Wake turbulence

K

KEN HARPER

Guest
I had the opportunity to shoot at my first indoor shoot in Ennis this past weekend. I went with expectations of shooting an agg of 2300 or better. I was sorely disappointed. All but three of the 12 shooters agged over 2100. I spoke to other shooters about their indoor shoot observations and Dan Killough told me something that may shed some light on how to explain some of the wild bullet deviations that we experienced this weekend. Dan has noted that the more people shooting in an indoor range usually results in lower scores. I’ve heard stories about the ghosts of RR Barn as well and wonder if it could be the same phenomenon as wake turbulence. Pilots are well familiar with wake turbulence. It is turbulence generated by wingtip vortices on takeoff and landing, times when the wings are generating high lift. The turbulence can linger on the runway for several minutes particularly in calm air. It can create serious problems for planes attempting to take off and land and has been known to flip small planes completely over. Bullets traveling in air also generate shock waves and vortices which can linger in calm conditions. It would make sense that the more bullets flying around, the more unseen turbulence is generated. There was certainly no other detectable wind movement on the few wind flags that were set up and there did not appear to be any changes in air density hence no mirage except that coming off warm barrels. Just a theory I thought I would throw out there.
 
Just a couple of thoughts, having competed in indoor .22 pistol matches, I noticed a couple of things: Most indoor ranges use high output fans to remove gunsmoke and lead particulate from the air. Although they don't create much air movement they do create some. This often varies with where you are on the line. Second, if the range uses flourescent lighting it can create some visual disturbance not readily detectable to the human eye. Flourescent lighting actually strobes at a very high cyclic rate, IIRC something like 200 times a second but at any rate it can impact your score. Not discounting your premise that wake turbulence has an effect, just additional items to think about.

Randy
 
static friction. inside in the winter furnace on and result is static and increase in friction. www.school-for-champions.com>physical science> physics-
 
also would not be surprised to analyze all the targets for misses vertical.
 
At the RR barn, my theory is that with a 20-30 degree difference from the bench to the target, a bullet that has yaw at the muzzle will have more yaw at the target due to the increasing air density. As the bullet's yaw increases, it is easier for it to veer off course.
 
I do some indoor practice in a small pistol range here with only four lanes. I did a little experimentation and one day when it was just me shooting there (luckily), I put strips of surveyor's tape up on each of the target holders and ran them down the range at different lengths. None of them moved a bit. However it was just me shooting with a .22 and I was taking my sweet time so it was maybe one shot a minute so the bullets couldn't have been disturbing the air too much.

However, I can count on my rifle not shooting nearly as well when there is someone else shooting, especially if they're popping away with a pistol or AR rifle (about the only other thing you'll see there). I imagine they are creating a fair deal of turbulence in the air, not to mention the mirage gets way worse with other people shooting.

I thought indoor shooting would be easy. Then I actually did it. I don't want to imagine shooting at a place like the Barn with a bunch of shooters.
 
one night at sullivan eagles Butch Hongisto put off collored smoke bombs,
you can really see the air currents..when the door is opened or the furnace kicked on....DON'T SHOOT:eek:
in places where there are steel back stops, tiny bits of lead fill the air around the targets and come flying back
 
martin hammond said:
also would not be surprised to analyze all the targets for misses vertical.
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I just went over my targets from the ARA Indoor Nationals. 8 targets two days many, many misses. One miss was 9 o'clock two at 3 o'clock. 37 leaked out the top and 37 out the bottom. On my BAD BAD target there 7 out the top and 7 out the bottom on all the other targets most were one or the other. Mornings out the bottom afternoon out the top. The even target was #3 about 1pm.

There are many very fine scores shot in the"Barn". RBA 250's with high X counts are no accidents. I just haven't been able to pull it all together yet.

I might note that it is VERY cold here in Georgia and I'm bored out of my scull.

Al Kunard
 
Al

Can you determine a pattern of location of the "misses". Asked differently, are the misses generally on the same rows target for target - or columns depending on how you shoot?
 
Wilbur said:
Can you determine a pattern of location of the "misses". Asked differently, are the misses generally on the same rows target for target - or columns depending on how you shoot?
Click to expand...

At first glance I don't notice a pattern -- except one bad shot would be followed by one or two others. In going over the match with Don Sitih and a couple of his friends they suggested that when a bad shot occurred go to the sighters untill the shots started grouping again, also shoot a couple of sighters when starting a new row.That might be a KEY!
I was using the Hall onepiece rest.

Al
 
Could this be a similar situation?

When I shot prone smallbore at a walled, open roof 50 metre range, we would run into a "mirage" issue winter nights. At about when we were half thru our 60 shots, a meniscus would form between what we believed to be air of different temperatures across the waterline of our target. You could generally see it thru the scope as it contorted up & down like one of those water beds your disreputable classmates adopted in the seventies, the result being high & low 8s.
 
John Kielly said:
When I shot prone smallbore at a walled, open roof 50 metre range, we would run into a "mirage" issue winter nights. At about when we were half thru our 60 shots, a meniscus would form between what we believed to be air of different temperatures across the waterline of our target. You could generally see it thru the scope as it contorted up & down like one of those water beds your disreputable classmates adopted in the seventies, the result being high & low 8s.
Click to expand...

Add to what you described a couple of big wood stoves adding thermals. that you can feel walking down range, plus the side slats are covered by thick Bisqueen (sp?) and when the wind gusts hit the walls you can feel the pressure on your ear drums! Again some fine scores are shot there!

Al Kunard
 
gambler said:
one night at sullivan eagles Butch Hongisto put off collored smoke bombs,
you can really see the air currents..when the door is opened or the furnace kicked on....DON'T SHOOT:eek:
in places where there are steel back stops, tiny bits of lead fill the air around the targets and come flying back
Click to expand...

When I shoot in my building which is 175' long, I turn off all fans and furnishes and shut the doors. There may still be some air currents but I can shoot a great deal better than outside on our club range. Of course, we shoot one at a time and there is no turbulence from the bullets of other shooters.

Concho Bill
 
now i know why, rich mills always got to the shoots first and took the lane next to the wall...less terbulance..da rat baxtard !!!!

i wonder if all those tiny lead fragments effected incoming rounds, the air was full of them:eek:
 
has anyone that shoots inside sorted rounds by height and determined if that is a factor? and inside is there a noticeable increase with keyholing. often times outside there are guys shooting .308's beside me and I thought if the turbulance from a .308 affects a .22 why aren't the rounds keyholling? how can many .22's create turbulance without an increase in keyholes?
 
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and if it's turbulance wouldn't the rounds tend to be misses at 3:00 wether the turbulance was from the shooters left or right it should have the same affect in turning the round?
 
martin,
Make a trip to the Rocky River BR barn this coming weekend and experience it for yourself. Until someone shoots the indoor matches a few times, they just won't believe what can happen. It defies logic, but there are reasons for waht happens, just hard to pin 'em down.
 
Kent, won't be going to the barn but if I was I would seperate the rounds that are the highest or tallest and run a test. if it is friction between the 2 surfaces it happens at the begining. I would see if the .960 height is more accurate than the .943 that eleys match ammo varies. tried to do a calcultaion and it appears that less than 3/100ths of a second is the difference betweeen a 90% timed rifle and a 50% timed. doesn't take much drag to influence a high or low round. if I was there in the morning I'd be shooting the .960 rounds. of course that could put me in last place but that wouldn't matter you as a shooter would know. and that's why sometimes I do what seems goofy things. just don't make the same mistake twice.
 
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