"Battle of Britain-SpitFire vs. Me-109's Fire Power" Topic

Hello Gents

I am working on a new WW II Aviation Game and I would like to tap into the vast library of knowledge so many TMP'rs have regarding the Battle of Britain.

I have read several books on the battle and on the aircraft that flew in it but what I would like to find out is some specific data on comparitive fire power between the Spitfire II and the ME-109E.

I know the basic set up for the Spits & Hurricanes were… 1. 8x Browning 7.7mm (0.303in) MG's
2. ammo supply – 300 rds. per gun
3. rate of fire 1,200(rds/min)

The ME-109…
1. 2x 20mm Oerlikon Cannon (60rds per gun)
2. 2x 7.92 mm MG's – ammo supply 1000 rds.per gun
3. rate of fire 1,100 (rds/min)

Questions I have are…
1. Could the ME-109 pilots simultaneously fire the MG's and the Cannons from the two switches they had on the stick?

2.I'm assuming that the RAF's 8 x MG's could fire 4x the bullets that the 109's 2 x MG's could, correct?

3.When the term "rounds per minute is given, does it
mean for an individual MG or the entire firing platform?

4. In general, when trying to calculate a firing factor for the Spitfire vs. the 109, would you rate them generaly the same or would one have a clear advantage?

5.The RAF's mg's vs. ME-109's mg's?

6.The 109's cannons impact?

Thank you in advance and I'm looking forward to your replys on the subject.

Regards,

Skip

From my Ballantine "The Luftwaffe' by Allen Price -
3 second burst from 1940 spitfire 10lbs.
3 second burst from 1939 109 18lbs.

Using 'Aces over Europe' or 'Pacific' one could select what pairs of weapons to fire – so that HAS to be correct ; ).

When I game CY6 Guadalcanal I allow players to select mg or cannon or combination of 2,4 or 6 MG's – jams and out of ammo are devasting otherwise -esecially with pilot training thrown in (Greens tend to use up a lot of lead). Unless the gun is a single mount don't let them fire it individually. Oscar has a 12.7 and 2 7.9's (I think) so either all in concert, the 12.7 seperately or the 2 7.9' seperately. Cannons are not as accurate at longer range (course depends on how far out you've synched your mg's). but they pack a greater punch – see weight chart above. Individually the mg's are the same, would rate all 30cals similarly – a p47 according to the same source pounds out 20lbs with 8 fifty cals. and a Typhoon 35lbs. A later 1942 me109 puts out 35lbs. 3 20mm's and 2 13mm hmg's. I would worry more about the skill behind the stick than the difference between similar mg's. A 109 does put out a goodly chunk of lead, if it hits for 3 seconds, compared to a spitfire, with all it's weapons then will do close to double the damage. Those 20's are nasty – if they hit. Does 1/4 damage with mgs alone. the planes are ABOUT the same sturdiness. About the same manueverability and speed, slightly smaller 109. I'd give the edge to the pilot, and who is worried less about their fuel. Though the British air sea rescue was supposedly atrocious compared to the German -don't have figures for this, someone will correct me (hopefully without jumping down my throat!). Round per minute is for each of the weapons. So, a Spitfire would use up all it's ammo if no jams and mashed the firing button, in 15 seconds putting 2400 rounds down range. Someone might correct me on this too!

Yes, they could fire both cannon and mg simultaneously.

I would use a combo of weight of fire and # of rounds per turn to determine damage.

Brucka

Thank you, good bit of info. I need to clarify one thing you mentioned above. Could an ME-109 Pilot simultaneously fire his MG's and Cannons,or does he have to fire one or the other?

Also, that 1939 ME-109, 18lb 3 second burst, was that just MG fire?

And, while I'm thinking about it, when a Spitfire was firing his 8x MG's and if a jam occured was it limited to a single MG or did the jam usually result in the entire MG platform freezing up?

Everything else you mentioned I have read and totally agree with you on concerning the Battle of Britain.

Skip

Hi Sundance

I was in the middle of responding to Brucka's comments when your post flashed up.

Simultaneous it is. The weight & rate of fire I will be factoring in the Firing & Damage section.

