Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Slade on January 01, 2012, 07:22:41 AM
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Hello All,
This is directed toward P-51b pilots, where do you tend to set your convergence and why?
Thanks,
Slade :salute
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I set the P-51B convergence to 350 yards.
Why? Because I have that as my standard convergence in almost all fighters. Particularly within a class of fighters with the same armament (.50 cal in this case) it doesn't make much sense to me to have different convergences, as this requires you to memorize different aim points.
The 350 setting proved the most versatile one for my personal combat style, as I use do the whole range from getting close & saddling up to long range (800+) sniping. in particular I open fore at D1000 when attacking bombers in .50 cal equipped planes. (I'm mainly buff hunting when flying the 51B)
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Snailman,
Thanks for the feedback.
Just so I am clear on your answer, when attacking another fighter with convergence at 350 where would to begin shooting? Ideally yes 350 but just curious if you find 50 cals effective out a bit while convergence set to 350.
[Sidebar]
I noticed some in F4U's set their convergence (50 cals) out to 500 or 550 so as they can "lead" the track of bullets better. Maybe it is the nature of F4U that close in shots are under the cowling otherwise. I don't know.
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Just so I am clear on your answer, when attacking another fighter with convergence at 350 where would to begin shooting? Ideally yes 350 but just curious if you find 50 cals effective out a bit while convergence set to 350.
Depends fully on the situation. Of course I always try to get as close as possible, but I shoot at almost every distance if I see a good opportunity.
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Convergence is a very personal thing. I have a horrible aim but I'm sure it's due to not enough pratice. I only get to play once a week, and like golf you just can't get better doing that.
From my experience, one of the things I read was that the range numbers are set up so that as soon as it changes from 400 to 200 you are at 300 yards out. So the idea is set your convergence to 300, and shoot when you see that number switch. Simple right? Well the top guns say that the best way to get kills is to set up crossing shots, get into a scissor or force an over-shoot and take your shot as they cross in front of you on your wing-line (left to right, or right to left). The problem then becomes timing your overshoots to coincide with that yardage number change over. :rolleyes:
After watching a bunch of my films I noticed I was shooting farther out for most of my crossing shots so moved my convergence out to 425 and my hit percentage started going back up. What I'm saying is set them one way and try it for a day, film the runs and then look at how and what your doing. Adjust as needed. Everyone is different. Don't be afraid to tweak it.
Last thing, PRACTICE !!! :D
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I like 300. I'm not a Pony pilot, but whenever I fly .50s, it seems when I get under 300, just a quick burst will cause them to go boom. My favorite attack is when you come in from behind and fast, so you have a wing profile and have the ability to hit everything: canopy, wing, fuel, engine, etc by just leading the bullets a hair. And I have tracers off.
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I generally set for 300-350 based on I will try to get as close as possible just before ramming - then fire away a burst.
Further you are tends to lead to more ammo sprayed, if you are on top you can't miss.
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I usually set 350-375 in PonyB and FM2, only 4 guns. In 6 shooters i stretch out to 400 max, but as the other post said try different ranges and figure out what works best for you. Remember that stick jitter comes into play the further you stretch out your convergence so check your deadband setting on your stick. It all boils down to personal preference. <S>
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I set ALL of my fighter air to air (vs other fighters) to 300.
If I go up bomber hunting then I set convergence to 400.
If I up with the full intention to hammer ground targets, namely ammo bunkers, radar towers, barracks, or soft gv's, I set convergence to 400.
Forget which weapons or platform you are using, ultimately it doesn't matter. The bulk of your fighter vs fighter kill shots are inside 400 yards, and in actuality they are inside 300 yards. The chance of anyone being able to really land hits on an enemy fighter at 400+ is a lot lower than one may think. Only in the straight away do you land enough hits, especially with MG's, to do enough damage worthy enough to mention. REMEMBER, when you set convergence you are also setting "trajectory". When people set their convergence at 650 yards, they are much higher at 300 than they realize. In a dogfight, you need to use your sights to the fullest, and having to compensate for trajectory against a target that spends the great bulk of the "on target" time inside 400 yards is absolutely wasteful of resources. Also, when the range indicator says "400", it means the enemy plane is between 400 yards and 201 yards.
With regards to the P51B, FM2, and any other 4/.50 cal fighter (or other such lightly gunned plane), forget trying to get kill shots on anything beyond 400 yards. Save your ammo for shot inside 400 yards. Set your convergence at 300 and once the indicator says "400", let 'em have it. Those fighters NEED "time on target" to get the kill and they NEED as many rounds to connect in as small of an area as possible. Setting the convergence at 650 (or 500, etc) is very contrary to allow that to happen.
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A little off topic...
I've been flying a lot of Japanese planes lately, and of interesting not, I am now having immense difficulty hitting now with browning .50's and hispanos. my aim has gotten much better with the 262 though as a result.
I almost always fire at distances of 250 or less however and dispersal of the rounds at ranges has little effect for me. However it appears as far as ballistic drop is concerned, I'm so used to that that I a am way over correcting when flying other planes.
I set all japanese planes at 250 convergence
109's and 190s at 250 unless I take the quad-cannon A8 and thats 250 and 300
Me262 is 450 and 500
Dual hispano's are 300
Quad Hispano's are 400
Browning .50s are 400
37mm Yak and Il2, and hurri2D are 400
Everything else is 300
But once again my aim is not very good, I like to get so close I could toss a rock and hit the other plane. and since I'm rambling :uhoh The point of the post was how interesting it is that I have alot of trouble with planes with good ballistics as a result of flying planes that have poor ones. Theres gotta be something I'm on to here :/
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I'm a 400 yard man in the B and D --- gives me the best dispersion ratio as close as 200 and as far as 600.
