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[SAS~Storebror]

Gentlemen: Why, if it's so utterly enervating to you, didn't any of you get your bums up yet to change it?
It's no rocket science.
Even the Sourcecode of the Classfile doing this is available.
It's your choice: You can keep complaining, you can throw the whole pack away (and thereby accept that you'll have to live with a ton of other shortcomings) or you simply fix it (so others can complain about what you think was "real" harharhar...  ).
It's really that simple.


Mike

[WxTech]

Mike,
For some reason I was thinking this might involve the flight model; I didn't think to look in Java. 

If I can figure this out (unlike some other problems that are beyond my pitifully meagre skilz), there's also the I-153P awaiting the treatment...

Thanks!

[SAS~Storebror]

Fine, fine. Glad that someone takes up the task.
On our Subversion Repository you will find the project sources in "\trunk\Storebror\Jugs Reloaded\src".
The classfile you will want to look for is "com\maddox\il2\objects\air\P_47ModPack.java".
Take a look at the "void bubbleTopTailSway()" method. I'm sure it'll ring a bell for you when you see it.


Mike

[WxTech]

Mike,
Thanks a bunch. Now, where to find this Subversion Repository, as I've not heard of this before...

Glenn

[SAS~Storebror]

It's our collaboration tool, the Superschool Tutorial thread is here: https://www.sas1946.com/main/index.php/topic,31243.0.html
Putting it simple, you need to sign up here: https://app.assembla.com/user/new_signup
Then tell me your email address by PM, so I can invite you, and then finally login to assembla and see what we have.


Mike

[Wing Walker]

Everything in aircraft is designed to balance. 

I'm pretty sure the either were synchronized with one on both wings firing at the same time, or the rate of fire was high enough that the difference between each gun was milliseconds, and all 6 would fire off within the same second or two.

Also, this would be a common problem to all wing mounted MGs, but wing mounted was the standard
 for most aircraft of WW2. 

If this caused a "spray" there would defiantly be mentions of it from pilots in the record, not just of P-47s, but from everyone.

Also, it is worth mentioning that tail design does effect stability...

At my former job, a pilot told me about his Beechcraft V-tail Bonaza would have a side to side "shimmy" effect from the Vtail while flying.

Though something like that wouldn't cause the plane to constantly yaw from side to side, it would be more of a vibration.   

Anyway, video of a P-51 test firing 6 .50cals... the fire rate is high, all guns fire almost in the same second, there is recoil to the aircraft:
https://youtu.be/niJ82YCiuYU?t=47

[SAS~Storebror]

I'm pretty sure the either were synchronized with one on both wings firing at the same time

No. Sorry, but simply no.
The cal .50 wing guns were not synced with anything. KISS principle. That's why they stuck to the wing mount, out of prop arc, just to keep things as simple as possible. No sync. Nada.

or the rate of fire was high enough that the difference between each gun was milliseconds, and all 6 would fire off within the same second or two.

All eight, other than that: Sure, the rate of fire was high.
Which doesn't keep physics from being applicable and as such, at any rate of fire, when guns are unsynced, there's a certain harmony which will cause the whole system to start swinging up.

Also, this would be a common problem to all wing mounted MGs, but wing mounted was the standard for most aircraft of WW2.

No such thing like "standard" in WW2 armament, but still: Yes, this was a common problem of wing mounted guns.
It was to be countered by excessive lateral stability of the aircraft in question.
Which the bubbletop Jugs simply didn't have until the tail fin was introduced.

If this caused a "spray" there would defiantly be mentions of it from pilots in the record, not just of P-47s, but from everyone.

No sorry, but this was a matter solely recorded on the P-47 to such extent that pilots reported it - and that's why I've implemented it.
In comparison to the P-51 for instance, the fuselage airflow on the P-47 was already rather distorted by the large front of the radial engine. That's probably why the whole effect was so much more pronounced compared to the Pony.

When the Bubbletop canopy was introduced on the P-47, it cause the plane to lose it's lateral stability to an extent where it would "sway" it's tail all the time. Just a little. Nasty, but no reason for further concerns... if there wasn't the issue that once firing the guns, the sway would become excessive. The plane simply wasn't stable enough on the lateral axis to counter the harmonics caused by 8 wing guns firing at the same time.
This got reported by pilots, and Republic solved it by introducing the tail fin.
That's it. Simple as that. And that's why the bubbletop P-47s without tail fin spray their ammo like they do in the Jugs reloaded pack.
Take it or leave it.


Mike

[WxTech]

Chicken and egg?

Could it have been the case that the lateral instability was not much worsened by firing the guns, but rather it became more noticeable just because of the desire to keep fire directed where needed?

It seems odd that an instability should be largely 'latent', only to be unleashed to the full at an aggravating +/- 2 degrees via vibration. Shouldn't the model have at least some of this sway occurring all the time?

[SAS~Storebror]

Shouldn't the model have at least some of this sway occurring all the time?

It does.


Mike