Well, uhhh, NO vibe.....
on nearly every point you are wrong. You really need to read a book on this because I can't explain it all. I assumed that you knew more of bullet flight dynamics than nennstiel-Ruprecht.
Your first point that the wind blows the bullet over is simply wrong. This is nothing at all like a boat in a river.....As an example, think this through logically accepting that the numbers are representative of real-world situations. Equal wind in all.
-Bullet "A" may be launched at 4000fps and travel 1000yds in one second (time AND distance) and be "blown over" 15ft.
-Bullet "B" may be launched at only 2000fps and travel the same 1000yds in the same wind and take LONGER doing it (time AND distance) and be "blown over" only 7ft.
-Bullet "C" may be dropped for a full three seconds (longer TIME than the others) and blow over only a few inches.
WHY?
In the "boat in the river" model, the boat and a dropped poohstick will travel equal distance over time once you factor the vectors.
Your second contention that changing the trajectory early on has a larger effect than later in flight is fodder for a fruitful discussion but not knee-jerk easy. (BTW the analogy often used is the hook shot in bowling. Get your hook to break right before target impact and you've got a strike, break too early and you've collected a poor hit or a gutter.) Problem is, a bullet's not a bowling ball. Second problem is, a bullet reacting to a bump doesn't just assume a new vector like a pool ball either. It CAN'T. (BTW, this view was popularized by a member of this board in the book "The Ultimate In Rifle Accuracy." and while "not true" is still accurate in the sense intended.)
Your statement
"A lot of the "drift" distance, comes from turning the bullets direction of travel." is simply not true. I know what you mean by it and AS YOU DESCRIBE IT, it's not true. First of all, it's irrelevant, we're assuming full value crosswind, full course. This assumed value is implicit unless stated otherwise. There are no bumps happening here......bumps are freakin' MINDbenders....all fishtailey and spirally and full of residual moments and right-angle torques.
And THIS statement.....
"Not to put too fine a point on it...But that's pretty much the definition of what a model is. A means to put observed behavior into terms that accurately describe and predict the results." is kinda' technically "true" BUT........ just because the AD1750 model of medicine included "vapours" and "humours" as causes of sickness, and just because these terms WERE a way to describe conditions. And just because methods used based on these presumptions.descriptions sometimes WORKED, doesn't make the model valid. The development of the microscope and discovery penicillin dramatically changed the models, and later the discoveries of WHY penicillin worked led to new working hypotheses and NEW work. Sure, there are many "models" of the bullet's flight, including nennstiel-Ruprecht's version but only ONE right one. (provable/repeatable) And generally a model arrived at in a bass-ackwards fashion like "The Lag Model" or Didioms Theorem do little to approach the WHY. Find the WHY and the true model follows. It HAS to. (Science is funny that way.... and yes, even alinwa can see that) This all goes back to why I fought you so hard on the muzzle brake thing. If you really understand WHY then formulas and the use thereof become irrelevant. SHORTCUTS yes, but irrelevant to the WHY.
And this statement again shows that you believe that wind is blowing the bullet over. IT'S NOT...... A bullet is not a sail, it's 'wayyy cooler than a sail. This also shows why you believe that a bullet with more yaw will show a measurably lower BC, again, not true for real.
And this last,
"That is in still air, which has less effect than moving air. The "Rolling on the airstream" model is still used because it still accurately predicts the observed behavior. Which does pretty much "make it right". But that is another, and separate, problem - and results from the fact that the rotation is slowing much less rapidly than the linear velocity - so the rifling grooves start acting more like the dimples in a golf ball and less like the fetching on an arrow."
WRONG! On several levels. First of all it's just WRONG to make statements like
"Which does pretty much "make it right". " That's just SICK man! The "rolling on the airstream model" is still used for ONE reason, Askins said it and grunts is dumb. And it doesn't "predict" anything, it's an archaic attempt at EXPLAINING observed phenomena. Back to the vapours and humours...... history is rife with, nay infested with, nay BUILT ON flawed models....... but the flight of a spin-stabilized projectile is WELL UNDERSTOOD, a different thing entire.
"Rolling on the airstream" doesn't withstand even casual scrutiny. Except with round balls from smoothbores...... rotating at right angles to direction of travel like thrown curveballs. And even then, supersonic behaviour isn't the same as subsonic. Round balls fired from a rifled bore exhibit EXACTLY the same flight characteristics as pointy buwwets.
And the "fetching dimples" thing is just silly. Any imperfections on the surface of the bullet are not only buried beneath the laminar flow but behind and shielded by an enormous shockwave. the only thing that could possible be generated by the rifling grooves would be another shock wave from an extrusion artifact, and it
small!
I'll refrain now as I'm not willing to let this devolve into some sort of opinions thing. This isn't stuff I've made up
and I'm sorry to have drug you into it. I've got a really minor quibble with the current explanation of wind induced VERTICAL drift. But we're not on the same page here.... I HEAR and UNDERSTAND your word pictures. But we're literally BOOKS away from each other here. Try "Rifle Accuracy Facts" by Vaughn for an easy and fun read. "Understanding Firearms Ballistics" by Robt Rinker for a slightly befuddled but overall readable ballistics text. "The Bullet's Flight, from powder to target" by F.W.Mann for a bunch of seminal work (and flawed models) and McCoys "Modern exterior ballistics: The launch and flight dynamics of symmetric projectiles" for the FACTS........ And Askins and Hatcher for a bunch more flawed models. Since't we're on the subject of models and their rightness.
But not one clearly demonstrates WHY a bullet blown left will impact high because they don't deal in extreme accuracy. Brian Litz tried over on The Mother Of All..." winddrift threads tried but I'm not convinced that he actually
knows. He uses a bunch of "averaging over time" verbiage. In the end, most folks fall into SOME iteration of a bullet "following it's nose" as though all drag rules just "don't apply in this instance......"
But they DO impact high, leftern-blown bullets, and I've got an explanation WHY..... I just don't know for sure that it's right. And we certainly aren't going to solve it until we agree upon what base drag does to trajectory! THEN we can explore whether the precession moment is torque-free movement or torque-induced....and whether still air "spindrift" could be related to vertical drift...... (not "flying," vertical drift)
in a hookah-free environment
And please, keep Bill out of it!
Meantime, I'll go and brush up more on the difference in WORK DONE by elastic VS inelastic collisions in a gaseous environment. I see your viewpoint there too, now. I don't totally agree because I don't totally understand all the WHYs involved, but for now I'm convinced....
al
