Bomber Gunners in Sim

[Spitfire976 4]

I'd like to start with a small disclaimer:

I'm new to simulator battles, and I don't think bombers should be removed from the game mode as they depth to it.The first time that I really flew a bomber was in SB, so I'm talking mostly from a fighter pilot perspective. I urge the bomber pilots to read the whole post, and post their suggestions/arguments for the question brought. Last but not least to avoid repeating "in my opinion" all that has been written bellow is my point of view.

 

However at the moment bomber gunners are more effective than they should be certain situations. And to be clear, I'm not complaining about been killed when you sit behind a bomber for a long time, that's the fighter pilot's fault, and I'm my opinion gunners should be more effective in this situation. But at the moment if a player chooses to a take control of the gunners,as they should because the AI can't aim, they have a 3rd person view of their aircraft, allowing them to track a fighter in a way that no crew member can. That allows the player to prepare a lead shot on a aircraft that they shouldn't see, making them unrealistically accurate for any experienced player. 

 

The obvious solution would be introducing the gunner position to each bomber, however this is a complicated process that realistically would need a year or so to be complete. I don't know how problematic a improvement for the  AI  accuracy is, but if it is possible to improve by a good margin, it would be fair change to lock the controls for the gunners as a stop gap mesure.

 

Feel free to post other ideas bellow, this is just a thought on how to improve the game. I'd love to see the gunner positions and multiple player crews in game.

[[email protected] 924]

The gunner view should be fixed to the view from that point.In other words,when on gunner,the view shouldnt be allowed to traverse the entire 360 degrees but only the vector of that position.I personally believe it would be a  good stopgap measure to fix the player in the cockpit as in a fighter and buff the AI to its previous capacity.

[D3athCZE 337]

On 5. 7. 2017 at 6:13 AM, *memnoch1911 said:

The gunner view should be fixed to the view from that point.In other words,when on gunner,the view shouldnt be allowed to traverse the entire 360 degrees but only the vector of that position.I personally believe it would be a  good stopgap measure to fix the player in the cockpit as in a fighter and buff the AI to its previous capacity.

you mean like few years ago that fighters were being sniped at 1.2 km of thick cloud with 100% accuracy?

[HueHuey 758]

1 hour ago, D3athCZE said:

you mean like few years ago that fighters were being sniped at 1.2 km of thick cloud with 100% accuracy?

Some still do that.

The good Beaufort players are basically impossible to kill alone.

[John_Q_ 1,535]

A temporary solution until Gaijin gets some placeholder turret models, is to lock the gunner to AI control. 

Edited July 8, 2017 by JohnQ11939ChtBan

[Kernow1346 1,847]

Every sim I've played seems to have suffered from AI gunners being a bit **** when it comes to 'unmissable' zero-deflection short-range shots v non-manoeuvring fighters on their 6 and yet at the same time being a bit too good, a bit too often, at long-range, high-deflection shots on the beam.  Of course WT adds the 3rd person gunner issue too.

 

Lock the external gunner view and buff AI gunner's short-range ability maybe?

[KH_Alan 5,256]

I almost don't fly bombers at all but is it possible to experience gun jam or overheat (increase spread) on bomber turrets? If not maybe that could be added so one should use short bursts like it was done in reality.

[Zettman 1,798]

Remember how long we had to fight to finally get limited ammo for gunners?Before they used to have unlimited ammunition on all turrets. I still meet bomber players ingame who complain about that 'nerf'. Well, I call it realism.

 

I would prefer the angle lock view for every gunner position, which memnoch1911 suggested as a interrim solution before getting gunner pits. AI gunners are already better than their real life counterparts. Just today I spoke to man at the Pensacola Naval Aviation Museum, whoes father was a B29 crewmen durring WW2 over the Pacific. He told me how his dad telled stories about Japanese fighters diving on them, which they could not intercept, even when several Bombers where pointing their gunners at their approach and prepairing theirself before they even got into firerange.

