Author Topic: WW2 fighter gun effectiveness  (Read 1659 times)

Offline Kweassa

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WW2 fighter gun effectiveness
« Reply #45 on: December 03, 2002, 07:38:09 PM »
IL-2 view system is good. Frankly, the now-standard "SNAP"-style view changes are almost entirely the same in quality in every game that uses this method.

 However, as some philosopher mentioned, "God's in the details". A small modification makes such a great impact, typically concerning the views, in the air combat sim genre. A half-inch "bar" represented on the monitor that conceals the enemy plane for only half a second is enough to make you completely lose your track of the enemy, and the fact that there is no way around it becomes the single largest problem in an otherwise superb game that is likely to influence other games for a generation.

 The customizable head positions, while too lenient in the older planes, is a very reasonable choice, an innovative small idea which people rate so highly of AH! The recently modelled planes have a very reasonable 6-view limit.

 Another thing is the "snap" speed in IL-2 is so damned slow. I would understand if it had something to do with the G-forces, and differs upon different conditions, but however, in every given situation the snap is so undesirably slow that frustration builds for people used to AH.

 If AH would have a view system that would not allow a transition from 5->6->7 O'clock views(there's an old thread concerning this idea which I've suggested on two programmable 6 views), and would implement some neat-o features such as seen in IL-2, it would be absolutely perfect!

 ......

 Another problem:

 IL-2 cockpits are pictoresque, with photo-realistic levels of detail, which is very good. However, there might be a problem with this.

 Generally, there is a possibility that a 3D perspective from the actual cockpit, and a 3D perspective represented in a separate way by 2D methods, might actually differ in perspective.

 What I mean by this is the cockpits in AH are actual views from inside of the cockpit that is modelled within the plane. To put it simply, AH builds a 3D model with cockpits intact, and then they put a "video cam" on the seat of the cockpit.

 However, IL-2 uses cockpits that are modelled separately from the plane. I have reason to believe that the perspective of the cockpits in IL-2 is modelled from photo data taken at the pilot's seat. In other words, they build a 3D model for the plane, then, they take pictures from the pilot's seat, and then, they build a "panoramic-3D" view around the lens of a video cam based on the pictures they got.

 So, in effect, AH perspective goes from 3D to 2D(monitor), while IL-2 goes 3D(actual cockpit)->2D(photo data)->3D build based on 2D(cockpit modelling process) and then again to 2D(representation on monitor). This might tend to warp the views a bit, compared to what AH offers.

 The two examples are the cockpits of the Fw190 and Yak series in IL-2. These two planes both offered excellent visibility in real-life, and yet in IL-2 they are severely limited even in forward visibility(!), due to problems of the "3D" built cockpits somehow being depicted in a way which it feels more like "2D" than 3D. The forward canopy bars are humongous for both these planes, and a real frustration factor to the people who fly these planes. You can struggle to find a way aroud this by switching view angles with SHIFT+F1, but it still is severely limited.

 In AH, while the cockpit bars are too thin, still it represents a more accurate "scale" of perception which would be closer to what a pilot sees in real life.

 I'm not sure if I described this in a way people can actually understand.. :D , but I hope you can get the general idea.
« Last Edit: December 03, 2002, 07:41:01 PM by Kweassa »

Offline RAPIER

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Gun Effectiveness
« Reply #46 on: December 03, 2002, 08:40:16 PM »
Tony, the discussion you posted on the effectiveness of guns and ammo was great.  I also really enjoyed the relative merits of the BBs on your link.
Thanks, NHRapier

Offline Tony Williams

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WW2 fighter gun effectiveness
« Reply #47 on: December 03, 2002, 11:12:35 PM »
Quote
Originally posted by bozon
from the article:
 
in AH the german mg151/20 is WAY weaker then the hispano.
2 hispano hits will almost always result in a crippling damage while in the mg151/20 it takes about twice as many. I spent some time blasting away at the drones off-line and the hispanos kill much easier.


Note that I only said that the M-Geschoss was equal to the Hispano. The Luftwaffe usually mixed these rounds with others; typically, there were two M-Geschoss, two HEIT (with only a very small amount of HE) and one API or APHE. The overall effectiveness of the ammo belt would have been less than the Hisso's, which is why the MG 151/20 ammo scores 16 while the Hisso's scores 20.

