Is bullet drag calcualted in game?

[SmokinLoon]

Thanks Lusche. Have you done the calculations on MG damage/distance? I have been wondering about it for a long time with respect to the other (potential) advantage of cannons which is most of the damge is done by the explosion so they lose less of their damage effect over distance than MG do.  Let's say at 100 ft it takes one 30mm, or 20 .50 cals to knock a wing off, at 1500yrds it still takes one 30mm but 40 .50cals.   

Ever looked at it?

The controls in that kind of test would be very difficult to maintain.  It almost isn't really worth testing because of the infinite amount of variables in the field that are present when considering the damage dealt to a player controlled object.  Vs a static OBJ (town building, ammo bunker, fuel tank, barrack, etc) it is easy and that testing has proven that there is no difference in damage dealt be it 200 yards or 1000 yards.  That is something I've directly tested using both AP and HE rounds.

 

[bustr]

Velocity at 1800ft(600yds) drops to about 1915 ft\sec for the 50cal.

For all practicle concerns, the AAF determined that the fighter mounted version of the 50cal had an effecitve range to damage other aircraft and to still hold a practicle dispersion pattern was 2000ft(666yds). Ever wondered why the max convergence for fighters in the hanger is 650yds? Except for the Mk108, your dispersion patterning in all fighters is a 4Mil cone at all convergence distances 30cal, 50cal, 20mm.

4Mil @ 900ft  (300yds) = 3-4ft
4Mil @ 2000ft(666yds) = 8-10ft

Now bounce this cone around by fractions of a degree shooting at a 666yd target and you get rounds everywhere. At 300yards half of everywhere. And so forth closer. Dispersion is your real issue trying to hit anything with 30 - 20mm past 400yds. The 50cal MG type with the longer barrel in the M16 would hold it's velocity enough to be effective at 1200yds if you can hit anything moving with the dispersion. Probably why 4 were ganged close together.

[Vinkman]

Velocity at 1800ft(600yds) drops to about 1915 ft\sec for the 50cal.

For all practicle concerns, the AAF determined that the fighter mounted version of the 50cal had an effecitve range to damage other aircraft and to still hold a practicle dispersion pattern was 2000ft(666yds). Ever wondered why the max convergence for fighters in the hanger is 650yds? Except for the Mk108, your dispersion patterning in all fighters is a 4Mil cone at all convergence distances 30cal, 50cal, 20mm.

4Mil @ 900ft  (300yds) = 3-4ft
4Mil @ 2000ft(666yds) = 8-10ft

Now bounce this cone around by fractions of a degree shooting at a 666yd target and you get rounds everywhere. At 300yards half of everywhere. And so forth closer. Dispersion is your real issue trying to hit anything with 30 - 20mm past 400yds. The 50cal MG type with the longer barrel in the M16 would hold it's velocity enough to be effective at 1200yds if you can hit anything moving with the dispersion. Probably why 4 were ganged close together.

Good info Buster. This thought was raised from another thread talking about the P-38 gun pack, and that it was great for killing buffs. Killing buffs is tough inside 1000 yrds because they kill you first. (just talking dead 6. I know.."never attack dead 6...blah...blah) But I wondered if a P-38 could hang back at 800-1000 and light up a wing tank without getting too shot up. All the guns in the nose would be an advantage because the dispersion is very low. But then I thought "maybe the rounds hit like duds at 1000 yrds so you can't take advantage of the guns being "clustered". 

I've killed a lot of Buffs in a 410 with the 50mm by hanging back at 1500 yrds. The 50mm can reach them and still kill a buff with 1 hit. Again its the HE that kills the buff not the KE of the round. But 410 are SLOWWWWWWWWWWW and handle poorly. IT's not easy to catch 25-30k Bombers in it, and if fighter shows up you toast.

The 38 has great fire power, but I think it may drop significantly with distance. I want to calculate the KE difference but need to calculate the speed over the distance traveled to solve it. With your data and solve for the drag by comparing it to a no drag formula. With the coeficients and drag term solved for, I can calulate it at any distance after firing, then I can campare the KE at various differences.

[Changeup]

The controls in that kind of test would be very difficult to maintain.  It almost isn't really worth testing because of the infinite amount of variables in the field that are present when considering the damage dealt to a player controlled object.  Vs a static OBJ (town building, ammo bunker, fuel tank, barrack, etc) it is easy and that testing has proven that there is no difference in damage dealt be it 200 yards or 1000 yards.  That is something I've directly tested using both AP and HE rounds.

 

Isn't the "hit" model in AH by area of the plane?

[hitech]

Damage to ground targets and player controlled objects are 2 different systems.

For player controlled objects.
1. Drag is completely modeled , including altitude effects.  A simple test shooting different directions from bombers will show this statement to be true.
2. Damage is modeled on a per round type.Both it's speed and explosive components can be modeled independently on a per bullet type basis.

3. Damage to ground structures are  a very simple damage model Ordnance does type x does y based on 3 x values. There are basically 3 types of ground object soft, hard and armored.
    Each ordnance has 3 damage values based on if it is hitting a soft, hard or armored structure.
    The ordnance also do blast radius damage to near by structures based on the distance to the object.

HiTech

[Vinkman]

Damage to ground targets and player controlled objects are 2 different systems.

For player controlled objects.
1. Drag is completely modeled , including altitude effects.  A simple test shooting different directions from bombers will show this statement to be true.
2. Damage is modeled on a per round type.Both it's speed and explosive components can be modeled independently on a per bullet type basis.

3. Damage to ground structures are  a very simple damage model Ordnance does type x does y based on 3 x values. There are basically 3 types of ground object soft, hard and armored.
    Each ordnance has 3 damage values based on if it is hitting a soft, hard or armored structure.
    The ordnance also do blast radius damage to near by structures based on the distance to the object.

HiTech

thanks HiTech 

[Vinkman]

.50 cals lose 25% of their Kenetic engery at 400 yards, and 70% of their kenetic engery at 1000yrds. So at 1000yrds you have to hit with about twuce as many bullets as you do at 400yrds to do the same damage. That's a big difference.


Cannon engery loss would be less because the HE portion does not decrease with distance travelled.

[Karnak]

.50s fired from the tail gun of a bomber keep their energy better than the .50s fired from the pursuing P-51D.  At the muzzle the bullets from the bomber's tail guns are going about 700mph slower and that means less E loss due to drag, plus the P-51 is running into the bomber's bullets whereas the bomber is running away from the P-51's bullets.

[Vinkman]

.50s fired from the tail gun of a bomber keep their energy better than the .50s fired from the pursuing P-51D.  At the muzzle the bullets from the bomber's tail guns are going about 700mph slower and that means less E loss due to drag, plus the P-51 is running into the bomber's bullets whereas the bomber is running away from the P-51's bullets.

They kept their energy better? 

They start with less energy because they leave the gun 300mph slower, relative to the air. So they have less energy and travel less distance, relative to the point they were fired from.  A persuing plane is running at the bullet at 300+ mph, so it will meet the bullet at the shorter distance, and it's forward velocity will add to the energy of the impact. I belive it's the same as if they are both stationary.

[Agent360]

Regarding the last two posts above this one involving the speed of the aircraft and its effect on the bullets.

The velocity on Bustrs chart >> 50cal = 2870 fps

The chart doesn't give a bullet weight but a quick search revealed ww2 50 cal ball ammo at 46 grams or converted to grains at 709

Using the standard formula for calculating foot pounds of energy we get the following

Bullet velocity 2870 at 709 grains =12964.72 ft-lbs

Bullet velocity 2870 plus speed of aircraft at 300 mph(440 fps)...actual bullet velocity of 3310 and a 709 grain bullet = 17244.69 ft-lbs

That is a difference of 4279.97 ft-lbs or about 25% more.

Of course this is assuming a situation where the bullet is fired strait with no g effects.

A bomber shooting a tail gun moving at 300 mph will have its bullet ft-lbs reduced by 25 %.

Gravity is already calculated in ft-lbs calculations. If you add in g forces or angle of attack...say the gun is pointed 45 deg of the tail of the bomber then the calculations will change.

If two planes fly directly at each other at the same speed firing the same gun and bullets then the ft-lbs will be the same for each plane. If one is flying slower than the other then the ft-lbs will change for each plane accordingly.

I submit that given average speeds of aircraft in the game and guessing at a closure speed depending on the angle of attack that the difference in ft-lbs one is gaining or loosing based on closure speed of BOTH aircraft that the effect of damage is less than 10 %. Then add in drop in velocity over distance and the ft-lbs becomes almost irrelevant in the damage model.

In the end one is only getting 1 to 3 % of additional or loss of ft-lbs of additional damage possibility....not very much and probably not worth considering.

But then one begins to think about it.....get going 500 mph in a dive on buffs at a 30 deg deflection angle head on....and add in the speed of the buff and the ft-lbs of your bullets start to look pretty good for getting the best bang for your buck.

Turn that around and start shooting at a plane accelerating away from you by 100 mph and distance is far the same goes...you aint damaging jack...LOL

just a thought.

[Karnak]

They kept their energy better? 

They start with less energy because they leave the gun 300mph slower, relative to the air. So they have less energy and travel less distance, relative to the point they were fired from.  A persuing plane is running at the bullet at 300+ mph, so it will meet the bullet at the shorter distance, and it's forward velocity will add to the energy of the impact. I belive it's the same as if they are both stationary.

Drag increases as speed increases.  Therefore, relatively, the rounds fired from the tail gun lose the energy they start with at a slower rate than the rounds fired from the perusing P-51.

[Agent360]

Drag increases as speed increases.  Therefore, relatively, the rounds fired from the tail gun lose the energy they start with at a slower rate than the rounds fired from the perusing P-51.

The tail gun bullets start with a negative value of velocity....less the fps the buff is flying. The p51 starts with a positive value.

Drag doesn't matter. It is just a constant used to calculate velocity...like gravity is a constant. Yes, drag is a coefficient of speed but drag is factored in to a bullets stated velocity. Drag is more of an aeronautical issue. Drag in bullets is not worth considering when calculating kinetic energy because it has already been considered based in the bullet design, its weight and powder load.

[Karnak]

The tail gun bullets start with a negative value of velocity....less the fps the buff is flying. The p51 starts with a positive value.

Drag doesn't matter. It is just a constant used to calculate velocity...like gravity is a constant. Yes, drag is a coefficient of speed but drag is factored in to a bullets stated velocity. Drag is more of an aeronautical issue. Drag in bullets is not worth considering when calculating kinetic energy because it has already been considered based in the bullet design, its weight and powder load.

If the two were shooting at a stationary target, yes.  But in the case where they are shooting at each other, no.  The P-51s bullets will lose more energy by the time they hit the B-17 than the B-17's bullets will lose by the time they hit the P-51.  In this scenario each bullet hitting the P-51 has more energy than each bullet hitting the B-17.

[hitech]

The tail gun bullets start with a negative value of velocity....less the fps the buff is flying. The p51 starts with a positive value.

Drag doesn't matter. It is just a constant used to calculate velocity...like gravity is a constant. Yes, drag is a coefficient of speed but drag is factored in to a bullets stated velocity. Drag is more of an aeronautical issue. Drag in bullets is not worth considering when calculating kinetic energy because it has already been considered based in the bullet design, its weight and powder load.

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

[Agent360]

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

When the b17 drops the rock its going the speed of the b17 to start with. Factor the speed, mass, gravity and air density and we can calculate ft-lbs for the rock. Obviously the ft-lbs of the rock will decrease as speed decreases relative to the target. Nothing else is changing. Only the speed of the rock.

Calculate the speed of the P51 and add that to the rocks speed then we can calculate the ft-lbs of the rock when it hits the P51.

In your case the rock starts of with 0 speed....so it must be falling due to gravity at a speed up to terminal velocity. The P51 must be moving at some amount of speed to hit the rock.

I don't see how drag is a factor here. Given an objects velocity, drag should have been already factored into the velocity to start with....as far as bullets go anyway.

Drag is a by product of atmosphere. In a vacume drag is not a factor.

My point is that when calculating ft-lbs(kinetic energy) of a bullet, drag is already included when the bullet velocity is calculated.

I may be totally misunderstanding your post though.