[Senilix 3,643]

@Zettman Please post more from your communication with people that knew them, or run's a historic museum - History is important to know so we don't do the same error's again :-)
Edit: Still the same fast fingers, on a other keyboard thow

Edited July 10, 2017 by Senilix

[Spitfire976 4]

On 05/07/2017 at 1:13 AM, *memnoch1911 said:

The gunner view should be fixed to the view from that point.In other words,when on gunner,the view shouldnt be allowed to traverse the entire 360 degrees but only the vector of that position.I personally believe it would be a  good stopgap measure to fix the player in the cockpit as in a fighter and buff the AI to its previous capacity.

 

Locking the gunner movement to it's firing arch is a good idea,it's better than buffing the AI as they're random by nature and we would have a situation like the AAA in game right now, where you can't really use a reliable technique to avoid it's fire.You can't allow the player to use the look around button to see the 360 degrees though, because you will still see an aircraft that you shouldn't, and you can guess the lead required. Another thing that must be considered is implementation, because if it takes just a bit less than the development of gunner pits,it's better to focus on the full feature than in it, thus it  wouldn't work as good stop gap. One last point would be the controls, a button switch between gunners would be required.

Just a clarification on the buff I proposed: I don't think they should buff the ability of the AI to take deflection shots,as those were incredible difficult to a gunner to do. I think they should be more effective when a plane stays on a bomber's six or in a predictable course for too long. 

 

On 08/07/2017 at 1:23 PM, KH_Alan said:

I almost don't fly bombers at all but is it possible to experience gun jam or overheat (increase spread) on bomber turrets? If not maybe that could be added so one should use short bursts like it was done in reality.

 

I don't think that would change much though, the larger issue is the current  accuracy. Also I wouldn't be able to say how fast does a bomber gun overheat, but as they're the same that were mounted in fighters for most cases, I doubt that they have different stats in the game code, because that would be complicated to do.

  

Edited July 10, 2017 by Spitfire976
Just a minor change. I've forgot to leave spaces between the quotes and what I've written, so I've added then.

[KH_Alan 5,256]

20 minutes ago, Spitfire976 said:

I don't think that would change much though, the larger issue is the current  accuracy. Also I wouldn't be able to say how fast does a bomber gun overheat, but as they're the same that were mounted in fighters for most cases, I doubt that they have different stats in the game code, because that would be complicated to do.

True, but AI gunner is shooting constantly which would make guns overheat quite fast and make their spread bigger thus less accurate at least it should be like that. Human gunner has more control over it and overheating might not be an issue but gun jam might as its random occurence.

[Spitfire976 4]

23 hours ago, KH_Alan said:

True, but AI gunner is shooting constantly which would make guns overheat quite fast and make their spread bigger thus less accurate at least it should be like that. Human gunner has more control over it and overheating might not be an issue but gun jam might as its random occurence.

 

I don't have a lot of knowledge about firearms, but I don't think that full auto fire would affect the accuracy of a bomber turret, because of the way they were mounted. I agree with your point with the weapon jamming by full auto fire, I really don't recall seeing a turret with a jammed gun in game and that should happen. All that said, it's a good idea to force gunners to burst fire as a fighter needs to, and the AI should be programmed to do it as well in my opinion. 

[Spendius 328]

They added a few patches ago the small green indicator that turns to red as the gun heats (similar to indicator in arcade). The gun jams if you fire too long.

 

I think it was a mistake to include that indicator in SB, especially with so many people advocating for a reduction of easy autopilot mouse-aim bomber gameplay. In my opinion, the best quick fix gaijin could do about bomber gameplay, is remove the gunner view completely. No more autopilot, no more mouse-aiming gunships.

[KH_Alan 5,256]

2 hours ago, Spitfire976 said:

 

I don't have a lot of knowledge about firearms, but I don't think that full auto fire would affect the accuracy of a bomber turret, because of the way they were mounted.

The way they are mounted doesn't help when barrels overheat. And on full auto they might overheat. When barrels overheat they deform a bit thus causing bigger spread. Question is not if barrels overheat question is how soon do they overheat?

[Spitfire976 4]

4 hours ago, KH_Alan said:

The way they are mounted doesn't help when barrels overheat. And on full auto they might overheat. When barrels overheat they deform a bit thus causing bigger spread. Question is not if barrels overheat question is how soon do they overheat?

