Spit V vs 109F...

[ATAG_Lewis]

I know that throughout the war there was a technology race between certain aircraft...The Spit vs 109 being a famous contest where one excelled past the other then vice versa...With patch 5.0 being the next patch and hopefully including Spit V and 109F what differences are we to expect with the Spit V verses the 109F...Which was better in terms of firepower, speed, manoeuvrability etc...

[ATAG_Colander]

Gliding distance will be 9:1 ratio between the two

[ATAG_Lolsav]

Situation:

Lewis in Spitfire V and Lolsav in 109F.

Lolsav says:
http://www.intriguing.com/mp/_sounds/hg/pointy.wav

:D

[Vadr]

in my humble experience, there isn't a lot of difference in the 109F vs Spit V fight from the 109E/Spit I...with one exception.

Caveat: all this depends on the flight models of course, but I have a lot of faith in the Team Fusion crew.

The 109F will still out-climb, out-dive and out-accelerate the Spit V, and should be faster at most altitudes. Spiral climbs, scissors, and vertical maneuvering will still be important tools in the 109 pilots bag, while the Spit driver can still rely on instantaneous and sustained turn performance, so not a lot changes there (the top speed comparisons will be interesting).

The BIG change, and the one that should have the most important affect on the dogfight, is in firepower...and that cuts both ways. The Hispano-Suiza cannons on the Spit V are *fearsome*, and a lot of 109 drivers who have gotten away with dancing in front of Spit/Hurri .303s (I myself am guilty) are going to find themselves floating under silk in very short order. Those guns have greater muzzle velocity than the 109E cannons, greater range, and greater hitting power. I weep for the poor bomber pilots.

OTOH, while the single nose-mounted F cannon is an overall reduction in firepower, the MG 151/20 is a superior weapon in all respects to the MG FF mounted on the E model, allowing the 109F driver to make snap, deflection and long range shots that the E driver could only dream about. It rewards a good shooting eye.

Should be loads of fun. :)

<S>

[Gromit]

Depends on which model 109F, the SpitVb and the 109F was a pretty even matchup until the F4, then the 109 steps ahead on outright speed, but the Spit was always capable of out turning the 109, roll was similar and climb depended on speed and alt.

Firepower definatly suffered in the earlier F the original had an MGFF in the nose (E has 2) and the first MG151 was a 15mm which was universally disliked, the 20mm MG151 improved matters but uses a smaller cartridge than the Hispano, so Muzzle energy wise the Hispano is always going to be more powerful.

Don't forget there are many variations of Spit V as well.

In Malta the Spit V was able to match the 109F and early G with experienced pilots, so it should be a good matchup.

Only problem is it will leave other airframes behind and you can bet everyone will be flying the best models, our poor old Hurricanes and G50's are going to be a rare sight.

[ATAG_Lolsav]

Only problem is it will leave other airframes behind and you can bet everyone will be flying the best models, our poor old Hurricanes and G50's are going to be a rare sight.

Depends on the map makers :D

Well a "evolutive" pilot carrier mode (if that was achievable online) would be interesting, where the ones who die less would have better planes. A reward for virtual life preservation for instance.

Rough example: A pilot is novice fly hurricanes/g50/Spit I -->flys 5 sorties without dieing, gets promoted and be able to fly the "next level" planes, so on... If dies its demoted.

Now a problem with this: It gets more "gamey", insted of a simulation. Or maybe not, because you have to strive to stay alive, resulting in more cautious pilots.

Anyway its just dependent on map makers and their skills to create the balance.

[Gromit]

How about we reverse that, the more kills you get the worse the plane you can fly?

That would separate the men from the boys, and give the new guys a bit more chance!



On the subject of plane availability, I see your point, I am however not optimistic considering the number of Spit iia and 109E4N/B we see in play regularly.

[Vadr]

As lolsav said: "it depends on the map makers"

In the old Warbirds sim main arena, they had the concept of a 'rolling plane set'. They had planes from the 109E/Spit I to the Me 262/Spit 14, so it was a little more involved. Over a period of about 28 days; the first day or two would have only 1940 aircraft available, then for the next day or two, the 1941 aircraft would be added to those available, then in the next couple of days 1942 etc., all the way to the very last day of the RPS, which was the only day the 262 was available. The last 2 days had the Dora/Spit 14.

We could to do something similar here (maybe with the ATAG Bomber arena?).

Just a suggestion. Restricting available aircraft based on pilot skill/lack thereof always seems to lead to resentment. If we could implement something like an RPS at least the playing field would be even.

Note: Gromit is completely correct about the different 109s and their armament. I was talking about a Spit-Vb/109-F4 matchup in my earlier post. Didn't realize this was in the 'War History' section. I got here from 'New Posts'. My bad. :)

[RAF74_Buzzsaw]

There are a large number of variants... you can't make a sweeping generalization about which might be better, you need to examine each version in detail and decide which version is being compared to which version.

For the 109F's, for example, you have the following:

109F-1: DB601N engine, (same as the engine in the E-4N), one MG/FFM cannon with 60 rounds firing through the prop, plus the two LMG's.
109F-2: DB601N engine, one MG/151/15mm cannon, (very high velocity, very accurate, but no high explosive rounds) firing through prop, plus two LMG's. Slightly reduced performance, higher stall speed, due to increased weight of larger cannon and ammunition
109F-2 (Late): DB601N engine, one MG/151/20mm cannon, firing through prop, plus two LMG's. (increased weight)
109F-2-Trop: Same as above, but with enlarged air intake filter (increased weight)
109F-4: DB601E engine, rated at 1.30ata boost at 2500 rpm, one MG151/20mm cannon firing through prop, plus two LMG's. (increased weight over F-2, thus higher stall speed)
109F-4-Trop: Same as above, but with enlarged air intake filter
109F-4 (Late): DB601E engine, rated at 1.42ata boost at 2700 rpm, one MG151/20mm cannon firing through prop, plus two LMG's.
109F-4 (Late)-Trop: Same as above, but with larger filter

All the 109's had the fuselage/wing/tail design changes... these were primarily incorporated to provide a more aerodynamic frame, and higher speed, to allow better maneuver at the higher speeds which combat was now occurring, and which the 109F's were now capable of achieving. As part of this, there was a sacrifice in low speed maneuver... the F model had inferior low speed lateral maneuver than the E model. The F's Stall speed, with the higher weight, was also slightly higher than the E.

For the Spitfires, you have the following:

Spit IIB: Same as the IIA, but with reduced performance, higher stall speed due to 20mm gun and ammunition extra weight... Two 20mm Hispano cannon, 4 LMGs.
Spit IIB (Late): Same as above, but with improved lateral maneuverability due to retro-fitted metal ailerons
Spit VA: Merlin 45 rated at +12 boost/3000 rpm, eight LMGs, fabric ailerons (increased weight and higher stall speed over IIB)
Spit VB: Merlin 45 rated at +12 boost/3000 rpm, two 20mm Hispano cannon, 4 LMGs, metal ailerons (increased weight and stall speed over VA)
Spit VB (Late): Merlin 45 rated at +16 boost/3000 rpm, two 20mm Hispano cannon, 4 LMGs, metal ailerons
Spit VB - Trop: Same as above with extra weight and reduced performance due to larger filter.

Spitfires initially were equipped with fabric ailerons, but as the RAF noted in 1941 the 109F was more maneuverable at higher speeds, the metal ailerons were introduced to counter this advantage.

So the fact is, when you look at all the models, comparisons are very much dependent on which version is compared to which.

You'll need to wait till TF 5.0 is out to really find out. :-) :P

I will also say that you can see from the above list how much work is required... so I hope everyone is patient... TF 5.0 will be done as soon as our resources will allow.

[Vadr]

Well, there's a post on the TF Facebook page that says there will be an F-4, so I remain very hopeful :D

[Gromit]

No takers for the F1 then?

Everyone's going to be in F4 lates :-P

[Karaya]

109F-2: DB601N engine, one MG/151/15mm cannon, (very high velocity, very accurate, but no high explosive rounds) firing through prop, plus two LMG's. Slightly reduced performance, higher stall speed, due to increased weight of larger cannon and ammunition

Just a minor comment: The MG151/15 did have high explosive rounds (HEI), even the 13mm MG131 had them. However in both cases the HE filler was quite small (~2g & 1g respectively).

http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Munition/handbuchderflugzeugbordwaffenmunition1936-1945.pdf

I've also made a rudimentary performance graph comparing the upcoming fighters. Continuous lines are for WEP (+12lbs for the RAF, Start/Not for the LW), dashed for the next best power setting that isnt WEP (+9lbs boost for the RAF, Steig/Kampf for the LW).

