Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: vonKrimm on February 26, 2010, 02:20:08 PM
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I can hit BUFFS and kill them with everything from 7.7mm BBs to 75mm punkins' (sometimes even landing afterward), EXCEPT the blasted 30mm! :furious
I keep all my guns set between d350 & d450 and know where the rounds will go for a given weapon type. What I would like to know is: should I decrease the convergence on the 30mm and flatten the trajectory or increase the range and lead more to allow for the lumbering flight of the taters?
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Decrease.
250 yards.
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Convergence is a secondary mode of aiming. Primary mode is proper leads and angles. I suspect your crossing angles aren't getting you close enough and along the same lines, you aren't shooting your 30mm's with enough lead.
Convergences will only affect tater connections on the fringes. A good tater shot aimed at the center of an aircraft will connect regardless of what the convergence is set at(for reasonable distances). Study your approach to efficiently setting up a perfect 30mm shot and make sure it is sound.
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I can hit BUFFS and kill them with everything from 7.7mm BBs to 75mm punkins' (sometimes even landing afterward), EXCEPT the blasted 30mm! :furious
I keep all my guns set between d350 & d450 and know where the rounds will go for a given weapon type. What I would like to know is: should I decrease the convergence on the 30mm and flatten the trajectory or increase the range and lead more to allow for the lumbering flight of the taters?
I have found that no matter what my convergence is, K4 Taters suck azz. A buddy and I compared German 30s on 2 different LW Aircraft, FW-190A8 and BF-109K4. We came to the conclusion taht 30s on A8 hit no prob and demolish anything while K4 jsut seems to be firing Paint every other round, lol. I would say just get a buddy and got to DA and work out the kinks and then you will know where to set Convergence , etc.
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I have found that no matter what my convergence is, K4 Taters suck azz. A buddy and I compared German 30s on 2 different LW Aircraft, FW-190A8 and BF-109K4. We came to the conclusion taht 30s on A8 hit no prob and demolish anything while K4 jsut seems to be firing Paint every other round, lol. I would say just get a buddy and got to DA and work out the kinks and then you will know where to set Convergence , etc.
That's a pretty crappy conclusion, since both planes use the same Mk108 30mm.
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The Ta-152 seems fine to me. Or, would you rather me tell that lame story of the D800 Yak kill again? :D
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I bet your trouble with the k4 is that it is a hub or center mounted cannon. The other luft planes all have wing mounted 30mm's. Probably your lead you need to work on.
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I bet your trouble with the k4 is that it is a hub or center mounted cannon. The other luft planes all have wing mounted 30mm's. Probably your lead you need to work on.
bar the 152,
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set the convergence to 250 and hold your fire till you can read the markings on the plane :devil
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set the convergence to 250 and hold your fire till you can read the markings on the plane :devil
Alas, by which time your taters are all gone
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set the convergence to 250 and hold your fire till you can read the markings on the plane :devil
So 6k out lol
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bar the 152,
Or the 262, or the 110. Come to think of it, the only luft ride with 30mm's in the wings is the A8 :D
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Or the 262, or the 110. Come to think of it, the only luft ride with 30mm's in the wings is the A8 :D
And G14 ;)
Actually the A8 and the 163...technically speaking ;)
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And G14 ;)
What plane is that, never heard of it, neither has warhed?
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And G14 ;)
Actually the A8 and the 163...technically speaking ;)
Um, no, those are 20mms.
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Um, no, those are 20mms.
Only if you are nub enough to take the 20mm option. ;)
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Only if you are nub enough to take the 20mm option. ;)
I never do :D
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Okay, yesterday I changed the convergence to d250 and upped a 262 in AvA, and got bounced by a PonyD on take-off! :O Yup, I got caught low & slow; every pile-its wet dream. :o He made a pass that oiled my left engine as I was turning, so I made my turn a 180 back to base & into the sun (where he lost me) and was able to build-up enough speed to let me re-engage on my terms. We ended up having a nice little fight between the trees, where I finally got a gun solution at d200 & removed his vertical stabilizer with a quick burst.
Then I took my new convergence settings to the MA & got some lancs that seemed to be looking for our CV in only two passes; I still hit a piece of the last one & that put an end to my fun as I lost all four cannon to the collision. I don't think I'll curse the Mk 108 anymore, at least until I take a 109k4 out. :D
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Big difference between a 262 and a K4: four times the taters in the air.