Tony Williams: Military gun and ammunition website and Discussion forum

Offline Tony Williams

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Re: Gun Effectiveness
« Reply #48 on: December 03, 2002, 11:13:37 PM »
Quote
Originally posted by RAPIER
Tony, the discussion you posted on the effectiveness of guns and ammo was great.  I also really enjoyed the relative merits of the BBs on your link.
Thanks, NHRapier


Thanks for the message, I'm glad you enjoyed it!

Tony Williams: Military gun and ammunition website and Discussion forum

Offline Pongo

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WW2 fighter gun effectiveness
« Reply #49 on: December 03, 2002, 11:55:38 PM »
I really think that vs Aircraft. And at 300 or less yards. the 151/20 is the equal of the Hispano in AH.

Offline niklas

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WW2 fighter gun effectiveness
« Reply #50 on: December 04, 2002, 03:40:34 AM »
Just a question:

Why is the russian Shvak shell listed as a "x99R", when the length of the shell was only ~60mm??

A relict of the original 12.7mm project?

And how does it come that T. Williams page lists a m.v of 750-790m/s (confirmed by a german doc i have), while many other pages list 860m/s for the 20mm Shvak?

thx

niklas
« Last Edit: December 04, 2002, 04:08:13 AM by niklas »

Offline Kweassa

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WW2 fighter gun effectiveness
« Reply #51 on: December 04, 2002, 05:32:19 AM »
But Pongo.... EVERYTHING is equal to everything else at those ranges! :D

Offline Tony Williams

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WW2 fighter gun effectiveness
« Reply #52 on: December 04, 2002, 07:36:42 AM »
Quote
Originally posted by niklas
Why is the russian Shvak shell listed as a "x99R", when the length of the shell was only ~60mm??


It's the cartridge case which measures 99mm long, not the shell it fires. Along with the calibre, this is the standard measure of a cartridge because the shells or bullets fired can vary in length, but the case never does (well, not normally anyway).

Quote
And how does it come that T. Williams page lists a m.v of 750-790m/s (confirmed by a german doc i have), while many other pages list 860m/s for the 20mm Shvak?


Probably my fault. I discovered a reference to 860 m/s years ago and have used it ever since. However, I have recently looked a better references, more closely, and discovered that the 750-790 m/s is accurate. It is possible that the very long-barrelled version of the gun used in engine mountings produced the higher velocity.

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Offline hitech

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WW2 fighter gun effectiveness
« Reply #53 on: December 04, 2002, 08:57:05 AM »
Tony, I would be interested in seeing the same tables at different ranges. I.E 200 400 600 800 and 1000 yards. Would also be interesting in your rate of fire table if you could put in a factor for frequency of hits (i.e. flatter traj = higher rate of hit ).

3rd you could also put in altitude factors for each 5000 ft, because it drasticly changes the energy side of the equation.

HiTech

Offline Pongo

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« Reply #54 on: December 04, 2002, 10:04:22 AM »
Quote
Originally posted by Kweassa
But Pongo.... EVERYTHING is equal to everything else at those ranges! :D

Not really. Rof and hitting power are not. Even the mgff seems considerably worse then the 151/20 at 300 yards.

Offline F4UDOA

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WW2 fighter gun effectiveness
« Reply #55 on: December 04, 2002, 10:31:50 AM »
Tony,

I noticed in your chart you have the M2 .50 cal AP but not the HE. I understand that the typical loadout especially in the PAC theater was a mix of AP, HE and tracer.

How did the HE (or incendiary) round fair??

Also based mostly on AH it seems the .50 cal has great trajectory ability. Is this directly because of muzzle volocity or are other factors more important?

Offline HoHun

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WW2 fighter gun effectiveness
« Reply #56 on: December 04, 2002, 11:05:52 AM »
Hi Hitech,

>Would also be interesting in your rate of fire table if you could put in a factor for frequency of hits (i.e. flatter traj = higher rate of hit ).

Here the shooting accuracies the Luftwaffe considered to be realistic against heavy bombers under combat conditions:

d (m) - Ph MG151/20 - Ph MK103 - Ph MK214
500 - 9.1% - 10.0% - 10.5%
1000 - 3.3% - 3.8% - 3.8%
1500 - 0.8% - 1.3% - 1.5%

The 50 mm MK214 as a large-caliber high-velocity weapon of course had a significantly flatter trajectory than the MG151/20, but that only paid off beyond effective range.

