Technical question about shooting

[nrshida]

In my particular choice of aircraft & flying style I have spent a considerable amount of time at the bottom of rope attempts. Sometimes I have a brief snapshot. I've noticed I have to lead in strange ways. Having never had the occasion to fire a firearm I read that when shooting upwards you have to aim under - because the zeroing point will now be misleadingly below where you need to aim.

My question is, with a convergence set to say 600, by about how much do I have to aim under? Assuming I'm standing on my tail then does shooting over more distance equate to more 'hold under' as gravity is primarily affecting the shot only in a vector opposite to the travel and thus affecting velocity only? So the two vectors continue to diverge at a linear rate?

I have done a fair bit of archery, but always suspected on some instinctive level it was unwise to shoot upwards to explore what would happen.

[Bizman]

nrshida! You're back! 

Unfortunately I can't answer your question but remember, it's time to get the mosquito repelling plants in your patio.

[LCADolby]

There's alot of maths involved in answering that question, and variables in bullet calibre as well as diagrams of bullet flight trajectories. 

But YAY! SHIDA! 

[Ratsy]

As stated above, there is math and science.  Then there is 'sight picture'.

There is a Gunnery Training course on video from Ryno.  I took the live course and the basics of lead and drop became crystal clear to me.  I am still an average shooter, but that is not Ryno's fault.  It's a great place to start.

Pick a gun sight that meets your needs and stick to it in every plane you fly.  I use the US Mark 9 as recommended by Ryno (only because it is his preference).  In the process of practice you can develop a sight picture that will guarantee an increase in hit ratio.

The course is on VuduVince's YouTube Channel and is in six parts.

Part One is here: https://www.youtube.com/watch?v=WoeZIX5TnAI

I hope this helps you at least as much as it helped me.

Good luck.

 

[8thJinx]

Have you read T.O. 00-25-35 "Fighter Pilot Gunnery"?  It might be worth it to read it.  I have a copy, but I'm sure it's on the internet somewhere.

[Wiley]

This question gets my brain working in interesting ways.



Here's a good generic illustrative picture.  Forget about the specific numbers on the image, just consider the fact that on the one sight in path, the bullet goes above line of sight, while on the other sight path, it doesn't happen to get above the line of sight.

Now if you consider a situation where you're shooting so that your line of sight is exactly vertical, the way the barrels are mounted means the bullets will actually be falling "up" from your perspective, because the gun barrels are pointed past vertical.

What this seems to indicate is for the vertical shooting situation, you'd want your convergence set so that the angle of the guns stays as close to the line of sight as you can get it.  It won't be as simple as the shortest or longest convergence, because for the bullet to get there at 650, it's got to travel fairly high over LOS.

It looks to me like a bunch of trial and error testing would be needed to figure out where to put it for specific planes, because the spacings are going to be different.  Bustr, I know you must want to do this.

Wiley.

[Randy1]

I think the replies are missing the OP's question surrounds shooting while in a vertical climb.  That is how I read the OP.

[bustr]

Offline.

Up your ride and set the target to the following:

.target 200 360 90

[ .target range heading azimuth]

The target will now stay 200 yards directly over you. Pull up vertical and try to hit the center. Then you will see the game relationship to the center of your reticle and your bullet stream.

This turns off the target:

.target 0

I doubt anyone is always going straight up without some amount of motion trajecterally versus just going straight up. And then when you set your convergence, you are angling your guns up from the center line of your ride. Even with "motor mounted" cannons Hitech allows you to elevate the trajectory by lowering the breech mounting which was impossible in the real WW2 rides. Also if you are flying a wing gun only ride shooting inside of your convergence, you need to favor one side or the other to get enough rounds on the con to do any good in some cases.

Unless you want to learn a boring and frustrating way to park your rides facing down hill on a slope off the end of a runway to setup a static bench stand. Just fly your ride at about 300-320 TAS auto level heading north offline. Bring up the target at 100, 200, 300, 400 and 600. Tap the trigger, holding down for a heavy impact pattern will slow the plane down and change your AoA. Then watch the relationship of your reticle center to the impacts at the different ranges. 

[morfiend]

Nish,

  Try the lead calculating gunsight!  To enable offline goto arena settings,look for flightmodeflags and select change,then check the LCG box then just press tab to enable it.

  It's a good way to develop a sight picture and may help with your question.


   

[Kingpin]

...at the bottom of rope attempts... I've noticed I have to lead in strange ways.

My question is, with a convergence set to say 600, by about how much do I have to aim under?

Hi Shida, very good to see you!!

First, before you go and watch the film that Vudu did of my Introduction to Gunnery course (Kingpin=RynoRush, for those who don't know), I will point out that there is nothing about vertical shooting in there, as it was a basic course.  However, there is a discussion in the videos of using the .target command as a practicing tool, which may come in handy.