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Hurricane & Spitfire performance figures are taken from http://www.wwiiaircraftperformance.org/
The Bf109 figures are taken from official manuals (F-1/2 Kennblatt) http://kurfurst.org/Performance_tests/109F1F2_Kennblatt/Kennblatt_fur_Bf109F1F2_DB601N.PDF
and Rechlin flight tests (F-4). http://kurfurst.org/Performance_tests/109F4_Datenblatts/109F4_dblatt_calculated.html
The Bf109E figure is backed up by a french test flight of a captured aircraft. http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

[Gromit]

According to your graph Karaya the 109E is faster on the deck and up to 1000m than a MkV?

Looks a bit off, where did the 109 figures come from?

[Karaya]

I did not add the 109E myself, this entire graph is based on the Messerschmitt AG data sheet for the Bf109E with DB601A under guaranteed engine power. And yes, the Mk.V was slower on deck than the Mk.Ia for example. At +12lbs boost the Merlin 45 generates a little less than the Merlin III (~1270hp vs 1310hp). The Merlin 45 however has the advantage of a much more powerful supercharger giving it superior performance at altitude where most of the fighting at the western front took place. Fighter development in the UK & Germany went towards improving high altitude performance, sometimes at the expense of low alt performance as can be seen from the graph. The most dramatic changes in topspeed happen at higher alts not on deck.

22450

22451

Sources are quoted just under the graph btw.

[VO101_Kurfurst]

According to your graph Karaya the 109E is faster on the deck and up to 1000m than a MkV?

Looks a bit off, where did the 109 figures come from?

Depends on the boost on the Merlin 4x series, IIRC the first versions were limited to +9, then gradually raised that to +12 and finally +16 in mid 1942. But even the +16 variants barely crept over 500 km/h, the ones at +9 did around 460 only. Keep in mind the 45 was basically the single-speed version of Merlin XX and it was tuned for better altitude performance at the expense of low altitude performance, the cannons and radiators also chipped down quite a bit of speed.

The 109E figures are from the official type specification sheet for the Bf 109E w. DB 601Aa engine, and the figures closely resemble the 5 min 1.35ata rating achieved on the V15a flight test. So its a bit more fiery at low alt (1045 PS).

Finally, a bit of nitpicking, "accurate" for the MG 151/15 might not be the best choice of words, it was not bad, and had terrific ballistics and high velocity (~hit probability); however as far as dispersion goes the MG FF was the most accurate and reliable of all cannons in the LW arsenal, and perhaps the world, too, with only 1 mil(!!) bullet dispersion, and practically never jamming. High velocity and ballistic power usually acts against dispersion with automatic weapons, for the simple reason the powerful rounds flex the associated long barrel quite a bit and subsequently fired rounds will suffer for it.

[RAF74_Buzzsaw]

Depends on the boost on the Merlin 4x series, IIRC the first versions were limited to +9, then gradually raised that to +12 and finally +16 in mid 1942. But even the +16 variants barely crept over 500 km/h, the ones at +9 did around 460 only. Keep in mind the 45 was basically the single-speed version of Merlin XX and it was tuned for better altitude performance at the expense of low altitude performance, the cannons and radiators also chipped down quite a bit of speed.

The 109E figures are from the official type specification sheet for the Bf 109E w. DB 601Aa engine, and the figures closely resemble the 5 min 1.35ata rating achieved on the V15a flight test. So its a bit more fiery at low alt (1045 PS).

Finally, a bit of nitpicking, "accurate" for the MG 151/15 might not be the best choice of words, it was not bad, and had terrific ballistics and high velocity (~hit probability); however as far as dispersion goes the MG FF was the most accurate and reliable of all cannons in the LW arsenal, and perhaps the world, too, with only 1 mil(!!) bullet dispersion, and practically never jamming. High velocity and ballistic power usually acts against dispersion with automatic weapons, for the simple reason the powerful rounds flex the associated long barrel quite a bit and subsequently fired rounds will suffer for it.

Spit V's and the Merlin 45 were only limited to +9 in the prototypes... +12 boost was already being used by the earlier versions of the Merlin, (III/XII) in the field and for that reason, there will be no Spit V model limited to +9 in TF 5.0.

As has been mentioned, Spitfire development focused on achieving higher speeds at high altitude, rather than down low. The decision not to continue with the Merlin RM 2SM two speed supercharger in the Spitfire III, (engine later developed as the Merlin XX in the Hurricane) due to technical difficulties, but instead to quickly release the MkV with the single speed version of the supercharger which equipped the Merlin XX meant low speed performance was sacrificed to a certain extent.

Regarding the definition of accuracy in a airborne weapon, any description has to include most critically, muzzle velocity, as that element of a weapon's performance is the surest way to increase accuracy and avoid the omnipresent fact of gravitational drop. An airborne weapon fires from all positions, inverted, in a climb, in a dive, etc. etc.... fire from the flat and level almost never happens, and whatever the accuracy an MG/FF might achieve on a bench in a testing lab where convergence can be plotted exactly, knowing the weapon is exactly level, is far less relevant to real world conditions. Higher muzzle velocity means less time for gravity to take effect. This is why the Luftwaffe replaced the MG/FFM with the MG151/20mm. (which had higher dispersion than the MG/FFM but higher muzzle velocity)

[ATAG_Flare]

What are the main differences between the HS404 and the MG151/20?

[RAF74_Buzzsaw]

What are the main differences between the HS404 and the MG151/20?

Recommend you look at this page for a general evaluation.

http://www.quarryhs.co.uk/WW2guneffect.htm

MG151/20mm is 20X82

Hispano 20mm is 20X110

[Karaya]

This site is also a useful resource:

http://users.telenet.be/Emmanuel.Gustin/fgun/fgun-in.html

Mind you however that the values listed in the gun performance table are averaged in regards to muzzle velocity & projectile weight which is less of an issue with the Hispano than with the MG151/20. All 20x82 projectiles for the MG151/20 but the Minengeschoss (92g) were in the 115-117g region. Muzzle velocity of the rounds also varied greatly between 705m/s to 805m/s.

[Gromit]

It's extremely difficult to model cannon shells effectiveness with any creditable accuracy as there are a considerable number of factors to calculate.

The emphasis is nearly always placed on blast, but no matter what 20mm shell it carries only a pitiful amount of explosive, the pressure wave radius is extremely small and affected considerably by any voids or hard structures that can channel or reflect the wave, it's extremely complicated.

The real damage causer in a shell is the fragmentation, whilst the effective pressure wave may be measured in inches, the fragmentation pattern is in feet causing damage much further from the detonation point, post war ammunition development has focused entirely on the fragmentation field, it's density and velocity, modern rounds use less explosive but a far more advanced material for the casing, no modern weapon retains the M-Geschoss principle as this was found to be flawed and less effective than a fragmentation round. even your average terrorist worked out lacing bombs with ball bearings and nails did far more damage than just HE.

[Karaya]

Gromit, the Luftwaffe came to the exact opposite conclusion, namely that fragmentation as the primary cause of damage is too unreliable as it relies on the statistic probability of a shrapnel hitting something vital. That is why the Minengeschoss round was introduced with the MG FF/M cannon which relies on overpressure blast effects rather than fragmentation. It certainly did not carry a "pitiful" amount of explosive, its 18.6g of HE filler being about 3 times as much as that of other comparable rounds. The Minengeschoss btw lives on in present day ammunition such as the 30mm HE rounds found on the British ADEN & French DEFA cannons (which were heavily influenced by the German MG213 & MK213 revolver cannons).

[VO101_Kurfurst]

Spit V's and the Merlin 45 were only limited to +9 in the prototypes... +12 boost was already being used by the earlier versions of the Merlin, (III/XII) in the field and for that reason, there will be no Spit V model limited to +9 in TF 5.0.

That is a clearly a wrong result of a flawed research for the 1941 period no doubt accepted to give balancing boost for RAF fighters to give them a fighting chance.


no modern weapon retains the M-Geschoss principle as this was found to be flawed and less effective than a fragmentation round. even your average terrorist worked out lacing bombs with ball bearings and nails did far more damage than just HE.