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and since we're on the subject of convergence...
How much in our game does it make a difference I wonder.
If I snapshot an enemy with .50s at a range of 200, what would be the difference in damage if I was converged at 400 vs 200?
I understand how this would work in RL but how much of a difference in AH :headscratch:
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I agree 100% with what you guys are saying about getting in close before firing. As I've stated in previous threads on this subject, I recommend setting convergence at around 300 yards and firing as the icon counter changes from D400 to D200.
I noticed some in F4U's set their convergence (50 cals) out to 500 or 550 so as they can "lead" the track of bullets better. Maybe it is the nature of F4U that close in shots are under the cowling otherwise. I don't know.
I don't doubt that some set their guns up this way; I've repeatedly heard of some doing it for years...
However, this is in fact based on an erroneous assumption on how trajectory works in AH (and in RL). By setting convergence out that far on the wing-mounted F4U .50's they're actually keeping their rounds LOWER (in relation to the LoS) throughout the range of their bullets. This works opposite of their intentions. To get the effect they desire they'd need to set their convergence in very close (@150 yards) but this would also cause them other problems. It would give them the trajectory they desire in order to make it "easier" to lead targets turning with them in a circle, while at the same time making it less likely that they could hit anything or at least that they'd be able to land enough concentrated hits to be effective.
Some people try to do the same thing with cannon rounds. That's also a strategy that sounds good on the surface, but that doesn't actually work as advertised.
See the last few posts of this thread to see what I mean-
http://bbs.hitechcreations.com/smf/index.php/topic,291146.0.html
REMEMBER, when you set convergence you are also setting "trajectory". When people set their convergence at 650 yards, they are much higher at 300 than they realize.
Not for wing-mounted guns (i.e. the P51B). With a convergence of 650, the bullets are still below the gun sight (and the LoS) at 300 yards (assuming a level shot under "perfect" conditions). Not all that much too low either (you'd likely hit both wings of a fighter by aiming at the center of its fuselage).
Check out the 600/300 screenshot in reply #24 of the linked thread.
Also, when the range indicator says "400", it means the enemy plane is between 400 yards and 201 yards.
The "D" number is in the center of the 200yd space between icon changes. So, D400 actually covers the space between 300 and 499 yards. This can be verified by using the film viewer. The D200 icon would be displayed for an airplane between 100 and 299 yards.
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and since we're on the subject of convergence...
How much in our game does it make a difference I wonder.
If I snapshot an enemy with .50s at a range of 200, what would be the difference in damage if I was converged at 400 vs 200?
I understand how this would work in RL but how much of a difference in AH :headscratch:
Once you learn to land hits with the crossing shots at around the D200 range (an actual 300yards) you'll be much more effective with a brief shot if you have all of your guns focused to a single point at that range (by having convergence set at about 300yds. A brief shot with .50's set like that (and at that range) will zip the wing right off of almost any fighter in AH like a chainsaw.
Hitting a fighter at any range other than what you have your convergence set will do several things. One of those is that it'll split your bullets into two separate groups rather than one (this almost always happens anyway, because you're almost never able to maintain exactly the correct distance from your target). This is bad though because it ensures that none of your bullets will go where you're aiming, and that they'll be split into two groups (one or both of which may miss your target completely).
As range increases bullet spread increases due to the modeled dispersion as well, which means that if you have your guns set for 400yds and hit a target at 400 yards, your bullets are spread out more than they would be if you had them set at 200 and hit a target at 200. The bullets are slowing down as well. Overall, this means that a "perfect" shot at 400 is somewhat less effective than a "perfect" shot at 200yds. The bullets are slower and more spread out at 400 yards. This isn't to say that the guns aren't effective at those longer ranges, they're just not quite AS effective, even under "perfect" conditions.
Bullets essentially just poke holes in the other airplane, and that doesn't do much if you don't hit something important (like a spar). Just poking holes in the wing (or fuselage) all over the place won't effect the other plane much. You need to land a concentration of bullets into the correct place, while close enough so that your bullets have enough energy, and for long enough to significantly damage the vital part you're targeting. Placement, energy, and time.
In reality you can't have everything though, so it's a question of "happy mediums" or "best" set-ups, rather than "perfect" set-ups.
Your bullets have the most energy at the moment they leave the muzzle; they begin slowing down right away, so setting convergence in close will maximize bullet energy at impact. Setting convergence in too close will cause problems though, and make it unlikely that you'll be able to hit anything either closer or further than exactly at convergence (see the linked thread above). Setting convergence out too far brings dispersion, reduced energy, smaller apparent targets, and increased time-of-flight into the equation (which translates into increased leads and a more-difficult judgement of the speed and flight-path of your opponent), and also leads to some misunderstandings when it comes to trajectory. So, closer is better than further; as long as you don't come in too close.
What's "too close"? I'd say around 200yds and closer based on what I know when it comes to trajectory. Some of the early-war planes may do well though with a 200-250yd convergence. What's too far? Personally, I think 400 is getting "way out there", but surely 450 is what I'd consider too far. That leaves the space between 250 and 350 to be in what I consider to be the "optimal" range for most weapons when it comes to landing the most rounds possible "on target".
Based on my own shooting preferences, I've settled on 275 as my best convergence point. I like to begin aiming as I come through the D400 "zone", and solidify my aim to fire just after I close to the D200 mark (which means I'm firing at just under 300 yards whenever possible).
The end result though, is that long-term you'll be more effective on those crossing 200yd shots if you have your convergence set to 200 than you would if you had it set to 400...
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Not for wing-mounted guns (i.e. the P51B). With a convergence of 650, the bullets are still below the gun sight (and the LoS) at 300 yards (assuming a level shot under "perfect" conditions). Not all that much too low either (you'd likely hit both wings of a fighter by aiming at the center of its fuselage).
