Author Topic: Lazy 30mm question  (Read 4070 times)

Offline bustr

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Re: Lazy 30mm question
« Reply #45 on: January 18, 2011, 03:24:51 PM »
So you guys are happy with your HUB mounted 30mm being angled to shoot up through the engine in the game to achive the distance you pull the convergence line out to so you can fire the round over your line of sight and drop it perfictly into the center of the target?

I have provided you the real world data that shows this is impossible and was never implimented in this manner in any german fighter while it was mounted in the engine. I was hoping to get more than a crickett gallery from some of this games Avatars of skill and gamemanship before I wishlisted this obvious technical error. I've seen several of this audience argue in these forums over real world performance tech data with a vengence.

What is different in this case??

It's not like I'm trying to argue performance numbers from 6 different sources with 6 different values. All of the 109 armerors manuals show the same balistics for the motokanone with the 20mm and the 30mm mounted. HUB firing cannons are fixed in place and the round drops under the nose out of the spinner. I even found pictures of the Yak's VK-105PF. Looks like the 20mm is strapped in to fire center of the hollow airscrew reduction tube. http://en.valka.cz/viewtopic.php/t/54646

Page 60 109F MG151/20
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20%20F-2%20F-4%20Wa.pdf

Page 23 MK108.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-6%20U4%20Bedienungsvorschrift%20-Wa.pdf

Page 30 MG151/20.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-5%20G-6%20Wa.pdf

Or you can translate the relevent section where the armorer is told the motorkanone is fixed mounted parallel to the line of the engine.
bustr - POTW 1st Wing


This is like the old joke that voters are harsher to their beer brewer if he has an outage, than their politicians after raising their taxes. Death and taxes are certain but, fun and sex is only now.

Offline moot

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Re: Lazy 30mm question
« Reply #46 on: January 18, 2011, 05:34:35 PM »
What is different in this case??
Gameplay? Like flaps not modeled as real ones (self-retract). I personally wouldn't care either way.  I don't think it'd be hard to adapt to.
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Offline Spork

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Re: Lazy 30mm question
« Reply #47 on: January 18, 2011, 06:04:22 PM »
I think the math was over Spork's 5th grade math. :)


 :aok

Everything I have been saying is being confirmed by Moot and now Grizz with his math. I was stating from the very beginning that mtnman's math was wrong and the 63% "golden round" was wrong. Now Grizz "showed" his math and he got 97% also, you guys aren't thinking three dimensionally. We do not fight on a 2D plane.


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Offline moot

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Re: Lazy 30mm question
« Reply #48 on: January 18, 2011, 06:33:37 PM »
The bottom line isn't what the bullet stream itself looks like, but what it looks like from the target's reference frame.

I want to script something to show what does what (rof, speeds, angle, tracking, etc) with a little graphics app, but I don't know how to write code that well yet.  I'll do it once I do know.
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Offline bustr

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Re: Lazy 30mm question
« Reply #49 on: January 18, 2011, 06:43:56 PM »
Gameplay? Like flaps not modeled as real ones (self-retract). I personally wouldn't care either way.  I don't think it'd be hard to adapt to.

Probably not hard at all. You would have to remember your round drops away faster than ever before at closer engagement distances if HiTech recoads the motorkanone and cousins. Testing offline with the cannon at 150 the best percentage hit range with the MK108 was at 100-250+- for fighters. 400+- for bombers which fits with the german tech expectations for the ballistics of the MK108 30mm.

HiTech can change the flaps to non-auto in moments and let us rip them off for awhile. Might change the predator pyramid in the game for a tour or two. The angery posts in here would be entertaining.

But, a whole technological family of wheapons systems being modeled to fire in a manner physically impossible in the face of the evidence. A bit gamey beyond auto flaps and definately training wheelish with pink handel bar tassels even for the Grizzinator. Or have the muppets been aware of this discrepency all along and not mentioned it to anyone?

