Hispano vs. MG151 In-Game Relative Effectiveness

[Stoney]

Youre the one being educated on the subject in this thread.  Do not reply to me as if im not following the subject matter.   

Hey, I wasn't calling you out Murder.  I was trying to state that since the data you linked to was effectiveness versus objects, it wasn't going to help the discussion since Urchin et al had already discussed the fact that the damage versus objects wasn't the same as the air-to-air damage.

[Murdr]

Ill explain the datas relevence when I have a keyboard.

[Murdr]

The table I posted a link to eariler is a fair representation of the chemical power, or potential energy of HE rounds.  Both of these are HE cannon rounds, and it is entirely accurate to cite that in AH the MG151 has 88% the explosive power of the Hispano, which is constant regardless of range.  It is not completely irrelevent to 'vs aircraft'.  Anyone who has vulched with cannons, without actually hitting the plane with the round would be aware of this.

Sorry if I got testy, but I was just trying to point out a reference to the test you already tried to perform with more accurate results expressed in a game based metric rather than some abstract scale.  And the linked page already stated the difference between objects and enemy damage modeling.


On the kinetic energy side, here are some velocity figures I derived from offline testing.

MG151/20
average speed at 400 yards = 2146fps (average of 15% loss of kinetic energy from point blank)
average speed at 800 yards = 1294fps (average of 50% loss of kinetic energy from point blank)

20mm M2
average speed at 400 yards = not measurable
average speed at 800 yards = 2478fps (average of 15% loss of kinetic energy from point blank)
average speed at 1000 yards=2190fps (25% loss)

As an anicdotal point of reference, a head on shot at a 600mph closure rate adds 880fps of effective speed.

[Urchin]

If you don't mind me asking Murdr, how did you arrive at those numbers?

Also, while I know I have read that AH's damage model favors kinetic energy over chemical energy (which is why the MG-FF sucks so much, even compared to the MG-151), I don't know of any way to test and see what that impact is.

[Charge]

AFAIK we should not have a plane that uses MG-FF without M option. The M would bring a significant boost to its power as it sucks so much in muzzle velocity department.

MGs has 700m/s MV even in MG-FFM but due to its chemical nature it cannot really use it to its advantage except for better ballistics.


Something to consider when calculating HE power:

Hispano HE: 11.3 grams of Tetryl 7,570m/s (RE1,25) or Composition A (91% RDX (EV 8,750m/s) +9%wax)

MGs: 18.6 grams of Penthrite (PETN) 8400m/s (RE1,66) or RDX with aluminum powder (called HA41) claimed to add 40%* effect to normal penthrite, RDX has 8,750m/s (RE unknown) (additional clay in HA41?)

*Aluminum powder is used because it can use the excess oxygen from the RDX explosion to increase the heat and blast effect of RDX.


Considering that most calculations on the subject are made with TNT figure it can be concluded that the filling of the HE grenade does make a difference. But even if it does it is just too bad for MG151/20 that blast effect is not given much emphasis in AH.
 
Note: RE (relative energy) for TNT (6900m/s) is 1.



-C+

[Murdr]

By measuring average bullet drop at range with convergence set to minimum.  With drop and gravity "time to fall a distance" can be determined.  With time and distance downrange average velocity can be determined.

[Tony Williams]

As a matter of interest, official German velocity loss and time of flight figures for their aircraft ammo were as follows:

Loading/notes    MV m/s    V/300m    V loss  secs/300m   V/600m  V loss  secs/600m

7.92 mm AP 10g   810   538   33%   0.453   348   57%   1.159
13mm HEI 34g   750   501   33%   0.49   337   55%   1.22
15mm HEI 57.5g   960   743   23%   0.357   583   39%   0.816
20mm HEI 92g 1   695   432   38%   0.551   281   60%   1.428
20mm HET 117g 2   720   552   23%   0.477   422   41%   1.101
30mm HEI 330g 3   500   370   26%   0.696   264   47%   1.660
30mm HEI 330g 4   500   429   14%   0.649   370   26%   1.403
30mm AP 355g 5   960   862   10%   0.33   776   19%   0.697

Notes:
1 –   M-Geschoss fired from an MG-FFM.
2 –   fired from an MG 151/20.
3 –   M-Geschoss Ausf.A fired from an MK 108.
4 –   M-Geschoss Ausf.C fired from an MK 108.
5 –   Hartkernmunition fired from a MK 101 or MK 103.

German information from a different source document indicated that HS 404 HET shells slowed from 880 to 675 m/s at 300 m and about 500 m/s at 600 m, reductions of 23 % and 43 % respectively.