Except of course all the post-war ADEN and DEFA derivatives of the wartime Mauser MG 213 revolver cannon and the Minengeschoss that was de facto standard in all post-war jet fighter designs. ;)

Fragmentation, especially with tiny fragmentation effect of a small shell is only useful as long as you can damage sensitive critical components in an aircraft, but since in the 1930s all modern designs went to all metal monocoque building, where all the structural loads were taken by the skin itself, rather than by fasteners and braces, it did make sense to destroy the structure itself. This could be better achieved by blast in small enclosed places, as the fragments would be otherwise be stopped by even by structural elements in which they could only cause tiny holes.

Regardless of whether we speak of the physical work (in case of shells: destruction) done by fragments or gas pressure, they both originate and cannot be greater than the source of their kinetic energy: expanding gas pressure generated by the explosion of the charge, i.e. the total potential energy of the explosives in the shell minus the force needed to break up the shell in the first place. Since traditional fragmentation shells have thicker walls and less explosives (explosive energy - 1/2 - 1/3 in comparison to mine shells in fact) in them than high capacity shells aka "Mine shells",, i.e. both the available energy is less and the energy loss (breaking up the shell) is less in the old type of shell and thus the potential net or "useful" energy (destructive effect) shall be also considerably less.

The relation of kinetic energy of the projectile vs its chemical energy is also simple to understand: the shell gains all its KE by the propellant that fires it from the barrel (and the propellant that fires the shells is always a magnitudes less powerful and violent than the explosive charge inside the fired shell - otherwise the barrel would simply blow up), and then looses a great deal (cca. 50%) of it due to slowing down by air resistance by the time it actually hits the target. It usually also cannot transfer all that KE into the target (=destruction), but only the amount necessary to penetrate the material(s) that it hits. Of course if it hits and destroys something vital like a main spar connection its already enough, but that's a rare occasion. In contrast, most of the explosion within the shell will be directly used for destruction in the confined structure of an aircraft.

[Gromit]

Except of course all the post-war ADEN and DEFA derivatives of the wartime Mauser MG 213 revolver cannon and the Minengeschoss that was de facto standard in all post-war jet fighter designs. ;)

Fragmentation, especially with tiny fragmentation effect of a small shell is only useful as long as you can damage sensitive critical components in an aircraft, but since in the 1930s all modern designs went to all metal monocoque building, where all the structural loads were taken by the skin itself, rather than by fasteners and braces, it did make sense to destroy the structure itself. This could be better achieved by blast in small enclosed places, as the fragments would be otherwise be stopped by even by structural elements in which they could only cause tiny holes.

Aden and Defa used the mauser rounds initially but after testing were re designed with less explosive , a heavier case (more fragments) and greater velocity, the originals , and we are talking 30mm here not 20mm, in a much larger 30mm round you would think the concept has merit, but the rounds were were found to be prone to deflection and had very poor penetrating effects, so the M-Geschoss was dropped in the late 50's and no weapon has used the principle since.

Your second statement is utterly incorrect, and history proves it by charting modern weapons development, even small fragments at the extremely high velocities created by the bursting charge (over 5000ft/sec) create considerable damage to structures over a wider area, which is why modern ammunition uses the principle. High explosive, especially as little as 18g has poor capability to damage structural members even in the close proximity the small blast radius requites, to cut or hole structures shaped charges are used!

70 years have passed and a lot more scientific testing has proven fragmentation is the king when it comes to creating damage.

[VO101_Kurfurst]

70 years have passed and a lot more scientific testing has proven fragmentation is the king when it comes to creating damage.

Teller Ede would strongly disagree. Do you see any fragments? ;)

http://pop.h-cdn.co/assets/15/33/1439572019-main-explosion.gif

Now, nobody says that HE shells are a general, end of it all solution (hence why the Germans also retained old type HEIFRAG in the belts) but as far as WW2 goes, that was quite simply the best solution for the given targets, just as full caliber APHE was the best anti tank solution against WW2 targets. I think you are a bit lead astray by the fact that post WW2 the aircraft targets have also greatly changed, jet engines are for example far more vulnerable fragments than pressure, and the aircraft are bigger and tougher as well, and nowadays a fighter could weight as much as a WW2 heavy bomber, and have so much power (thrust) some of them, at least theoretically, can almost fly without even wings. Well actually helicopters do just exactly that. So you have better chances with fragments hitting some of the more numerous and more vulnerable criticals than trying generally smashing down the structure. Not so much in WW2.

[Gromit]

Your grasping at straws bringing up atom bombs in a discussion about autocannon ammunition :ind:

your not really going to argue decades of weapons development has made things less effective, are you?

Fragments hit pilots, wiring, pneumatics, hydraulics, tyres, joints and control mechanisms as well as structural members, they do that now just as they did back then irrespective of what engines are fitted, 18g of explosives are not enough to create as much damage as fragments do over a much larger radius, and that's the real issue, the blast radius of that small an amount of explosive is literally inches, weapons developments have proven the concept, and discarded the M-Geschoss!

Did you know the effective radius of a Mills bomb grenade is over 30ft, yet the lethal blast radius ( the distance the shock can kill a human ) is less than 6 ft, an example of the differences between relying on blast and relying on fragmentation!

Do some research on the work of Gerry Bull if you want enlightening on how much intricate detail is put into the science of fragmentation dispersion and creation,

[Vadr]

"Back in my day, we had to walk to school. 10 miles. Through the snow. Barefoot. Uphill both ways".

Sorry, this conversation is just funny to me, given how much effort I had to put in to getting the Warbirds devs to model explosive ammunition at *all*. We were basically firing 20 and 30mm slugs at each other for the longest time. I had the head dev come watch a squad practice session one time. Head-on passes in 262s against B-17s. All he wanted to do was marvel at how the shells were going all the way through the bomber and lodging in the tail. Moron.

Amazing how times have changed in the flightsim world.

I have nothing constructive to add other than to urge some civility. Carry on smartly gentlemen.

<S>

[Vlerkies]

20 or 30mm HE canon rounds impacting on a fighter aircraft of the time will have a devastating effect if we are all honest with ourselves here.
The debates around these rounds of all types is more aimed at bigger planes like heavy bombers and their effectiveness to get them out of the air fast and efficiently with the least amount of ammo expended.

As I was told while burning in a few seconds flat from .303's, just don't get hit.
:salute:

[Gromit]

The conversation is about the differences between the Hispano and MG151 as asked above, so you have to look at the whole picture to gauge the effectiveness.

There is a tendency in gaming circles to bestow the MGS round with magical properties, now no one is saying they didn't go bang and cause damage they obviously did, but the concept was proven later to be flawed in small calibre ammunition.

what you give with one hand you take away with the other, by making the casing much thinner and using greater filler you remove the mass to create fragments, the down side to this, despite creating a bigger bang was a 20mm shell could not carry enough explosive to make the concept a front runner, 18g is the equivalent of a 1 inch cube of cheese, the other problem lay in the lighter shell often failed to penetrate even deflecting off the aircrafts skin if the angle was insufficient, this also affected the 30mm shell which is why that was re designed as a heavier shell with greater velocity and therefore more striking energy for the ADEN.

The Hispano round used the explosive as a bursting charge, not so much to create blast but to shatter the shell and create high energy fragments, hence as little as 6g of filler, post war developments showed this was the more effective concept and that is what we see in todays explosive cannon ammunition.

So when you look at a weapons effect, muzzle velocity and striking power you have to factor in a lot more than just the bang a certain weight of explosive makes!

[RAF74_Buzzsaw]

Kinetic, blast and fragmentation effects are modeled in quite a bit of detail in CoD.

The weapons systems in the game are a result of further development of the work which went into 1946, and are probably the most complex seen in a Flight Sim.

In combination with an extremely detailed damage system, there is really no other game which reachs CoD's standards.

The above arguments are really in fact, irrelevant, all the concerns have already been met.

[III./ZG76_Saipan]

Kinetic, blast and fragmentation effects are modeled in quite a bit of detail in CoD.

The weapons systems in the game are a result of further development of the work which went into 1946, and are probably the most complex seen in a Flight Sim.

In combination with an extremely detailed damage system, there is really no other game which reachs CoD's standards.

The above arguments are really in fact, irrelevant, all the concerns have already been met.

on a side note, getting too close to a burning fuel storage facility on fire will cause your plane to ignite. not sure if you high alt fliers knew that.

[ATAG_Lolsav]

on a side note, getting too close to a burning fuel storage facility on fire will cause your plane to ignite. not sure if you high alt fliers knew that.

You are right, in theory :D

We are used to see a fire on a fix location. A moving airplane, with strong wind facing foward, due to speed, would make the flames go backward, opposite direction of the fuel tank :recon:

P.S. Hi Saipan!

