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Super slow .50 caliber rounds


unltd

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M20 API-T and M8 API are the rounds that the Sabre used after the upgrade from the M2 to M3 Guns and they stopped using the WWII surplus ammo.

 

 

Both have a muzzle velocity of around 900m/s or 2950 fps.

 

 

 

The Sabre had a bad initial reputation when it got to Korea, it had not been in use in winter and was armed with the M2 and using old ammunition stocks it was natural that it seemed the underdog against the Mig with three cannon.

 

 

 

It's reputation was not helped by the fact that it took so long to get the first kill of a MiG-15 by a Sabre and it was a difficult kill. Lt Col Hinton's feat was widely reported and quoted, he used most of his ammunition to down that first MiG.

 

 

 

Shortly thereafter the F-86A's were retrofitted with the M3 and all subsequent Sabres arriving in theater were also equipped with the M3 and newer ammunition supplies were also sent and better choices were made, now using the M8 and M20 round.

 

 

 

Lt Col Hinton's and the experiences of other pilots early encounters with MiGs seem to have resounded with many including Belsimtek as we have rounds that are not working very well.

 

 

 

Watch gun camera footage from Korea, note the date and you can see that later footage takes very few rounds to down a MiG, at high alt you get a lot of white vapor (fuel) and at low alt you get a fireball after a short burst or two.

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Good news! I have been in contact with an ED tester. If we somehow can provide detailed and concise reports (including synopses, sources, hard data, steps to reproduce, tracks, etc.) he will submit that to ED.

 

So sharpen your pencil boys. This issue might be easy to change via .lua edit, but we need some documentation to back up how it should be, before they (ED/BST) will make an official change to the current behaviour.

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Excellent! It is very easy to correct the major shortfall in the Shell...lua in the weapons database script. AZ did a ton of work this way including adding late model canon. The muzzle velocity is clear and plain as day. Way low below 860 m/s. In the file just a couple lines above is a magical M round red tracer at 930 m/s. Not sure what era or weapon fires that. Then there are all the additional v variables that follow in the shell and aircraft file. Barrel warp is in the F-86 lua and crazy high. Lowering it to 0.001 across the board with multipliers of 1.0 works pretty well. But still, I found the Sabre guns jam at high altitude within the first few bursts. They come back at low altitude. This is a new effect in the Beta update.

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It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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Good news! I have been in contact with an ED tester. If we somehow can provide detailed and concise reports (including synopses, sources, hard data, steps to reproduce, tracks, etc.) he will submit that to ED.

 

So sharpen your pencil boys. This issue might be easy to change via .lua edit, but we need some documentation to back up how it should be, before they (ED/BST) will make an official change to the current behaviour.

 

This information has been given to Belsimtek in the past. Most of it can be found in this forum so is readily compiled. The only thing they did was change the M2 to the M3 browning and the ammunition type from M2 and M3 to M20. The muzzle velocity still appears to be wrong.

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  • 3 months later...

Yup. Rob, if you could give us good citations for the M3 and M20 data you posted, that would be a good start. And we need the stats on the ammo used not just the gun, to be sure the muzzle v is right. 900 m/s looks very good in game so if we can get the data to back it up, ED and BST should be able to make the change. Also, I think the g-suit and barrel warp lines in the aircraft .luas could be tweaked as well.

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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It appears the entire barrel line in the F-86 is copied from the MiG-15. Or in other words, the barrel dynamics of the M2, M3, 50 cal are based on the canons of the MiG. That may be the source of the difficulty. I backed them off way down by at least 75% and the groupings improved a lot. I can post my lines later.

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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It’s the other way around. F-86F was released way before MiG-15bis. What irritates me a bit is that it is so easy and quick to fix in the lua. Yet It has not been touched since release. Such an incredible work of Belsimtek, falling on the finish line... :cry:

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  • 1 month later...

Woah, I just saw this now. That's funny, either way the exact similarity of the two different weapons having the same barrel dynamics shows a lack of effort or a simple oversight. I think it is really hard to imagine that a canon with low muzzle velocity but big punch would have the exact same barrel dynamics of machine gun with high muzzle velocity and smaller punch. Maybe it's based on metallurgy and some kind of average? But the weapons are different and barrels must be too. And of course the rate of fire fix was not a fix but an exponential worsening because it wasn't thought out. I agree because this very aspect of the Sabre was one of it's saving graces, that kept it competitive in the new jet environment. Now we may also see that the Sabre barrel dynamics were based on something earlier still and THAT may be the culprit. I have seen the lines elsewhere, I think we are on to something.

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It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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It's not directly comparable... but i think maybe I found a reason for the heat/barrel warp appearing like this. I know that for most of it's existence, the ARMY version of the Browning .50cal, the barrel would overheat very rapidly. I mean crazy fast, even despite the much slower cyclic rate of fire, and much thicker/heavier barrel (as compared to the flight versions with high rates of fire).

 

Is it possible this well known quirk of ground .50's has mistakenly been assumed by a dev, to be exactly the same in jet use? I think maybe this could be.

 

Let's keep in mind, that despite the higher rate of fire, 400 knots of air cooling should cool any barrel a lot more than say a light breeze for the infantry versions! So I would assume the barrel would be less likely to overheat in a Sabre, than the typical Army ground versions. But I think the history and pilot anecdotes would be best to consult on this matter.

 

At one time, I heard someone's opinion that the reason for ground barrels overheating, may be due to the rifling twist rate being too much, that it was causing unnecessary friction buildup. Seemed a bit plausible, but then maybe the faster twist might have helped ensure stability at long ballistic distances? I dunno, kind of academic to the discussion. All I know is the few times I fired one, it got hot very fast!