The "D" number is in the center of the 200yd space between icon changes. So, D400 actually covers the space between 300 and 499 yards. This can be verified by using the film viewer. The D200 icon would be displayed for an airplane between 100 and 299 yards.
I understand your point clearly, but I'm speaking on terms of setting the guns to 650 vs setting them to 300 and having a smaller "sweet spot" by using the 300 yd setting. There are fewer variables to account for if the guns are used where they are most effective and when the shot are more often connected, i.e. inside 400 yards. In short, player does not have to take in to account "shooting high" at targets under 400 if the convergence is set to 300 (figuratively). If the convergence is set 650, they do.
Thanks for clarifying the D400, etc. I thought I read in a thread when I first started playing back in Jan-Feb of 2007 than the 400 icon meant it was between that marker and the next lower distance icon. I'll pass along the info. :aok
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If the convergence is set 650, they do.
Nope, this is the part you have backwards.
I agree with you on the rest; I'm just pointing out that this part is a misconception.
With a convergence of 650, the bullets will not be high at 300-400yd (with wing-mounted guns). The bullets will be low at 300 yards.
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Disregard, posted in the wrong thread :/ apparently beer has alcohol in it! who knew :uhoh
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I set all .50 cal equipped AC at 400 because this seems to be where the conv and ballistics cause the most damage to anything you light up
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These might help. Never understood why these WW2 diagrams were never in the AHWiki.
From what I've read in 8th AAF documents the assumption for the .50cal was a 1000 yard effective range. Both the P51B/D and P47 were set so the rounds passed up and through the gunsight line of sight at 300-350 vertical convergence dropping back through near 1000. Crossing of the streams horizontal convergence was set to 250-350. I have some NAVY diagrams for the FM2, F6F and F4U-1 but, in the feild the pilots often had their convergence changed to look more like the P51 or P47 diagram. The NAVY command was more concerned with maximum coverage of rounds on Japanese bombers so had very different vert/horz convergences reccomended from their research department. The pilots learned better in the feild what worked to maximise effectiveness.
The FW A8 diagram is for compairison. The long ranges are for bombers and to account for the less than flat trajectory. 250M is the max sweet spot for fighter to fighter getting enough rounds sprayed at a small fast target. The longer trajectory with the MG151/20 is for bombers which are relatively standing still. In the game I set my MG131 and MG151/20 both to 400 which keeps the dispersion and elevation inside of a 30Mil circle between 200-400. Remember in the A8/F8/D9 both the MG and cannon are firing HE rounds. Or so I hope that is modeled into the MG131 in the game.
This is a link to a slide show with everything german WW2 ammo.
http://www.slideboom.com/presentations/292375/German-ammunition,N%C3%A9met-l%C5%91szerek-13mm-50mm
P51B Convergence/Trajectory/Dispersion Chart.
(http://img109.imageshack.us/img109/3683/p51bguns.gif)
P47 Convergence Chart.
(http://img823.imageshack.us/img823/1227/p47conv.gif)
FW190 A-8 Convergence/Trajectory Chart.
(http://img515.imageshack.us/img515/5097/fw190a8gunconv.gif)
Abbreviations/ Translations:
AP = Amour Piercing.
API = Amour Piercing Incendiary.
HE = High Explosive.
Br. = Brand (Incendiary).
Gr. = Granate (grenade).
L/Spur = Leuchtspur (Tracer).
m = mit (With).
O = ohne (Without).
Patr. = Patrone (Cartridge).
Pzgr. = Panzergranate (Amour piercing grenade).
Spr. = Spreng (High explosive).
Sprgr. = Sprenggranate (High explosive grenade).
vk. = Verkürzt (Shortened = It has a short burning tracer).
W. = Warme Übertragung (Heat transmitted = Tracer initiated self-destruction).
Zerl. = Zerleger (Self-destructing element).
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I suggest as mtnman has posted to practice via filming your flights to see at what range you start shooting ( or what range /distance when shooting at an enemy plane you are connecting the most )
then adjust your convergence accordingly.......
but once you figure out which convergence setting is ideal for your preference, then forget about watching the counter and trying to time your firing of your guns with the counter hitting a certain distance!
what you really want to do, is BURN the PLANE SIZE image into your memory........ look at the plane, look at where the wingtips are in accordance to your rings on your boresite, and burn that image into your memory
once you practice this enough, your memory/brain cells will take over and you will not need to worry about the icon counter never again, your memory will tell you "fire now"
this works for all types of shots, dead six, crossing shots, deflection shooting <---- one thing about deflection shooting is to go into the TA or offline and turn on the tracking shot ( Green X ) this will help train your brain to recognize how much lead to allow for deflection shooting depending on the angle, or speed & g's being pulled for a certain angle of attack....... this too can be practiced enough that you can make a mental snapshot ( mental image ) to burn into those brain cells of yours...... then when you find yourself in a particular situation your brain will tell you "Fire Now"
practicing this, and practicing what that mental image/visualization of the plane size looks like will eventually help your gunnery improve, verses trying to use convergence settings & the icon counter and solely trying to rely on the icon counter to try and fire your guns to shoot down an enemy plane
just a different perspective of how to go about improving one's gunnery in Aces High
hope this helps
TC
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whenever im in my 51s i would have my convergence cross starting at 350yards, the next being 375 and if in the P51D the third (innermost guns) at 400yards
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Nope, this is the part you have backwards.
I agree with you on the rest; I'm just pointing out that this part is a misconception.
With a convergence of 650, the bullets will not be high at 300-400yd (with wing-mounted guns). The bullets will be low at 300 yards.