[rel4y]

There is a tendency in gaming circles to bestow the MGS round with magical properties, now no one is saying they didn't go bang and cause damage they obviously did, but the concept was proven later to be flawed in small calibre ammunition.

what you give with one hand you take away with the other, by making the casing much thinner and using greater filler you remove the mass to create fragments, the down side to this, despite creating a bigger bang was a 20mm shell could not carry enough explosive to make the concept a front runner, 18g is the equivalent of a 1 inch cube of cheese, the other problem lay in the lighter shell often failed to penetrate even deflecting off the aircrafts skin if the angle was insufficient, this also affected the 30mm shell which is why that was re designed as a heavier shell with greater velocity and therefore more striking energy for the ADEN.

The Hispano round used the explosive as a bursting charge, not so much to create blast but to shatter the shell and create high energy fragments, hence as little as 6g of filler, post war developments showed this was the more effective concept and that is what we see in todays explosive cannon ammunition.

So when you look at a weapons effect, muzzle velocity and striking power you have to factor in a lot more than just the bang a certain weight of explosive makes!

Please give a source for this statement related to the effectiveness on WWII aircraft. I have read an official german doc which states the exact opposite of what you are insisting with the reason being that gas expansion or high chemical energy will cause intense dismantling of surface area, which thus causes excessive drag, unbalance and structural instability. Furthermore it leads to structural weakening with possible subsequent or instant failure of the aircraft frame when the chemical effect is triggered in close proximity. Mind that the detonator of the Mineshell for the 151/20 had a delay, so it would pass about 2/3rds through the skin and release its chemical energy on the inside of the hit structure.

In turn small fragments of HE munition cause only marginal surface area damage due to fragment size and fragmentation speed. Because of lack of fragment mass, penetration capability and target energy transfer is highly limited. Even with very high detonation velocity of RDX or PETN filler the fragment speed is limited by (a modification of) the Gurney equation. The fragment velocity may still be above 0.5 km/s but the resulting momentum will be extremely unimpressive.

lets take a look at a Hispano II HE round:
fragment density ~7.7 g/cm^3
fragment size 6mm*5mm*4mm -> V= 0.12 cm^3
fragment mass 7.7 g/cm^3 * 0.12 cm^3 = 0.924 g -> projectile weight is 130g, HE filler is 6g, therefore fragment mass is about 1/134th of the projectile hull, sounds very reasonable
fragment velocity v = (M/C + 1/2)^(-1/2) * sqrt(2E) = (124g/6g + 1/2)^(-1/2) * 2.5 mm/us = 543 m/s -> this is a first order approximation of fragment velocity for a 6g Tetryl filler, actual velocity will be lower
kinetic energy Ek = m/2*v^2 = 0.000924 kg/2 * (543 m/s)^2 = 136 J
momentum p = m * v = 0.000924 kg * 543 m/s = 0.5 N*s

For comparison a 40 grain .22LR has an Ek of 142 J and a p of 0.86 N*s.

So in conclusion an "average" large 20 mm fragment has 58% the momentum of a .22LR and 95.8% the kinetic energy. Sounds dangerous doesnt it?! ;)
Now I was just looking at initial kinetic energy and momentum, if you like we can also calculate the retaining Ek and p in 0.5 m distance, after penetration of an aluminum sheet or both.


the other problem lay in the lighter shell often failed to penetrate even deflecting off the aircrafts skin if the angle was insufficient

Deflection has got nothing to do with projectile weight in practice for 20mm munition. All that matters is impact angle, projectile rigidity and projectile shape. As you may notice the tips of MG 151/20 and Hispano HE projectiles are flat at the very top, which on impact causes a perpendicular (to the impacting plane) component to the directional vector of the projectile. Now since aircraft surface aluminum sheets are neither very hard nor very tough and rigid in respect to 20 mm projectile momentum, penetration is rather likely even at oblique angles. Only if the edge of the projectile tip fails to "dig into" the aluminum, deflection will be the consequence.

So your claim is very much an opinion because in term of history and science it severely lacks substance.

[VO101_Kurfurst]

I was just about to point out how incredibly tiny these 20 mm fragments are in practice (actually the largest one is usually the detonator in the head that travels forward), but rel4y did this already in much more detail than I could.

Now, as for blast effect, I have a German report on the destructive effects of an exploding 2cm Minengeschoss and the overpressure curve measured from the point of detonation. The first readout is at the a radius of 30 cm (i.e. diameter = 60 cm), or about 1 foot, where the pressure was 42 atü (atmospheres pressure over ambient pressure) or about cc. 43 kg/cm2. That is about the equivalent of the sea pressure at a depth of 430 meters. Such pressure will easily crush even high strength steel alloys pressure hulls of submarines, the very best WW2 subs for example were typically only good for 300 meters crush depth. Naturally the pressure decreases very quickly with distance but then again with the typical dimensions of aircraft structure it isn't much of a problem, fighters fuselage for example were typically about 70-80 cm wide at their widest point (engine/cocpit), wings are rarely more than 30 cm at their thickest point.

[Gromit]

Please give a source for this statement related to the effectiveness on WWII aircraft. I have read an official german doc which states the exact opposite of what you are insisting with the reason being that gas expansion or high chemical energy will cause intense dismantling of surface area, which thus causes excessive drag, unbalance and structural instability. Furthermore it leads to structural weakening with possible subsequent or instant failure of the aircraft frame when the chemical effect is triggered in close proximity. Mind that the detonator of the Mineshell for the 151/20 had a delay, so it would pass about 2/3rds through the skin and release its chemical energy on the inside of the hit structure.

In turn small fragments of HE munition cause only marginal surface area damage due to fragment size and fragmentation speed. Because of lack of fragment mass, penetration capability and target energy transfer is highly limited. Even with very high detonation velocity of RDX or PETN filler the fragment speed is limited by (a modification of) the Gurney equation. The fragment velocity may still be above 0.5 km/s but the resulting momentum will be extremely unimpressive.

lets take a look at a Hispano II HE round:
fragment density ~7.7 g/cm^3
fragment size 6mm*5mm*4mm -> V= 0.12 cm^3
fragment mass 7.7 g/cm^3 * 0.12 cm^3 = 0.924 g -> projectile weight is 130g, HE filler is 6g, therefore fragment mass is about 1/134th of the projectile hull, sounds very reasonable
fragment velocity v = (M/C + 1/2)^(-1/2) * sqrt(2E) = (124g/6g + 1/2)^(-1/2) * 2.5 mm/us = 543 m/s -> this is a first order approximation of fragment velocity for a 6g Tetryl filler, actual velocity will be lower
kinetic energy Ek = m/2*v^2 = 0.000924 kg/2 * (543 m/s)^2 = 136 J
momentum p = m * v = 0.000924 kg * 543 m/s = 0.5 N*s

For comparison a 40 grain .22LR has an Ek of 142 J and a p of 0.86 N*s.

So in conclusion an "average" large 20 mm fragment has 58% the momentum of a .22LR and 95.8% the kinetic energy. Sounds dangerous doesnt it?! ;)
Now I was just looking at initial kinetic energy and momentum, if you like we can also calculate the retaining Ek and p in 0.5 m distance, after penetration of an aluminum sheet or both.



Deflection has got nothing to do with projectile weight in practice for 20mm munition. All that matters is impact angle, projectile rigidity and projectile shape. As you may notice the tips of MG 151/20 and Hispano HE projectiles are flat at the very top, which on impact causes a perpendicular (to the impacting plane) component to the directional vector of the projectile. Now since aircraft surface aluminum sheets are neither very hard nor very tough and rigid in respect to 20 mm projectile momentum, penetration is rather likely even at oblique angles. Only if the edge of the projectile tip fails to "dig into" the aluminum, deflection will be the consequence.

So your claim is very much an opinion because in term of history and science it severely lacks substance.

A bit of reading regarding initial fragment velocity http://www.dtic.mil/dtic/tr/fulltext/u2/a800105.pdf

Err no my claim is a statement of historical fact based on decades of weapons development , could you explain without wasting everyone's time on dubious mathematics why the MGS principle was evaluated post war by the US UK and USSR and yet not one of them adopted the principle, and no other manufacturer uses the principle today?

It's a simple question if you could just answer that please.


can you also explain why in light of your post about deflection why the UK weapons development establishment re designed the original 30mm MGS shell due to deflection issues in testing?

[Gromit]

I was just about to point out how incredibly tiny these 20 mm fragments are in practice (actually the largest one is usually the detonator in the head that travels forward), but rel4y did this already in much more detail than I could.

