kallend 2,146 #1 January 28, 2004 During the Battle of the Falkland Islands in WWI en.wikipedia.org/wiki/Battle_of_the_Falkland_Islands the British naval force engaged the German ships at a range of about 10 miles. They wasted about 1000 shells before they figured out why they were consistently missing the targets by about 100 yards despite having guns that were accurately sighted. They then scored 60 direct hits, effectively destroying the German forces. What was the cause of the error?... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
lawrocket 3 #2 January 28, 2004 Curvature of the earth??? My wife is hotter than your wife. Quote Share this post Link to post Share on other sites
quade 4 #3 January 28, 2004 Man, I think this one is all too easy. They were in the southern hemishpere and had not corrected their guns for the Coriolis effect and how it works in the opposite direction than the northern hemisphere. (According to Winsor, I know less than nothing about guns.)quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
n2skdvn 0 #4 January 28, 2004 miscalculated the amount of powder needed?if my calculations are correct SLINKY + ESCULATOR = EVERLASTING FUN my site Quote Share this post Link to post Share on other sites
skydyvr 0 #5 January 28, 2004 Yep, the Coriolis Effect. The coolest thing about teachers -- they tend to use the same examples over and over again, so I recognized this from Physics 101 (w/cal) immediately. . . =(_8^(1) Quote Share this post Link to post Share on other sites
downwardspiral 0 #6 January 28, 2004 QuoteMan, I think this one is all too easy. They were in the southern hemishpere and had not corrected their guns for the Coriolis effect and how it works in the opposite direction than the northern hemisphere. (According to Winsor, I know less than nothing about guns.) Oh yeah? Bet you don't know how to adjust an SKS for the Coriolis effect.www.FourWheelerHB.com Quote Share this post Link to post Share on other sites
pilotdave 0 #7 January 28, 2004 I thought this was gonna be the "shooting the monkey out of the tree" problem. Dave Quote Share this post Link to post Share on other sites
kallend 2,146 #8 January 28, 2004 QuoteMan, I think this one is all too easy. They were in the southern hemishpere and had not corrected their guns for the Coriolis effect and how it works in the opposite direction than the northern hemisphere. (According to Winsor, I know less than nothing about guns.) Very good! You get a ... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 2,146 #9 January 28, 2004 Since that one was too easy (Hey Quade, explain how to calculate the Coriolis effect for us) try this one: Why do bullets fired from rifles that give counterclockwise spin (seen from rear) tend to drift left, while if fired with clockwise spin they tend to drift right?... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
Kennedy 0 #10 January 28, 2004 QuoteWhy do bullets fired from rifles that give counterclockwise spin (seen from rear) tend to drift left, while if fired with clockwise spin they tend to drift right? Same reason props tend to pull an aircraft to the right or left as the accelerate for take off. Same reason a curve ball curves and a floater "floats" [sink less quickly].witty subliminal message Guard your honor, let your reputation fall where it will, and outlast the bastards. 1* Quote Share this post Link to post Share on other sites
skydyvr 0 #11 January 28, 2004 CF differntial induced by gravity pulls the bullet over? . . =(_8^(1) Quote Share this post Link to post Share on other sites
quade 4 #12 January 28, 2004 Quote (Hey Quade, explain how to calculate the Coriolis effect for us) In a nut shell? It's just inertia. You want a procedure to calculate it? For northern hemisphere (speed of rotation of planet at launch latitude - speed of rotation of planet at target latitude) X calculated time aloft = distance If positive correct to the west, if negative correct to the east. Should be close enough for jazz.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
kallend 2,146 #13 January 28, 2004 QuoteQuoteWhy do bullets fired from rifles that give counterclockwise spin (seen from rear) tend to drift left, while if fired with clockwise spin they tend to drift right? Same reason props tend to pull an aircraft to the right or left as the accelerate for take off. Quote Yes (in essence). There is a gyroscopic precession that forces the nose of the bullet or shell to the left (or right), causing a drift in that direction. Propellors also have an effect called "P-factor" which has to do with the relative pitch of the blades to the airflow, which does not apply to the bullet. P-factor and gyroscopic effects act in the same direction for props, so the total effect is quite large. Same reason a curve ball curves and a floater "floats" [sink less quickly]. That is "Magnus effect", and doesn't apply in this case, rotation is about a different axis.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