Sorta as gamey as the fact our K14 is being presented to us in "Locked" mode which means we should have either a ring and dot centerd over the left paralax lens or a 6-pointed star and dot centerd over the right paralax lenz. Only if the MK8, N3 or N9 gunsight is used do you get a centered graticule in a P51.
bustr - POTW 1st Wing


This is like the old joke that voters are harsher to their beer brewer if he has an outage, than their politicians after raising their taxes. Death and taxes are certain but, fun and sex is only now.

Offline grizz441

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Re: Lazy 30mm question
« Reply #50 on: January 18, 2011, 07:14:48 PM »

 :aok

Everything I have been saying is being confirmed by Moot and now Grizz with his math. I was stating from the very beginning that mtnman's math was wrong and the 63% "golden round" was wrong. Now Grizz "showed" his math and he got 97% also, you guys aren't thinking three dimensionally. We do not fight on a 2D plane.


Spork

The only reason MtnMan's and my math differed was being I used a different plane length.  Had I used his plane length the probabilities would be equal.  MtnMan's math was not incorrect.  
The way we are idealizing the problem works fine for 2D.  I was also going to post a sketch of how "throwing your nose" parallel to the bogey as you fire taters increases the probability of a connection, but I ran out of time today.  It would be more difficult as well.

Offline kilo2

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Re: Lazy 30mm question
« Reply #51 on: January 18, 2011, 08:39:42 PM »
So you guys are happy with your HUB mounted 30mm being angled to shoot up through the engine in the game to achive the distance you pull the convergence line out to so you can fire the round over your line of sight and drop it perfictly into the center of the target?

I have provided you the real world data that shows this is impossible and was never implimented in this manner in any german fighter while it was mounted in the engine. I was hoping to get more than a crickett gallery from some of this games Avatars of skill and gamemanship before I wishlisted this obvious technical error. I've seen several of this audience argue in these forums over real world performance tech data with a vengence.

What is different in this case??

It's not like I'm trying to argue performance numbers from 6 different sources with 6 different values. All of the 109 armerors manuals show the same balistics for the motokanone with the 20mm and the 30mm mounted. HUB firing cannons are fixed in place and the round drops under the nose out of the spinner. I even found pictures of the Yak's VK-105PF. Looks like the 20mm is strapped in to fire center of the hollow airscrew reduction tube. http://en.valka.cz/viewtopic.php/t/54646

Page 60 109F MG151/20
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20%20F-2%20F-4%20Wa.pdf

Page 23 MK108.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-6%20U4%20Bedienungsvorschrift%20-Wa.pdf

Page 30 MG151/20.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-5%20G-6%20Wa.pdf

Or you can translate the relevent section where the armorer is told the motorkanone is fixed mounted parallel to the line of the engine.

I do not know enough about the ballistics of the real deal to really comment. I am looking into it now though. If it changes for whatever reason not a big deal I set my cannon at 225.

Maybe you should post it in the wishlist so we don't further hijack this thread. I have a feeling it will stir some people up.
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Offline Muzzy

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Re: Lazy 30mm question
« Reply #52 on: January 18, 2011, 09:30:46 PM »
:huh

So like, 300 convergence is good, right?


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Offline moot

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Re: Lazy 30mm question
« Reply #53 on: January 18, 2011, 09:44:33 PM »
Put it wherever you most often take your shots.  After using it for a while, adjust from that setting as needed.
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Offline grizz441

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Re: Lazy 30mm question
« Reply #54 on: January 18, 2011, 09:57:57 PM »
So you guys are happy with your HUB mounted 30mm being angled to shoot up through the engine in the game to achive the distance you pull the convergence line out to so you can fire the round over your line of sight and drop it perfictly into the center of the target?

I have provided you the real world data that shows this is impossible and was never implimented in this manner in any german fighter while it was mounted in the engine. I was hoping to get more than a crickett gallery from some of this games Avatars of skill and gamemanship before I wishlisted this obvious technical error. I've seen several of this audience argue in these forums over real world performance tech data with a vengence.

What is different in this case??