Now, as for blast effect, I have a German report on the destructive effects of an exploding 2cm Minengeschoss and the overpressure curve measured from the point of detonation. The first readout is at the a radius of 30 cm (i.e. diameter = 60 cm), or about 1 foot, where the pressure was 42 atü (atmospheres pressure over ambient pressure) or about cc. 43 kg/cm2. That is about the equivalent of the sea pressure at a depth of 430 meters. Such pressure will easily crush even high strength steel alloys pressure hulls of submarines, the very best WW2 subs for example were typically only good for 300 meters crush depth. Naturally the pressure decreases very quickly with distance but then again with the typical dimensions of aircraft structure it isn't much of a problem, fighters fuselage for example were typically about 70-80 cm wide at their widest point (engine/cocpit), wings are rarely more than 30 cm at their thickest point.

Can you give us an example of fragment size based on any evidence?

The MGS was assessed post war, can you explain why if it so effective it was discarded, it's also interesting to note the filler of other ammunition in this calibre, and explain why no one else considered the concept practical or superior to a fragmentation shell?

And please stop with the silly off topic nonsense, first atom bombs, now submarines!

[rel4y]

A bit of reading regarding initial fragment velocity http://www.dtic.mil/dtic/tr/fulltext/u2/a800105.pdf

Err no my claim is a statement of historical fact based on decades of weapons development , could you explain without wasting everyone's time on dubious mathematics why the MGS principle was evaluated post war by the US UK and USSR and yet not one of them adopted the principle, and no other manufacturer uses the principle today?

It's a simple question if you could just answer that please.


can you also explain why in light of your post about deflection why the UK weapons development establishment re designed the original 30mm MGS shell due to deflection issues in testing?

OK, simple question why do you post a 1943 document which I have indeed read just yesterday when this recent document from 2007 https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/4625/1/Szmelter%2010-3.pdf shows this type of calculation is still used. Now funny thing is the paper you posted actually is Gurneys initial publication in which the very formula I used above was initially (in different appearance) formulated. The calculations I posted are perfectly valid, while surely I could have used a more refined shape than a simple tube the difference would be pretty much irrelevant. Just for fun I will also calculate the penetration of contemporary aluminum hulls for your "high energy fragments" to make everyone realize just how clueless you argue.

Now for your simple question, the fragmentation effect of modern projectiles is indeed very adequate to disable turbine engines with rpm ranging from 8000 to 11500. The key point being that only slight damage to fan, compressor or turbine will lead to catastrophic engine failure in case of jet engines. A WW2 era engine block will wave at you with a smile when hit with - as you call them - "high energy" fragments. High projectile velocity is a given when considering the speed at which aircraft nowadays fly around. Now that noone is shooting at 4 mot bombers with a cannon anymore, structural damage to flying surface is a non factor in aerial combat (engine and systems being the target), jet engines are used in fighters, cannons in practice are used mainly for ground attack, yes that makes me really wonder why noone is using mine shells anymore. You are deliberately or not comparing apples to oranges and stating false information as fact.

Ok so you are talking about 30mm shells not 20 mm in the deflection discussion, I see. Well first of all there is a v0 and terminal velocity difference between a 30mm and a 20mm shell. Second which type did they redesign the pointed type or the flat type fuse? Third what does redesign mean? Fourth on what surface and at what angle did deflection occur. Fifth may I take a look at the document and see for myself which facts you distorted.

PS: If you would like to know average or even fragment mass distribution, there is a good model around. Just google ARAET-TR-07001.

[Vlerkies]

A single 30 mm

http://i.imgur.com/V8Ar1j9.png

Some guncams

https://www.youtube.com/watch?v=_aqJwHdMDK0

[rel4y]

This US publication released right after the war ended also puts the MK 108 30 mm mine shell in very high regards. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA800394
As can be seen mine shells rely heavily on structural damage while fragmentation causes engine damage through liquid leaks.

It does however state in the introduction:


Insofar as future aircraft are composed of similar structure, fuel cells, or powered by similar engines,
the Information obtained in the present tests can be applied directly to the corresponding components
of other aircraft, with due correction for presented areas and physical arrangement. For slight structural
changes, the vulnerability of future aircraft can be estimated. When certain components only are
radically different (such as advanced designs of jet engines as opposed to the obsolescent I-16 jet engines
available for these firings) some estimation is possible, but in any event, only the new component need be
subjected to damage tests for the estimation of the overall vulnerability of the new aircraft.

That doesnt tell us much about the comparison of a MG 151/20 mine shell and and a Hispano Mk.II HE.

[Vlerkies]

Just as an aside for the Stuka huggers, the glorious BK3.7cm beast


https://www.youtube.com/watch?v=cU6OK1zSxKg

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[Gromit]

OK, simple question why do you post a 1943 document which I have indeed read just yesterday when this recent document from 2007 https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/4625/1/Szmelter%2010-3.pdf shows this type of calculation is still used. Now funny thing is the paper you posted actually is Gurneys initial publication in which the very formula I used above was initially (in different appearance) formulated. The calculations I posted are perfectly valid, while surely I could have used a more refined shape than a simple tube the difference would be pretty much irrelevant. Just for fun I will also calculate the penetration of contemporary aluminum hulls for your "high energy fragments" to make everyone realize just how clueless you argue.

I posted the document as on seeing your calculations I realised straight away you had been googling and this was the first one that popped up as you confirmed, it seems you have no real life experience or knowledge of this subject and rely on maths to try and make a point, what us older guys term as "trying to baffle with science" where the problem lies in your calculations is you have absolutely no idea of the actual size and therefore the weight of the fragments, and as you well know KE= velocity squared x weight divided by 450240 if you like to work in Ft/Lbs as I do with my firearms, without this critical input you will have to make up a spreadsheet of a variant of weights and therefore energy results.
You chose a particularly light fragment weight with no credible reasoning other than to suit your argument, which also has no merit as fragmentation is neither consistent nor fully predictable and without the ability to reference this vital information your calculations are merely guesswork.


Now for your simple question, the fragmentation effect of modern projectiles is indeed very adequate to disable turbine engines with rpm ranging from 8000 to 11500. The key point being that only slight damage to fan, compressor or turbine will lead to catastrophic engine failure in case of jet engines. A WW2 era engine block will wave at you with a smile when hit with - as you call them - "high energy" fragments. High projectile velocity is a given when considering the speed at which aircraft nowadays fly around. Now that noone is shooting at 4 mot bombers with a cannon anymore, structural damage to flying surface is a non factor in aerial combat (engine and systems being the target), jet engines are used in fighters, cannons in practice are used mainly for ground attack, yes that makes me really wonder why noone is using mine shells anymore. You are deliberately or not comparing apples to oranges and stating false information as fact.

Now unfortunately this is your straw man argument as you have completely failed to see the forest for the trees here.
The early development of cannon armament especially for the RAF was due to the increase in armour fitted to enemy bombers rendering the .303 less and less effective, the armour protected crew and engines, and this is where your really falling down by your constant reference to engines, you do realise the belting of cannons was not all MGS or HE, it was a mix of AP-Incend-HE, the whole point of this mix is there are many vulnerable systems on an aircraft and by varying the ammunition hitting the target you had more chance of critical damage, it is extremely unlikely you can guarantee hits on a particular point on an opponent, it does not take much thought to realise what the AP round was designed to do, the MGS was not there to primarily destroy engines it was there to damage the myriad of systems not protected by armour such as the cooling, fuel and oil, controls and surfaces, the incendiary role is obvious.

if your trying to destroy engines HE is seriously handicapped by the armour, which is why you need AP, and weirdly you seem to think the casings of jet engines are thin alloy sheet and piston engines are one solid monolithic block, you do comprehend there are a large number of components critical to the engine bolted to the outside, all of which are susceptible to fragmentation damage as is a cast alloy block dependant on fragment size?

Post WW2 the gun was still the primary air to air weapon until the advent of the missile, and yet no nation adopted the MGS in this role, no nation that evaluated the German weapons during the war copied the principle and none developed it further, and even more bizarre post war West or East Germany did not retain the concept, could this be simply because the conventional HE/Frag round was simply as effective as the MGS? or good enough not to proceed, certainly looks that way, so no one is distorting facts, what your doing is arguing what basically amounts to "sorry sir we hit it with a Rapier but it was made in WW2 so the missile didn't work", it's total nonsense, weapons have advanced considerably and ammunition with it, yet nearly all retain the basic premise that fragmentation is the critical aspect!

