and counterweight closer to the pivot it has to be heavier to work, but the windshield wiper effect is conquered, and the additional weight, while increasing the down force on the pivot, should not be a problem with the materials commonly in use. A steady breeze, that has a stable direction does not show the problem. Wind that changes angle rapidly, and continues to do so is a better test. Another issue that can slow response is too close "sail areas" of what is in front of the pivot, and what is behind it. Putting the propeller close to the pivot helps deal with this problem, when the areas are close, because it gives a leverage advantage to the vane. Or I could be wrong about all of this.:D
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Boyd, I think what you are saying is still the same as I am...that the center of pressure must be behind the center of gravity. Along with that, less mass, or overall weight will tend to respond and also correct itself in a switch faster, without "over running". So I think we mostly agree, but there is nothing good IMO about "extra" weight in a wind flag. --Mike
 
Smiley Hensley makes one of the most popular wind flags in the east. Some big shooters use them. Look where his daisy is relative to the pivot. Static balance and center of pressure do not not tell the whole story. Weight close to the pivot is is no big deal (within reasonable limits) if the pivot is a good design. One of the lightest and most elegantly built flags that I have ever seen jitterbugs in a fast switch to the point that it is almost useless.
 
I'm familiar with his flags. Google up vertical stability in relation to airplanes. Center of pressure and center of gravity do tell the whole story..or very nearly so. My flags are very smooth and don't have the jitters like you are talking about. I did make some changes that cured that in my earlier version and it was all relative to CP vs. CG.--Mike
 
Yes, that is why a bullet has to be spin stabilized or tumble, and why a dart does not have to be. The ultimate test is obviously how a thing works. If yours work well then the design is correct. I have Hood flags, and in the past, the way that I sort out which of the many possible combinations worked best is to build one of each and watch them both at the same time....basically adhering to that fine old American engineering tradition...cut and try.
 
Boyd Allen said:
Yes, that is why a bullet has to be spin stabilized or tumble, and why a dart does not have to be. The ultimate test is obviously how a thing works. If yours work well then the design is correct. I have Hood flags, and in the past, the way that I sort out which of the many possible combinations worked best is to build one of each and watch them both at the same time....basically adhering to that fine old American engineering tradition...cut and try.
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I've spent several thousand dollars cutting and trying. I wouldn't admit that to any crowd other than fellow BR shooters...we're the only ones that just might understand and give a hoot. They are a very good flag, but it has taken a lot of help, trial and error, and money. Damn, I love BR!--Mike
 
KEITH MYERS said:
I have a set of double vain flags that I removed the daisy wheels. I then replaced the daisy wheels with painted wood balls. My question is the flag supposed to be balanced so at the pivot point both ends weigh the same? I was thinking (Again) that if one end was lighter than the other the flag would be more responsive to subtle changes.
Click to expand...

Keith, to answer your question...I'd try balancing them equally first, and adjust it to be very slightly tail heavy if they get the jitters. The jitters, or windshield wiper effect will be most noticeable in heavier conditions. They will likely slow down somewhat when you do this. This is just my experience with them, but seems to hold true with the several different kinds of flags that I have tried it on. I hope this helps and sorry for getting off topic.--Mike Ezell
 
Another part of the balancing equation is making sure the pole is plumb (straight up and down) on which the flag sits. A couple of years ago, my physics class did a wind flag project. Too make a long story short - we made an "el cheapo" wind tunnel and a bunch of measuring devices. We took several flags and balanced them according to their directions - did a test. Took the same flag(s), same wind, etc and changed the angle of the pole. The flag(s) did not react the same. The time it took to stabilize was much longer and the angle in which it stabilized was different. However, the angle difference was so little, that I doubt anyone would be able to tell at 50 yds, let alone 100. The time would be the bigger issue.
Just something to consider.

Stanley
 
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Boyd Allen said:
By moving the counterweight or combination of propeller and counterweight closer to the pivot it has to be heavier to work, but the windshield wiper effect is conquered
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Don't you love it when practice agrees with theory?;) For a given mass, static balance is proportional to the distance from the pivot, while angular momentum is proportional to distance squared. For a statically balanced flag, the one with heavier weight closer to the pivot has less polar inertia.

Cheers,
Keith
 
Apollo said:
Another part of the balancing equation is the balancing of the pole on which the flag sits. A couple of years ago, my physics class did a wind flag project. Too make a long story short - we made a "el cheapo" wind tunnel and a bunch of measuring devices. We took several flags and balanced them according to their directions - did a test. Took the same flag(s), same wind, etc and changed the balancing of the pole. The flag(s) did not react the same. The time it took to stabize was much longer and the angle in which is stabilized was different. However, the angle difference was so little, that I doubt anyone would be able to tell at 50 yds, but the time would be an issue.
Just something to consider.

Stanley
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Do you mean "plumb" the pole, i.e., make sure it is perfectly vertical?
 
If I remember correctly, Jackie wrote of using cheap Radio Shack tripods for flag stands so that he could plumb their pivots. All in all, not a bad idea. When an out balance flag is out of plumb, it will come to rest heavy side down, and in doing so create an incorrect impression of downrange conditions.
 
What I use, and many others, is a bubble level "glued" to a piece of delron (roughly 2") with a 1/4" hole (or whatever your flag hole diameter is) drilled in it. When setting the pole, simply stick the bubble level/delron on and plumb the pole when sticking it in the ground.
 
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