Thank you

Go here: link

Read this: Cannon or Machine Gun? The Second World War Aircraft Gun Controversy

and this: WW2 Fighter Armament Effectiveness

and this: Ideal WW2 Fighter Armament

oh, yeah, and this: The Battle of Britain: Armament of the Competing Fighters

If that doesn't answer your question, buy his WWII book. Williams and Gustin know more about aerial guns than anyone else, including the people who actually design them. (That's because today's engineers don't know the entire history from WWI forward.)

No, the 18lbs included the two 20mm cannon.
Not sure if you can 'toggle' off pairs of guns – for gaming purposes, as I explained above, I allow it. So in a 'jam' – for gaming purposes – if you were firing 4mg's then four would jam – in a Spit. leaving you four more to work with – either fired as a pair or can fire using all of the remaining four.
Same with the 109 – you can chose to fire either or both – jams in CY6 are based upon die roll, and you use different dice for different guns so you know whether it was the mg's or the cannon that jammed.
Many good rule sets out there, I prefer CY6 – simple personal bias – each may treat this subject differently?

I don't believe the Spitfires had the option of firing weapons separately, unless they had a mix of weapons on their aircraft, e.g. both MG's and cannons.

Germans, with two types of weapons, apparently could, but would usually fire both at the same time.

Hi

Hmmmm.

The germans needed selective fire. The weight issue isnt quite right in that the MGFF got better during the period and they changed the drums for more ammo.

But in essence, the cannon runs out of rounds in 8 to 10 seconds, while the MGs chattered on.

The cannons have a vastly superior range for actually doing damage. During the BOB, the 303 was found to start sliding along the plexiglass rather than penetrate, for instance, at ranges around 400m.

R

<quote>Germans, with two types of weapons, apparently could, but would usually fire both at the same time.</quote>

The point was to only fire the MGs, "walk" the fire onto the target, and then pull the trigger for the cannons. Since the designers expected the MGs to fire a long longer, the difference in ammo was expected to more or less even out (both would last for the same amount of "real" firing).

That might work, assuming similar muzzle velocities, but that wasn't the case with many weapons.

Another factor to consider is that the cannon shells have explosives. It is a little more complicated than a weight of the round downrange. I don't have a magic formula.

Rich

Hi

The "walking" round was only used by the japanese as far as I know, though the guns were similar. Like most early war 20mm, all were off the krupp patent. the only real difference was that the germans used an electronic primer which pretty much ment no misfires.

But there was abut 800fps difference in the muzzle velocities of the two weapons, and the energy carried by the rounds ment that the trajectories were even more different than the rounds suggest.

That is the bad news. The good news is that most of this stuff doesn't matter! Vibrating platform, the airplane, vibrating guns combined means that pretty much everything is being sprayed in a cone about 1.5degrees across, meaning that at anything more than 150 yards or so, the rounds are all over the place.

The USAF determined in the 1948 Strategic bombing survey that the essence of the issue was weight of fire alone, not if it was ball or explosive. Further, it was determined that it was possible to treat damage as a statistic, in essence, given poundage of hits versus airfram produced the statistical likely hood of a system failure. The numbers might seem small unless you realize the cone of fire thing. Something like a B17, for instance, would take about 9pounds of hits for the statistical likelyhood of a critical system failure.

Rocky

Thank you gents

I do appreciate all the feedback and information given.

I will put it to good use.

Regards,

Skip
legends-in-time.com

Could US fighters select the number of guns they fire? I have never heard of that before. I knew it was common for cannon armed planes to have selectors, as they had very limited widows of effectiveness and limited ammo. So you would fire the cannon when it counted.

This was true of early war P-39s, the 20 could be deselected to save ammo.

--Tom

I would like to recommend the book "Flying Guns of WW2" by Williams and Gustin (available from Airlifebooks.com and recently reprinted). After reading this book, I am now in the process of totally revamping the firing charts to Knights Cross. The key insight was the discussion of the design of the ammunition and then how guns were designed to match the rounds.

These are some of the same issues I dealt with in the original conversion of Blue Max to Knights Cross.