Ok so you are talking about 30mm shells not 20 mm in the deflection discussion, I see. Well first of all there is a v0 and terminal velocity difference between a 30mm and a 20mm shell. Second which type did they redesign the pointed type or the flat type fuse? Third what does redesign mean? Fourth on what surface and at what angle did deflection occur. Fifth may I take a look at the document and see for myself which facts you distorted.

The document, was a discussion on the WW2 aircraft website regarding the use of Luftwaffe ammunition stocks in the ADEN gun fitted to Hawker Hunters, if your that fanatical please go dig through the posts I am certainly not wasting my time on someone with such an attitude, the original information may well have come from the Mike Williams site, and if your going to post , please refrain from using terms like "distorted" when all you have brought to this discussion is dubious maths and uninformed comments

PS: If you would like to know average or even fragment mass distribution, there is a good model around. Just google ARAET-TR-07001.

Weapons engineers used to collect and analyse fragment samples to determine optimum materials, I have seen such examples during my service as an Artilleryman and can quite confidently say they come in many shapes and sizes, I don't think an internet programme is going to provide anything other than a rough guide.

[Gromit]

This US publication released right after the war ended also puts the MK 108 30 mm mine shell in very high regards. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA800394
As can be seen mine shells rely heavily on structural damage while fragmentation causes engine damage through liquid leaks.

It does however state in the introduction:



That doesnt tell us much about the comparison of a MG 151/20 mine shell and and a Hispano Mk.II HE.

No it doesn't but interesting none the less.

[VO101_Kurfurst]

Post WW2 the gun was still the primary air to air weapon until the advent of the missile, and yet no nation adopted the MGS in this role, no nation that evaluated the German weapons during the war copied the principle and none developed it further, and even more bizarre post war West or East Germany did not retain the concept, could this be simply because the conventional HE/Frag round was simply as effective as the MGS? or good enough not to proceed, certainly looks that way, so no one is distorting facts, what your doing is arguing what basically amounts to "sorry sir we hit it with a Rapier but it was made in WW2 so the missile didn't work", it's total nonsense, weapons have advanced considerably and ammunition with it, yet nearly all retain the basic premise that fragmentation is the critical aspect!


Can we stop with the BS please about how Mine shells were not used? This is an 1971 Swedish film on firing trials of their fabled S-tank, now lookie lookie what this Draken is wielding, is it not our stubby yellow friend Minnie?


https://youtu.be/MiWCpIJ5dBw?t=9m20s

[rel4y]

Sure I googled the equation, I read a couple of papers on it and calculated. Thats what you learn to do in University. The problem is that you obviously dont undestand the concept of it. I even gave you a paper which deals with fragment size distribution and a fragment size 136th of total shell mass is on the large side. My calculation is still perfectly valid and in reality fragment mass and velocity will be lower. The Gurney equation I used is flawed at high M/C ratios because it doesnt consider gas momentum and it doesnt take into account that the shell will break up when flow stress is increased beyond material limit.

Feel free to show me where my maths are wrong and do your own calculations.

I was responding to your claim "no modern weapon retains the M-Geschoss principle as this was found to be flawed and less effective than a fragmentation round.". The US paper from 45 clearly states that the Mineshell is about equally effective as a much larger fragmentation shell and it goes into detail about the damage caused. Furthermore it states exactly what you call a strawman argument as I quoted in an above post. So you must know better than the engineers who were paid a lot of money to do this ammunition assessment. Either you didnt read the paper or didnt undestand it.

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Now, where is the huge structural damage of fragmentation?

I have shown evidence in form of calculations and papers which completely contradict you. Physics and history simply disagree with you and its kinda silly to argue with them. You have so far brought up absolutely no evidence in defense of your claims. So now back up your claims or stand as a fool.

[ATAG_Lolsav]

Where i have to put the water on?

Of course passionate debates can always get a bit hot. So i ask again, where i have to put the water? Keep the debate civil, thank you!

P.S. i would edit that last sentence rel4y...

[Vlerkies]

Keep it tidy fella's

Some of the best technical discussions here get closed if we don't adhere to that simple rule.

:salute:

[Vlerkies]

While my command of the German language amounts to being able to order a beer, this may prove to be interesting.

http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Diverses/Flugwerkschutzes.pdf

[Gromit]

Sure I googled the equation, I read a couple of papers on it and calculated. Thats what you learn to do in University. The problem is that you obviously dont undestand the concept of it. I even gave you a paper which deals with fragment size distribution and a fragment size 136th of total shell mass is on the large side. My calculation is still perfectly valid and in reality fragment mass and velocity will be lower. The Gurney equation I used is flawed at high M/C ratios because it doesnt consider gas momentum and it doesnt take into account that the shell will break up when flow stress is increased beyond material limit.

Feel free to show me where my maths are wrong and do your own calculations.

I was responding to your claim "no modern weapon retains the M-Geschoss principle as this was found to be flawed and less effective than a fragmentation round.". The US paper from 45 clearly states that the Mineshell is about equally effective as a much larger fragmentation shell and it goes into detail about the damage caused. Furthermore it states exactly what you call a strawman argument as I quoted in an above post. So you must know better than the engineers who were paid a lot of money to do this ammunition assessment. Either you didnt read the paper or didnt undestand it.

22484

22485

Now, where is the huge structural damage of fragmentation?

I have shown evidence in form of calculations and papers which completely contradict you. Physics and history simply disagree with you and its kinda silly to argue with them. You have so far brought up absolutely no evidence in defense of your claims. So now back up your claims or stand as a fool.

No what you have done is switched the debate to the 30mm round, your calculations still are based on supposed fragment size not known data so still a guess as you have no way of proving what sizes are actually involved, so you use a fudge to suit yourself instead of considering the energy of larger fragments which if you bother to look at the shell construction there will be!

The only reason the 30mm is mentioned in this thread is because the Defa and Aden guns were questioned, also you still have not explained why 20mm MGS was dropped post 1945 by all nations and instead waffle about not the right shell!

Very interesting graphs by the way, shame the 20mm MGS is not represented.

[Gromit]

Can we stop with the BS please about how Mine shells were not used? This is an 1971 Swedish film on firing trials of their fabled S-tank, now lookie lookie what this Draken is wielding, is it not our stubby yellow friend Minnie?


https://youtu.be/MiWCpIJ5dBw?t=9m20s

Kurfurst several countries used Defa and Aden guns including LW stocks and post war production, and that includes the RAF, they did not however develop the concept and did not continue with the 20mm.

We all agree on that point, the issue here is the effectiveness of 20mm MG151 and Hispano, the 20mm shell capacity has a far greater bearing on this subject, unfortunately the debate is now being diverted onto the 30mm round.

[Gromit]

some interesting shots

http://theairtacticalassaultgroup.com/forum/attachment.php?attachmentid=7304&d=1391472708

http://theairtacticalassaultgroup.com/forum/attachment.php?attachmentid=7305&d=1391472739

You may note the different sizes in the holes produced by the fragments, unclear however which actual round caused the damage other than 20mm.

[rel4y]

Ok my last post on this topic. You switched the debate to 30 mm, I calculated for 20 mm fragments. Dont turn this around.


can you also explain why in light of your post about deflection why the UK weapons development establishment re designed the original 30mm MGS shell due to deflection issues in testing?

Youre also grasping at straws by saying I intentionally used a small fragment.. Once again the fragment I calculated for is 1/134th of the mass. So if the projectile would splinter into 134 equal fragments, these would have exactly the mass I calculated for. Do you expect a fragmentation round to blast into 10 pieces, 20 pieces or 50 pieces? With the paper I provided we could calculate an approximation of average fragment size, but to you all maths and physics are dubious. Therefore I wont waste my time. Take a look at these 20 mm and 35 mm grenades instead and believe whatever you wish. Also take a look at fragment shape and give a wild guess how this could influence penetration.

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I doubt that the shots you posted show mine shell damage. As I said before mine shells penetrate the surface und detonate on the inside, therefore the sheets will be bend to the outside. In this picture the metal is deformed to the inside all around and therefore the detonation must have happened outside the skin. Now either something went wrong with the shell or this was not caused by a mine shell. Either way its not representative.

Now to get this straight, I am not saying the mine shells were incredibly better than every other ammunition. They were designed for a specific application profile and fulfilled their purpose very well. I am simply disagreeing with this "..M-Geschoss principle.. was found to be flawed and less effective than a fragmentation round." because every source disproves it.

PS: All the information about development, reason and damage assessment of the german side is in the link Vlerkis posted:


http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Diverses/Flugwerkschutzes.pdf

[ATAG_Snapper]

Keep it tidy fella's

Some of the best technical discussions here get closed if we don't adhere to that simple rule.