SHOOTING FROM A BOMBER QUESTION:
For this question, let's say all things being equal, you are in a bomber tail gun and the enemy is following behind you (closing of course) at the same altitude. I know speed, AoA, wind, etc all play a factor, but to start with let's keep it simple in order to have a place to start from.
So how can I relate all of these examples you guys have given with ballistics, range, etc when gunning from a bomber?
When do you start to shoot at an icon? With .50s do you aim high at 1000 or dead center? With .303 do you have to wait until enemy is at 300?
What would be the farthest out you can start shooting with .303 and .50 and what is the optimal range to shoot at?
What distances would you aim high? What distance would you aim low?
Some planes "lob" their rounds into the bombers so in a bomber what would a good range to start shooting?
In a bomber I use the distance icons more than I do when in a fighter so what yardage numbers do I look for when shooting?
Do you guys recommend a particular gunsight for the bombers that would help better so you know when to shoot when the plane "fills" a certain part of the gunsight?
Also when shooting from the center bomber from the tail you can see all mg bullets converge at a certain point..what distance is that?
Thanks
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However, this is in fact based on an erroneous assumption on how trajectory works in AH (and in RL). By setting convergence out that far on the wing-mounted F4U .50's they're actually keeping their rounds LOWER (in relation to the LoS) throughout the range of their bullets. This works opposite of their intentions. To get the effect they desire they'd need to set their convergence in very close (@150 yards) but this would also cause them other problems.
Not for wing-mounted guns (i.e. the P51B). With a convergence of 650, the bullets are still below the gun sight (and the LoS) at 300 yards (assuming a level shot under "perfect" conditions). Not all that much too low either (you'd likely hit both wings of a fighter by aiming at the center of its fuselage).
If you sight in a 50 or any other caliber to hit point of aim at 400 yards - your actual trajectory will be ABOVE the line of sight all the way out to 400 yards, then below the line of sight beyond 400.
If you are a hunter or target shooter and you want a basic sight in philosphy that says " I want to be able to hold on the heart at any range up to say 250 yards with a 30-06/150 grain bullet - the sight in at ~ 1 3/4" above the bulls eye at 100 yards. The bullet will be ~ 1.5 inches low at muzzle if using a scope (about 3 feet low in a P-51 for a K-14), climb to 1.75 inches above point of aim at 100 yards , reach apogee at about 160 yards at nearly 2" above line of sight, then back to zero Line of sight at 250 and fall off thereafter.
If you want to zero at 400 yards relative to line of sight the trajectory of the bullet will be way above line of sight for all of the middle range and be dead on at 400, then forever low after that. If your real life 51 was sighted in at 400 and you were real close you would be shooting under, then in the middle ranges you would be shooting high.
I know my father's 51B and D were sighted for 200 yards... and he believed he never stared shooting until under 300 yards
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Was the horizontal convergence at 200 and the reticle adjusted for center on that while the general trajectory was the pass up through at 300-350 and drop back in about 800-1000? Or did his armeror adjust horizontal and vertical convergence to 200 then lock the reticle center to that? The latter would have him shooting high at 300 while the former a bit more straight on relatively. Did he mention what average speed the convergence was adjusted for?
The 51's tail was jacked up on a static stand until the corrisponding nose angle of attack was achived for a given flight speed at a given altitiude. Then the convergence and elevations were set for the guns at which point the armeror set the center of the reticle's piper. Some pilots with more experience had different ideas about their convergence.
The N9 gunsight which was in the P51B and early D models before the K14 had a low and high pipper adjustment that the armeror manualy set and locked from the cockpit. A bit like the 14 degree down 3 degree up visier linie adjustment the Revi16b was capable of to mount in 109's. Then everything else not needing a severe down look to follow a HUB cannon 0 degree line initial trajectory and drop off. From what I can tell by reading manuals the high and low N9 setting corrisponded to near and far shooting requirments like air to air or ground straffing. And then some pilots had different ideas from experience. The most extreme case the Bueamont modification of the MkII in Typhoons from the ring and bar with cellphane tape that lead to the Type I MkIII single dot on the inside of Typhoon and Tempest windscreens.
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Was the horizontal convergence at 200 and the reticle adjusted for center on that while the general trajectory was the pass up through at 300-350 and drop back in about 800-1000? Or did his armeror adjust horizontal and vertical convergence to 200 then lock the reticle center to that? The latter would have him shooting high at 300 while the former a bit more straight on relatively. Did he mention what average speed the convergence was adjusted for?
I had a long talk with several 355th armorers a couple of years ago - more details below. Basically the target (a Hex pattern for P-51D and square for P-51B) was set at 200 and each of the guns were boresighted individually - one to each individual 'ball' -outboard low, inboard high (IIRC about 2' square patter) for B, same for D except center gun to center target within Hex. I suspect the armorers had no particularly clear expectation regarding POI at 1000 yards - I know my father would not have.
The reticle was centered for 200 yards to match the center of the target
The 51's tail was jacked up on a static stand until the corrisponding nose angle of attack was achived for a given flight speed at a given altitiude. Then the convergence and elevations were set for the guns at which point the armeror set the center of the reticle's piper. Some pilots with more experience had different ideas about their convergence.
I didn't ask about flight speed but suspect 300 kts - have no idea regarding 'altitude compensation'. Rough speculation says set for 20K from a ballistic POV and then at sea level your rounds ought to be slightly low for same AoA as there is more drag on the round at SL and the bullet should drop a little more.
The N9 gunsight which was in the P51B and early D models before the K14 had a low and high pipper adjustment that the armeror manualy set and locked from the cockpit. A bit like the 14 degree down 3 degree up visier linie adjustment the Revi16b was capable of to mount in 109's. Then everything else not needing a severe down look to follow a HUB cannon 0 degree line initial trajectory and drop off. From what I can tell by reading manuals the high and low N9 setting corrisponded to near and far shooting requirments like air to air or ground straffing. And then some pilots had different ideas from experience. The most extreme case the Bueamont modification of the MkII in Typhoons from the ring and bar with cellphane tape that lead to the Type I MkIII single dot on the inside of Typhoon and Tempest windscreens.