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Possible but the fact that the exact line of code is copied into the MiG file suggests something entirely different, and along the lines of a project management failure as opposed to dogged, hard fought, super attention to detail historical research. I will check other .luas and see if I can find more.

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It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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OK P-51 uses something different:

 

-- Guns

Guns = {

-- Left wing outboard M2

BrowningM2({

muzzle_pos = {-0.045, -0.410, -2.427},

effect_arg_number = 436,

mixes = {

{2, 2, 2, 2, 2, 2, 2, 4},

{2},

{4}

},

count = 270,

barrel_circular_error = 0.0024,

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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Dora uses:

 

Guns = {

-- LH MG 151/20

MG_151_20({

 

barrel_circular_error = 0.0007,

 

plus:

 

{name = "HeatEffectExt", shot_heat = 20.9, barrel_k = 0.462 * 16.6, body_k = 0.462 * 35.4},

 

AND MG 131!

 

{name = "HeatEffectExt", shot_heat = 4.103, barrel_k = 0.462 * 3.7, body_k = 0.462 * 14.3},

 

Sabre:

 

{name = "HeatEffectExt", shot_heat = 4.103, barrel_k = 0.462 * 3.7, body_k = 0.462 * 14.3},

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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Do you see what I see? The Dora's MG 131 machine gun has the exact same barrel dynamics as an F-86 Sabre, How is this possible?

 

Spitfire uses on the 303:

 

barrel_circular_error = 0.0009,

 

FW-190 A8 (AI) uses on 131:

 

{name = "HeatEffectExt", shot_heat = 4.103, barrel_k = 0.462 * 3.7, body_k = 0.462 * 14.3},

 

Which is fine if it's an MG 131.


Edited by Squiffy

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It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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MiG-15 uses on the 23mm:

 

{ name = "HeatEffectExt" , shot_heat = 7.823, barrel_k = 0.462 * 2.7, body_k = 0.462 * 14.3 },

 

and on the 37mm

 

{ name = "HeatEffectExt" , shot_heat = 7.823, barrel_k = 0.462 * 2.7, body_k = 0.462 * 14.3 },

 

or exactly the same... as the M3 on the Sabre? What? you mean we have cannon accuracy and barrel deflection on a 50 cal barrel? How do you explain the exact same equation across 3 different weapons, 2 of which are canons and NOT high muzzle velocity, rifled machine guns? The barrel circular error option was much better and way more flexible. Or should I say was used more flexibly. You can see the changes out to 4 decimal places or more, when the cursed barrel warp equation was ham-fisted across 3 dissimilar weapons. At least the Doras different canons got full consideration in the barrel warp effort. I think it ended there.

 

If we hear why the equations work the way they do we may learn more but up to now it looks like an oversight. :(


Edited by Squiffy

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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Here is my F-86 uber M3 barrel warp or lack thereof. There is a huge amount of room for adjustment here but nothing has been done.

 

{ name = "HeatEffectExt" , shot_heat = 1.012, barrel_k = 0.045 * 1.0, body_k = 0.025 * 1.0 },

 

shot heat = heat added by each round?

barrel_k = barrel deflection * some multiple?

body_k = bullet or weapon deflection * some multiple?

 

An explanation of this will help a lot.


Edited by Squiffy

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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I goofed a bit with the 131 versus the cannons. The barrel warp equations are 'slightly' different but still very close.

 

Then I found these just today:

 

https://www.northropgrumman.com/Capabilities/50CalAmmunition/Documents/M20FactSheet.pdf

 

https://www.northropgrumman.com/Capabilities/50CalAmmunition/Documents/M33BallFactSheet.pdf

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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  • 3 months later...

PM Big Newy or Nine Line and ask them to take a look at this thread (nicely) and maybe we can get it confirmed as reported.

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Thank YOU NineLine! Sorry for all my ranting. It's mainly due to the critical tactical nature of this aspect of the F-86. High G, High muzzle velocity was the way the Sabres fought historically. And the MiG-15 was a tough and worth adversary as an interceptor. You could even say that the differences discovered with this match up (as well as lessons from WWII) could be the main reason for the separation of roles in the next generation jets: superiority fighters v interceptors. and also why the F-4 was born without a gun...going too far. ;)

[sIGPIC][/sIGPIC]

It's perfectly ordinary banter Squiffy, "Bally Jerry, pranged his kite, right in the 'how's your father.'" - Monty Python, RAF Banter Sketch.

Squiffy, a. slang. 1. Intoxicated; drunk. 2. Askew, skew-whiff. - OED

 

"Put that sucker in a 4G turn and keep it there!!" - Maj. Gen. "Boots" Blesse

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It’s the other way around. F-86F was released way before MiG-15bis. What irritates me a bit is that it is so easy and quick to fix in the lua. Yet It has not been touched since release. Such an incredible work of Belsimtek, falling on the finish line... :cry:

 

 

It's the countless little details like this that prevent me from purchasing anything new from DCS. If they would just fix these simple problems, I'd be a spending fool. It baffles and aggravates me no end.

I love the F86 but the gun issues really kill it for me. Between the terrible warpage after only a few rounds and the slow speed of the rounds, it's just not really very fun. I remember saying something about the guns very early in the F86's release, and it's still an issue. I don't fly the F86 because of this. There are several modules that I just keep grounded for these kinds of reasons.

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Precisely.

 

I know NineLine et al will be now extremely busy with the F16 support (and after that the F15 or whatever the next hype train is) but taking a look in the bug channel for that aircraft is a bit galling when comparing to the F86 or other older modules. Each and every thread in the F16 bugs has been edited with [Confirmed] or [unable to reproduce] etc in the topic subject and is clearly being treated seriously.

 

I do not understand why Belsimtek or ED cannot fix what appears to be a simple little issue and almost certainly a config setting somewhere. It's not like we're asking for them to redo the flight model or create extra content...

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