Fair enough, the deformation of the barrels would affect the accuracy. Overall War Thunder is rather lenient on overheating on all aspects so I'd assume that it will take a long time to guns overheat in game. Decreasing the time it takes would be a good idea against bombers like the Tu-4, B-29, BV-238 whose rate of fire is extremely high. That would impact all planes that use those guns though, I'm not against it myself, however as it affects all planes, maybe it would need to be discussed in it's own thread. 

[Amyel 1,657]

15 hours ago, Spitfire976 said:

I don't have a lot of knowledge about firearms, but I don't think that full auto fire would affect the accuracy of a bomber turret, because of the way they were mounted.

The mount to solid frame will prevent if from moving (as whole) however recoil still has to go somewhere - so in this case within gun itself. Also - bigger the gun bigger the shell. Therefore spring gases going back to eject used shell, tilt the chamber (although it might be slightly different with ammo belt) to accept another shell must be at higher pressure. The weight of mechanism being shuffled front and back is enough to make it less accurate - especially if the gun is hand operated. On the other hand sometimes higher weight of a gun makes it a bit easier to keep it steady.

 

About overheating - the very first version (air cooled as those we have in game) M2 were able to shoot up to 75 rounds before overheating. With up to 850rpm that gives around 5 seconds of continous fire. But then we would have to see a break in shooting. M2HB (heavy barrel) was supposed to be able withstand for way longer. I do not know which one we have in bombers right now (can't check it as in office right now).

But true - with time the accuracy should be an issue as the barrel gets flexible. Also with metal expanding : 1.there is higher chance to lodge shell in a barrel; 2.The expansion of the barrel leads to greater windage and escape of the hot gas propellant, which leads to lower muzzle velocity and, since the bullet is rattling around more as it goes down the bore, less accuracy.

 

Just looking into M2HB (M296 which is newer version of AN/M2 design for choppers - difference of adjustable RPM and single shot) manual:

Combat firing is unrestricted but bursts of longer than 150 rounds may lead to gun stoppage due to overheating of the gun barrel.

A 50 round per minute burst restriction is required because the M296 machine gun is air-cooled. Because of the absence of cooling medium, the temperature of the barrel rises rapidly during firing. The longer the burst, the higher the temperature attained. The progressive heating of the barrel gives rise to several effects some of which are as follows:

• Accelerated wear of the bore.
• Expansion of the barrel leading to loss in bullet velocity and finally to tumbling of the projectile.
• Stoppage of gun caused by the expanded barrel seizing in the trunnion block or flash suppressor.
• . Ignition (cook-off) of the propelling charge by the heat of the barrel.

 

A 50 round per minute burst restriction allows the gun to fire a maximum of one 50-round burst or a maximum of five 10-round bursts in a given 60 second period. Any combination of bursts is permissible as long as only 50 rounds are fired in a 60 second period. Example: At time zero, a 10 round burst is fired. Ten seconds later a 24 round burst is fired. Ten second after that a 15 round burst is fired. Essentially, a total of 50 rounds have been fired in approximately 20 seconds. The gun has reached its 50 round threshold and should therefore be allowed to cool for 40 seconds prior to firing the next set of bursts.

 

If an overheating burst is fired, the gun should be cleared within 10-seconds after completion of the burst. IF the gun cannot be cleared within 10 seconds, the round should be allowed to remain in the chamber a minimum of 5 minutes, making sure the gun is aimed in the opposite direction from personnel and equipment. If an attempt is made to clear the gun between the 10 second and the 5 minute period, the extracted cartridge may explode outside the weapon causing serious injury to personnel or equipment.

 

For AN/M2 mounted in planes  - I'm not sure how the temperature/cooling is affected by plane air stream - but i do not thhink that WHOLE barrel was outside of a plane to be cooled that way.

 

P.S. Sorry for a long wall of text.

[Spitfire976 4]

7 hours ago, Amyel said:

The mount to solid frame will prevent if from moving (as whole) however recoil still has to go somewhere - so in this case within gun itself. Also - bigger the gun bigger the shell. Therefore spring gases going back to eject used shell, tilt the chamber (although it might be slightly different with ammo belt) to accept another shell must be at higher pressure. The weight of mechanism being shuffled front and back is enough to make it less accurate - especially if the gun is hand operated. On the other hand sometimes higher weight of a gun makes it a bit easier to keep it steady.