Good info on the N-9 and of course all the D-5 and -10's had N-9s until ~ Aug/Sept when K-14s were first being installed in the field so the process was the same for B and D until ~ Dec/Jan when nearly all the field mods had been achieved and all the D-15 (and K-5?) and beyond had factory K-14s (IIRC).
The armorers had a 90 degree telescope like device with cross hairs ahich was inserted in the breech of the 50's to actually adjust each gun mount.
As for my fathers B/D I have no idea what the N-9 was set for, nor the base AoA. He also did not care for any built in dispersion - wanted it on target with max concentration at 175 to 225
Good to chat, you know your stuff'
Regards,
Bill
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If you sight in a 50 or any other caliber to hit point of aim at 400 yards - your actual trajectory will be ABOVE the line of sight all the way out to 400 yards, then below the line of sight beyond 400.
Yes for single gun being fired by a person - if you are shooting a .50 cal rifle because your LoS ( your eye ) is right there in line with the barrel of the gun, it most definitely will rise above the line of sight and then drop back down to the target center.......
No for aircraft's wingmounted guns - now in an aircraft with wingmounted guns, the LoS is much higher than the muzzle/barrel of the wing mounted gun, and therefore the bullet will always be below the line of sight until it hits the convergence setting ( or target one is aiming at depending on distance target is away from them )......
Mtnman has posted data acknowledging this many times, you can do a search for his gunnery / convergence posts / threads
hope this helps
TC
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When i was playing back in the day i had mine set to 350. Not only for the 51B but for almost all other .50 cal's. Why? Because it seems to work the best for me, and how my flying style was.
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I set all my guns to 300.
crossing shots are more for taters...I have found they do not work as well for 50's....you need a bit more time on target with the 50's unless of course you kill the pilot.
so saddling and deflection shooting works better for me with the non cannon, whereas I set up crossing shots for taters :aok
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If you sight in a 50 or any other caliber to hit point of aim at 400 yards - your actual trajectory will be ABOVE the line of sight all the way out to 400 yards, then below the line of sight beyond 400.
If you want to zero at 400 yards relative to line of sight the trajectory of the bullet will be way above line of sight for all of the middle range and be dead on at 400, then forever low after that. If your real life 51 was sighted in at 400 and you were real close you would be shooting under, then in the middle ranges you would be shooting high.
Your explanation works with a rifle, but not with an aircraft with wing-mounted guns. It's a common misconception though, and confuses many people.
The reason your description works for hand-held firearms is because the LoS is only slightly above the barrel.
The reason it doesn't work for wing-mounted guns is because the LoS is NOT slightly above the barrel, but quite a bit higher (roughly 5ft above it for an aircraft like the F4U; I haven't worked out the measurements exactly for the P51). It's like standing up, and firing your rifle with your toe while it's on the ground. The bullet will never come above the LoS in that case until it meets the target. If it does come above the LoS before it hits the target, it would be impossible for it to hit the target. That's because the LoS has shifted several feet in relation to the barrel.
For a more in-depth explanation look at the thread I linked to earlier.
I know it seems odd at first; I used to shoot competitively and it took me a little while to figure it out myself.
Oops, sorry TC. Didn't see your post at first.
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Was the horizontal convergence at 200 and the reticle adjusted for center on that while the general trajectory was the pass up through at 300-350 and drop back in about 800-1000?
The range where the rounds "drop back in" wouldn't be "set" on purpose. It would be an accidental "by product" of what range the convergence point was set at, factored against the height the LoS was above the barrels and the actual trajectory of the bullets. The bullets will fall back through the LoS on the P51 at roughly the ranges you mention, for 300yd convergence, but that's just because that's how the bullet trajectory is shaped; not because it's "set" to do that.
I'm sure you know that, but it just looks odd the way you posed the question.
The only way you could "set" the point the bullets come back down through the LoS beyond the convergence point (but based on the convergence point) would be to raise/lower the pilot seat, raise/lower the guns (not tilting them, but physically moving them closer to or further from the LoS), or speed-up/slow-down the bullets themselves to either flatten or increase the trajectory arc.
That would be a lot of effort especially considering the "convergence" at that extended range would actually be two well-spaced groups triple the spacing of the guns in the wings. If the guns are spaced @15 feet apart in the wings you'd end up with two large, loose, patterns 45ft apart at 900yds. Each pattern would be very large (15ft diameter?) due to dispersal as well.
It also looks odd the way you've posed your question in regards to the 200 yard "cross" compared to the 300-350 pass through the LoS.
Have you found that they may have set the guns to converge at a point other than the LoS/gunsight at the range the bullets cross through the sight? So the horizontal component would be set fro 200 yards while the vertical was set for 3-350? That seems phenomenally odd, but I suppose that doesn't mean it didn't happen.
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Mtnman,
Could you reccomend an autolevel speed for this audience to fly their P51B/D at offline so they can see there trajectory across target ranges from 100-1000? They just need to remember the nose will push down 5Mil when they pull the trigger. The armeors instructions from the inside of the gun hatch on the P51D states the airspeed at 301 IA. I'm not sure how that corrisponds to the AH programatical environment.
From the Gun Hatch:
90% indicated airspeed at low blower
Critical altitiude 301 m.p.h.: Set airplane level<------Factory speed setting. Handbook has chart of other speeds.
Lugs 0' 35' nose up.
