Author Topic: Gunnery woes - I think we are all feeling them at the moment  (Read 8196 times)

Offline FESS67

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #45 on: September 22, 2016, 04:25:05 AM »
I really really like Dobs.

He is great fun to fly against and is obviously technically competent.  I have not yet found myself on the same side as him but when I do I will make sure to fight as hard for him as I fight for anyone....as long as the shot does not demand G forces or yaw, since we know I will miss every time  :D

HITECH - seriously, new blood is great for this game and he fights a good fight.  Call the fan boys to order at least to a point where they can at least debate an issue openly.  <peace>

Offline Dobs

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #46 on: September 22, 2016, 08:31:37 AM »
Appreciate the vote of confidence guys.

Why Bustr wants to know my background is beyond me, but yes I was a WB trainer in the past. Haven't been a trainer since 05 though.

So Bustr, now that I've answered my question. Here is yours--why does it matter if someone comes on the board and asks questions, or shows aptitude in a specific area? 

FLS has been polite, and backed up his answers--I'm not bucking for the Training Corp--been there done that, got the T-shirt. I'm not bucking for a CM job--no desire.  But I'm always about trying to help with whatever game/project I'm involved in. 

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Offline FLS

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #47 on: September 22, 2016, 09:45:11 AM »
Bustr likes to make sure the new guys feel welcome and appreciated.  :D

Offline Dawger

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #48 on: September 22, 2016, 10:40:23 AM »
I really really like Dobs.

He is great fun to fly against and is obviously technically competent.  I have not yet found myself on the same side as him but when I do I will make sure to fight as hard for him as I fight for anyone....as long as the shot does not demand G forces or yaw, since we know I will miss every time  :D

HITECH - seriously, new blood is great for this game and he fights a good fight.  Call the fan boys to order at least to a point where they can at least debate an issue openly.  <peace>

I wouldn't worry too much about Dobs dealing with the feeble attempts here to sidetrack his desire to learn what he can about how AH gunnery operates.

And its an important question for Dobs to get an answer to.

When someone has trained to perform a particular skill under a particular set of rules, in this case the rules of physics, learning to perform that same skill under a different set of rules, one must first learn what the rules are and then erase the the old training while re-learning the skill.

Someone who learned to played football on earth will have trouble playing on the moon for a while but will eventually excel.

Someone who has always played on the moon has no clue how much harder it is to play on earth and how much they would suck at it.

Offline FLS

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #49 on: September 22, 2016, 10:52:40 AM »
Dobs was answered on page 2.  :D

Discussion is welcome as is Dobs.  :salute

Offline bustr

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #50 on: September 22, 2016, 03:58:18 PM »
Like to keep the player's stats straight so I don't get any ringers with my fantasy football picks.
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 Kingpin

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #51 on: September 23, 2016, 01:32:16 AM »

Since I find this topic interesting...

I went ahead and did some testing in a B-29, firing the top turret and left waist gun at 90-degrees to the air flow (flying north, target at 600 yards due west (.target 600 270).

Unless I am interpreting the results incorrectly, it appears that Aces High does model a drag effect on bullets due to the airstream. 

Also, the air density does appear to be factored in as well.  Note the difference in the two results below.  Both are at the exact same air speed (257) and target range (600).  The only difference is altitude (5K and 20K).  It appears the drag was significantly less at 20K.

Result at 5K:


Result at 20K:



So, this begs the question why did I not see any noticeable effect in my yawing test in a fighter...? 

Any ideas?
« Last Edit: September 23, 2016, 01:33:51 AM by Kingpin »
Quote from: bozon
For those of us playing this game for well over a decade, Aces High is more of a social club. The game just provides the framework. I keep logging in for the people and Pipz was the kind that you keep coming to meet again.

Offline FLS

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #52 on: September 23, 2016, 09:25:03 AM »
If you recall my comment was the yaw angle, range, and dispersion didn't allow a noticeable result.  :aok


Offline Kingpin

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #53 on: September 23, 2016, 01:40:23 PM »
If you recall my comment was the yaw angle, range, and dispersion didn't allow a noticeable result.  :aok

Yes.  I came to the same conclusion when I told Dobs that air-density is modeled but that I couldn't produce an observable effect.  I wasn't ready to rule out modeling of bullet deflection due to the slipstream, just that I couldn't "see" a dramatic effect. 

I thought it could be due to my testing methods as well, so I wanted to raise the question. I think it would be interesting if I could see a smaller effect in fighter, just to prove it exists.

If firing at 257mph into the slipstream at 90-degrees yielded an average deflection of 60 feet at a range of 600 yards (assuming a bullet flight time of about .7 seconds - guestimated)...

What would the expected deflection be when firing into a 257mph slipstream at 15-degrees at a target of 300 yards (assuming a flight time of around .35 seconds)?


Any math-wiz want to tackle that one?  Anyone, anyone?  Bueller?  Bueller?   :)

<S>
Quote from: bozon
For those of us playing this game for well over a decade, Aces High is more of a social club. The game just provides the framework. I keep logging in for the people and Pipz was the kind that you keep coming to meet again.