It's not like I'm trying to argue performance numbers from 6 different sources with 6 different values. All of the 109 armerors manuals show the same balistics for the motokanone with the 20mm and the 30mm mounted. HUB firing cannons are fixed in place and the round drops under the nose out of the spinner. I even found pictures of the Yak's VK-105PF. Looks like the 20mm is strapped in to fire center of the hollow airscrew reduction tube. http://en.valka.cz/viewtopic.php/t/54646

Page 60 109F MG151/20
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20%20F-2%20F-4%20Wa.pdf

Page 23 MK108.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-6%20U4%20Bedienungsvorschrift%20-Wa.pdf

Page 30 MG151/20.
http://deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Messerschmitt/Me%20109/Bf%20109%20G-5%20G-6%20Wa.pdf

Or you can translate the relevent section where the armorer is told the motorkanone is fixed mounted parallel to the line of the engine.

Start a new thread in aircraft and vehicles or wishlist and I'll be happy to look at it.  I'd be interested in seeing a side profile of A k4 showing where the hub cannon is located in relation to the prop and doing the math myself to see if a tater lobbed up to a desired long convergence will in fact hit its own engine.  I am too tired and lazy to read all the off topic links right now.

Offline mtnman

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Re: Lazy 30mm question
« Reply #55 on: January 18, 2011, 10:00:36 PM »
If you can get larger gaps then you can get smaller gaps if target is moving and you aim/time burst just right.


You can get smaller gaps in space, but not in time, and it's easy enough to do.  To do it, you don't fire at a crossing target.  

A crossing target maximizes the spacial effect, to the 55 feet or so that Grizz and I came to.  The faster the target appears to be moving, (while you don't change heading) the larger the spacial "gap" effect.  At a given speed, a 90 degree crossing target has the highest apparent speed possible, so it maximizes the the effect of time between rounds.

On the other hand, firing at a target that appears motionless (directly in front of you, going directly away or directly towards you) would minimize the spacial effect.  In effect, it nullifies the effect of time between rounds.

And each shot in the stream is fired under differing conditions in a crossing shot (even if it isn't a 90 degree deflection).  The range is different, the angle up/down may be different, G's may be different.  The target's in a different spot.  An aim that's perfect for a fraction of a second will be terribly wrong a fraction of a second later, because the conditions are no longer what they once were...




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Offline mtnman

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Re: Lazy 30mm question
« Reply #56 on: January 18, 2011, 10:12:11 PM »

 :aok

Everything I have been saying is being confirmed by Moot and now Grizz with his math. I was stating from the very beginning that mtnman's math was wrong and the 63% "golden round" was wrong. Now Grizz "showed" his math and he got 97% also, you guys aren't thinking three dimensionally. We do not fight on a 2D plane.


Spork

As Grizz mentioned, we came to a different Hit% probability because he used a longer target aircraft than I did.  I used a 33ft fighter as a model, which is close for an F4U, Spit, or P51.  If you chose an aircraft that was larger than 55ft, you'd up your chances to 100%, or even open up the possibility that the target could now get hit by the first round, and the next round to come along, if the first round hit the front of the target.

On the other hand, if the target was smaller, say 25ft, the chance would drop to 50%.  If it was 12.5 ft, the chance drops to 25%.

And again, we're talking about a perfectly aimed shot, for arguments sake.

Apart from the target size, the chance of a hit also changes with the speed of the target.  If the speed of the crossing target doubled, the "gap" would double to 110 ft.  The 33ft targets chances of being hit would be 31% now...

Also, keep in mind that in stream of rounds from a gun firing as we've modeled, in the situation modeled, only one of the rounds would have any chance at all of hitting.  Say you fired a ten-round stream...  If the aim was perfect, and the timing was correct for the 6th round to connect, the other nine would be misses.  The chances would be 0% for the other rounds, 100% for the 6th round.
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Offline grizz441

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Re: Lazy 30mm question
« Reply #57 on: January 18, 2011, 10:15:29 PM »
Also, keep in mind that in stream of rounds from a gun firing as we've modeled, in the situation modeled, only one of the rounds would have any chance at all of hitting.  Say you fired a ten-round stream...  If the aim was perfect, and the timing was correct for the 6th round to connect, the other nine would be misses.  The chances would be 0% for the other rounds, 100% for the 6th round.