Once everyone does this and is on the same footing from a common experience, maybe they will understand better your presentation. If the convergence function is raising and lowering the gun barrels to achive the convergence range set IP at reticle center, then you may never see the round pattern above the reticle centerline.(other than in response to the 5Mil nose down during firing) This would suggest the convergence function also raises and lowers the gunsight centerline programaticly in responce to the change in the manner an armorer would in the cockpit during bore sighting.
If you look at the convergence chart for the P47, at 500 yards the average hight of rounds above the reticle centerline @500 is 9 inches and 200 -11 inches. 9 inches above or 11 inches below from 200-1000 yards looks like it's on the plate it's so small. So effectively you will get the optical illusion from the gunsight FOV that your rounds shoot almost flat to 1000 yards. The P51 will be a variation on 9 and 11 due to the guns being closer on the horizontal plain to the reticle centerline.
This is the reason for my comment about setting the 50cal vertical IP to 200 yards. It would require setting the reticle centerline lower because making the bullet stream pass up through the graticle CL closer to the gunsight than 300-350 would require increasing the gun barrel's loft. I wonder if the armeror was actualy asked to make the horizontal component cross at 200 while the N9 was set to it's low graticle CL line to pass through the center of the dispersion cloud at 200? The K14 had a fixed 100Mil ring with 10Mil cross to allow adjustment of the unit during borsighting.
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Because, it's not nearly as cool unless you've seen it yourself:
(http://i675.photobucket.com/albums/vv115/Babalon84/Pt%20Magu%20NAF%20Airshow%2010/NAFPtMagu10021.jpg)
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Mtnman,
Could you reccomend an autolevel speed for this audience to fly their P51B/D at offline so they can see there trajectory across target ranges from 100-1000? They just need to remember the nose will push down 5Mil when they pull the trigger. The armeors instructions from the inside of the gun hatch on the P51D states the airspeed at 301 IA. I'm not sure how that corrisponds to the AH programatical environment.
From the Gun Hatch:
90% indicated airspeed at low blower
Critical altitiude 301 m.p.h.: Set airplane level<------Factory speed setting. Handbook has chart of other speeds.
Lugs 0' 35' nose up.
Once everyone does this and is on the same footing from a common experience, maybe they will understand better your presentation. If the convergence function is raising and lowering the gun barrels to achive the convergence range set IP at reticle center, then you may never see the round pattern above the reticle centerline.(other than in response to the 5Mil nose down during firing) This would suggest the convergence function also raises and lowers the gunsight centerline programaticly in responce to the change in the manner an armorer would in the cockpit during bore sighting.
If you look at the convergence chart for the P47, at 500 yards the average hight of rounds above the reticle centerline @500 is 9 inches and 200 -11 inches. 9 inches above or 11 inches below from 200-1000 yards looks like it's on the plate it's so small. So effectively you will get the optical illusion from the gunsight FOV that your rounds shoot almost flat to 1000 yards. The P51 will be a variation on 9 and 11 due to the guns being closer on the horizontal plain to the reticle centerline.
This is the reason for my comment about setting the 50cal vertical IP to 200 yards. It would require setting the reticle centerline lower because making the bullet stream pass up through the graticle CL closer to the gunsight than 300-350 would require increasing the gun barrel's loft. I wonder if the armeror was actualy asked to make the horizontal component cross at 200 while the N9 was set to it's low graticle CL line to pass through the center of the dispersion cloud at 200? The K14 had a fixed 100Mil ring with 10Mil cross to allow adjustment of the unit during borsighting.
It'll take me a little while, but sure, I'll write something more detailed up and toss in some visual aids as well. I'll need to stretch it out over a few days since I don't have time to do it in one shot, and because I'll need to prepare some visuals.
I'll probably start another thread to do this though, because it'll derail this one and because there's no point in hiding the discussion in here; it'll probably get kind of lengthy.
For starters we're not really comparing apples to apples on the bore sighting thing. That's because that's all that P51 diagram is... It's a recommended method for bore sighting.
We don't bore sight in AH, and we don't "sight in" in AH. We don't need to, and I'm unaware of any real method to simulate either one in-game (or offline).
Bore sighting is not "sighting in". They're not the same thing, and they're not necessarily dependent on each other.
I need you to restructure this first sentence though, because I'm not sure what you're really asking.
Mtnman,
Could you reccomend an autolevel speed for this audience to fly their P51B/D at offline so they can see there trajectory across target ranges from 100-1000?
This question is too open-ended. They can fly at any speed they want to in auto-level to see their trajectory across target ranges from 100-1000 (yds).
They'll see different things/results though, depending upon what speed they choose and of course on how much variation they allow to contaminate their testing. Speed will definitely have an effect on things, so it would depend to a large extent on exactly what they wanted to test/see in order to pick a particular speed. Altitude will effect things too, so that would potentially have to be factored in as well.
I'll begin a new thread, but will place it in the Help and Training section. I'm going to begin it with the basic "How's and Why's", and plan to take it into the differences between shoulder-fired weapons and wing-mounted guns. If you have other topics to discuss, feel free, but I'm going to avoid too much detail on nose-mounted guns and cannons for now.
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I wish Hitech would be done with it and lock the "Hollow Airscrew" mounted autocannons at the engine 0 line.
They could not be tilted for bore sighting. The gunsight was adjusted from the cockpit like the Revi16B's negative 14 degrees, or lower stadia markings were included below the center dot for the ballistic drop. The N3 in the P39 comes to mind with the lower stadia mark bombing ladder. The Yak's ShVAK 20mm and NS-37 both fired almost flat compaired to the MG151/20 or MK108/30 so the PBP or PAK gunsights didn't need much adjustment. The Yak's had a centering mark on the backside of the prop.