P.S. Sorry for a long wall of text.

 

 A couple of points about that. First, the momentum of the moving components of a gun is small. Each one of them should be made to be light, as heavier components would waste the energy that you wish to transfer to the shell once that you depend on their circle to have continuous fire. Second, at the moment of firing, the moving parts of a gun reduce it's recoil, as their momentum will oppose the momentum of the projectile, and momentum is a vector. Third, guns are designed to have high energy but small momentum projectiles, that's why the muzzle velocity is extremely high, as momentum grows with the velocity and energy grows with velocity squared.Thus the recoil isn't extremely high for a mechanical construct, such as a dampening system, that could be introduced to bombers with little performance impact to the plane as they're already heavy. This is what I meant when I talked about the way the guns were mounted.    

 

As for the rest that you said, really interesting. I thought it would take longer for a MG to overheat. Two considerations however. First even though I like the idea of forcing players to use their guns in a more realistic manner, that would affect every gun in the game, thus the whole sim community would need to agree to that. Second, is the point you've brought up at the end. Even though air is an insulating medium, I do think that the air stream of the plane, along with the outside temperature, would affect the gun's performance and might increase the size of the allowed bursts. 

 

PS.: If this sounds like I'm being arrogant or impolite, I apologize. This is my analysis of a machine that I know little about,however with my knowledge about mechanics, I'm guessing the engineering required to make it work. And for all I know you could be studding physics yourself or have more knowledge about firearms, in that case, I'd gladly discuss the technical aspect further.   

 

 

[D3athCZE 337]

10 hours ago, Spitfire976 said:

 

 A couple of points about that. First, the momentum of the moving components of a gun is small. Each one of them should be made to be light, as heavier components would waste the energy that you wish to transfer to the shell once that you depend on their circle to have continuous fire. Second, at the moment of firing, the moving parts of a gun reduce it's recoil, as their momentum will oppose the momentum of the projectile, and momentum is a vector. Third, guns are designed to have high energy but small momentum projectiles, that's why the muzzle velocity is extremely high, as momentum grows with the velocity and energy grows with velocity squared.Thus the recoil isn't extremely high for a mechanical construct, such as a dampening system, that could be introduced to bombers with little performance impact to the plane as they're already heavy. This is what I meant when I talked about the way the guns were mounted.    

 

As for the rest that you said, really interesting. I thought it would take longer for a MG to overheat. Two considerations however. First even though I like the idea of forcing players to use their guns in a more realistic manner, that would affect every gun in the game, thus the whole sim community would need to agree to that. Second, is the point you've brought up at the end. Even though air is an insulating medium, I do think that the air stream of the plane, along with the outside temperature, would affect the gun's performance and might increase the size of the allowed bursts. 

 

PS.: If this sounds like I'm being arrogant or impolite, I apologize. This is my analysis of a machine that I know little about,however with my knowledge about mechanics, I'm guessing the engineering required to make it work. And for all I know you could be studding physics yourself or have more knowledge about firearms, in that case, I'd gladly discuss the technical aspect further.   

 

 

AFAIK: E = m*(v^2). This means that pistol's slide or similar mechanism on a MG will have same energy regardless of it's weight, since it's used energy stored in the smokeless gun powder(or other propellant such as nitrocellulose). However, I guess that M2 Browning works on short-recoil mechanism to feed new cartridge into the chamber, since gas operated slides were first used in STG44 that entered service in 1943. 

 

So, lets begin. Pistol, and by my guess M2 BMG works on the same principle. We are using energy stored in the propellant inside the casing to fire a bullet outside the barrel. By Newton's 3rd law every action initiates an opposite reaction. This means that same force which is pushing the projectile through the barell pushes the slide or whatever locking mechanism which locks the round in the chamber back. Lets expect that we are in the perfect universe and we do not have energy losses due to friction, gas escape etc. Therefore E₁(bullet energy) equals E₂(slide energy). m₁ is weight of the bullet, v₁ is the velocity of the bullet. m₂ is the weight of the slide and v₂ is the speed of the slide.