Which is why the best tatering strategy is to fire out in front and have the target fly through them.  I also prefer a slight rudder swing as I fire the taters which I believe increases the probability if you throw the nose at the proper angular velocity.  Caveat: This is for close shots with full profile.  Rudder throwing causes more inaccuracy in alignment.  Maybe I'll show mathmatically this weekend why throwing your rudder will actually increase the probability of a connection.

I remember one crazy tater shot I hit on you mtnman, it was from the side, you were going about 400 maybe a 70 degree crossing shot but you were never looking at me.  My entire focus was on an imaginery line way out in front of your line of action and hoping I lined it up correctly.
« Last Edit: January 18, 2011, 10:20:43 PM by grizz441 »

Offline mtnman

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Re: Lazy 30mm question
« Reply #58 on: January 18, 2011, 10:25:22 PM »
The real point of all this was to answer the OP's question, right?  And why would someone be looking for an effective convergence setting, apart from looking for a way to score some hits?

In reality, a "mid" range convergence would prove to be the best all-around, general purpose setting, if you went through a bunch of testing.  Trust me, I've done a LOT.  I've also done a ton of real-world shooting, with a variety of firearms in a variety of conditions/settings.  Personally, I'd go with a 300yd or so convergence, and I'd throw away the convergence-setting key at that point.  I'd learn to use the guns like that.  "Knowing" what they'll do comes with lots of practice.

A close setting will maximize your effectiveness at close range, but reduce it at the other ranges (where you're more likely to shoot anyway).  Same goes for a long-range convergence.  At long-ranges, dispersion alone messes things up, so even a shot at convergence distance isn't as effective as it could be...

Of course, that argument is somewhat nullified by the fact that the gun is nose-mounted near eye-level (which makes gunnery much simpler) and the fact that it only takes one hit to do serious damage.

The nose-mounting, and effectiveness of the round, should make this an easy gun to master.  Why do so many have trouble with it then?  RoF for one...  Velocity seems likely as well, but I haven't bothered to look it up yet.
MtnMan

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Offline mtnman

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Re: Lazy 30mm question
« Reply #59 on: January 18, 2011, 10:40:05 PM »

I remember one crazy tater shot I hit on you mtnman, it was from the side, you were going about 400 maybe a 70 degree crossing shot but you were never looking at me.  My entire focus was on an imaginery line way out in front of your line of action and hoping I lined it up correctly.

Ha!  I remember that!  Not like I could forget it, lol...

I'd be willing to bet though, that your strategy for the most part is to line up on a point in front of your target, relax on the controls, and fire a short burst a tad early?  If it misses, set it up again?  Rather than firing on a curving turn, you're flying more of a "stop-sign" circle, firing on the "flats"?  Pull, relax, fire, pull, relax, fire?

In effect, that's treating the guns almost like single-shot weapons, even though we benefit from the "stream" aspect, which can correct for miss-judged timing?

That's basically what I do...  There are times when I'll pull hard and squeeze, but for those I'm sure of a hit, and I know it.  Close in, slow target (even if it's crossing) and I can hit it even if I'm blacked-out.

Now, on sustained lead shots, I'd guess you'll hose 'em down too (or walk your rounds on target), but I'd wager you don't often fire sustained bursts while holding much pressure on the elevator?

The reason I ask is because what so many seem to do is think there's a "magic" convergence setting, that makes up for "something", and they experiment looking for it thinking when they find it it'll solve their gunnery qualms.

I'd guess most of the better shots in the game don't screw around with it much though.  They rely on a (or a few) simple technique(s) to score hits, rather than looking for a magic setting.
MtnMan

"Those who hammer their guns into plows will plow for those who do not". Thomas Jefferson