I know shooting at the offline target is not bore sighting. But, somehow a common terminology has to be agreed on to carry the discussion forward that players can grasp and communicate the subject to each other and back to the Trainers when asking questions. Offline Target = Shot/Dispersion Patterning. Still you can graph your ballistic trajectory with it, or coarsly using angular mil math the bore pattern. There is nothing wrong with technical granularity for those who are inclined. Different people learn differently ie, visulising of concepts at times.
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I know shooting at the offline target is not bore sighting. But, somehow a common terminology has to be agreed on to carry the discussion forward that players can grasp and communicate the subject to each other and back to the Trainers when asking questions. Offline Target = Shot/Dispersion Patterning. Still you can graph your ballistic trajectory with it, or coarsly using angular mil math the bore pattern. There is nothing wrong with technical granularity for those who are inclined. Different people learn differently ie, visulising of concepts at times.
Bore Sighting is literally positioning the target in the center of the bore. Basic purpose is to align the axis of the machine gun (or rifle) prior to Sighting In.. in order to ensure that the barrel was pointin at the target, more or less.
Sighting in is aligning the SIGHT to the theoretical point of impact of the Bore Sighted axis.
For a sporting or target rifle, bore sighting is a useful way of adjusting a scope to the bulls eye at a reasonable distance - say 100 yards - so that when starting the Sight In process of making fine adjustments, the barrel and scope are in pretty close alignment to the target before one round is expended.
For this discussion, precision requirements for fixed guns mounted in an aircraft are neither as high as a sporting/target rifle with sights nor could such precision be expected for a gun/sight system mounted to what amounts to a 'flexible' platform when used in actual conditions.
In the case of an operational Mustang, pre-equipped with say an N-9 sight and four .50 caliber M3's, the a/c would be jacked up until the target was acquired and centered by the N-9 sight. Then each of the Guns would be boresighted and adjusted to center on the target point. If you wished to be anal for sighting in to 300 yards, the armorer would adjust the elevation once more for each of the weapons so that the boresight axis would be, say, 8 inches above the target aiming point to account for ballistic properties over that range. I have zero idea regarding the practice of attempting such ballistic precision.
When new sights were installed at the factory, or K-14s were provided in field mod kits, IIRC there was a factory kit supplied which mounted on the cowl forward of the windscreen. It was used to Boresight the gunsight during installation, by adjusting the gunsight/mount to the target, then boresight and adjust the machuine guns. The Sighting In was then performed after the kit was removed, by making fine adjustments to the sight.
When bullet drop compensation computing was integrated into sights, no such adjustments were necessary when sighting in to the boresighted targets
Boresighting is essentially a laser line of sight with no ballistics built in.
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I was always curious about this:
Did they actually have a 400+ yard range that they would align the guns and sights to, or did they basically just do the math to know where the guns should aim on a target that might be something like 100 yards away?
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I was always curious about this:
Did they actually have a 400+ yard range that they would align the guns and sights to, or did they basically just do the math to know where the guns should aim on a target that might be something like 100 yards away?
The 355th FG had a 250 yard target/embankment combo - can't speak for rest of the groups.
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Do you think the 355 retained the the static angle of attack for the 301mph referenced speed while adjusting their patterning and reticle center at 250yd? I've looked at about 3 different static sighting setup pictures with P51D around the internet and all have the P51 with a slight down nose atitiude. Against the offline target 285 true was the speed at which the centerline of the engine stayed level with the centerline of the target. At 300 it was below or a nose down atitiude.
I compiled a list of true airspeeds offline for all of our fighters to keep the engine centerline, or on twins, fuselage centerline level with the offline target centerline. Wish I had a list of the factory speeds/nose atitiudes for those aircraft. It helped my sight picture quite alot at different ranges performing the testing to get all of those speeds against the offline target. Interesting the things you see during long drawn out testing you don't think about in the "seconds to react" sound and fury of the MA combat.
Or that could have been a wasted day out of my life........ :)
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Do you think the 355 retained the the static angle of attack for the 301mph referenced speed while adjusting their patterning and reticle center at 250yd? I've looked at about 3 different static sighting setup pictures with P51D around the internet and all have the P51 with a slight down nose atitiude. Against the offline target 285 true was the speed at which the centerline of the engine stayed level with the centerline of the target. At 300 it was below or a nose down atitiude.
I compiled a list of true airspeeds offline for all of our fighters to keep the engine centerline, or on twins, fuselage centerline level with the offline target centerline. Wish I had a list of the factory speeds/nose atitiudes for those aircraft. It helped my sight picture quite alot at different ranges performing the testing to get all of those speeds against the offline target. Interesting the things you see during long drawn out testing you don't think about in the "seconds to react" sound and fury of the MA combat.
Or that could have been a wasted day out of my life........ :)
I simply didn't know enough then to ask all the right questions but a couple of armorers are still alive in the 355th and i'll ask.
There isn't much of AoA for 301 mph TAS on the deck.
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Wonder how much nose down tilt was perceivable in the real cockpit suring the war while firing?
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Wonder how much nose down tilt was perceivable in the real cockpit suring the war while firing?
I wouldn't think any. For starters, they could just build the cockpit to have the seat and controls alignment "comfortable" at normal to high speeds. We're only talking about a very few degrees of difference over a 200mph range. I wouldn't think it'd be much more noticeable than driving a car up or down a very slight incline. Maybe even less noticeable, since apparent gravity in the plane wouldn't be as constant as it is in a car.
Also, the engine isn't necessarily mounted "level" with the plane. It would likely be tilted up or down a few degrees, and maybe even pointed a few degrees to one side or the other.
From what I saw in my P51 testing of a few days ago, 300mph or so is where the nose more-or-less stops dropping, regardless of how much faster than that you go. If that's modeled somewhat close to a full-scale P51, I think I see why they chose 301mph (indicated) as the "critical" speed. I'm not positive, but it looked pretty convincing in the TA...