The ROF for the 108 is slow enough that you could run a train between shells. With only one cannon, you can miss a lot of trains.
If you are finding it easier to hit with the 262 than the K4; I'd bet your lead may be just fine but your timing is off. Aim to hit with the first round.
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wasn't the mk108 considered some kind of armament milestone or something like that?
thought i read that someplace ...
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"The ROF for the 108 is slow enough that you could run a train between shells."
Same ROF as for Hisso and only a tad slower than MG151/20. But I do agree. I have had planes passing unharmed at 90 deg angle through my fire when flying A8 and firing 6 guns!
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ain't that just annoying as all get out ...
"The ROF for the 108 is slow enough that you could run a train between shells."
Same ROF as for Hisso and only a tad slower than MG151/20. But I do agree. I have had planes passing unharmed at 90 deg angle through my fire when flying A8 and firing 6 guns!
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"The ROF for the 108 is slow enough that you could run a train between shells."
Same ROF as for Hisso and only a tad slower than MG151/20. But I do agree. I have had planes passing unharmed at 90 deg angle through my fire when flying A8 and firing 6 guns!
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Accurate... I stand corrected.
I wonder if the speed of the projectiles results in the perception of a larger distance between rounds.
Conceptually (at this late hour) that seems to make sense.
EDIT: Yes, it does makes sense. Chance of hit would increase if the speed of the same number of projectiles, with the same distance between them, traveled faster than a comparable ROF weapon. The increased speed results in more shells passing though the target area in a shorter span of time.
Imagine standing next to a highway with a slow lane and a fast lane. In any amount of time elapsed, given equal distance between cars due to equal ROF, more cars will drive past you in the fast lane.
Which lane is easier to run across without getting hit?
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I can hit BUFFS and kill them with everything from 7.7mm BBs to 75mm punkins' (sometimes even landing afterward), EXCEPT the blasted 30mm! :furious
I keep all my guns set between d350 & d450 and know where the rounds will go for a given weapon type. What I would like to know is: should I decrease the convergence on the 30mm and flatten the trajectory or increase the range and lead more to allow for the lumbering flight of the taters?
Decrease to flatten out the trajectory and then get a feel for it from there. That way you don't have to aim below the plane at all, that really threw me at first.
For fighters, get in close (D200-250 max if your not used to the trajectory, and closer if your target is manuvering) and at low 6.
If its turning hard, try to make a slashing pass while its showing you its wings. Love to pwn 38's with the tater gun, nice big target, slower top speed, and lower climb rate. Sometimes when I get pwned in tanks, I just up a K4 and hunt 38's ignoring everything else.
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Accurate... I stand corrected.
I wonder if the speed of the projectiles results in the perception of a larger distance between rounds.
Conceptually (at this late hour) that seems to make sense.
EDIT: Yes, it does makes sense. Chance of hit would increase if the speed of the same number of projectiles, with the same distance between them, traveled faster than a comparable ROF weapon. The increased speed results in more shells passing though the target area in a shorter span of time.
Imagine standing next to a highway with a slow lane and a fast lane. In any amount of time elapsed, given equal distance between cars due to equal ROF, more cars will drive past you in the fast lane.
Which lane is easier to run across without getting hit?
I might be wrong... but I think the analogy is not pefect, as we can see the cars and try to get the right timing to cross the highway.
Now we have two guns. Gun A: 10rps, 800m/s, Gun B: 10rps, 500m/s
Now there might me 800m between the rounds of gun A), and 500m between rounds of gun B)... but in the end, it's one bullet every 0.1 seconds, now matter how fast they are.
In both cases, we have the same amount of time to squeeze our plane between 2 bullets. (At 300 mph, a plane travels about 43ft in 0.1s)
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i think luche is incorrect in the sense that yes the space between the rounds may be the same but the time the plane has to get it's length through the path of the round is reduced. in his example safe time is @63% less
i.e. along the line of fire there is a round at point x every 10th of a second, however the aircraft passing through point x however since the object passing through the point x intersection has a length as well it only @ 63% the time to cross the distance for the faster round than the slower round.
i think ...
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another thing is that it takes longer for the shells to get down range, meaning your target has more time (however small and amount it is) to see you, and screw up your aim.
