Author Topic: PLS HT look into Breda MG modelling! (Read 3918 times)

MANDOBLE · « **Reply #150 on:** February 06, 2002, 07:55:52 AM »

IMO, nose mounted guns are always better for air to air shooting than wing mounted ones, no matter the distance, no matter the quality of the pilot.
Look into the post war developed fighters, and prior to the guided missile era, most if not all the fighters had the guns mounted in the nose or wing roots.
With this placement you are gaining in precission at any range and plane performance. Obviously, the chances of hitting the enemy are reduced, but the chances of destroying the target if hitting are increased.

gripen · « **Reply #151 on:** February 06, 2002, 08:29:01 AM »

MANDOBLE,
Postwar fighters tend to have advanced gunsights, actually radar assisted in many cases (range measuring). I have admited right from the begining that center line is best location for guns. But question is if 1x armament in the fuselage armament is better than 2x in the wing for a average pilot without advanced gunsight.

My pretty well founded opinion has been right from the beginning that at short range fuselage armament have signifigant edge ie is better (no aiming problems). At convergence range wing armament is better because more concentrated firepower. And at long range wing armament is better because aiming errors are much more signifigant than optimal location of the guns.

See my examples and note that the second example shows just about how accurate aiming should be (99,9% of the aims within 5m center of the 1m correct aim point at 400m range ie 2x convergence range) to give advantage for the fuselage guns at long range. Real world error was much more (probably more than 10m) and also target size was bigger.

Aces tended to shoot from short range and therefore they could benefit from the fuselage armament.

gripen

(edited for a error in the text)

MANDOBLE · « **Reply #152 on:** February 06, 2002, 09:46:48 AM »

Is a centerline unsynchronized gun better than two wing mounted synchronized ones? IMO, yes.

Is a centerline unsynchronized gun better than two wing mounted unsynchronized ones? IMO, yes too.

Is a centerline unsynchronized gun better than six wing mounted unsynchronized ones? Probably not.

Here in AH you have a very good example in the 109G (1x20 unsynchronized) compared to 190A/D/F (2x20 wing root synchronized).

The Hit Percentage achieved by 109 is usually doubling the HP of the 190.

HoHun · « **Reply #153 on:** February 08, 2002, 01:42:29 PM »

Hi Gripen,

>You can certainly play with my simplified model and use it for purposes it was not made for; if the range is long enough, it will favor fuselage guns. But ranges beyond 500m are pretty unrealistic and if the dispersion is as high as Funkedup claimed and evenly distributed as in your model, then wing guns have advantage at very long range too.

Actually, adding dispersion increases the superiority of the centreline gun.

As explained above, to get overlapping fields of fire at ranges beyond convergence, it's necessary for the dispersion radius at convergence range to equal the the wing guns' offset from the centre. (That makes it 2 m @ 200 m for our example.) Assuming Gaussian dispersion, the 2 m @ 200 m should be our 3 * sigma value.

Here are the numbers for our example:

Range [m]; Phit 2 wing guns, Phit centreline gun
500   9,0%   8,7%
600   5,7%   7,2%
700   3,8%   6,3%
800   2,9%   5,5%
900   2,2%   4,9%
1000   1,8%   4,4%

The observations:

- The break-even range of centreline guns is shorter than without dispersion
- The superiority of centreline guns increases with range increasing beyond the break-even point

Regards,

Henning (HoHun)

HoHun · « **Reply #154 on:** February 08, 2002, 01:56:23 PM »

Hi again,

as it occurred to me while typing, the above numbers are with only half the necessary diversion to fulfill the overlap requirement.

Here are the numbers for full dispersion:

450 8,3% 8,2%
500 6,3% 7,4%
550 4,9% 6,7%
600 3,9% 6,2%
650 3,2% 5,7%
700 2,6% 5,4%
750 2,3% 5,0%
800 2,0% 4,7%
850 1,7% 4,5%
900 1,5% 4,2%
950 1,4% 3,9%
1000 1,2% 3,8%

It's interesting to note that more dispersion leads to poorer results for both weapons arrangement, but that wing guns are affected worse.