Offline Dawger

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #54 on: September 23, 2016, 01:55:19 PM »
Yes.  I came to the same conclusion when I told Dobs that air-density is modeled but that I couldn't produce an observable effect.  I wasn't ready to rule out modeling of bullet deflection due to the slipstream, just that I couldn't "see" a dramatic effect. 

I thought it could be due to my testing methods as well, so I wanted to raise the question. I think it would be interesting if I could see a smaller effect in fighter, just to prove it exists.

If firing at 257mph into the slipstream at 90-degrees yielded an average deflection of 60 feet at a range of 600 yards (assuming a bullet flight time of about .7 seconds - guestimated)...

What would the expected deflection be when firing into a 257mph slipstream at 15-degrees at a target of 300 yards (assuming a flight time of around .35 seconds)?


Any math-wiz want to tackle that one?  Anyone, anyone?  Bueller?  Bueller?   :)

<S>

If one assumes 1/6 th of the force vector applied (15 versus 90 degrees) over half the distance the result would be a 5 foot deflection.

Thats a total SWAG though

« Last Edit: September 23, 2016, 01:57:42 PM by Dawger »

Offline FLS

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #55 on: September 23, 2016, 01:57:59 PM »
Are you allowing for the different frontal area presented to the side load?

Offline Dobs

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Offline hitech

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #57 on: September 30, 2016, 02:05:28 PM »
Umm...no. 

So you are saying the fact that you are in a skid and because your target is moving, the bullets fired into a windstream of 200-400 mph are not affected?

(Image removed from quote.)

A nice excerpt from a forum:
From the top:

You are flying along at 360kph with 5 degrees of slip and fire at some object 300m away centered in your gunsight.
You bullet has a sideways motion of 100m/sec x sin(5) due to your forward motion being 5 degrees off your direction
of aim. Sin(5) = .0872, in one full second the bullet will be about 9m off to the side towards the direction of
flight. 300m takes more like 1/3rd of a second to reach.
IF the target is flying parallel to our plane at the same speed then he will move to the side at the same speed as
the shots do or just a tiny bit faster -- he will appear to stay directly in your sights while your shots appear
to be curving slightly away from your pipper.
IF the target is flying straight away from your sight, 5 degrees off parallel to your course then your shots will
miss by a meter or more.
IF the target is coming at you then the drift of your shots will be opposite to his drift, miss by more.

This is simple geometry. When geometry is unreal then check your assumptions again.

The longer the range, the greater the gap to deal with. At under 100m the bullet speed makes the difference very
small, by 200m you might not hit the part of the plane you aimed for, at 300m+ it's easy to miss a target.

If you are flying along and see an enemy plane close to the pipper then rudder over to center it, you are probably
in slip right then. Just know it and deal with it, the shot does not go where the pointed at the moment the shot
was made. Your speed, the bullet speed and the angle of slip have everything to do with it even before looking at
a target.

Believing that your shots all go where the pipper pointed is the dweeb mistake not to make. They don't.

Add in that ruddering the pipper over adds yaw which makes one wing go up and the other go down as well as gets
some nose up or down (tiny shifts depending on the rudder use) and in general, wobbles the nose of the plane.
Oh but that's supposed to be a modeling problem! Is it a pilot problem? Tiny nose shift = pipper moved 1+ tics!

Just to shake you all up, there's the vertical equivalent of slip as well. When I am flying slow my AOA must be
higher to generate the lift I need to follow my path. When I am flying fast my AOA must be lower. That moves
my sight up and down relative to my path. At some speed it's probably right but yeah there's vertical slip.


Break Break


 Anyhow, it appears from flying the game that it is not modeled (nor has it been modeled in anygame that I've been in).

Diagram is correct , but your math is way off. The missing piece of your math is that you are not adding the forward velocity of the aircraft to the bullet angle of travel.

The computation needs to take into account the bullet coefficient and the change in velocity relative to your planes forward motion. Notice the diagram is show with and with out drag I.E. Vacuum and non vacuum.

The deflection you are speaking of is completely modeled and is do to the slowing of the bullet relative you to your forward motion. I.E. just as if you dropped a ball out side if no gravity and no drag it would keep flying with you. Add air drag and it will fall behind you just as the diagram. The same effect is why your bullets travel farther in rear gunner vs forward gunner.

There are 3 other forces on the bullet that are not modeled.

One spin of the bullet and having the velocity vector coming slightly from the side. I.E. has an AOA.
2nd one is do to lift generated do to AOA of the bullet do to the above issue. (note lift is not up but sideways)
3rd is the change in the drag coefficient do to the above described angle.

These 3 effects are very very minor and are made up for in dispersion.

HiTech

Offline Dobs

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Re: Gunnery woes - I think we are all feeling them at the moment
« Reply #58 on: September 30, 2016, 02:28:33 PM »
Ty Hitech.

Seems I'm being a pain in the ass, so I'll stop.

I do appreciate your inputs and efforts at answering posts, but this is all qweepy stuff:)

Cheers!
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