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i think luche is incorrect in the sense that yes the space between the rounds may be the same but the time the plane has to get it's length through the path of the round is reduced. in his example safe time is @63% less
i.e. along the line of fire there is a round at point x every 10th of a second, however the aircraft passing through point x however since the object passing through the point x intersection has a length as well it only @ 63% the time to cross the distance for the faster round than the slower round.
i think ...
Hmmm still not convinced.
Every 0.1s there is a bullet leaving the barrel. So that means there is one bullet passing any point every 0.1 seconds too. I don't see how this interval is being shortened by bullet speed at all. (If the muzzle velocity would shorten this interval, the bullets would catch up with each other if the muzzle velocity were high enough - sounds illogical to me)
So every 0.1s there is a hit on point X.
An extreme example would be a light flashing once per second. "Muzzle velocity" = speed of light. But someone 100ft away would still have 1 second to cross a certain point, and not less because the light is so freaking fast.
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Hmmm still not convinced.
Every 0.1s there is a bullet leaving the barrel. So that means there is one bullet passing any point every 0.1 seconds too. I don't see how this interval is being shortened by bullet speed at all. (If the muzzle velocity would shorten this interval, the bullets would catch up with each other if the muzzle velocity were high enough - sounds illogical to me)
So every 0.1s there is a hit on point X.
An extreme example would be a light flashing once per second. "Muzzle velocity" = speed of light. But someone 100ft away would still have 1 second to cross a certain point, and not less because the light is so freaking fast.
Okay, let me see if I get it. Every .1 seconds a round travels down range. That .1 seconds determines the time between each bullet. The velocity of the bullet determines the physical separation between each round.
Derivation:
t=.1 vsub1=500m/s vsub2=300m/s
d=vt
d=(500m/s)(.1)=50m between each round
d=(300m/s)(.1)=30m between each round
So, we have a smaller space between each round. However, what matters is frequency. How many bullets pass through a single area in any given time. Because the frequency at the barrel is equal to the frequency down-range (the velocity is constant, therefore the spacing is constant) the amount of time between each round firing is equal to the amount of time between each round passing a single point in space. Because ROF is the same, frequency is the same, and therefore you have an equal amount of time between each round regardless of velocity.
HOWEVER, Sourdaukar nailed the true problem unintentionally. It is our ability to perceive the placement of the round downrange. Consider the extremes of a laser versus a slingshot. The laser is the 500m/s round, the slingshot is the 300m/s round. The longer the time between the bullet leaving the gun (point A) and the bullet arriving at the intersection of bullet path and target (point B) determines how much we must lead the aircraft.
As we all know, t=d/v, therefore, assuming the target is 300m away from you (Reasonable snapshot distance in AH), we get the following equations:
t=v/d
t=(300m)/(500m/s)= .6 seconds between the leaving the gun and arriving at the target.
t=(300m)/(300m/s)= 1 second between leaving the gun, and arriving at the target.
We have two factors here, lead, and pilot reaction. The 500m/s round gives the target only .6 seconds to move out of the line of fire. The 300m/s round gives the target a full second to leave the point of impact. So, the 500m/s round must lead the target by .6 seconds of flight time for the target; The 300m/s round must lead by 1 second. Assuming flight time for the targets are equal, and d=vt so, derivations applied assuming the aircraft is moving at, say 200m/s (Not realistic, just a random number),
d=vt
d=(200m/s)(.6)= 120m lead
d=(200m/s)(1)= 200m lead
So, you must put your line of fire 120m in front of the target with a 500m/s round, and 200m for the 300m/s round. As we know, the farther we must lead, the more time we must lead by, the harder it is to predict where the plane will be. The shorter the lead, the easier the snapshot, and the less thinking necessary for the shot, therefore, less lead=easier kill.
So, long story short, while the 500m/s round is not MATHEMATICALLY more effective, PRACTICALLY it is much easier to put the round on a moving target than it is to use a 300m/s round.
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:confused:
Yer smert.
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:confused:
Yer smert.
lol. I am BARELY passing high-school at the moment. I just FINALLY found a practical application for my AP Physics, lol.
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Well your understanding of physics is well beyond my own. "As we all know..." does not apply, methinks. :D
I'm still struggling with my conceptual vision, though. Let me try to explain it differently and you tell me what you think.
As most tater dweebs will confirm; the shot with the highest probability for success is a near 90 degree snapshot with wings perpendicular to the flight path of the EAC.
