Speedys magnus effect chart

[alinwa]

...and now you know why the Benchrest Central forums are a relative ghost town.

Monte, I didn't expect this from you.

 

[avidflyer]

Hey Randy.......just for you (and against my better judgement LOL) I'ma share something that's worked for me......



You say " for yours truly, that's the most difficult concept to grasp....."

Now I know that you DO grasp it, so I think what you may actually be saying ( because you are a NICE man, unlike me) is, " this is the most difficult concept for me to explain".....

This has worked for me....

Remember Gene Beggs' airplane analogies???

Well here's my version.

An airplane is flying due north in no wind. A wind comes out of the west, from the LEFT, and the plane starts heading to the right.......so the pilot turns the plane into the wind to stay stable and ADDS POWER to keep going straight......it PUSHES a little to make up for the new force.....

A bullet is also launched due north....encounters the same wind, it also has to adjust it's nose into the wind to stay stable BUT IT CAN'T ADD POWER........so it gets sucked ( dragged) downwind.

what does adding power have to do with anything, no need to add power for a crab correction just wondering maybe I'll learn something

look at my wind vector in the photo I had a 170 knot cross wind at 40,000 surely I didnt add any power I always run max thurst.

 

[alinwa]

View attachment 1024033

what does adding power have to do with anything, no need to add power for a crab correction just wondering maybe I'll learn something

look at my wind vector in the photo I had a 170 knot cross wind at 40,000 surely I didnt add any power I always run max thurst.

I'm presuming a timed arrival over a given ground track. If you always fly WOT then you'll just lose groundspeed when you crab as some of your power is used to "climb the sidehill"..... but regardless, unlike an airplane, when the bullet crabs (centers it's yaw of repose on what it feels, so that it maintains stability) it's decelerative force shifts to the side, essentially behind the nose...... it not only "slows down more quickly" it also "slows down sideways"

 

[243Mendoza]

... I believe that I read this either in Modern Exterior Ballistics, by Robert McCoy (had to read that one four times!),... RG

The original book did not have an index which is very inconvenient. Has anyone every generated an index for that book?

 

[Depart123]

I was advised by someone who does training several days a week that the impact on vertical is approximately 20% of the wind hold. Use as a starting point and refine based on experience.

Bryan Litz in the past has intimated that it is 10%. Take that for what it's worth, you may be closer to correct as far as I know.

 

[Joe Salt]

Everyone has been talking left and right wind if you want vertical shoot in a left right diagonal wind you'll see it every time.

Joe Salt

 

[CharlieNC]

Bryan Litz in the past has intimated that it is 10%. Take that for what it's worth, you may be closer to correct as far as I know.

MeanG the only thing I'm sure of is that its not simply a single fixed value, but depends on x,y, and z (meaning I don't know). While this is not so important in matches that allow sighters, it can kill you in the low key tac matches I shoot that start with cold bore and then rapidly vary wind angle and distance. Good training for hunting!

 

[butchlambert]

Bryan Litz is the MAN!