190D9 20mm guns, left deviation

[MANDOBLE]

Some of you will ask for a video, but this is something too easy to test and verify.

1 - Go to hangar, select D9 and set convergence to 600 yards
2 - Take off and select a course parallel to the wind (activate wind info from the clipboard top buttons).
3 - Level and switch on autopilot.
4 - Activate zoom.
5 - Regulate zoom to maximum.
6 - Start firing guns (20mm) ONLY.

You will notice 99% of the bullets deviating a lot to the left of the gunsight center, almost none going to the right.

Is that correct? If so, why?

[Urchin]

Hum, that is interesting.  I didn't notice that when I tested the guns.  Does it only happen at 600 yd convergence?

[MANDOBLE]

Try it with any conv, more noticeable with 600 or more yards conv.

[Urchin]

You may very well be right here, but I honestly can't tell.  The first test I did seemed to show that the bullets went down and to the left when I set the convergence to 600 and the target to 600.  I would have thought the 'beaten zone' would have been centered on the targeting dot, it did not seem to be.  However, the leftward drift I am not so sure about, because as I went to do my second and third tests I noticed the target 'drifting'.  Turns out I was a fraction of a degree off true north, which caused the target to drift very slowly to the right, which may very well have caused the center of the 'beaten zone' to appear to be off to the left of my target dot (btw, beaten zone is a 'land based' term, not sure if it applies to airborne MGs and cannon, but I can't see why not).  

I did think that if you set convergence at a certain point it meant that the bullets were supposed to 'hit' the crosshair at that point X number of yards in space, that didn't seem to be happening at 600 yards.  Seemed to be maybe 10 feet below the aiming point.

Perhaps the Mg151/20 round doesn't have enough velocity for a convergence setting of 600 yards?  I don't know.  It is rather interesting though, I hope HTC can look into it.

[Tac]

Tu sabes que si se desviara a la derecha seria un maricon

Sera que le jalas mucho hehehe.

A ver que dice HT  o los demas sobre tus resultados

[MANDOBLE]

Urchin, what target are you talking about. If it is the center dot of the GS, you simply align the wind and switch A/P ON.

The test is extremely simple, just level, set up a normal speed (250 MPH, for example), maximize zoom and start shooting, nothing more, nothing less. You will find almost all the bullets dropping at the left of GS center. 13mm MGs has the same problem in D9. The effect is really noticeable.

Now try 190F8, you will find that the bullets drop much more centered.

I was testing that with StSanta first time in Dueling Arena, I suppose DA has same setting as MA and offline, but not 100% sure.

Jeje, Tac, apuesto a que NA DA.

[Wotan]

mandoble offline you can type .target 600

it will put a bid bullzi in front of your plane as long as you head do north.

by keeping the plane exactly n and the gunsite centered in the target you can judge bullet drop and converge cone.

[MANDOBLE]

I know Wotan, thanks, but that was not involved in the procedure of the test. If you follow the steps described, you will see 99% of the tracers falling well at the left of the GS center (zoom on, and maximized). So, you'll notice the effect, in fact, a bit farther than convergence range. The effect is so noticeable that you dont need to see back dots painted at any target.

Perhaps that target could be used, but setting it at 700 yards for 600 yards convergence, and dont aimming to the center of the target, aming at the top of the target and centered horizontaly. The problem is that you will need to make corrections to keep the target at the desired possition.

[Karnak]

MANDOBLE,

The target can be set at whatever range you wish.

My question to you is, why not just zero the wind out?  That would take one factor out of the equation.

[MANDOBLE]

Same results with 0 wind. We tested that in DA, no way to change winds there.

[Urchin]

Mandoble, that wasnt what I was saying.  The .Target (the bigass bullseye) seemed to be drifting to the right very very slowly.  This would make it appear that your bullets were flying to the left of where you aimed them, although they in fact were hitting where you aimed (since your gunsight has moved relative to the target).   I think it was happening because I wasn't flying EXACTLY north, even though my compass said I was and my gunsight pipper was in the middle of the 'bullseye' when I started.  Perhaps if I wasn't pointed directly at the bullseye (perhaps only a half degree off) that would be enough deviation to make it appear that the guns were significantly off?

Perhaps I'm not doing a very good job of explaining it.  TAc or someone, can you make sense of what I am saying and post it in Spanish?  I'd try but my Spanish just isnt good enough to get my point across.

[Lephturn]

Originally posted by MANDOBLE
Some of you will ask for a video, but this is something too easy to test and verify.

1 - Go to hangar, select D9 and set convergence to 600 yards
2 - Take off and select a course parallel to the wind (activate wind info from the clipboard top buttons).
3 - Level and switch on autopilot.
4 - Activate zoom.
5 - Regulate zoom to maximum.
6 - Start firing guns (20mm) ONLY.

You will notice 99% of the bullets deviating a lot to the left of the gunsight center, almost none going to the right.

Is that correct? If so, why?

First of all, congratulations on running some tests!  See, this way you have some actual data we can discuss.  Much better.

But, I see a problem with your testing methodology.  Auto-trim for level.  The auto-trim modes constantly change your trim condition to attempt to maintain straight and level flight, but they are not perfect.  As you fire your guns, the auto-trim will be adjusting your trim condition and slightly changing your plane's direction and such.  If you use the .target and watch you pipper's movement against the target, you can see that it doesn't stay in exactly the same spot.

Now, I went to check this out myself, and here is what I found:

Tests done offline in the Duelling Arena terrain with all wind set to 0.  I went to 5k feet and about 350 MPH.  I set auto-trim to level and fired several long bursts from the cannons.

While there does seem to be a dispersion patter to the left generally, I'm not sure why.  The combination of the gun recoil and the auto-trim may be the problem.  I think we need to try and do this by manually flying the plane and holding the pipper dead center and shooting.  We could film that and with the target it would be quite plain if there was a problem.  I don't have time now, but I'll try that later tonight or tomorrow.

[MANDOBLE]

Done manually with 190F8 and D9, D9 massive dispersion to the left, F8 more balanced dispersion.

Done also with autotrim, D9 and F8, same results.

[J_A_B]

Maybe instead of a problem with the 190D-9's guns, there's a problem with its gunsight?   If the D-9's gunsight is centered incorrectly in the plane's model, this would explain why the D-9 loses accuracy despite using the same guns as on other 190's.

Just something to check out  

J_A_B

[MANDOBLE]

JAB, look at the image and the dispersion zone, now compare  right with left side of that zone , very different right?