Gun closure effect

[[CPT]Crunch]

Anybody know if the closure speeds going head on are added to the guns effective hitting power? 

 

 

[Finkeren]

1 hour ago, [CPT]Crunch said:

Anybody know if the closure speeds going head on are added to the guns effective hitting power? 

 

I'm pretty sure it is. 

[Field-Ops]

I know the speed of the rounds themselves are influenced by the platform's (firing aircraft) speed but I'm not sure about the damage. I get the feeling that headons are more devastating in general than firing in a chase scenario. Also if tests are to be performed I think HE rounds would be less variable than AP rounds. 

[Finkeren]

2 hours ago, Field-Ops said:

I know the speed of the rounds themselves are influenced by the platform's (firing aircraft) speed but I'm not sure about the damage. I get the feeling that headons are more devastating in general than firing in a chase scenario. Also if tests are to be performed I think HE rounds would be less variable than AP rounds. 

 

TBH comparing head-on shots with chasing shots has so many other variables, that it's not really comparable. The main reason head-ons are devastating is, that you mainly present your cockpit and your engine block as a target, where with a chase shot, you mainly present your, mostly empty, rear fuselage.

 

AFAIK the relative velocity between the projectile and the target is used when calculating damage, so closing speed would affect the energy of the projectile. The thing is, that the energy of the projectile  doesn't really matter in many situations, especially when shooting at aircraft, because most non-explosive/AP rounds will just pass straight through. It only really matters in terms of penetration to defeat armor, and as such it does play a role for tank-busting aircraft like the IL-2 and the Ju 87G. The odd 3-400km/h is not suddenly gonna make your rounds penetrate Tiger front armor, but it can help a bit on the marginals.

[[DBS]Browning]

31 minutes ago, Finkeren said:

 the energy of the projectile  doesn't really matter in many situations

 

That's a long way from saying is is not relavent or important.

[Finkeren]

1 minute ago, [DBS]Browning said:

 

That's a long way from saying is is not relavent or important.

And I said no such thing. 

[AndyJWest]

Somewhere there was a thread discussing the advantage a rear-facing gunner might have in terms of projectile velocity by the time it reached a chasing enemy - with the bullet going 'downwind' it should lose less of its kinetic energy. I think someone made a crack at the maths, though it necessarily had to make approximations, and I'm not sure any real conclusion was drawn. Certainly it should be possible to base damage modelling on kinetic energy calculations, though as Finkeren says, there are so many variables that it would be hard to prove it was done. I think all we are likely to be able to conclude (short of seeing the code, which is unlikely) is that the DM isn't obviously wrong in this regard.

 

If anyone did want to test this, I suspect that the best test might be via firing a stationary gun at a stationary target at different ranges. If the decrease in velocity over distance is modelled properly, damage from an AP round should decrease with distance. Won't tell you if the speed of a moving aircraft is factored in when relevant, but will at least (if you can get any meaningful results) tell you whether the damage model is capable of responding to such factors in the first place.

[[PFR]Sarpalaxan]

1 hour ago, AndyJWest said:

Somewhere there was a thread discussing the advantage a rear-facing gunner might have in terms of projectile velocity by the time it reached a chasing enemy - with the bullet going 'downwind' it should lose less of its kinetic energy. I think someone made a crack at the maths, though it necessarily had to make approximations, and I'm not sure any real conclusion was drawn. Certainly it should be possible to base damage modelling on kinetic energy calculations, though as Finkeren says, there are so many variables that it would be hard to prove it was done. I think all we are likely to be able to conclude (short of seeing the code, which is unlikely) is that the DM isn't obviously wrong in this regard.

 

If anyone did want to test this, I suspect that the best test might be via firing a stationary gun at a stationary target at different ranges. If the decrease in velocity over distance is modelled properly, damage from an AP round should decrease with distance. Won't tell you if the speed of a moving aircraft is factored in when relevant, but will at least (if you can get any meaningful results) tell you whether the damage model is capable of responding to such factors in the first place.

Yes, I Remember doing this. I think in the end I was lacking ballistic data of WW2 rounds. As for the head on comparison. There surely should be a difference between bullet's hitting with somewhere around muzzle velocity to bullets hitting with the added sum of the tas of both planes, but there is also the added benefit of hitting directly the Engine or cockpit without having to penetrate the whole rear of the Plane. Testing if there is any drag modelled should be relatively easy. Take an Airfield that has a known length, position a P-39 or me-262 on one end with a convergence = Length of airfield and a Target on the other end. Shoot at it and measure the time to impact. (Probably best done in Slow-motion). If the time is slower than what would be expected if the bullet travelled at muzzle velocity the whole time, there must be at least some factor of drag. Proving the damage values could prove much harder since the targets need to move at a much faster pace to show any measurable difference.

[[CPT]Crunch]

I'm kind of wondering if another object with closure speed has it's velocity figured into the equation.  I can see how your own velocity is quite easy to calculate into the gun equation, but how would the game understand your shooting at another specific entity and take into account it's angle and closure speed and insert that into the gunnery solution?  Seems pretty complex in certain circumstance. 

[AndyJWest]

2 minutes ago, [CPT]Crunch said:

I'm kind of wondering if another object with closure speed has it's velocity figured into the equation.  I can see how your own velocity is quite easy to calculate into the gun equation, but how would the game understand your shooting at another specific entity and take into account it's angle and closure speed and insert that into the gunnery solution?  Seems pretty complex in certain circumstance. 

 

The game doesn't need to understand what you are shooting at. All it needs to calculate is the relative velocities of objects that collide, which is simple vector maths. The difficult bit is deciding how you are going to use this information in a damage model which needs to be simple enough to give quick results, while also being reasonably realistic.