First,
Most planes had the capability to switch weapons – MG's or MG and cannon. Later war Wildcats were armed with 6 guns instead of 4 and the pilots hated it since the ammo per gun was less and would often deactivate 2 guns and hold them in reserve for when the other 4 ran out of ammo. IIRC there is a switch that lets you switch between two modes when pressing the firing trigger – usually MG only or MG + cannon

Second,
Pretty much correct, although both the Browning and MG17 fire at rates of approximately 1200 rpm. See comments below for MG placment having an effect on firepower.

Third,
Rounds per minute (RPM) usually refers to a single gun.

Fourth, Fifth and sixth,

Weight of fire is a totally inaccurate method of measuring comparative firepower unless the rounds are exactly the same size – a rifle caliber bullet (RCB) has little or no explosive payload and may be incendiary but then has little penetration power. A 15mm or 20mm cannon round on the other hand may be armor piercing, HE and incendiary all in the same round, so the effect of a hit from an MG round vs. cannon round is very different – i.e. ten RCB's do not equal one 20mm round.

Rates of fire are tremendously different in BoB – an MG fires at rates of 700-1200 rpm , while most of the cannon were in the 400-500 rpm range – which means cannon had less chance to hit, particularly at longer ranges, higher speeds and high deflection angles where the spread of fire was greater.

Placement of the guns – even though the Spitfire and Hurricanes had the same armament, the Hurricane was considered a better gun platform due to having the guns bundled together in two sets of 4 – the wide spacing of the guns in a Spitfire lead to more deviation, particularly at longer ranges where deviations in sighting the guns became more apparent. The fuselage mount of ME-109 MG's lead to a concentration of MG fire, even at long ranges since the guns did not have to be "harmonized". (the downside to the fuselage mount was the MG rate of fire was downgraded to match the propeller synchronization, thus reducing it to about 1000 rpm) Initially British planes were usually harmonized to 400 yards, although most aces preferred a shorter distance of about 250 yards. After some combat experience, most squadrons switched to 250 yards due to inability of pilots to accurately engage targets at long range. The effect of harmonization was to focus the fire of the guns to a single point at a specific range. The problem is that after that point, the lines diverge, thus reducing firepower. Planes with fuselage mounted guns don't need to be harmonized and so have concentrated fire pretty much through their entire range. Thus an Me-109 with two fuselage mounted MG's may have MORE firepower than a Spitfire with 8 MG's if the range is sufficiently past the harmonization point (ranges of 400+ yards).

Differences in firing profiles between MG's and Cannon – the MG's were often used to track the target then fire the cannons once aim was achieved, but this was only useful at short ranges. The ballistic parameters of the two different kinds of rounds began to diverge pretty rapidly. This also means that even when firing both types, at longer ranges their fire lines diverge meaning they are much less effective when fired in combination.

Damage done – a rifle caliber bullet has very little penetration power – major aircraft components such as struts, engine blocks, or light armor are sufficient to ward off penetration. A 20mm shell on the other hand can cause significant damage with a single hit – smashing spars, blowing out control wires and fuel lines from its explosive payload as well as its physical penetration. So the type of construction used in the plane is a major factor in how much damage is done. For instance the Hurricane, with it's fabric wings and wooden parts is much more susceptible to damage from RCB's than the He-111 with metal skin and thick structural members. Anecdotal evidence states that the Hurricane was better at surviving cannon hits since many just passed through the fabric and wood parts without detonating, whereas the Spitfire took the full brunt as the metal skin offered enough resistance to set off the cannon round fuses.

So to break down the fire power of a Spitfire vs. Me-109 you will need to factor the following questions in:

That is the range? – longer ranges, especially beyond the harmonization point will lead to few if any bullets striking.

What are you hitting with? The cannon round will do significantly more damage than a dozen MG rounds.

In reality, the best method would be to have a separate "to hit" roll and then a "damage" roll. Cannon would hit less often, but do more damage when they do hit. MG's and cannon hit at different rates, and MG's mounted differently would hit at different rates based on range.

Damage would then be a combination of penetration, HE and incendiary effects based on the type of round used.

From Williams and Gustin:
the 300 rpg of the British Brownings was enough for 16 seconds of fire. The 60 rounds of 20mm for the MG-FF was enough for 7 seconds. The 1000 rounds for the MG 17's was enough for a minute of fire.

Thank you Binhan

An excellent summary of the questions I put forth.