For this reason, I will use the highway example again - but with a twist.
Here are the facts:
1.) The subject area consists of a flat, grassy field to the west of center and a two-lane, single-direction highway to the east of center.
2.) Each lane has an on-ramp to the north of center and cars travel south in both lanes.
3.) Lane A of the highway is the slow lane. Lane B of the highway is the fast lane. Each lane is 10m wide.
4.) Cars enter the on-ramp at the same rate: One car every second. Spacing remains the same between cars in the same lane: 20m apart.
5.) Cars in Lane A travel at 20m/s. Cars in Lane B travel at 40m/s.
6.) You are driving across the field at 20m/s, towards the highway, at a perfect right angle, with the intention to cross the highway.
Now...
This makes the point (time and space) at which you cross the highway the "target area" and it makes you the target.
The target area is, for the sake of argument, a perfect square of 400m^2 (20m*20m).
It will take you 1 second to cross the target area.
Along the perpendicular path, it takes the cars in Lane A 1.0 second to pass through the target area and it takes the cars in Lane B 0.5 second to pass through the target area.
Given equal spacing of 20m between cars; the number of cars which pass through the target area in that 1.0 second you are crossing is different for each lane.
Therefore...
In Lane A, the slow lane, cars are traveling at a rate of 20m/s, 20m apart from each other, passing through a 20m target area. This means that in the 1.0 second it takes you to cross the target area, the maximum of number of cars which can pass through the target area during the time you are in the target area is one.
In Lane B, the fast lane, cars are traveling at a rate of 40m/s, 20m apart from each other, passing through a 20m target area. This means that in the 1.0 second it takes you to cross the target area, the maximum number of cars which can pass through the target area during the time you are in the target area is two.
The faster cars (shells), despite equal spacing (ROF), due to their speed advantage (m/s) have a 100% greater chance (1 v 2) of impacting your car (plane) while crossing the target area (ideal range and deflection).
Does that not make sense or am I over-simplifying it?
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They won't have equal spacing in distance Saur, despite (and because) having an identical RoF. The cars traveling at 1/2 the speed, will have 1/2 the distance between them. The time will be equal, but not the distance.
Think of it this way, two guns are both firing one round every second (or ramps with cars, if you prefer). Equal RoF (1 round/second). Bullets are coming out at 2000 FPS from one gun, and 1000FPS from the other. Fire them at precisely the same moment, and continue that process...
Precisely one second later, when the second bullets are fired, one of those initial bullets will have traveled 1000ft, while the other has traveled 2000ft.
So, while both guns are firing at 1 round/second, and each target is being hit at a rate of 1 round/second, the spacing between the two guns is different.
Where speed of flight really matters is in how arched the trajectory will be. The slower round falls (assuming both guns are firing identical bullets) at precisely the same speed as the faster round, but it takes twice as long to arrive at the target, so appears to fall faster.
Back to the initial example of 1000 vs 2000 fps, firing both guns at a target at 2000ft, one round will take twice as long to arrive, so has twice as long to fall... If the faster round hits 2ft low, the slower round would hit 4ft low.
Adjusting your convergence on nose-mounted guns is primarily about adjusting the trajectory, compared to effective range. Effective range is reduced with a reduced velocity, because the increased arch of the trajectory makes hitting things harder. Range-estimation is much more difficult, and much more critical as velocity is decreased. Misjudging range with a slow projectile means you shoot over your target, or under it, with a small window of "just right". A faster projectile has a flatter trajectory, for further, so is more forgiving of range-estimation errors.
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Therefore...
In Lane A, the slow lane, cars are traveling at a rate of 20m/s, 20m apart from each other, passing through a 20m target area. This means that in the 1.0 second it takes you to cross the target area, the maximum of number of cars which can pass through the target area during the time you are in the target area is one.
In Lane B, the fast lane, cars are traveling at a rate of 40m/s, 20m apart from each other, passing through a 20m target area. This means that in the 1.0 second it takes you to cross the target area, the maximum number of cars which can pass through the target area during the time you are in the target area is two.
The faster cars (shells), despite equal spacing (ROF), due to their speed advantage (m/s) have a 100% greater chance (1 v 2) of impacting your car (plane) while crossing the target area (ideal range and deflection).
Does that not make sense or am I over-simplifying it?