As pointed out above, flatter trajectory, i. e. higher muzzle velocity, also equalled higher dispersion, which would decrease the number of hits.

Time of flight of course is a beneficial factor, but it's value is greatest against moving targets - which means shorter effective firing ranges so the velocity advantage doesn't get to full effect.

Here's a time of flight comparison (from http://www.hitechcreations.com/forums/showthread.php?s=&threadid=67068&highlight=hispano)

d (m) - MG151/20: t (s) - 20 mm AP (2800 fps): t (s)
100 - 0.13 - 0.12
200 - 0.29
300 - 0.47 - 0.42
400 - 0.69
500 - 0.94 - 0.73

In practice, this works out to these limiting target speeds for each type of gun for a 90° crossing shot, based on the assumption that the sight from each cockpit is 100 mil below the sight line (as in the P-51D).

d (m) - MG151/20: v (km/h) - 20 mm AP M75: v (km/h) - Hispano advantage (%)

100 - 277 - 277 - 0%
300 - 230 - 245 - 7%
500 - 191 - 228 - 19%

(From http://www.hitechcreations.com/forums/showthread.php?s=&threadid=67068&highlight=hispano)

I'd say that any weighting of the results from Tony's tables according to assumptions about the hit probability would distort the results. The reason is that finally it's up to the pilot to choose his combat tactics according to the capabilities of his weapon.

Implying certain accuracies means implying certain tactics - which impedes the value of the weapon comparison as a tool for unbiased analysis.

(The most important tactical difference I'm thinking of is tracking shot versus snap shot.)

Regards,

Henning (HoHun)

Offline Tony Williams

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WW2 fighter gun effectiveness
« Reply #57 on: December 04, 2002, 03:30:50 PM »
Quote
Originally posted by F4UDOA
Tony,

I noticed in your chart you have the M2 .50 cal AP but not the HE. I understand that the typical loadout especially in the PAC theater was a mix of AP, HE and tracer.

How did the HE (or incendiary) round fair??

Also based mostly on AH it seems the .50 cal has great trajectory ability. Is this directly because of muzzle volocity or are other factors more important?


There was never a service HE round for the .50. The loadout for most of the war was equal numbers of incendiary and AP bullets, sometimes with 20% tracers added. From April 1944 this was largely replaced by the M8 API, which combined the features of both types in one.

The .50's flat trajectory out to long range is partly the result of muzzle velocity, partly the result of a very good ballistic coefficient (i.e. a heavy bullet, well streamlined).

Tony Williams: Military gun and ammunition website and Discussion forum

Offline niklas

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WW2 fighter gun effectiveness
« Reply #58 on: December 04, 2002, 05:55:22 PM »
Quote
Originally posted by HoHun
Hi Hitech,

>Would also be interesting in your rate of fire table if you could put in a factor for frequency of hits (i.e. flatter traj = higher rate of hit ).

Here the shooting accuracies the Luftwaffe considered to be realistic against heavy bombers under combat conditions:

d (m) - Ph MG151/20 - Ph MK103 - Ph MK214
500 - 9.1% - 10.0% - 10.5%
1000 - 3.3% - 3.8% - 3.8%
1500 - 0.8% - 1.3% - 1.5%

Henning (HoHun)


It should be noted that Luftwaffe research distinguished between single precision shots, and continous shooting.

A higher muzzle velocity of course helps for a single precision shot, but due to the larger recoil the result is different for continous shooting.
I assume Hohun values are for continues shooting

niklas

Offline niklas

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WW2 fighter gun effectiveness
« Reply #59 on: December 04, 2002, 06:05:12 PM »
This picture may give you an imagination of the influence of altitude and speed.

The goal is to hit a target at an distance of 1000m.

The trajectory is printed for altiude 0km and 10km and 10km with a approching relative speed of 200m/s

Obivously the trajectory varies so much that hits with satisfactoring precision at long range with different approching speeds and altitudes are only possible with a gunsight that "knows" speed, altitude, weapon trajectory etc.

niklas