Regards,

Henning (HoHun)

gripen · « **Reply #155 on:** February 08, 2002, 06:40:09 PM »

HoHun,
Wow, now you have found out that dispersion might not be homogenously distributed as you presented in your own model and which I BTW doubted. So why don't you carefully read again my text which you quoted.

And again, you are continously trying to use my second example model for the purpose it was not made for. The values in the model were setted to those just for to show how small aiming error and target should be at 2x convergence range if someone wants present 1x fuselage armament better than 2x wing armament. And you are continously using these values to show that I'm some how wrong on this. Real world values for the aiming errors at 400m range are much more likely closer to 10-20m and also target size is larger.

So, if you want to continue, please estimate real world aiming errors as I asked before and use also more realistic target size. Also ranges beyond 500m are irrerelevant.

gripen

HoHun · « **Reply #156 on:** February 09, 2002, 06:47:00 AM »

Hi Gripen,

>Wow, now you have found out that dispersion might not be homogenously distributed as you presented in your own model and which I BTW doubted.

Yes, and it easily lead to the conclusion that a centreline gun is superior to wing guns at long range. Thanks for your constructive doubts :-)

>And again, you are continously trying to use my second example model for the purpose it was not made for.

Not a problem, I'm continuously improving the model.

>Real world values for the aiming errors at 400m range are much more likely closer to 10-20m and also target size is larger.

I don't think you have any real-world records to prove that claim, do you? If you had, I'd be very interested, of course.

>So, if you want to continue, please estimate real world aiming errors as I asked before and use also more realistic target size.

I simply used the values you provided earlier. So what's your suggestion now?

>Also ranges beyond 500m are irrerelevant.

I'd tend to agree that they're academical :-) This doesn't mean I'm not interested in the answer, though.

Regards,

Henning (HoHun)

gripen · « **Reply #157 on:** February 09, 2002, 02:03:16 PM »

HoHun,
Well, if the distrubtion is standard then 99,9% of the aims within 5m from correct target point means that about 68% is within 1,67m, so it is easy to see that at 400m range such accuracy is pretty much impossible even if planes are in the same flight path. I have seen some Finnish Air Force ground target shooting data and typical results for a good shooter were around 40-50% to 6x6m target from 100-300m range, much less in the case of a poor shooter and longer range.

In the case of the different flight paths deflection can easily be say 20-40m (several degrees) and without advanced sight aiming is very unaccurate so here error is much larger. Anyway, we know that gyroscopic gunsights improved shooting accuracy dramatically so poor accuracy is pretty well documented.

My estimate is that 10-20m aiming accuracy at 400m range might be something a very good shooter reached and realistic target size should be around 2-3m. So these are my suggestions.

But actually I am pretty sure that you won't do that. I think that you have known since you understood the model that I have been right. Your attitude is clear as seen in the way you use my second model (funny thing is that you proved it true). Oh well, I said long time ago that you won't never admit that you are wrong on this. But lets do 200, anyway I've got some fun.

gripen

HoHun · « **Reply #158 on:** February 09, 2002, 04:57:37 PM »

Hi Gripen,

>My estimate is that 10-20m aiming accuracy at 400m range might be something a very good shooter reached and realistic target size should be around 2-3m. So these are my suggestions.

OK. And what results do you get from these suggestions?

Regards,

Henning (HoHun)

gripen · « **Reply #159 on:** February 10, 2002, 12:02:08 AM »

HoHun,
You asked suggestions and you got them, so it's up to you.. I got 8,3 hits with wing guns and 5,7 with fuselage gun at 400m assuming 20m error and 3m target. No dispersion again.

gripen

HoHun · « **Reply #160 on:** February 10, 2002, 03:45:17 AM »

Hi Gripen,

>No dispersion again.

Is there a special reason you left out dispersion?

Regards,

Henning (HoHun)

gripen · « **Reply #161 on:** February 10, 2002, 04:47:32 AM »

HoHun,
Yes, no dispersion beacause I don't know size or distribution of the dispersion. In the case of the built in dispersion like in the Russian guns or the M61 the pattern might not be distributed as standard. It is very probable that similar practices were used elsewhere too.

But it's up to you, if you want to ad dispersion then help your self (assuming that you have good data on it).

gripen