I see where you are coming from... but if you calculate this for a gun and airplane you will see muzzle velocity makes no difference.
Target: (fighter sized)
Plane length 10m
Plane speed 150m/s (approximarety 338mph)
The plane takes 0.07 s to fully cross the gun's line of fire (plane length/plane speed)
Regardless of MV, every 0.1 s there is a round appearing at that point. As the plane's crossing time (0.07s) is shorter than this interval, it has a chance to get through before the next round arrives.
Don't look at the whole distance the round is traveling. That can be confusing. Just look at that target point, where the vectors of target & round are crossing. Every 1/(ROF) seconds, a bullet will appear there.
Take my "flashlight" example again. If you are flashing the light every 1 (or 0.1) second, there is a flash every 1 (or 0.1) seconds even at distance, though the "muzzle velocity" is 299 792 458 m/s
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They won't have equal spacing in distance Saur, despite (and because) having an identical RoF.
THAT is what I'm missing... had not considered it.
Makes sense now, thanks.
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For what it's worth, this is what works for me.....
I use the Revi16d gun sight.
I pull up and start aiming where the arrow is (in the attached modified pic). Sometimes lower, depending on how many G's you are pulling. I have convergence set at d400 for the 30mm (even though it's a single cannon, it will have an affect on how you aim and is a personal preference) . I'll set mg's at d500, especially if I am flying with squaddies so I can spook a con off someone.
Obviously it is best to pull as little lead as possible, but the one being pursued usually panics when they hear that 108 barking. I have found that it is best to wait til you have a sure shot and squeeze off a few at a time. If nothing else flying with only 65 cannon rounds will teach you to husband your ammo :devil
(http://i239.photobucket.com/albums/ff107/tymekeepyr/GermanTaterRevi.jpg)
The 30mm rounds usually had 41 m (135 ft) of drop in the first 1,000 m (3,300 ft) of range. :O
So.... in a perfect world in perfectly level flight, using a perfect angle of drop (not accounting for wind, or arc of drop as it would not fly at a perfect downward angle, or other adverse effects on ballistics) it would go like this.
d200 = 8' - 2" of drop
d300 = 12' - 3" of drop
d400 = 16' - 4" of drop
d600 = 24' - 6" of drop
the angle of descent is (2) degrees or roughly 4' of drop for every 100' of distance (again a perfect angle, not a true ballistics arc)
(http://i239.photobucket.com/albums/ff107/tymekeepyr/200.jpg)
(http://i239.photobucket.com/albums/ff107/tymekeepyr/300.jpg)
(http://i239.photobucket.com/albums/ff107/tymekeepyr/400.jpg)
(http://i239.photobucket.com/albums/ff107/tymekeepyr/600.jpg)
Taking into account that a B-24 Liberator is about 18' tall, you have to just about point the center of the pipper OVER the buffs to actually HIT them with taters at d400 :O
That's why I usually don't use the center of the pipper for aiming 30mm's
I have not accounted for rate of fire in any of the above, but without a doubt, it comes into play.
Hope this helps.
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Back to the initial example of 1000 vs 2000 fps, firing both guns at a target at 2000ft, one round will take twice as long to arrive, so has twice as long to fall... If the faster round hits 2ft low, the slower round would hit 4ft low.
This isn't correct since the motion is parabolic. The eqn. of motion for the shell is based off the fact that accel is constant. Even if you ignore aero effects on the shell, you've still got:
x=x(0)*v(0)*cos(theta)*t
y=y(0)+v(0)*sin(theta)*t-gt^2/2
t is time, v(0) is muzzle velocity, theta angle off target in a simple horizontal example, x horizontal, y vertical
what can be pretty easily shown is that, if they both hit the target, because you've got to change your initial angle theta to a higher trajectory (up to 45 degrees) for the lower-speed shell, the two shells actually have to travel different distances (more for the slower one, compounding the time disparity) - unless you're using some flat-trajectory assumption, in which case, that's great IF YOU'RE FIRING YOUR SHELLS IN THE ABSENCE OF GRAVITY. Even in the case you posit, where they both drop below the target, the slower shell still has to travel farther, even is you use a simple, triangular assumption to calculate the distance.
BORON MUST LIVE. ONLY MY FRIENDS WILL POINT OUT MY WEAKNESSES. THANK YOU COMRADE STALIN.