[Schlowy]

Murdr, I'm not sure what you're saying, but isn't convergence independent of drop rate?
If ya set it 100 or 650, it only affects where a pair of cannons' bullets cross right? I mean, the gun barrels don't actually adjust up or down? (this has been a question of mine because it doesn't seem to make sense setting a center firing cannon on a 109... let alone the cowl guns, soo close...Or the inner guns on a 190...

Anyways, we're getting lots of info, and it seems like some of it is conflicting... if someone really really knows what they're talking about, sum this stuff up! pls 

[Anodizer]

Murdr, I'm not sure what you're saying, but isn't convergence independent of drop rate?
If ya set it 100 or 650, it only affects where a pair of cannons' bullets cross right? I mean, the gun barrels don't actually adjust up or down? (this has been a question of mine because it doesn't seem to make sense setting a center firing cannon on a 109... let alone the cowl guns, soo close...Or the inner guns on a 190...

Anyways, we're getting lots of info, and it seems like some of it is conflicting... if someone really really knows what they're talking about, sum this stuff up! pls 

Actually, they are adjusted "up and down"...  Think of it like this..  The cannon or mg round drops as it travels.  So, if you fire a cannon or mg and set the convergence out to D650, the gun itself has to be raised to compensate for drop..  The bullet or cannon round takes the trajectory of an arc..  I wish netaces.org was up because I'd just link they're explanation along with images... 

[Murdr]

If ya set it 100 or 650, it only affects where a pair of cannons' bullets cross right? I mean, the gun barrels don't actually adjust up or down?

The gun barrels do actually adjust up and down.  Convergence settings also effect gun elevation angle so that rounds trajectories will be passing through verticle center of the reticule at convergence range.

[BnZ]

So, is the bottom line of this that German 20mm shells stuffed to the gills with high explosives should possibly do as much or more damage per hit than Hispano 20mms? Or something else?

[Krusty]

As a matter of interest, official German velocity loss and time of flight figures for their aircraft ammo were as follows:

Loading/notes    MV m/s    V/300m    V loss  secs/300m   V/600m  V loss  secs/600m

7.92 mm AP 10g   810   538   33%   0.453   348   57%   1.159
13mm HEI 34g   750   501   33%   0.49   337   55%   1.22
15mm HEI 57.5g   960   743   23%   0.357   583   39%   0.816
20mm HEI 92g 1   695   432   38%   0.551   281   60%   1.428
20mm HET 117g 2   720   552   23%   0.477   422   41%   1.101
30mm HEI 330g 3   500   370   26%   0.696   264   47%   1.660
30mm HEI 330g 4   500   429   14%   0.649   370   26%   1.403
30mm AP 355g 5   960   862   10%   0.33   776   19%   0.697

Notes:
1 –   M-Geschoss fired from an MG-FFM.
2 –   fired from an MG 151/20.
3 –   M-Geschoss Ausf.A fired from an MK 108.
4 –   M-Geschoss Ausf.C fired from an MK 108.
5 –   Hartkernmunition fired from a MK 101 or MK 103.

German information from a different source document indicated that HS 404 HET shells slowed from 880 to 675 m/s at 300 m and about 500 m/s at 600 m, reductions of 23 % and 43 % respectively.

It's too early in the morning for me to comprehend that. Does that add up to what Murdr posted? Or is there a difference in the way HTC models our 20mms?

[Karnak]

So, is the bottom line of this that German 20mm shells stuffed to the gills with high explosives should possibly do as much or more damage per hit than Hispano 20mms? Or something else?

If the belt were 100% mine shells, yes.  With the normal belt being a mix of regular HE and mine shells, no.  What you would have is a bunch of shells that didn't hit as hard as the Hispano mixed with a few shells that hit harder.  AH doesn't model individual round types in abelt though so it just averages the amount done of that entire standart belt and assigns the damage evenly across the shells.  That means you have each shell hits a tad softer than the Hispano without the lower damage of the normal HE shells or the spikes of the mine shells.


This is actually the reason I am most concerned about players being able to set their own belts.  Everybody would just set 100% mine shells in German fighters and to hell with any historical accuracy.

[Tony Williams]

It's too early in the morning for me to comprehend that. Does that add up to what Murdr posted? Or is there a difference in the way HTC models our 20mms?

The RL velocity losses are much higher.

Tony Williams: Military gun and ammunition website

[Stoney]

It's too early in the morning for me to comprehend that. Does that add up to what Murdr posted? Or is there a difference in the way HTC models our 20mms?

And, unless I did my math wrong, Murdr's velocity numbers are a bit higher than those posted by TW.