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View Full Version : Hepl Wanted on P47 Convergence Experiment ( You out there Gibbage?)



Blutarski2004
07-18-2007, 10:51 AM
Could someone with some extra time on their hands try the following gun convergence experiment with a P47 -

Set inside guns at 200 meters convergence and outside gun at 400 meters convergence.

Conduct target shoots at 150, 200, 250, 300, 350 meters and 400 meters, 10 seconds of fire from all guns at each range (using unlimited ammo option).

Capture gun pattern images and post.


I'm trying to find a way to make a decent P47 pattern harmonization (or somethingresembling it) within the confines of the IL2 convergence method. I'm especially interested in seeing how the two lines of fire relate with each other and the pilot sight line


Thank you.

Blutarski2004
07-18-2007, 10:51 AM
Could someone with some extra time on their hands try the following gun convergence experiment with a P47 -

Set inside guns at 200 meters convergence and outside gun at 400 meters convergence.

Conduct target shoots at 150, 200, 250, 300, 350 meters and 400 meters, 10 seconds of fire from all guns at each range (using unlimited ammo option).

Capture gun pattern images and post.


I'm trying to find a way to make a decent P47 pattern harmonization (or somethingresembling it) within the confines of the IL2 convergence method. I'm especially interested in seeing how the two lines of fire relate with each other and the pilot sight line


Thank you.

VMF-214_HaVoK
07-18-2007, 02:50 PM
For me 200 is the place to be for both. It really does not matter what your convergence is if you do not shoot within it. Everyone has there idea of whats best, but whats best for one is not always best for another. Load up QMB and start shooting friendlies and there you will find what works best for you. No test will help this matter.

S!

Viper2005_
07-18-2007, 04:56 PM
My gut says that the outer guns should converge at a closer range than the inner guns since this will produce a pair of "nodes" where the bullets from the inner and outer guns cross in addition to each primary convergence node.

The easiest way to see this is to draw it on paper, but I'll just type it:

Node #1 is where the inner and outer guns converge.
Node #2 is where the outer guns converge.
Node #3 is where the inner and outer guns converge again.
Node #4 is where the inner guns converge.

NB - the above doesn't account for bullet drop which is a whole different kettle of fish. I do not know whether gun elevation is changed along with azimuth when convergence is set in IL2 and therefore I do not know whether this matters in game.

Anyway this "crossover" system effectively gives you more chances to put concentrated fire down on the target in exchange for limiting the maximum concentration to about half that available were to you converge all your weapons on a single point.

Setting the inner guns to a shorter convergence than the outer guns doesn't pay because then you lose a node but AFAIK gain nothing. With this system:

Node #1 is where the inner guns converge.
Node #2 is where the inner and outer guns converge.
Node #3 is where the outer guns converge.

This doesn't matter a great deal with the P-47 because the inner and outer guns are very close together anyway. But with something like the Fw-190A it can make a noticeable difference.

Cajun76
07-18-2007, 08:27 PM
FWIW, I've had mine set up like Viper suggested for a long while, with the inner set farther than the outer. Kind of a diamond pattern. Mine are set to 300 and 250 atm, gives me the option of shooting just about everything, fighters, bombers and ground strafing.

While the method of crossing the inner and outer had been there for a long time, my congervence has changed as patches have modified the way the Jug handles and the .50's squirt. Your mileage may vary.

I wish I had the time to test Blutarski, good luck.

Blutarski2004
07-18-2007, 08:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Originally posted by Viper2005_:
My gut says that the outer guns should converge at a closer range than the inner guns since this will produce a pair of "nodes" where the bullets from the inner and outer guns cross in addition to each primary convergence node.

The easiest way to see this is to draw it on paper, but I'll just type it:
</div></BLOCKQUOTE>

..... As a matter of fact, that's exactly what I did. The goal of my exercise is to create something approaching an "easier-to-hit-with" broad pattern harmonization within the gun convergence limitations imposed by IL2.

I just ran a graphical experiment based upon convergence of the inner guns at 250 yards and the outer guns at 350 yards. Results as follows, expressed in 4-mil dispersion disks:

200 yards - (4-mil disk = 2.4 ft diameter)
ctrs of inner gun disks about 4 ft apart;
ctrs of outer gun disks about 8 ft apart and slightly higher than the inners.
Overall pattern: about 10'w x 3'h with a gap of about 2 feet in the center.

250 yards - (4-mil disk = 3 ft diameter)
ctrs of both inner gun disks merge on the sight line; ctrs of outer gun disks about 5 ft apart and slightly higher than the inners.
Overall pattern: about 7'w x 4'h with interlocking 4-mil disks.

300 yards - (4-mil disk = 3.6 ft diameter)
ctrs of both inner and outer gun disks about 2.5 ft apart; ctrs of outer gun disks slightly higher than the inners.
Overall pattern: about 7'w x 4'h with interlocking 4-mil disks.

350 yards - (4-mil disk = 4.2 ft diameter)
ctrs of outer gun disks merge on the sight line; ctrs of inner gun disks about 6 ft apart and lower than the outers.
Overall pattern: about 10'w x 5'h with interlocking 4-mil disks.

400 yards - (4-mil disk = 4.8 ft diameter)
ctrs of outer gun disks about 4 feet apart; ctrs of inner gun disks about 10 ft apart and slightly lower than the outers.
Overall pattern: about 15'w x 7'h with interlocking 4-mil disks.

450 yds - (4-mil disk = 5.4 ft diameter)
ctrs of outer gun disks about 4 feet apart; ctrs of inner gun disks about 10 ft apart and slightly lower than the outers.
Overall pattern: about 20'w x 8'h with touching 4-mil disks.

Beyond 450 yards, the pattern becomes too divergent to be useful IMO. At 200 yds only about half the area of the fire pattern rectangle is covered by dispersion disks. But, between 250 and 450 yards, we have a pretty good fire pattern going. In rough terms:

250 yds - 28 ft2 (bullet density factor = 10 per ft2)
300 yds - 28 ft2 (bullet density factor = 10 per ft2)
350 yds - 50 ft2 (bullet density factor = 6 per ft2)
400 yds - 105 ft2 (bullet density factor = 3 per ft2)
450 yds - 160 ft2 (bullet density factor = 2 per ft2)


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
NB - the above doesn't account for bullet drop which is a whole different kettle of fish. I do not know whether gun elevation is changed along with azimuth when convergence is set in IL2 and therefore I do not know whether this matters in game.

Setting the inner guns to a shorter convergence than the outer guns doesn't pay because then you lose a node but AFAIK gain nothing. With this system:

Node #1 is where the inner guns converge.
Node #2 is where the inner and outer guns converge.
Node #3 is where the outer guns converge.

This doesn't matter a great deal with the P-47 because the inner and outer guns are very close together anyway. But with something like the Fw-190A it can make a noticeable difference. </div></BLOCKQUOTE>

..... Agree on both points. Another observation which I made was that wing-mounted guns firing from outside the prop arc just cannot produce a really useful harmonization pattern for very short ranges. The one point which favors the 109 and other a/c with similar armament configuration.