 

E₁ = E₂

m₁ * v₁² = m₂ * v₂² 

 

m₂ is constant, therefore v2 will vary depending on bullet's weight and velocity. Therefore the exact amount of coituses about wasted energy is 0.

Edited July 13, 2017 by D3athCZE

[Amyel 1,657]

14 hours ago, Spitfire976 said:

First, the momentum of the moving components of a gun is small.

Well, not  really - it has the same energy to whitstand as bullet that has been shot - as explained by D3athCZE. So acceleration of the parts needs to be considered as well (and mechanical issues that comes with it, but i don't think that needs to be modelled in game tbh)

 

14 hours ago, Spitfire976 said:

Each one of them should be made to be light

Unfortunately this is not exactly a case as a chamber and barrel need to be able to take repeated (at very short intervals) exercise of gases being uncompressed at very high pace. Light materials had no structural integrity for it - especially in case of M2, considering cartridge and energy brought by explosion of propeller.

 

14 hours ago, Spitfire976 said:

Second, at the moment of firing, the moving parts of a gun reduce it's recoil,

The recoil momentum acquired by the gun exactly balances the forward momentum of the projectile and exhaust gases (ejecta), according to Newton's third law, known as conservation of momentum. In hand-held small arms, the recoil momentum is transferred to the ground through the body of the shooter; while in heavier guns such as mounted machine guns or cannons, recoil momentum is transferred to the ground through the mount.
Dampening mechanisms take away a part of recoil but the rest is still going to the mount.
And because mount is a stiff physical point of the plane, there's no much a way for that energy to be disperrsed in soft, controled method. It's a hard and abrupt stop, which is transferred back to the gun again. Thus yet again decreasing accuracy at prolonged firing.
For mechanically/electrically (basically remotely) controled turrets it may be different as the whole thing is a frame. However at this point for such turrets we should have mouse JOYSTICK and not direct mouse control.

 

14 hours ago, Spitfire976 said:

First even though I like the idea of forcing players to use their guns in a more realistic manner, that would affect every gun in the game, thus the whole sim community would need to agree to that.

I think it's something we have in fighters right now. I guess it shouldn't be different for bombers. So first - no overheating "red circle". Player needs to control the time guns are firing. No hit markers confirming that your aim is bang on on target. Only visual assesment (and crit mesages, which i personally think should be gone totally) should be the indication you are actually hitting target.

 

14 hours ago, Spitfire976 said:

Even though air is an insulating medium, I do think that the air stream of the plane, along with the outside temperature, would affect the gun's performance and might increase the size of the allowed bursts. 

As i said i'm not sure here. I know that barrels are outside should and can be cooled be air stream (to what extend though?), but it's not just barrel. It's also a chamber which i think stays well inside the vehicle.

 

14 hours ago, Spitfire976 said:

If this sounds like I'm being arrogant or impolite, I apologize.

No need for that, no one knows everything. And even when one thinks so, one can still be wrong. (to be clear - talking about myself here!)

[Spitfire976 4]

11 hours ago, D3athCZE said:

m₁ * v₁² = m₂ * v₂² 

Automatic guns require a spring to work, thus the equation is incomplete. Also the equation in the current format can't give you a sine or cosine function, thus it can't represent a periodic phenomenon.You also can't ignore the energy lost by heat, given that this is a really inefficient process and we're discussing the overheating of the gun.The right one would be:

1/2*v1^2*m1+1/2*v2^2*m2-1/2*k*x^2= deltaE. This equation would give you the position of the firing mechanism at any given time, but you will need to use the differential notation, and determine the inicial conditions.

 

8 hours ago, Amyel said:

Unfortunately this is not exactly a case as a chamber and barrel need to be able to take repeated (at very short intervals) exercise of gases being uncompressed at very high pace. Light materials had no structural integrity for it - especially in case of M2, considering cartridge and energy brought by explosion of propeller.