Skip

Hi

"harmonization" only worked on the ground.

And, since WW2, after the work done by the USAF, I apologize for disagreeing, but weight of fire ended up being the message, not the mix of rounds as you put it above.

R

Rocky,
Weight of fire is only useful if comparing apples to apples or rifle caliber bullets to rifle caliber bullets. Even when comparing rifle caliber bullets (.303) to heavy machine gun bullets (0.50) the comparison suffers. In general the problem is that a dozen rifle caliber bullets will do less damage than an equivalent weight of heavy machine gun bullets or cannon shells – for instance you can shoot thousands of rounds of rifle caliber bullets at 1/2 steel plate and never penetrate, while 0.50 and 20mm cannon will. Late in WW2 and later, most planes were equipped with 20mm cannon or larger, and so weight of fire becomes an acceptable comparison because you are comparing cannon to cannon, not MG's to cannon. But early in WW2, the mix of MG's, HMG's and cannon are so diverse that you need to compare the type of rounds used, not just the weight of fire.

For instance a .303 browning round (7.7mm x 56R) weighs about 11 grams. A 20mm x 80RB round for the MG-FF weighs 120-130 grams depending on HE/AP or HEI load. The ratio is thus about 11:1 for weight. Eleven browning rounds will not penetrate 1/2" steel structural member, but a 20mm round will.

In addition, the ballistics of each type of projectile is different. RCB's with a lower mass, lose velocity more rapidly than heavier bullets and shells, and since they tend to be solid projectiles, most of their damage is velocity dependent, thus reducing their damage at range. Cannon shells on the other hand maintain a higher velocity for greater distance, and in additon carry an HE or incendiary payload, so their damage potential does not drop off as much at longer ranges. So at long range, the damage potential of 5 kg of RCB's is decreased even more than 5 kg of 20mm cannon shells than when they are fired at close range.

--Binhan

Hi

In previous posts, when I brought this up, I identified the range aspect.

How about "if in effective range"?

R

I've always thought it the case that for much of the war 2 guns was considered reasonably effective anti-fighter armament – albeit they generally got to be HMG's and cannon pretty quickly – the Soviets had 2 guns as the armament for most of their fighters for most of the war – the Yak fighters mostly had 1 x 20mm cannon & 1 x 12.7mm mg (a few had 2 x 12.7's, a few has 23mm, and we'll ignore the 37 & 45mm ones for the time being!)

The LaGG 3 started with 5 MG's – 3 x 12.7mm & 2 x 7.62 – but they quickly got rid of the 7.62's.

The amount of ammo carried by the 109's for their 7.92's shows that they were expected to be the main armamant – the 20's only at close range or for larger a/c.

Later in the war 109's and 190 derivatives often had only 1 cannon (20 or 30mm) and 2 x HMG's (13 or 15mm), and reading accounts of Buffalo pilots vs various Japanese army types in Asia the 2 x 7.7mm on the Oscars were perfectly adequate to cut them to pieces (the Buffaloes didn't face Zero's AFAIK).

Nates also had only 2 MG's, but were even slower than the Buffaloesand didn't do quite so well! But I have read of an account by a NZ pilot over Burma where one of his comrades was killed by a single rifle-calibre bullet because the armoured seats hadn't been fitted to their a/c – the only hit on the entire a/c.

Multi-cannon armamament like the Hurricane II, FW-190A, G & F was the exception – even the 2 x 20mm on the Spitfire was prety heavy for the era!

Hi

Al, actually the ammo isn't proof. The 20mm in the 109s and spits and everyone else prior to 42 were derivitive of the the Krupp patents for the weapon. Initally, the guns, oerlikon, hispanod, mapan, america and so on were all the same gun with a 60 round drum. There was no way to change drumbs in flight, thus the limit. Later they got 90 round drums that would fit in SOME situations.

The 30cals in the cannot period were considered as "better than nonthing" but each power considered the cannons to be the actual weapon.