:salute:

+1

:salute:

[Vlerkies]

some interesting shots

http://theairtacticalassaultgroup.com/forum/attachment.php?attachmentid=7304&d=1391472708

http://theairtacticalassaultgroup.com/forum/attachment.php?attachmentid=7305&d=1391472739

You may note the different sizes in the holes produced by the fragments, unclear however which actual round caused the damage other than 20mm.

I have seen those before Gromit with links to the pilot and flight.
I seem to remember that it was attributed to AA with a basic frag type round, not the m-geschoss. Will have to do some digging though to confirm, or deny ;)

[Vlerkies]

The result of being hit by Anti Aircraft fire on a Rhubarb over the Zuider Zee on November 13, 1943. Flight Lieutenant Arthur Sager of 416 Squadron RCAF managed to return to base with the damaged aircraft. Sager managed to bring his Spitfire Mk. V back to Colishaw even though his radio had been destroyed and he was slightly injured.
http://spitfiresite.com/2007/11/art-sager-416-squadron-rcaf.html

In his own words


Luckiest: November 13, 1943, Flight Commander with 416, Chad Chadburn’s Wing, Digby, Lincolnshire. Duff weather and, wanted some action, got permission to lead a four-man rhubarb to look for some Huns practicing dive bombing in the Zuider Zee. They’d been sinking coastal shipping in the North Sea. Flew at wave-top level from Coltishall, planning to hit the Dutch coast a few miles north of Ijmuiden where Intelligence said there were no guns. Either they’d just been installed or, more likely, I missed the landfall because 30 seconds from the beach there was an explosion. Stunned, woke up with cockpit full of smoke, broken glass all over.

I pulled back the hood and looked for a soft place to land when suddenly realized that the good old Merlin was still ticking over. Radio and some instruments gone but otherwise apart from a draft, everything pretty normal. Got close to No.3 and waved at him to take over and go on but when I turned 180 degrees he and the others followed. Followed me all the way back, expecting me to ditch at any moment. They’d seen the hole behind my head. I hadn’t, or I’d really have been scared. Kissed the armour plating behind the seat when I got out.
http://flyingforyourlife.com/pilots/ww2/sa/sager/

[Gromit]

Ok my last post on this topic. You switched the debate to 30 mm, I calculated for 20 mm fragments. Dont turn this around.

No I didn't Karaya and Kurfurst brought the subject up, this thread is about the 20mm



Youre also grasping at straws by saying I intentionally used a small fragment.. Once again the fragment I calculated for is 1/134th of the mass. So if the projectile would splinter into 134 equal fragments, these would have exactly the mass I calculated for. Do you expect a fragmentation round to blast into 10 pieces, 20 pieces or 50 pieces? With the paper I provided we could calculate an approximation of average fragment size, but to you all maths and physics are dubious. Therefore I wont waste my time. Take a look at these 20 mm and 35 mm grenades instead and believe whatever you wish. Also take a look at fragment shape and give a wild guess how this could influence penetration.

your calculation of fragment size is based on a generic model available to the public, draw your own conclusions why it may be a bit vauge, just one look at the Spitfire photographs will give you some idea of how far out your 134 part could be, and this is the issue, you are trying to state absolutes when what you have is a generalised may or may not be accurate assumption, having seen many different types of fragment from many different calibres I would conclude your count could well be far fewer than you think especially in older small diameter rounds, but as the information is not forthcoming you will have to create a spread of possible results to get a clear idea of what is probable

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again vastly larger and more modern rounds and at least now you may grasp how important the weapons engineers think your small fragments are, funny how they didn't grasp the importance of your blast comes first

I doubt that the shots you posted show mine shell damage. As I said before mine shells penetrate the surface und detonate on the inside, therefore the sheets will be bend to the outside. In this picture the metal is deformed to the inside all around and therefore the detonation must have happened outside the skin. Now either something went wrong with the shell or this was not caused by a mine shell. Either way its not representative.

Never said it was but it is extremely representative of why your calculations are in error, the information your missing is in those photographs, no offence but an hour on google does not make you an expert in this field, as I mentioned before you fail to see the forest for the trees, concentrating on single detail is fine only when you are able to put the pieces into the bigger picture, your obviously not stupid and your maths skills exceed mine so I leave it to you to figure out why maybe taking on board what someone with over six years experience in artillery may bring to the party, "blowing shit up" is what we did, and I assure you I have little misconception of just how big a bang you get out of 18g, contrary to Hollywood I believe you would be disappointed, hopefully you may one day get some real life experience to back up your maths as that would be fascinating, so have a good look at the photographs, see if you can figure out where your going wrong, in the meantime if anyone wants to know what I am referring to ask me on TS when we are on

Now to get this straight, I am not saying the mine shells were incredibly better than every other ammunition. They were designed for a specific application profile and fulfilled their purpose very well. I am simply disagreeing with this "..M-Geschoss principle.. was found to be flawed and less effective than a fragmentation round." because every source disproves it.

Maybe you are not understanding me, if I rephrased "flawed" and said the other nations did not find the concept to offer any advantage over a fragmentation round, and since then none have re visited it, would that make more sense to you?

PS: All the information about development, reason and damage assessment of the german side is in the link Vlerkis posted:

I did see and have seen it before, but there are a lot of arms producers in the world, being a minority of one is not a sound recommendation when everyone else equally intelligent does not agree

[ZG15_robtek]

@ Gromit,

the result of my reading here is, the Minengeschoß was the best ammo available to hurt planes BEFORE the jet-age, later on fragmentation became more important as the target profile changed.
So it really doesn't matter what happened after wwii, because that is not the time frame that is of interest here.
have fun
robtek

[Vlerkies]

@ Gromit,

the result of my reading here is, the Minengeschoß was the best ammo available to hurt planes BEFORE the jet-age, later on fragmentation became more important as the target profile changed.
So it really doesn't matter what happened after wwii, because that is not the time frame that is of interest here.
have fun
robtek

This ammo was developed early on and as the war progressed continued along the path purely for its destructive power, through all the calibers. Not because it was rubbish.

It was very effective at rendering more than enough significant damage to an airframe, to neutralize them quickly and efficiently with the least amount of rounds on target.

Consider the heavy bomber situation later on, and the upscale of the canon itself. It worked and worked well. To say it did not, or that 8 x 303's was better is disingenuous when it comes to rounds on target.
One can comfortably argue that as the war progressed the newer pilots were far less effective, but then we all know that that was largerly due to attrition and lack of experience. The seasoned vets hammered home.

They packed a punch, it never had the muzzle velocity of traditional AA 20 or Hispano canon sure, and aim and accuracy suffered as a result but human pilots would easily adjust to this lag if you will. What it lacked in velocity it made up in bang.
The lower velocity was a given in the design of the casing and 'intentional in the design itself', to light weight the round and allow more ammo to be carried on the platform. It was Luftwaffe specific.

These types of canons, Oerlikon, Hispano, whatever, were not lightweights and adding them at the expense of x number of traditional MG rounds to a fighter of the time would be a considered decision for sure. One the RAF realized they could no longer avoid making.
It worked and worked pretty darn well.

It packs a heavy punch in Cliffs as well.

[Gromit]

This ammo was developed early on and as the war progressed continued along the path purely for its destructive power, through all the calibers. Not because it was rubbish.

It was very effective at rendering more than enough significant damage to an airframe, to neutralize them quickly and efficiently with the least amount of rounds on target.

Consider the heavy bomber situation later on, and the upscale of the canon itself. It worked and worked well. To say it did not, or that 8 x 303's was better is disingenuous when it comes to rounds on target.
One can comfortably argue that as the war progressed the newer pilots were far less effective, but then we all know that that was largerly due to attrition and lack of experience. The seasoned vets hammered home.

They packed a punch, it never had the muzzle velocity of traditional AA 20 or Hispano canon sure, and aim and accuracy suffered as a result but human pilots would easily adjust to this lag if you will. What it lacked in velocity it made up in bang.
The lower velocity was a given in the design of the casing and 'intentional in the design itself', to light weight the round and allow more ammo to be carried on the platform. It was Luftwaffe specific.

These types of canons, Oerlikon, Hispano, whatever, were not lightweights and adding them at the expense of x number of traditional MG rounds to a fighter of the time would be a considered decision for sure. One the RAF realized they could no longer avoid making.
It worked and worked pretty darn well.

It packs a heavy punch in Cliffs as well.