 

Indeed, even more in ww2 as steel was the most used material. The intervals are longer than you think actually, firing 600 rounds per minute as the M2HB, you would have a frequency of 10 rounds per second. Assuming that the mechanism would have the same length of the whole bullet at 0.138 m, it would need to cover the distance twice each circle, giving a linear velocity of just 2.76 m/s which is roughly 450 times smaller than the projectile muzzle velocity at 928 m/s. As the projectile mass is 0.647 Kg, the mechanism would have to weight nearly 300 Kg to counter the momentum of the shell(Momentum = velocity*mass). The gun without a bipod weights 38 Kg, but as the M2 is recoil operated, a good portion of the mass will have momentum.Assuming 30 kg is the weight of the bolt and barrel( total guess to make the result be 10%  ) the momentum of the moving parts of the gun would be 10% of the momentum of the projectile.Take the numbers with a grain of salt as they're taken from the wikipedia, however I don't think that they would be wrong enough to change the conclusion that their momentum is small.  

 

8 hours ago, Amyel said:

The recoil momentum acquired by the gun exactly balances the forward momentum of the projectile and exhaust gases (ejecta), according to Newton's third law, known as conservation of momentum. In hand-held small arms, the recoil momentum is transferred to the ground through the body of the shooter; while in heavier guns such as mounted machine guns or cannons, recoil momentum is transferred to the ground through the mount.

 

Absolutely correct. The recoil depends on the momentum of the part of the system. However the moving parts of the gun have a velocity that opposes the velocity of the projectile, thus it to helps counter the recoil of the gun, not increase it.

8 hours ago, Amyel said:

Dampening mechanisms take away a part of recoil but the rest is still going to the mount

 

Now we enter in a another way to counter momentum: Impulse(force*time). As long as the dampening system can provide the right force, it can virtually remove the recoil of the gun as it can act infinitely close to t=0. This is the way we counter recoil on a firearm, however as we need to account for the reaction time of our body, we can't act at t=0, thus the gun acquires a velocity. 

 

Disclaimer: The system I'm using is the gun and it's internal components. The operator and mount are external to the system, thus they act as external forces. I believe this is the easier way to study the system. Great discussion on the matter btw.

 

8 hours ago, Amyel said:

So first - no overheating "red circle". Player needs to control the time guns are firing. No hit markers confirming that your aim is bang on on target. Only visual assesment (and crit mesages, which i personally think should be gone totally) should be the indication you are actually hitting target.

Agreed. I haven't thought about this, but it is a unfair advantage. Also think that they should remove the indication of critical hits, and as we're in the subject, oil/water leaks should be crits in game.  

 

8 hours ago, Amyel said:

It's also a chamber which i think stays well inside the vehicle.

Yes it would affect the temperature of the gun. But you need a fourrier series to model that, and as the temperature is not a constant,and worse is a sine or cosine function this would be complicated as hell. I think it's overkill to put it in game.

 

On 12/07/2017 at 9:18 AM, Amyel said:

P.S. Sorry for a long wall of text.

I guess I'm sorry too now  .

[D3athCZE 337]

Yay! Physics on forum! I am starting to like it. 

Moreover, I would like to apologize for simplified equations. I am a mere SW & HW engineering student, not a Mechanical engineer.

[Amyel 1,657]

14 hours ago, Spitfire976 said:

The intervals are longer than you think actually

All depends on purpose - is 0.1 secs long in auto-fire? Do not know.

14 hours ago, Spitfire976 said:

Assuming that the mechanism would have the same length of the whole bullet at 0.138 m, it would need to cover the distance twice each circle, giving a linear velocity of just 2.76 m/s

Ah, yes - but this is ideal condition case ( for a half of a way that is)
In such case it means that the vector direction changes at exactly half way and holds the same speed value throughout the whole movement - which IRL is not going to be true to air friction/ material to material friction and material flexibility/softness and energy loss.

And, frankly, it's not going to be linear in a whole process. But yes - 2.76m/s is the minimum average speed that needs to be achieved by a chamber to be able to come back to firing position if we are going to have sustained repeated fire solution.