Rocky

Bf-109 had problem with firing wings mounted cannons, due to recoil and aiming problems, which makes hittin fast moving fighter difficult.
In fact BF-109E may fire both MGs and cannons, but it was rather uneffective. The cannons was converged on rather longer distances and shooting from short range make them inaacurate. On longer ranges the MGs was uneefective, because they did little damage and had diffent trajectory. Bf-109 from version F had cannon shooting thought propeller hub.
The later FW-190 had MG151/20 (better then MG FF) mounted in the wings, but very close to fuselage and still some pilots still claimed that one cannon shooting thought propeler hub was more effective. The MG FF located far in the wings of FW-190 tend to be uneffective and were often removed to save the weight.
Also MGs wasn't able to get full rpm, because it shoot thought propeller.
On the other side, as I remember, during BoB some fo BF-109 had MG FF/MM which increased the stopping power of the cannons greatly.
If I have to compare firepower BF-109E with MG/FF and Spitfire armed with 8 Brownings I'll rather bet on Spitfire.

Hi

Actually, post war studies came to the opposite conclusion. The weight of fire and kenetic energy of the 20mm gave it all the advantages.

The MG/FFm had the larger drums and a higher rate of fire.

The only difference between the MG/FF and the Hispano in the Spit II(and the Bloch 151/2 et al) was that the Hispano used a mechanical firing pin, and the Oerlikon versus was fired with an electric primer.

Don't put too much stock in the "central location" part of the equation. As I said each gun, vibration and all produces a cone of fire 1.5degrees across. At, say, 200 yards, the overlap is such that the effct is an oval rather than round, but the real effect isn't appreciably different.

One odd issue with the 30cal Browings is that at ranges of 200 or so yards the rounds would start to deflect and slide along the side of the fuselage and even the plexiglass of the canopies rather than penetrate. Early hispano 404 mountings in the spit 2 gave a lot of grief, but the brits persisted. Seems they were convinced by seeing the long streaks running down the sides of the canopies from this that they 303 wasn't the weapon of choice here.

As far as the anacdotes, pilots say things! Testing sometimes agrees or not.

Famously, Galland found the central gun inadequate and has his own Fs modified with the addition of a MG/FF in each wing.

The central gun on the 109 only returned to the E's firepower level with the later Reinmetal Borsig 151/20. And actually exceeded it when they got, in small numbers, the Mk103 or 108 30mm gun.

Tests we made with the 30 blew our minds at Aberdeen. I have photos in my file of single rounds hitting spits and blowing them into two pieces at 200yards. Those tests were one of the reason that most of the post war jet systems went to 30mm guns.

Rocky

If a gun jammed it would just be the one gun itself that jammed. So if you had 8 guns, and had a jam, you would be firing 7 guns.

RockyRusso, I've never say, that 20mm was worse than 7,7 MG's – I've just pointed, that 20mm cannons mounted in the weak wings of Bf-109E wasn't perfect idea – the German constructors had the same feel ;)
Generaly, Spitfires were better suited to carry armament in their bigger wings, including a pair of 20mm cannons and MGs or even two pairs of cannons.

That the history shows that location of cannons had a meaning. The Russian pilots, for example, tend to had the wing armament romoved from P-39 as their clams it was uneffective. Most of the planes also had the wing guns converged, so I think if it doesn't mean nobody whould care about such, complicated anyway, process.

On the other side, the weight of the salvo it's only one factor important when comparing the weapons. The things like balistics, ammo weight and supply, unreability or number of bullets within square meter also counts. I personally think – that in this period – the best solution was made by Americans, who armed their planes in the rows of 12,7 MGs, which combines the firepower, huge ammo supply and excellent ballistics.

Hi

Lord, actually, the stuff I refer to is from post war studies specifically in the Strategic Bombing Survey of 1948 and the tests at Aberdeen post war.

it wasn't know at the time, and the anacdotes are just that and didn't stand up to analysis. I know, too geekey. This is getting into my "day job" in the 70s and 80s with the USAF.

The issue with weight of fire that was beginning to be understood was that the weapons and targeting were limits. As I think I mentioned here, outside of 200yds, the brits were discovering that 303 might slide along a surface and be deflected by plexi-glass. The problem was that there weren't good solutions on offer. The brits HAD licence for the Hispano 20mm with its problems.

The US had started favoring the .50 in the thirties. The US had figured out part of the story with sectional density and carry, but part of the equation was that they had the best 50 in the world…one still in service! But without scientific study, initially the designers "compromised" by having a mix of .50 and 30.

