Is bullet drag calcualted in game?

[guncrasher]

Think of the 0 speed  case,The b17 drops a rock , the 51 will run into it, the 51 drops a rock, there is no way the b17 will ever run into the rock.  The drag is what makes the rock from the b17 hit the 51.

The same condition exist when the bullet is moving.

HiTech

you talking about a regular rock or skyrock?  cause I swear he never misses my b17's no matter what the  speed is.


semp

[hitech]

Agent:
Let b = muzzle vel of bullet.
Let A = speed of plane.
Assume tail chase with both b17 and p51 travelling same speed.


let v1 = airspeed of b17 bullet
let v2   airspeed  of p51 bullet


V1 =  b - a
v2 =  b  + a

now the key to this is that drag is related to the square of vel.

Sinc V2 > V1 V2 will decelerate at a faster rate.

So after 1 sec of travel the delta of V2 will be greater then the delta of v1

Hence the builet from the b17 will travel a greater distance and retain a higher vel relative to the airplanes then the bullet from the p51.


HiTech

[Changeup]

Agent:
Let b = muzzle vel of bullet.
Let A = speed of plane.
Assume tail chase with both b17 and p51 travelling same speed.


let v1 = airspeed of b17 bullet
let v2   airspeed  of p51 bullet


V1 =  b - a
v2 =  b  + a

now the key to this is that drag is related to the square of vel.

Sinc V2 > V1 V2 will decelerate at a faster rate.

So after 1 sec of travel the delta of V2 will be greater then the delta of v1

Hence the builet from the b17 will travel a greater distance and retain a higher vel relative to the airplanes then the bullet from the p51.


HiTech

Pffft....I knew that....Geezus Agent.  Dumbazz

[Agent360]

Agent:
Let b = muzzle vel of bullet.
Let A = speed of plane.
Assume tail chase with both b17 and p51 travelling same speed.


let v1 = airspeed of b17 bullet
let v2   airspeed  of p51 bullet


V1 =  b - a
v2 =  b  + a

now the key to this is that drag is related to the square of vel.

Sinc V2 > V1 V2 will decelerate at a faster rate.

So after 1 sec of travel the delta of V2 will be greater then the delta of v1

Hence the builet from the b17 will travel a greater distance and retain a higher vel relative to the airplanes then the bullet from the p51.


HiTech

It seems like we are looking at this problem from opposite sides of the equal sign...LOL

According to Newton:
"Every body persists in its state of rest or of uniform motion in a straight line unless it is compelled to change that state by forces impressed on it."

I agree that drag is a factor. The issue is how much drag effects the bullet due to the speed of the airplane and how much this drag effects kinetic energy at the point of impact relative to the distance the bullet travels.

I submit that the degree of kinetic energy changed by drag is "insignificant" in terms of the damage model in this game...and in real life for that matter.

The fact that AH2 models this is awesome. It goes to show that this game is a notch above anything out there....hehe actually there's not really anything competing with AH2 but that's another issue.

In the formula you post I agree.

My case on the issue is that given actual closing speeds the factor of drag can almost be ignored.

Consider this:

I tried to write this in the form of a brain teaser.

There are two planes flying at the same altitude. Plane 1 is moving at 200 mph ( a little over cruising speed of B17). Plane 2 is following Plane 1 and is moving at 400 mph (reasonable attack speed in a p51)

Plane one is firing a gun from its tail exactly 180 deg from its heading of 0 deg. Plane two is flying a heading of 0 degrees and is on the same axis and heading as Plane 1. Both Planes are flying level.

Plane 1 and Plane 2 are firing a 50 cal bullet with a 709 grain weight and a power load which results in a bullet velocity of 2870 fps at the muzzle.

Both planes begin firing at each other at the exact same time with the exact same fire rate at a distance of 400 yards at the speeds stated above.

Assume any gravity value and any air density value as long as both are used for both Plane 1 and Plane 2

What will be the ft-lbs (kinetic energy) of the first bullet fired from Plane 1 when it hits Plane 2?
What will be the ft-lbs (kinetic energy) of the first bullet fired from Plane 2 when it his Plane 1?

Free beer to the first one to solve.

Bonus question:

Which bullet has more drag. Plane 1 or Plane 2?

