Bullets Ricochet on Water!?

[EtherealN]

I'm not going to trawl through a bunch of hard-to-get journal papers to solve your problem for you. I have a job to do. :P

 

But since you were so sure of your observations in the simulator being of an error, perhaps you could do them? They would, after all, prove your point. Or, if you dig through those journal entries and give me the formulas, I could do it - but at that point you might as well do it yourself since you'll be sitting on the formulas anyhow. (But if you don't have the math skills to do it, sure, I can try if I get the time.)

[ff4life4]

...I see now there have been four other debates on this issue... But I can guarantee you that I, personally have witnessed for hours how some guys sitting in a small boat were fishing with an M16! I didn't witness not one single ricochet! The shooting angle was not > 30°. No need to mention that the velocity of an M16 bullet is a lot less than the caliber of any machine-gun used on planes. The ricochets I'm talking about are happening in DCS at an angle > 30°!

 

 

Lets see:

5.56mm XM193 Ball: 20" Barrel ~3165 fps

7.62x51MM M80: 24" Barrel ~2,799 fps

.50 Ball M2: ~2930 fps

 

EDIT: Also were you shooting tracers to see if you had a ricochet or not, bullets can be very difficult to spot, even if they are slow off a ricochet

[SkateZilla]

Edit: Im not getting into this discussion,

 

I've seen bullets ricochet off solid objects, water, and even denser air :p.

 

Just have to have a large enough difference in velocity resistance and within a certain angle/velocity/resistance/surface tension.

Edited July 30, 2013 by SkateZilla

[EtherealN]

Aye.

 

GAU-8 is somewhere around 3500 feet per second: but remember that this is muzzle velocity.

 

Sitting close to ground and shooting a rifle at the surface means the projectile will retain most of it's KE. An attack aircraft typically strafes from a mileor so away, meaning the projectiles will have bled a LOT of it's KE before striking.

 

Conclusion: the rounds of an attack aircraft most likely strike with less velocity than the M16 - and since velocity squares for energy, might have a LOT less energy to play with compared to other factors. (Yes, the rounds are bigger, but they also have a greater contact area.)

Edited July 30, 2013 by EtherealN
lol, typo

[BiBa]

I'm not going to trawl through a bunch of hard-to-get journal papers to solve your problem for you. I have a job to do. :P

 

But since you were so sure of your observations in the simulator being of an error, perhaps you could do them? They would, after all, prove your point. Or, if you dig through those journal entries and give me the formulas, I could do it - but at that point you might as well do it yourself since you'll be sitting on the formulas anyhow. (But if you don't have the math skills to do it, sure, I can try if I get the time.)

Ok I'll see what I can do... In the meanwhile out of that scientific brochure, let us temporarily agree on the following:

"the average limit of Bullets ricochet on water is <18° and NOT <30°, let alone form, velocity, mass and spinning effect". until the contrary is proven. My allegation of an error was in respect of ricochet taking place on high diving angle >30°. So I may have to revise my <10° for now as I took also into account the high velocities of all Guns I encountered in A-10C, P51D, Ka-50 etc. Also you're right about the velocity loss from far distances, let alone shot < or > gravity factor (Direction Up or Down)

Edited July 30, 2013 by Biba

[Phantom88]

Have you ever skipped a Rock on Water? Speed=Reflection.

[EtherealN]

let us temporarily agree on the following:

"the average limit of Bullets ricochet on water is <18° and NOT <30°, let alone form, velocity, mass and spinning effect". until the contrary is proven.

 

Sure, I'm game with that.

 

But given that waves can have considerable deflection from the mean surface, it does thus follow that you might be able to get ricochets even at >30. Can we agree on that too?

[ARM505]

Not only do they skip, they can skip more than once. I've personally observed the good 'ol Ma Deuce bounce them like crazy (ship mounted .50 cal), some of them skipping a couple of times into the distance (or at least until the tracer burned out). Obviously being ship mounted (and firing at floating barrels) you can get an idea of the rather flat angle they hit the water at.

[pyromaniac4002]

I, personally have witnessed for hours how some guys sitting in a small boat were fishing with an M16!... No need to mention that the velocity of an M16 bullet is a lot less than the caliber of any machine-gun used on planes.

 

...Which is another reason why a 30 mm round is more prone to ricochet off of water.

 

You know how they say jumping in to water from a bridge is basically equivalent to doing the same with a surface of concrete? Well the same idea applies.

 

Both the bullet and the water have their own inertia, and at the moment that they collide they exert equal and opposite forces on one another. Although the muzzle velocity of the NATO 30x173 mm out of a GAU-8 is only a couple hundred more feet per second than the 5.56x45 mm out of an M-16, the weight of the bullet (grain) means that the 30 mm is carrying kinetic energy that is at least an order of a magnitude greater than the 5.56 mm. That being the case, the 30 mm round is subjected to a great deal more force when it hits the water as compared to the 5.56 mm. That force is easily enough to alter the trajectory of the round enough to cause a ricochet.

[sobek]

That force is easily enough to alter the trajectory of the round enough to cause a ricochet.

 

But that force is speed and displacement dependant. The moment that the water surface normal speed component of the bullet reaches zero, the force should also reach zero. Of course that is an enormous simplification, as there are other force imbalances as long as the bullet is not symmetrically submerged in water (also it is spinning, which adds another source of complication).

 

I would actually be very surprised to see an analytic solution for this problem.

Edited July 30, 2013 by sobek

[BiBa]

Sure, I'm game with that... But given that waves can have considerable deflection from the mean surface, it does thus follow that you might be able to get ricochets even at >30. Can we agree on that too?