The british, later than BoB did produce versions of their wings that could put 1 .50 browning instead of the 2 .30s with the cannon.

The real issue with spit/109 wasn't wing weakness, but size. This is a aero problem. The short version is that the thicker the wing is as a percentage of chord, the faster it reaches its critical mach number. Both planes are about 13% thick, if memory serves, but the 109 narrower chord also produces a smaller space in the wing. The cannot required a big bulge on the bottom of the wing. As the F model was trying to address critical numbers, the issue was a cannon problem. The 109 is just too small!

It was thought that the higher rate of fire of the MG151/15 would be a good enough substituted for the two slower MG/FFs in the wing. But it wasn't Not until the MG151/20 came along was good enough.

Rocky

Chiming in late. Most nations had given up on rcb's by mid war. The 109G-2 upgraded to 12.7's in the G-6 variant in mid 43. The Spits were already mainly relying on the hispano to kill anything and the .30 cals were just there for aiming assistance and last ditch spray and pray when the hispano ran out. The US had already gone to 50's.

The Russians loathed .30 cal. "paintscratchers" and ripped them all out in '42, as being not worth the weight penalty. Hence the reduction of the LAGG's 5 guns to 2 and the loss of the P-39's pod mounted (and thus, agility-killing) wing .30's.

In late '42, the Russians developed the UBS 12.7 which was a super-effective hmg with a very high rpm capactity and penetrating power. Thus, they could get away with mounting only 1 hmg, as opposed to the 2 inferior hmg's mounted by the Germans. The Russians also carried a 20mm for serious close-in shooting and of course, the 37mm in some of their later Yaks.

Legends, First of all a link to my rules
link
Not just a shameless plug, but they concentrate on BoB. I have been asked if I plan to release aircraft for later war. The trouble is that the tech improved so much that the stats would be too high to comfortably fit into the game. The solution would be to write aircraft 'scaled back' to fit in with the rules – a bit like how Spearhead and Modern SH use the same rules but the stats for the modern tanks are similar to the WW2 ones- you can't mix and match (M1 vs Tiger 2). So I suggest stick with a easily defined period (ie 1940)

2nd- when I wrote 'Angels 1-5' I picked the Mk I/II Spitfire as the 'bench mark'. I got that to 'fly' properly, then related all other stats for other planes to that. That is why a .303 burst equals '+3': 1 sec = +1, so the spit ammo is +3 +3 +3 +3 +2 (empty) because they had 14 seconds of usable ammo (side point- the pilots would have tracer put at the end of each 3 secs on ammo on the belt, so they could see when the burst had ended. The last 2 secs were high proportion of tracer as an 'you're out' warning.)
The system is a d6 + ammo bonus +/- deflection, -1 per 10cm range: Results 2+ allow rolls for damage- the better the hit, the more damage can be rolled for (Hit on a 2 and the damage is d6-3, a 5 gets you d6-2, 8 gets you a d6 and so on)

109s are +5 +5 +5 -2 -2 = 3 bursts of cannon, then only the 2 mgs left (vs 8 of Spit/Hurri).

What I find surprising is no one mentioned why only 9s of 20mm in the 109. The ammo took up a lot of room, which is why the 109 had those bulges on the wings. Even they were a compromise- the more ammo, the bigger the bulges, the worse the performance.

Hi

Aerodynamically, the bulges were insignificant. The difference between the early 60 round drum and the later 90 even more so. You will note that spits also got bulges.

Rocky

Hussar,
the reason for the ammo limit is that at the time, the ammo drums were standardized to 60 or 90 round drums. Only when they went to belt feeds were larger capacities available. The downside to belt feeds are two fold – they take up a lot of room and you have to place them carefully to avoid jamming the belts. Spacing belts was the primary issue as you had to avoid the main structural members and yet have a relatively flat and clear area for the belt to lie in. If you take up too much room in the wing, then you displace stuff like fuel tanks, oil or coolant radiators or control wires.

As the British found in early trials with the HS, even a "good" arrangement to feed the belts may not work if the aircraft is pulling g's in a turn and thus jamming the belts if you try to fire.