freeflir29 0 #14 January 28, 2004 QuoteBet you don't know how to adjust an SKS for the Coriolis effect. "Kentucky Windage?" Quote Share this post Link to post Share on other sites
rehmwa 2 #15 January 28, 2004 Thinking in terms of pressure - clockwise = more pressure on the left side of the bullet pushes it right. Using the spin of a golfball for hooks and slices ass an analogy, it's simple, but the bullet is spinning on a different axis..... In any case, then the analogy would assume the bullet is "rising" relative to it's spin axis for some reason. i.e., it flies in a nose down attitude to the relative wind..... But I don't know if that last part is true or not - does a spinning bullet have negative pitch? ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
damion75 0 #16 January 28, 2004 QuoteQuoteQuoteWhy do bullets fired from rifles that give counterclockwise spin (seen from rear) tend to drift left, while if fired with clockwise spin they tend to drift right? Same reason props tend to pull an aircraft to the right or left as the accelerate for take off. Quote Yes (in essence). There is a gyroscopic precession that forces the nose of the bullet or shell to the left (or right), causing a drift in that direction. Propellors also have an effect called "P-factor" which has to do with the relative pitch of the blades to the airflow, which does not apply to the bullet. P-factor and gyroscopic effects act in the same direction for props, so the total effect is quite large. Same reason a curve ball curves and a floater "floats" [sink less quickly]. That is "Magnus effect", and doesn't apply in this case, rotation is about a different axis. In case I can help with this one - it is to do with the spin of the shell in the tube, nothing to do with the spinning of the earth!! We compensate for this using firing tables calculated by very clever and boring guys in the artillery world firing over 25km... for rifles over 300/400m it really doesnt matter... As for the first question, I would be very surprised if it was anything to do with the Corialus effect which does not usually affect anything smaller than cloud formations (and no - according to the scholars of oxford it does not affect the way a sink drains!) As an instructor at the UK school of artillery I have covered all this in some depth!*************** Not one shred of evidence supports the theory that life is serious - look at the platypus. Quote Share this post Link to post Share on other sites
kallend 2,146 #17 January 28, 2004 Quote In case I can help with this one - it is to do with the spin of the shell in the tube, nothing to do with the spinning of the earth!! We compensate for this using firing tables calculated by very clever and boring guys in the artillery world firing over 25km... for rifles over 300/400m it really doesnt matter... As for the first question, I would be very surprised if it was anything to do with the Corialus effect which does not usually affect anything smaller than cloud formations (and no - according to the scholars of oxford it does not affect the way a sink drains!) As an instructor at the UK school of artillery I have covered all this in some depth! It does have an effect on artillery - easily calculated, even Quade can do it.. For "Big Bertha" in WWI the Coriolis effect shifted the aiming point about a mile, in accordance with the calculation (at the latitudes in question, Paris is moving about 7mph slower than the Belgian border where the gun was fired. The shell's flight time was around 10 minutes, so Paris moved about a mile relative to the gun during the shell's flight). And there was a Coriolis problem at the Battle of the Falkland Islands in 1914. According to NASA "The effects of the Coriolis Force must be considered for things that move relative to the Earth, especially at the higher latitudes of both hemispheres. For example, in World War I, during a naval battle near the Falkland Islands (off the east coast of South America, about 52 degrees south latitude) between the German and British Navy, British gunners were surprised to see their salvos falling 100 yards to the left of the German ships. The engineers who designed the sighting mechanisms were well aware of the Coriolis deflection and had carefully considered it, however, they neglected the fact that not all sea battles occur in the Northern Hemisphere. Thus, during the engagement, the initial British shots fell at a distance from the targets equal to twice the Coriolis deflection."... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites