PLS HT look into Breda MG modelling!

[gatt]

Well, I've read almost everything about the C.202 and the C.205 and I've never ever seen something about synchronized rate of fire. However, whats interesting is what I've read on a plate fixed to the cockpit of a Series 5 fighter (dont remember if a C.205 or a G.55 cockpit): "Dont fire with MG when RPM are between X and Y".

[GRUNHERZ]

Hooligan:

From Tony Williams:

I read an account recently of a survey of the opinions on fighter armament of experienced RAF commanders (including Stanford Tuck) written in January 1942. This stated that many RAF pilots would have preferred the armament of the Me 109 because it was concentrated in the nose, even though it was much lighter than the armament of current RAF fighters.



But what would the actual Spitfitre pilots know, they were too busy flying the planes and fighting in them.....


The only people who know anything about WW2 fighters are people who play games. Right Hooligan?

[LUPO]

GATT wrote:
I've read almost everything about the C.202 and the C.205 and I've never ever seen something about synchronized rate of fire.

Neither did I!

Do you think that somone could give us an answer to those questions, GATT?
 

GRUNHERZ wrote:
I read an account recently of a survey of the opinions on fighter armament of experienced RAF commanders (including Stanford Tuck) written in January 1942. This stated that many RAF pilots would have preferred the armament of the Me 109 because it was concentrated in the nose, even though it was much lighter than the armament of current RAF fighters.

The Italian ace Gorrini wrote exactly the same. He preferred his 12,7 to the spifires armament because of the better concentration of fire. That's the reason why I posted the question above:Is dispersion in Aces High calculated just by gun, or by mount & gun? (Repetita iuvant...) Nobody knows?

[HoHun]

Hi Gatt,

>Well, I've read almost everything about the C.202 and the C.205 and I've never ever seen something about synchronized rate of fire.

Let's assume that there's only one point during each rotation of the propeller where the gun is allowed to fire.

With the engine at continuous power at 2300 rpm and a gear ratio of 1:1.685, the longest possible delay (just short of one full revolution) would be 44 ms, extending the interval of 86 ms between 2 shots of the free-firing gun to a total of 130 ms - yielding a rate of fire of 460 rpm. However, on the average, only half a revolution would be spent waiting, so the interval would be 108 ms for a rate of fire of 560 rpm.

With the engine at 2800 rpm, the average synchronization delay would be 14 ms for a rate of fire of 600 rpm.

If the synchronization system was more sophisticated in being able to trigger each 120 degrees of rotation (between the 3 propeller blades, that is), the average delay would be down to 4.7 ms for a total rate of fire of 660 rpm.

I don't know about the Italian synchronizer gear, but the German weapons were electrically triggered and could have allowed multiple trigger actions for each revolution. I've got a picture here of a Me 109E on the factory range, with a cardboard disk mounted instead of a spinner that shows 3 sets of holes at 120 degree intervals. Unless the photograph was staged for propaganda purposes (which is a possibility), I'd believe that the Messerschmitt at least had "best case" synchronizer gear :-)

(The Macchi in Aces High on the other had seems to have the "worst case" synchronizer gear that's only capable of triggering once every 360 degrees.)

Another interesting aspect of the Messerschmitt photograph is that there are actually 2 sets of holes each 120 degrees that are about as far apart as the two machine guns on the cowling. Obviously, both guns were triggered simultaneously so that they hit the rotating disk in different places.

Regards,

Henning (HoHun)

[Wotan]

hohun can you post that pic or do you have a link?

[Hooligan]

LUPO:

I believe the 7.7mm guns are mounted inboard of the propeller tips so they are also synchronized (accounting for their poor rate of fire also).

As far as whether or not the Breda's were synchronized:  There is no question that they were.  Machine gun rates of fire were not exact.  If the specified rate of fire for a normal breda was about 700 then this really means something like a range of about 650-750 (depending upon any number of things).  Propeller RPM could be theoretically be adjusted to for a given rate of fire, but without some sort of synchronization apparatus then there would be no way to prevent the guns from being fired at the exact moment when a propeller blade would be hit.  Further, the variation in machine gun rates of fire would mean that there is no way to guarantee that machinegun would fire at the desired rate unless some sort of synchronization gear were employed.  The Breda guns on the 202 must have been synchronized.

I have no reason to believe that HTC’s ROF information for Breda MGs is wrong.  Do you?

If you use the target command offline and play with convergence settings I do believe that you will find that dispersion of center mounted guns is noticeably less than dispersion for wing mounted guns.  This is easy enough to test.

GRUN:

You seem to be implying that something is wrong with the Geman guns in AH.  And you are basing this on the rather ambiguous statement that some UK pilots stated that they thought they would prefer the centerline gun mountings of the 109 (pilots who did not in fact ever fire the 109 gun set against enemy aircraft).  Have you ever considered just letting a gunnery thread go on without contributing your obligatory whine about LW gun modeling in AH?  If you really think that center mounted guns suffer some disadvantage vs. wing mounted guns in AH I suggest you compare the 4 .50s in a P-51B to the 4 .50s in a P-38, particularly at longer ranges.

Hooligan

[HoHun]

Hi Wotan,

>hohun can you post that pic or do you have a link?

The picture can be found in "Me 109 - der siegreiche deutsche Jäger" by NSDAP-Reichsbildberichterstatter Professor Heinrich Hoffmann, München, 1941.

Unfortunately, I don't have a scanner so that I can't post the image.

Regards,

Henning (HoHun)

[HoHun]

Hi Hooligan,

>And you are basing this on the rather ambiguous statement that some UK pilots stated that they thought they would prefer the centerline gun mountings of the 109 (pilots who did not in fact ever fire the 109 gun set against enemy aircraft).

There's nothing ambiguous about the RAF pilots' statement. They saw a major advantage in having the armament concentrated close to the centreline of the aircraft, and considered this advantage to be large enough to overcome the disadvantage in weight of fire. Though they couldn't back up the latter point with combat experience, this comment was based on their estimate of the effectiveness of their wing guns and the difficulties associated with them. In short, I think they knew well what they were talking about.

It's interesting that the Luftwaffe pilots had the opportunity to compare wing cannon to nose cannon directly when the Me 109F was introduced. Mölders' comment "One in the nose is better than two in the wings" ironically mirrored the RAF pilots' point of view exactly.

(Though initially other Luftwaffe pilots had some doubts, this was because the first batch of Me 109Fs was delivered with a 15 mm cannon, not with the 20 mm that became standard later.)

Regards,

Henning (HoHun)

[gripen]

Well, all Germans were not so sure about this, IIRC Galland stated something like "flying targets are usually shot with  the shotgun".

gripen

[Nashwan]

(Though initially other Luftwaffe pilots had some doubts, this was because the first batch of Me 109Fs was delivered with a 15 mm cannon, not with the 20 mm that became standard later.)

I thought the very first 109Fs had the MG FF 20mm in the nose.

I think the German pilots may have thought 1 MG151 in the nose was better than 2 MG FF in the wings.

[SageFIN]

Originally posted by Hooligan
I have no reason to believe that HTC’s ROF information for Breda MGs is wrong.  Do you?

There's no question that the cowl guns were synchronized. But as Ho Hun pointed out, the resulting ROF would vary depending on the method of the synchronization. Do you have any reason to believe that HTC would have exact info about the synchro capabilities of the MC. series? I don't think that such information is easily come by, as gatt's and LUPO's ventures with Macchi documentation have pointed out. Also, the planes are quite numerous (and some of them very exotic).

Sooo...

I would guess that each synchronized gun in this game has it's ROF reduced to a same set percentage, as it would probably be the most easily implementable way. This should be easily verifiable within the game. I remember that at least the ROF of synchronized Mg151's has been tested and compared to the unsynchronized values from books. Can't remember what the results were though, it was quite some time ago.

If I would care one bit about the way synchronized guns are implemented in the game, I'd probably test them all myself. However, I prefer planes with .50 and Hispano wing armament (or nose, as with the P-38 and Mossie), so for me it's a non-issue. LW enthusiasts might be interested.

[HoHun]

Hi Gripen,

>Well, all Germans were not so sure about this, IIRC Galland stated something like "flying targets are usually shot with  the shotgun".

Galland's final reply to Mölders' "One in the nose is better than two in the wings" was "I'd rather have all three". Accordingly, Galland did not pull out the "one in the nose" when he flew his unique F-6/U conversion since he didn't actually oppose Mölders - but his real concern were bombers. Against fighters, accuracy had priority, against bombers, it was weight of fire.

Regards,

Henning (HoHun)

[HoHun]

Hi Nashwan,

>I thought the very first 109Fs had the MG FF 20mm in the nose.

You're right, but the pilots knew that the MG FF/M was an interim armament until the new MG151 became available. "First batch" was the wrong term, I was actually thinking of the first significant variant of the Friedrich.

Regards,

Henning (HoHun)

[LUPO]

Hooligan wrote:
I believe the 7.7mm guns are mounted inboard of the propeller tips so they are also synchronized (accounting for their poor rate of fire also).

Negative. You're wrong. During WWII the 7,7 mm SAFATdidn't found any application, as a synchronyzed gun for firing through the propeller disc . The 7,7mm were used in combination with the 12,7 mm. But 7,7mms were installed in the wings and firing OUTSIDE the propeller disc.

Hooligan wrote:
I have no reason to believe that HTC’s ROF information for Breda MGs is wrong. Do you?

Mate, try to understand. I don't believe neither that HTC information are simply wrong nor that there's a conspiracy against italian planes in AH. This is simply stupid.
Aces High was the first on line simulator wich modelled italian aircraft and, as an italian enthousiast of flighsims, I greatly appreciate their job.
I'm simply trying to understand if the gunnery of 202 in Aces High is historically accurate. If it was so weak in real life as it is in the simulation.
And, looking at number and the kind of planes  the 202 was able to shoot down during WWII, I believe is possible that, becouse of the compromises due to the presence in the AH plane-set of aircrafts  of different period of the war, the gunnery of some planes is exaggerate whilst the gunnery of others is less effective than it was.
Punt.

Sage FIN wrote:
I would guess that each synchronized gun in this game has it's ROF reduced to a same set percentage, as it would probably be the most easily implementable way.

Affirmative, SageFIN. I found a very intersting link about how different parameters of planes are modelled in CFS.
Click here to acces the site
This site is about creating flight models for the computer that fly within 1% of the performance of their real world counterparts.
One of the infos I got there is that for the guns that fire through the propeller, they reduce the rate of fire by 15%!!!
This is perhaps historically accurate, altough 15% could be considered as a rough approssimation.
If Aces High use the same parameters our beloved 202 will remain, as it is, toothless.

[Hooligan]

LUPO:

Concerning the 7.7mm:

I don't have access to much information about the c.202, so I can't tell for sure but those 7.7mm guns look pretty far inboard to me.  Perhaps they are just past the spinner.  However the ROF in AH is 800.  This seems rather low for a non-synchronized gun (Gustin states a ROF of 900 for these).

Sage:

I am certain that HTC does not reduce ROF for all guns by the same percentage.

Mg151s in AH have an ROF of 700 normally and 630 when synchronized (inboard guns in the FWs).  Presumably the Bredas would go from 700 to 630 also if all synchro guns were uniformly reduced.  I also measured all the ROFs in HTC prior work (Warbirds) and synchro/non synchro ROFs there definitely were not proportional in uniform ratios.

I have looked into aircraft weapon information quite a bit and one of my conclusions is that HTC knows a lot more about it than I do.  However they determined their ROF information I expect that it is quite accurate.

Also, I expect that if it is wrong they will quickly fix it if somebody comes up with data to show them.

Hooligan