A drum feed has none of this problem – the rounds are don't get out of position as easily and the installation is very compact, although they tend to be a little tall (thus the bulges).

If have a choice of a weapon with practically guaranteed 7 seconds of fire or one that may or may not fire up to 15 seconds, which would you stake your life on?

-Binhan

Aerodynamically the bulges may have made little difference – but I wonder about teh weight of the weapon and ammo?

Waht was the weight of a 20mm cannon with it's 60 rounds vs (a couple of?) 303's with 250 each?

Aloysius,
The MG-FF weights 25 kg. A Browning .303 weighs 10 kg. Ammo weight is 92-134g/round for 20mm MG-FF ammo depending on whether its HE, HEI, AP or M-Geschoss. Browning ammo is 9.8-11.3g per round depending on whether its incendiary or armor piercing.

Weight of gun per se is not an accurate indicator of overall weight as factors such as muzzle brakes, firing mechanism (pneumatic, electrical or mechanical), mounting type, additional reinforcement for recoil or channels for ammunition bins etc are not usually factored in the listed weight for the weapon. Obviously having two weapons vs. one doubles these accessory weights.

For instance, the MG-FF was the preferred weapon for German aircraft due to its relatively low recoil – it could be mounted without any extra strengthening of the mount and also produced less vibration when firing. Other cannon produced higher rates of fire, higher muzzle velocities, etc. but at the cost of higher gun and mounting weights.

So using the above weights – An MG-FF weighs about 2.5 times
a Browning and ammo weights are about 10 time greater. So taking a single 20mm MG-FF with a 60 round load, it will come in about 33kg. Two Brownings with 250 rounds each are about 26 kg. This does not include weight of a drum or magazine, firing mechanism, bracing, etc.

Placement of the weapon also highly affects performance – two Brownings placed close to the wing tip is more detrimental to the roll rate than an MG-FF placed closer to the wing root.

In addition, the ammunition weights do not include the weight of the belt (disintegrating, fabric, steel, etc). Drums do not link the ammunition and so do not have this additional weight penalty.

-Binhan

There is another correction to the weights given before. I only listed the projectile weight, not weight of the cartridge. Cartridge weight could vary as some were more lightly loaded than others in an attempt to make the trajectories of different type of projectiles match more closely – i.e. a heavier bullet may be loaded with more powder to produce a muzzle velocity similar to a lighter bullet with a lighter powder load.

So the previously listed numbers don't include propellent or brass weight.

-Binhan

Hi

The weight of the E-1 with 30cal mg in the wings is about 300pounds lighter than the E3 with the cannons. or just shy of 2 pounds of wing loading, or a change in initial turn radius from 270 down to 254, meaning still wider than either hurricane or spit, while giving up the ability to kill them with a single burst.

Rocky

Binhan,

Which ruleset do you favor that reflects best, the above mentioned factors?

King Cobra,
Most rule sets abstract firing in such a way that most of the differences listed above are lost in the granularity of the fire resolution – i.e. the difference between a Spitfire's and Hurricane's arrangement of guns does not show up in most systems. Most games treat a .303 MG the same whether its Russian, American, British or German without regard to mounting position (fuselage guns fire slower), ammunition type and cartridge loading, or ease/difficulty of the guns jamming.

For game play reasons this is usually a reasonable method as the focus should be on playing the game and not having to look up a whole bunch of charts to simply fire the guns.

On the other hand, a well designed system will have incorporated these factors into the game mechanism where the player doesn't have to do anything extra.

A quick check is to compare a Spitfire I's and Hurricane I's firepower in game. If they are different, then the game designer is aware of difference and has tweaked the shooting mechanics to take it into account. If not then that level is not present in the game. I haven't done the firing comparison with many other rule sets as I tend to find it easier just to modify my own set, Knights Cross.

For instance, Knights Cross shows a slight difference between the Spitfire and Hurricane – the Hurricane is Stability A for firing vs. Stability B for the Spitfire. This provides a medium bonus for firing at short ranges and a small bonus at long ranges. The actual difference is not as great as the rule set shows it to be, but it is tweaked to give it a more flavorful feel – pilots will have a reason to choose flying a Hurricane over a Spitfire.

-Binhan

Hi

GIGO

R