What I found was that at speeds lower than 300 the nose was somewhat (or even quite a bit) elevated in level flight, but lowered as speed built and was "pretty dang level" at 300mph and up (indicated). I wonder if the extra 1mph they list is just a way of saying >300mph? Got me...
Also, 301mph indicated is right around top speed for the pony at 20k.
I tested both the P51B and the P51D with practically identical results, and I did it at 1K, 10K, and 20K alts.
It makes sense really, since the airspeed is measured by the air pressure against the pitot, and the air pressure is also what's dictating the AoA and speed required to maintain level flight at a given speed. Of course at alt I was flying faster than 301mph (400+mph), but I was still doing 301 indicated. The nose cannot just keep dropping as speed increases because it would eventually go into a negative AoA. If it actually maintained level flight with a negative AoA there'd be something quite odd about the design. Maybe with a flat-bottomed airfoil, high speed, and lots of down elevator trim or an incorrect wing incidence? Even then I'd be surprised.
Also, I suspect that it would be fairly "odd" to do too much firing at the top-end speeds (much above 301 indicated). It took full throttle and some time to achieve those speeds, and as soon as maneuvering begins you begin losing speed.
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I was always curious about this:
Did they actually have a 400+ yard range that they would align the guns and sights to, or did they basically just do the math to know where the guns should aim on a target that might be something like 100 yards away?
They could do it either way, and they did it both ways.
The guns could be bore sighted using the dimensions given in the diagram bustr posted.
That was basically a target used to align the sight and gun bores at a target 1000 inches away. That target may have actually pointed the bores at a mathematical point, or it could have had the trajectory mathematically factored in to those points, or it could have even been made up after live-fire sighting a planes guns in (by placing a blank target in front of the plane, sighting through the bores, and marking the target in order to more accurately bore sight future planes). Regardless, to truly get the guns firing accurately they'd have needed some live firing and adjustment following bore sighting; bullets don't actually fly to the point the bore points. They'll drop with gravity of course, but will also drift to one side (depending on which direction the rifling is cut). Add in the other factors that effect bullet flight and it gets pretty easy to miss a 4' x8' sheet of plywood at 300yds with bore sighted guns.
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P51 in auto-level flight at 150mph indicated. 1K, 10K, 20K alt. Note the high AoA due to the low speed.
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss6.jpg)
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss10-1.jpg)
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss14.jpg)
@301mph indicated at 1K, 10K, 20K alt. Note this is 411mph true at 20k.
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss9-1.jpg)
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss11-1.jpg)
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss15.jpg)
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And at @350mph indicated... Note that the nose doesn't drop much with this increase in speed. Also note that although the aim-point doesn't a APPEAR to be much different, the center ring of the target is 20ft in diameter, so there's more difference than it appears at first glance. Really just a tiny change in AoA though.
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss8.jpg)
(http://i107.photobucket.com/albums/m309/Mtnman_03/ahss12.jpg)
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Would that mean the 5Mil+- nose down in response to firing the P51D guns when you test against the offline taget is not realistic? So then it isn't a factor in your aim while in MA combat ergo then was not a factor in the real WW2?
Remember when I tested all of the fighters in the game some time back with my Miltest gunsight on full zoom for dispersion patterning? Wing guns cause the nose to lower. Lavochkins raise up. Center nose mounted stay level. I beleive the 262 raises a bit due to the 4 MK108. You didn't give the range you set the target to. I'll have to duplicate it being equal to the width of the K14's reflector plate. I bet on full zoom the anglular mil math at 301 will show the K14 center to be near the manuals 32 inches above the fuslage reference line.
Looks like you use a 20Mil+- dot for your gunsight by eyeball guesstimation.
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Would that mean the 5Mil+- nose down in response to firing the P51D guns when you test against the offline taget is not realistic? So then it isn't a factor in your aim while in MA combat ergo then was not a factor in the real WW2?
Remember when I tested all of the fighters in the game some time back with my Miltest gunsight on full zoom for dispersion patterning? Wing guns cause the nose to lower. Lavochkins raise up. Center nose mounted stay level. I beleive the 262 raises a bit due to the 4 MK108. You didn't give the range you set the target to. I'll have to duplicate it being equal to the width of the K14's reflector plate. I bet on full zoom the anglular mil math at 301 will show the K14 center to be near the manuals 32 inches above the fuslage reference line.
Looks like you use a 20Mil+- dot for your gunsight by eyeball guesstimation.
Sorry Bustr, I was in a hurry to get out and chase some ducks with the falcon... As I walked out I thought "Oops, forgot to tell everyone I had the .target set to 300yds".
The gun sight I use is just one I picked up years ago; I don't remember from whom. I don't pay much attention to it in actual shooting, and I have no idea what size it is. It's just a reference point that I keep in my peripheral vision. I've actually had times when I did game re-installs and lost it, so had no sight at all for a while. Surprisingly that didn't see to matter when it came time to shoot.
I really don't know anything about the Mil references or about the nose up/down movement. I know the F4U nose moves, but I just take quick little shots anyway so it doesn't seem to be something that effects me. I have no idea about how it compares to reality.
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I'm a 400 yard man in the B and D --- gives me the best dispersion ratio as close as 200 and as far as 600.
It works cuz he saws me right in half
(http://i259.photobucket.com/albums/hh319/thadeGza/panda-chainsaw_small.jpg)
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It works cuz he saws me right in half
(http://i259.photobucket.com/albums/hh319/thadeGza/panda-chainsaw_small.jpg)
That pic is awesome :)
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325 is standard in most aircraft - frankly I don't shoot at 400 yards out, I shoot closer to 200 - and never miss.