No one is saying it did not work Vlerkies, what we can surmise however is that it was not enough of an improvement to warrant copying it or developing it further, the problem is as you note in Robteks post above {quote} the Minengeschoß was the best ammo available {quote}, and it is this that my post is aimed at, it's a constant notion you find in gaming circles, mostly because no one bothers to consider the actual circumstances and how these rounds fit in to the overall effect of a weapon.

Oh by the way whilst you bring up the subject of machine guns and the reason Cannons were adopted, have you seen this image 22504 imagine being trapped in the alloy tube that makes up the fuselage, no wonder armour became a necessity!

[Gromit]

@ Gromit,

the result of my reading here is, the Minengeschoß was the best ammo available to hurt planes BEFORE the jet-age, later on fragmentation became more important as the target profile changed.
So it really doesn't matter what happened after wwii, because that is not the time frame that is of interest here.
have fun
robtek

It's an unrealistic notion though Rob, the idea a modern round would not work on a WW2 era aircraft is absurd, consider what this idea actually entails, a lot of engines back then were liquid cooled, this factor alone would make fragmentation dangerous to the collection of cooling pipes, radiators, header tanks etc that make up just the cooling system, when you add in hydraulics, the oil tanks, pumps, coolers, fuel systems, controls just to name a few.

Lets consider the engine for a moment as this seems to be a bone of contention, the cylinder block is just one part, what about the induction piping from the supercharger, a hole in that and there goes your boost, what about the timing covers, a hole in that and stripped gears and your valves are going to be smashed by the pistons, the ignition system, the oil system, an engine is covered in vulnerable sub systems, and this does not take into consideration the AP and Incendiary ammunition that is arriving along with the HE, jet engine casings are not made of tinfoil, they are extremely robust construction, but again they have vulnerable components, a modern round could do more damage to a WW2 aircraft than any ww2 counterpart because it's a far more developed concept, weapons have not gone backwards in 70 years.

[235 Sqn. Coldstreamer (QJ-X)]

Thanks chaps, you've given me my Research project for my masters Degree in Explosive ordinance engineering.

The effects of 20 mm Minengeschoss ammunition on a Aircraft frame.

[rel4y]

hopefully you may one day get some real life experience to back up your maths as that would be fascinating

That statement is actually not very appropriate, but I cant blame you since we dont know each other. I did a tour to Afghanistan in 09 when my regiment was assigned to QRF of northern Regional Command. We were hit several times by artillery and mortar shells in form of IEDs on patrol and one time I suffered a concussion myself.

Now for the real reason of this post, does anybody have any reliable data on Hispano ammunition dimensions, production and explosives. It seems the US made ammo had Tetryl or Pentolite fillers while british shells had TNT fillers. Also the color code was apparently different.

[235 Sqn. Coldstreamer (QJ-X)]

colour coding
22518

22519

I'll have a look at work for production info and british filling for 20mm ammo, as british munitions at that time were being filled with tnt/rdx mix not solely tnt. But i wont confirm this till i can get more info from munitions data record sheets.

Will be intresting as Tetryl, Pentolite are about 20% more powerful than TnT

[rel4y]

These are the ones I have found as well, additionally this one. Oerlikon and Hispano munition seem to differ only in the casing not the projectile. A small RDX charge surrounding the fuse was probably used as a booster stage.

22521

[RAF74_Buzzsaw]

colour coding
22518

22519

I'll have a look at work for production info and british filling for 20mm ammo, as british munitions at that time were being filled with tnt/rdx mix not solely tnt. But i wont confirm this till i can get more info from munitions data record sheets.

Will be intresting as Tetryl, Pentolite are about 20% more powerful than TnT

The game does differentiate between types of explosives, and the power generated.

There are ratings for the various explosive types used as filler in German, British, US, etc. HE rounds.

Oleg is way ahead of you. :D

[Bren]

... does anybody have any reliable data on Hispano ammunition dimensions, production and explosives. It seems the US made ammo had Tetryl or Pentolite fillers while british shells had TNT fillers. Also the color code was apparently different.

For the explosive filling, British Hispano rounds used tetryl; 10.2g in the HE round and 7.0g in the HE/I round.
American HE/I rounds were the same as the British, though supposedly they had an alternate HE/I version with 6.5g of RDX.
The original French rounds used pentolite; approximately 10g for the HE round and approximately 8g for the HE/T.

[rel4y]

For the explosive filling, British Hispano rounds used tetryl; 10.2g in the HE round and 7.0g in the HE/I round.
American HE/I rounds were the same as the British, though supposedly they had an alternate HE/I version with 6.5g of RDX.
The original French rounds used pentolite; approximately 10g for the HE round and approximately 8g for the HE/T.

Hey!

Whats your source? I am pretty sure the Brits used a TNT filler at least till 44. I found a bit of data on the dimensions and a bunch on aerodynamics.

2259222593225942259522596

[Bren]

The British used TNT in several of their Oerlikon-type 20-mm ammunition, but the Hispano rounds in service used tetryl.

From numerous wartime manuals/documents.

[rel4y]

Cool, thats interesting. Would you be so kind to post some of these manuals/documents, because its really hard to find anything primary about the british Hispano 20mm on the web. For US stuff there is a bunch around.

[Bren]

Can't really post anything at the moment - but 235 Sqn. Coldstreamer (QJ-X) posted an example above.

Note the British HE and HE/I rounds have 'CE' stenciled on them. CE (Composition, Exploding) = tetryl

[Akula93]

There are a large number of variants... you can't make a sweeping generalization about which might be better, you need to examine each version in detail and decide which version is being compared to which version.

For the 109F's, for example, you have the following:

109F-1: DB601N engine, (same as the engine in the E-4N), one MG/FFM cannon with 60 rounds firing through the prop, plus the two LMG's.
109F-2: DB601N engine, one MG/151/15mm cannon, (very high velocity, very accurate, but no high explosive rounds) firing through prop, plus two LMG's. Slightly reduced performance, higher stall speed, due to increased weight of larger cannon and ammunition
109F-2 (Late): DB601N engine, one MG/151/20mm cannon, firing through prop, plus two LMG's. (increased weight)
109F-2-Trop: Same as above, but with enlarged air intake filter (increased weight)
109F-4: DB601E engine, rated at 1.30ata boost at 2500 rpm, one MG151/20mm cannon firing through prop, plus two LMG's. (increased weight over F-2, thus higher stall speed)
109F-4-Trop: Same as above, but with enlarged air intake filter
109F-4 (Late): DB601E engine, rated at 1.42ata boost at 2700 rpm, one MG151/20mm cannon firing through prop, plus two LMG's.
109F-4 (Late)-Trop: Same as above, but with larger filter

All the 109's had the fuselage/wing/tail design changes... these were primarily incorporated to provide a more aerodynamic frame, and higher speed, to allow better maneuver at the higher speeds which combat was now occurring, and which the 109F's were now capable of achieving. As part of this, there was a sacrifice in low speed maneuver... the F model had inferior low speed lateral maneuver than the E model. The F's Stall speed, with the higher weight, was also slightly higher than the E.

For the Spitfires, you have the following:

Spit IIB: Same as the IIA, but with reduced performance, higher stall speed due to 20mm gun and ammunition extra weight... Two 20mm Hispano cannon, 4 LMGs.
Spit IIB (Late): Same as above, but with improved lateral maneuverability due to retro-fitted metal ailerons
Spit VA: Merlin 45 rated at +12 boost/3000 rpm, eight LMGs, fabric ailerons (increased weight and higher stall speed over IIB)
Spit VB: Merlin 45 rated at +12 boost/3000 rpm, two 20mm Hispano cannon, 4 LMGs, metal ailerons (increased weight and stall speed over VA)
Spit VB (Late): Merlin 45 rated at +16 boost/3000 rpm, two 20mm Hispano cannon, 4 LMGs, metal ailerons
Spit VB - Trop: Same as above with extra weight and reduced performance due to larger filter.

Spitfires initially were equipped with fabric ailerons, but as the RAF noted in 1941 the 109F was more maneuverable at higher speeds, the metal ailerons were introduced to counter this advantage.

So the fact is, when you look at all the models, comparisons are very much dependent on which version is compared to which.

You'll need to wait till TF 5.0 is out to really find out. :-) :P

I will also say that you can see from the above list how much work is required... so I hope everyone is patient... TF 5.0 will be done as soon as our resources will allow.

Is this the list of 109Fs that we can expect in next patch, also will 109F4Z make the list?

[IIJG27Rich]

This is my best chance to finally shoot something down, let's put it that way. :salute: