P-38 Convergence

[StokesAk]

They are hipanios, wont they have just about the same trejectory as a .50?

[Cajunn]

They are hipanios, wont they have just about the same trejectory as a .50?

Hispanos or closer in ballistics  to the .50 cals compared to the other 20mm in the game but there is still a difference and there should be its a heavier round its like comparing a 22/250 cal. to something like a 308 cal. ballistics or close but not the same

[StokesAk]

Ok, thank you.

[mtnman]

If your going in a nice straight and level line it would all work out perfectly but if your pulling back on the stick even slightly then everything changes. In the real world I'm sure there is an exact science to this but this is HTC's world. All 50's don't shoot the same here and is dependent on how HTC see's fit to model the planes for use here.

Which is why I mentioned that if you were firing at anything other than 1G your results would be skewed...

And I highly doubt that HTC has changed anything with the P51 or F4U guns.  I believe the flight model for the individual planes is probably not tied directly to the ballistics model.  I could be wrong, maybe HTC will let us know.

The common "slang" we use is that cannon rounds drop faster than MG rounds.  In reality, they probably drop at nearly the exact same rate per second.  If you took a cannon projectile, and a MG projectile (minus the case) and dropped them at the same time from the same height, they'd likely hit the ground at almost the same time.  Density differences and surface area may cause them to be not quite identical, but still they'd be so close that it would surprise you.  One may fall slightly faster, but not much.

So they fall at about the same rate. 

The thing that makes the cannons appear to fall faster is the time it takes them to reach the target.  It takes them longer, so they fall further, but not faster... 

I'd actually expect that the larger size and lesser density of the cannon projectiles would make them fall slightly slower than the MG rounds.  Something tells me whatever the cannon rounds are filled with to make them go "pop" is less dense than the lead MG round.  The denser MG round would fall faster unless the cannon round had less surface drag.

For ease of math, lets say they fall at the same rate,  10 feet per second (not realistic, but easy math...).  Again for ease of math, lets say the MG round flies 2x as fast as the cannon round (again, not realistic, but easy).  We fire them at a target 200 yds out.  At the instant the MG round hits the target, the cannon round is 1/2 way to the target.  Both rounds have fallen the same distance at this point (let's say 1 foot).  The MG round is done, there's a hole in the target.  The cannon round still needs to continue the flight, and is still falling.  When it gets to the target, it's 2 feet low.  Not because it fell faster, but because it took 2x as long to get to the target.  It fell twice as far, but not twice as fast.  See what I mean?  Time is the important factor.

I see the opposite effect with my muzzleloading rifle when I fire the heavier projectiles vs the lighter round balls.  The round balls hit LOWER than the heavier bullets at the same range.  How can that be???  It's time again...

The lighter ball (235 gr) starts out at a faster speed, but slows down quickly, losing almost 1/2 of its velocity at 100 yds.  The heavier bullet (400gr) starts a bit slower, but retains its speed much better (more mass, but equal frontal area).  Although it starts slower, it ends its journey with a higher velocity, and an overall lesser TIME.  Because it gets to the target quicker, it falls less, even though it and the ball fall at nearly the same rate, vertically, per second...

Confusing?  Maybe...  But also pretty neat!

[Hazard69]

In my limited experience with convergence (and this is with the P38's ofcourse) all the rounds (mg and cannons) hit bullseye at convergence distance (Tested with .target offline).

The cannons fly a greater arc (due to all the excellent reasoning explained earlier by those in the know) and so will deviate more if fired not at convergence distance.
What prompted me to bring my convergence down from 650 to 450 was the fact that in a dead six, one g shot, my cannon rounds wouldn't land on targets 200 yards ahead of me. They were flying over the target of course, and I was experiencing reduced lethality (after all that work getting the target slowed  )

Another factor would be g forces being pulled at the time of shooting. Higher Gs = more deviation in trajectories between the 0.50s and the 20mm (due to increased mass and slower velocity perhaps?).

I think, since only a small % of your shots will be taken at just 1g (unless you're one of those pros and manage to unload before every shot ), most people set the 20mm a little further out, to sort of compensate for this increased drop, without altering its low G trajectory too much.

Thats just my $0.02.

[Hazard69]

In my limited experience with convergence (and this is with the P38's ofcourse) all the rounds (mg and cannons) hit bullseye at convergence distance (Tested with .target offline).

The cannons fly a greater arc (due to all the excellent reasoning explained earlier by those in the know) and so will deviate more if fired not at convergence distance.
What prompted me to bring my convergence down from 650 to 450 was the fact that in a dead six, one g shot, my cannon rounds wouldn't land on targets 200 yards ahead of me. They were flying over the target of course, and I was experiencing reduced lethality (after all that work getting the target slowed  )

Another factor would be g forces being pulled at the time of shooting. Higher Gs = more deviation in trajectories between the 0.50s and the 20mm (due to increased mass and slower velocity perhaps?).

I think, since only a small % of your shots will be taken at just 1g (unless you're one of those pros and manage to unload before every shot ), most people set the 20mm a little further out, to sort of compensate for this increased drop, without altering its low G trajectory too much.

Thats just my $0.02.