 

14 hours ago, Spitfire976 said:

As the projectile mass is 0.647 Kg

a small mistake on your part - this is a weight of WHOLE cartridge not just the projectile (42 grams)

But just taking momentum in here (mass * velocity) 0.042g*928m/s = 40 kgm/s (rounded)

To achieve exatcly the same for a gun you have 40kg * X = 40 kgm/s, which implies velocity of chamber is 1m/s (and as you have pointed out - that wouldn't do)

 

What momentum doesn’t help determine is how much energy is contained in the movement of an object. An object’s Kinetic Energy is determined by half of its mass times the square of its velocity so the same energy needs to be applied to chamber (but maybe i'm wrong on taking energy instead of momentum in here but they are somwhow linked to each other)
So it gives 18kJ of energy to get bullet of such weight to such speed.
So taking 40kg for a gun, and applying that energy to it (KE = 0.5*M*V) gives you actually 30m/s(at the highest).

Due to dampening mechanisms and conditions mentioned earlier that speed is of course getting smaller as chamber traverse back. But you also have to remember that chamber is not going forward with the same speed/energy or momentum. The whole energy that made it move back is either dispersed by dampening and the rest is moved to the frame.
At this point chamber goes back to firing position by a strength of a spring only (well, also a knockback helps a bit).

 

14 hours ago, Spitfire976 said:

However the moving parts of the gun have a velocity that opposes the velocity of the projectile, thus it to helps counter the recoil of the gun, not increase it.

Oh, maybe a bit of wrong wording on my part. Agree that recoil is descreased by dampening spring etc. but the rest of energy still goes to frame (and being knocked back to a gun again as frame is stiff/solid point).
It will decrease overall ACCURACY on prolonged shooting as accumulated recoil from every shot will add a bit of energy wave going back and forth. In extreme case if these energy waves would be synchronised, the effect would be multiplied.

 

 

14 hours ago, Spitfire976 said:

Yes it would affect the temperature of the gun. But you need a fourrier series to model that, and as the temperature is not a constant,and worse is a sine or cosine function this would be complicated as hell. I think it's overkill to put it in game.

True dat

I'm not sure if actually temperature changes with altitude to be honest.

I have recently been flying only figters (mostly 190 A1 with passive radiator) and observed that oil/water temperatures were getting lower with altitude. However that might be due to lower ATA pressure.

 

 

I do know it's all simplified and maybe we should consider all condition as heat dispersion, parts fitting and all but i think that would be (along with the ambient temperature question) a bit too much to code.

 

P.S. Found sth like this - intersting read
http://mdr.simr.pw.edu.pl/index.php/MDR/article/download/80/80

 

P.S.2 -yet again wall of text :/

 

 

[Spitfire976 4]

8 hours ago, D3athCZE said:

Moreover, I would like to apologize for simplified equations.

 

No need for that. Your analysis isn't wrong, and for a estimation you could make the deltaE=0. You just forgot the spring.

 

8 hours ago, D3athCZE said:

Yay! Physics on forum!

Yay, hope we're not frighting people with it though . 

 

4 hours ago, Amyel said:

Ah, yes - but this is ideal condition case ( for a half of a way that is)

 

Yes, my analysis is rather simplified. It was more to give a idea of the phenomenon than to describe it fully. For that we would need the spring stiffness and the locking mechanism maximum force. 

4 hours ago, Amyel said:

a small mistake on your part - this is a weight of WHOLE cartridge not just the projectile (42 grams)

 

I thought that I had made that mistake, my bad.

 

4 hours ago, Amyel said:

What momentum doesn’t help determine is how much energy is contained in the movement of an object. An object’s Kinetic Energy is determined by half of its mass times the square of its velocity so the same energy needs to be applied to chamber (but maybe i'm wrong on taking energy instead of momentum in here but they are somwhow linked to each other)

 

As both momentum and energy "come" from Newton's Laws of Motion the result should be the same. I think that momentum would be more useful in this scenario, as you would know the parameters of the spring and frictional force of the lock in the project. To use energy you'd also require the work done by the frictional force, thus adding a integral of a periodic function to your model, which often is not nice. All that said, we would need those parameters, and I doubt we'll find them on the internet as I don't think they want home made M2's soonTM .

4 hours ago, Amyel said:

It will decrease overall ACCURACY on prolonged shooting as accumulated recoil from every shot will add a bit of energy wave going back and forth. In extreme case if these energy waves would be synchronised, the effect would be multiplied.