Bullet hitting the first wave on its slope side will definitely smoothen the angle of surface friction to a ricochet, altering an angle of 30° to <20°, depending on the wave height. Yet I'm not quite sure what happens after the first wave ricochet, because the encounter with the next subsequent wave would be on its ascending side, therefore should intercept its track rather to a halt than a second ricochet. However, I say this now with reservations. This needs definitely more physical elaboration.

 

If desired as agreed, the responsiveness of ricochet must be in DCS in this case dependent on weather. But that's not the case. The food of thought behind my thread in the first place was to spare the Graphic-card any redundant calculation that can be rather applied, there where badly needed...

[NineLine]

Yet I'm not quite sure what happens after the first wave ricochet, because the encounter with the next subsequent wave would be on its ascending side, therefore should intercept its track rather to a halt than a second ricochet.

 

How can you be sure it will hit the ascending side? Not all waves are the same size... neither is the spread of the bullets, etc...

[sobek]

If desired as agreed, the responsiveness of ricochet must be in DCS in this case dependent on weather.

 

Oh come on, it's not like we don't have enough people complaining about performance. What's next, you want real time bullet warping from contact with foliage? There's more pressing issues than to incorporate a physics model for something that is a) rather complex to calculate and b) has little impact on gameplay. It's all about scope. Your's has too much magnification.

Edited July 30, 2013 by sobek

[Double_D]

Its apple's and orange's..theory...who care's about bullet ricochet ...:doh:

 

Sobek is right..how far is too far on realizm..if you want real life senerio then " Join The Armed Forces of your country.." and get all the realizm there..

[BiBa]

How can you be sure it will hit the ascending side? Not all waves are the same size... neither is the spread of the bullets, etc...

I'm talking here about the track of one single Bullet. If its first contact is on the wave slope, the second ricochet would be on the next ascending wave. It's not easy sometimes with words to draw a clear picture. Therefore attached is a drawing

[NineLine]

Still doesnt make much sense, perhaps we need to discuss the randomness of snow flakes in DCS World now :)

 

I'm talking here about the track of one single Bullet. If its first contact is on the wave slope, the second ricochet would be on the next ascending wave. It's not easy sometimes with words to draw a clear picture. Therefore attached is a drawing

[BiBa]

Oh come on, it's not like we don't have enough people complaining about performance. What's next, you want real time bullet warping from contact with foliage? There's more pressing issues than to incorporate a physics model for something that is a) rather complex to calculate and b) has little impact on gameplay. It's all about scope. Your's has too much magnification.

You're twisting things upside down! You take one sentence out of the context and delete the core of the call, so again:

The food of thought behind my thread in the first place was to spare the Graphic-card any redundant calculation that can be rather applied, there where badly needed...

[BiBa]

Still doesnt make much sense, perhaps we need to discuss the randomness of snow flakes in DCS World now :)

My point of view in the whole debate was not to perfect the performance of ricochet, but rather to refrain on the use of superfluous effects, especially the one that breaches over the wedge of realism! The same attitude have I towards all kind of counterproductive nagging that turns academic disclosure down.

Edited August 11, 2013 by Biba

[Double_D]

Apples & Oranges...apples & oranges..hmmm what to choose..come on its a sim there will always be something not right..maybe in the near or far future you will get your perfection ricohet effect..but being this is a computer simulation there will be certain limitations...not only on coding but clients systems..time to move on..:doh:

 

Next you will want to talk about how the apple fell from the tree l..

 

My point of view in the whole debate was not to perfect the performance of ricochet, but rather to refrain on the use of superfluous effects, especially the one that breaches over the wedge of realism! The same attitude have I towards all kind of counterproductive nagging that turns academic disclosure into grousing whiner.

Edited July 30, 2013 by Double_D

[BiBa]

Apples & Oranges...apples & oranges..hmmm what to choose..Next you will want to talk about how the apple fell from the tree l..

...apples & oranges..hmmm...I see...I think somebody is suffering from an unbalanced diet. If Melons can fly, this place would be an Airport...

 

 

I pledge members who find this topic boring to spare us their sarcasm and go bashing their frustration elsewhere!

Edited July 31, 2013 by Biba

[Double_D]

...apples & oranges..hmmm...I see...I think somebody is suffering from an unbalanced diet. If Melons can fly, this place would be an Airport...

 

No you are now missing the point you are going on and on about a way too little detail that won't be changed in the sim and nobody really cares about that much....my diet is fine...and apples keeps the doctor away...:doh:

[Yo-Yo]

I must clear things up. Nobody will calculate ricochet for each bullet taking in account local surface normal vector then bullet deformation and reflection angle, etc, etc.

 

Probability, distribution and random are the keywords in this case.

 

Of course, having mirror-like water surface we never see ricochets will be at angles more than 12-14 degrees, for example.

If we presume that waves are present the probability distribution spread to the higher angles.

So, the ricochet density is lower at angles 20 and more deg but they are not impossible.

[Hellfire257]

I've seen bullets ricochet off solid objects, water, and even denser air :p.

 

Can you clarify the bolded part please? You've piqued my curiosity with that one.

[BiBa]

...I've seen bullets ricochet off solid objects, water, and even denser air...

Can you clarify the bold part please? You've piqued my curiosity with that one.

It also can even happen on thin air. It's about the proportion between volume, mass, speed and the transit between two different Air density. (Vacuum in this case) Take the Space Shuttle as an example: its like a huge bullet, which if its re-entering sequence in the atmosphere is at a too high angle, it can burn up. If it is too shallow, it will bounce back on the thin air toward space. This is called an outer space ricochet. The angle thematic is similar to the ricochet of a bullet on a water surface.

[IvanK]

Here is a document Done by the French Air force on Ricochet risks. This was done based on the Defa 30mm as fitted to the Mirage III includes both Terrain and water. Annotations and highlights are mine.

Defa 30mm Ricochets.pdf

Edited July 30, 2013 by IvanK