We could re write this and say that both planes are moving at the same airspeed. In that case I do agree with you...in the fact that drag is effecting the bullet.

But, show me how drag effects kinetic energy and by how much? That is the question I've been seeking all along.

[Karnak]

Agent,

For AH bump the B-17's speed up to about 300mph and the range up to about 1000 yards.  The difference becomes significant at that point.

[hitech]

Agent : It is impossible to answer your question with out providing a bullet co. The drag is not an insignificant piece of the equation.

HiTech

[Agent360]

Agent : It is impossible to answer your question with out providing a bullet co. The drag is not an insignificant piece of the equation.

HiTech

Just for kicks say the bullet co is 0.61 (G1) ....just in case anyone wanted to actually solve.

About your formula example a few posts above.

Ok. So velocity is squared in the equations. So drag does increase with velocity. No issues there.

bullet A = 2000 fps
bullet B = 3000 fps

How is it possible for bullet B to have less kinetic energy than bullet A at any time during its trajectory?

It does not matter that it was fired from in front of or from behind a plane. We just have to correct the bullet velocity based on the speed of the plane.

I understand that the faster something goes the more drag it has and like wise the slower the less...hence a "trajectory"

If two shooters point at each other and fire the same bullet but one is firing at 2000 fps and the other at 3000 fps. How is it that the faster bullet ends up having less kinetic energy at the point of impact? (Remember you said that both planes were moving at the same speed)


PS - I know you don't have time to give a math education and that I am probably wrong and that I am currently the definition of your sig...LOL but I enjoy recreational mathematics and find this topic interesting. I may be more suited to dabble in something more elementary but I am enjoying this none the less

[kvuo75]

Just for kicks say the bullet co is 0.61 (G1) ....just in case anyone wanted to actually solve.

About your formula example a few posts above.

Ok. So velocity is squared in the equations. So drag does increase with velocity. No issues there.

bullet A = 2000 fps
bullet B = 3000 fps

How is it possible for bullet B to have less kinetic energy than bullet A at any time during its trajectory?

It does not matter that it was fired from in front of or from behind a plane. We just have to correct the bullet velocity based on the speed of the plane.

I understand that the faster something goes the more drag it has and like wise the slower the less...hence a "trajectory"

If two shooters point at each other and fire the same bullet but one is firing at 2000 fps and the other at 3000 fps. How is it that the faster bullet ends up having less kinetic energy at the point of impact? (Remember you said that both planes were moving at the same speed)


PS - I know you don't have time to give a math education and that I am probably wrong and that I am currently the definition of your sig...LOL but I enjoy recreational mathematics and find this topic interesting. I may be more suited to dabble in something more elementary but I am enjoying this none the less

kinetic energy needs a frame of reference

[hitech]

kinetic energy needs a frame of reference

Agent. What this means is the energy relative to the ground, the plane shooting the projectile, or the plane the projectile will hit. The faster projectile will have more energy if it hit a stationary target. But when hitting a target coming towards it, and another away from it, the one hitting the target from the front will have more total energy. And the one chasing the plane will have less.

HiTech

[Karnak]

Agent. What this means is the energy relative to the ground, the plane shooting the projectile, or the plane the projectile will hit. The faster projectile will have more energy if it hit a stationary target. But when hitting a target coming towards it, and another away from it, the one hitting the target from the front will have more total energy. And the one chasing the plane will have less.

HiTech

And the projectile hitting the target coming towards it will, functionally, have greater effective range due to the distance being closed and lower parasitic drag because of its lower velocity compared to the atmosphere it is traveling through.

If the B-17 fires at the 400mph P-51 at 1000 yards, the P-51 will move 586ft per second closer to the point from which the .50 was fired while the 300mph B-17 will move 440 feet per second further from the point at which the .50 was fired.  In addition the higher parasitic drag on the .50 fired by the P-51 means that it loses velocity in relation to the B-17 faster than the .50 fired by the B-17 loses it in relation to the P-51.  Additionally the B-17's 300mph retreat from the P-51's .50 slightly reduces the energy transfer of the hit while the P-51's 400mph rush to meet the B-17's .50 somewhat increases the energy transfer of the hit.