 

Yes now I understand the point you've made in the start, and agree with it. If there's no dampers in the system the energy will steadily increase in the spring over time, making the mechanism move faster each circle. This would make the movement less predictable, thus reducing the accuracy. Also, this might be the reason for guns jamming in full auto fire, as the friction would reach it's limit, the mechanism will alter it's frequency, causing a bullet to be poorly introduced into the gun. 

 

4 hours ago, Amyel said:

I'm not sure if actually temperature changes with altitude to be honest.

I have recently been flying only figters (mostly 190 A1 with passive radiator) and observed that oil/water temperatures were getting lower with altitude. However that might be due to lower ATA pressure.

 

The temperature of the outside would steadily decreasing as you gain altitude, but it would be constant in time. The chamber temperature would be a cosine function most likely,as at t=0 the temperature would be the same as the outside, and it would increase with the energy for each shot fired. Both the ATA pressure and the air temperature are responsible for that. I think that the thermodynamics in War Thunder need a major overhaul  though. No plane could keep 10 min on WEP or stay a entire sortie on EC on 90%, and engines are way more fragile to overheat than they are in 

game, but this is a discussion for another time.  

 

P.S's:

4 hours ago, Amyel said:

P.S. Found sth like this - intersting read

Interesting indeed. I might have understood it wrong, but they're also trying to stabilize the bolt with the damper. And how did the Warsaw university of technology get a 50 cal?

I like the tangent that we went on this.

Last but not least, 2x2 on the walls of text now  .

 

 

 

 

 

Edited July 14, 2017 by Spitfire976
Saying something is constant and variable in the same sentence. A tad confusing :).

[Amyel 1,657]

3 hours ago, Spitfire976 said:

And how did the Warsaw university of technology get a 50 cal?

Quoting wiki (but still in this case i think is fine):

Polish high caliber machine gun, designed in 1999. A modification to soviet NSW machine gun. Uses 12,7x99 cartridges.

 

3 hours ago, Spitfire976 said:

I think that the thermodynamics in War Thunder need a major overhaul  though.

We have waited LONG time just to get different temps on different maps. I wouldn't hold breath if i were you

 

But i do thank you for interesting discussion in VERY CIVILISED manner.

I think i learnt quite few things in here.

 

 

[Officer_bobkills 1,331]

Gunners are broken, they should be either AI or axis controlled (as turrets actually were in most bombers). Mouse-aim makes them way too accurate, which renders planes with gunners unplayable in SB — which is too bad as they're some of my favourites.

By the way, for the mechanics of an M2 - you wouldn't solve it with energy you should use momentum to find the impulse from the gaseous expansion on the action (recoil operated for an M2 if memory serves), then solve for the dissipation of that impulse into the spring (I'm assuming you want to solve for the spring's dT). Couple that with some material properties and you could theoretically calculate how the spring heats up — but to do that you have to solve for how it cools which would be a pain. You might want to go back and check your equations, several of them have been wrong. 

 

The issue actually comes to the barrel (based off reading about USAAF procedures for M2s). Prolonged firing caused too much heat to build up in the barrel and could lead to a runaway gun. As it's air cooled it doesn't cool very well (when compared to the heat generated with prolonged firing). If you want to check, grab your heat transfer book (everyone's favourite class!) and it should be like an ideal cylindrical fin (assuming the interior of the barrel is at a constant temp, which it isn't but doing it another way would be harder and this should be close enough). 

 

If you want to solve it:

• If they're flying at 30 000' (indicated) the air temp would be ~-44C (using standard atmosphere).
• The barrel OD should be available online (for simplicity, neglect the ID)
• Guesstimate the energy put in to the 'fin' based off the energy in the casing (chemical) subtracting off about double the energy in the bullet (kinetic E in the bullet, and because actually finding it would take time, just use that for the energy in the action) and some energy in the casing (it heats up too) — if you want to be really good you can take a stab at the efficiencies of combustion, how much energy from the combustion actually goes out the ed of the barrel via dissipating gas, etc.
• The cook-off temp for 0.50 BMG should be available online
• Chamber temp is assumed to be the barrel temp as they're in direct contact (assuming the chamber is cut out of the barrel as many guns are)

From that you should be able to calculate the rate of fire which can be sustained without ammunition cook-off. Damn, I'm glad undergrad is over.