There is also mention of the "upward angling" of the guns and that rounds rise from the barrel to reach the pipper at your convergence setting.  This is the effect you are seeing.  The "hold under" required in your "standing on your tail" shooting position is due to this arcing of the rounds from the guns to the pipper.  Essentially, your rounds are traveling in a very steep parabolic curve with you looking up the inside of the curve, so they appear to rise relative to your sight picture.

As far as "how much to hold under", there are too many variables in play, including the aircraft and armament you are using and the range of the target at which you are shooting.  That said, these things can be tested and practiced.

I was also going to suggest using the .target command, just as Bustr mentioned above.   You can also (offline or in the Training Arena) use the lead computing sight.  I would go further and try setting the target to different ranges and angles vertically from 65 degrees up to 90 degrees to see how that affects your ballistics and hold off center.  It's also a good flying exercise to get a feel for how much energy you need to get an adequate shot on a target at those angles, how to trim on angle so you can hold more steadily on the target and learn the sight picture for the various angles.

This sounds like an interesting topic to explore and I would be happy to offer to do some live testing and practice shooting with you, with me flying as your "roping target" if you would like to meet up in the Training Arena some time to work on this.

<S>
Kingpin
(Formerly RynoRush)

p.s. Sorry for some redundancy, as I see now some other detailed replies were made while I was typing!  Hope to see you in the TA some time.

[nrshida]

nrshida! You're back! 

Hi Bizman. Sorry I'm so appalling at email contact. Has been a very busy time. I always remember your advice! 

Actually I'm back briefly I think. Have this monumental, conceptual, scratch-built, lateral-thought-out joystick project (bit like my throttle but bigger). Just wanted to check myself and see if I still enjoy flying enough to complete it. I don't think my old Mac will run AHIII so I thought I'd get in quick. Otherwise it's the trash can and 6000 tiny problems fewer I have to solve   
So far spent a couple of hours in the MA getting ganged like a poop in a fly storm. I'll let you know 

But YAY! SHIDA! 

Yay Dolby! \o/  Have you been behaving yourself?


Thank you everybody for the info. I'll look into all of that. Interesting point Wiley about convergence settings. I don't think convergence goes out far enough to make the shots 'flat' in the vert. The farther the better.

I think the replies are missing the OP's question surrounds shooting while in a vertical climb.  That is how I read the OP.

Yes firing pretty well straight up. Not much info on that even on firearms sites.


Bustr I had completely forgotten about the third argument to .target. Thanks.

I'm a bit weird, I suppose I should have mentioned that. I don't actually use a gunsight in the Ki-84. I began by estimating within the framing then learned how a good shot looked. Archery, see. Having a bit of trouble adjusting in the vert though and it's apparently a lot of my shots in the MA.

[nrshida]

Hi Shida, very good to see you!!

Hi Kingpin, I remember you as RynoRush. Long time. Yes firing upwards is a bit esoteric. When in form and NOT firing in the vert I can often tap 5-6 Ho-5s at 600 yards if the target is slow - on a good day. Lots of trigger time on those.

My schedule's a bit unpredictable. If you see me on please say hello and we can do some testing. I'll in the meantime do some offline testing 

[nrshida]

Did some quick and dirty testing. I tried the Ki-84 - cannon only. P-38J both weapons firing at once, Ta152 - firing both weapons but separately, P-47 (earliest one) - all guns, K-4 - 30-mm only, N1K - all weapons firing at once. I had 600 convergence set for everything and set the target at 300 yards above. Remarkably, they all place about the same distance above the sight!

You don't actually have to hold under as much as I was lead to believe. The biggest issue is that in the vert you have to push forward on the elevators otherwise the aircraft fall steadily onto their backs. This makes the nose a bit bouncy. The shot is hard to keep dense. The P-38 was far and away the most stable standing on its tail.

Interesting.

[Owlblink]

I have enjoyed reading this discussion!

I noticed that within the gunnery videos that Ryno had Vudu aim at the intersection of his coursair's horizontal and verticle stabilizer, when at half "convergence" (harmonization? I know the guns are not converging at a point but spread around the desired shooting distance so not familiar with what one would technically call it), to hit the ring roots of the coursair. In this example it seems that the bullet streams are hitting below the center point of the crosshairs leading one to conclude that they would have to aim slightly above the target, if going by the piper, correct? Yet we are also talking about "Holding Under," does this mean at some point you should aim thd piper below the enemy? Just looking for clarification

To contribute further to this conversation, I have resently begun target shooting with handguns. One of the variables that can throw off the bullets impact point vs where the shooter is sighting is what part of the index finger is pulling on the trigger. To clarify, if you are using closer to the of your finger to pull the trigger, the run will yaw and cause the bullet to be off where you believed you were aiming. Why do I bring this up? Well if someone is using a twisty stick, it is possible that the same principle will have an effect if their stick's yaw is very sensitive, causing them to activate the rudder slightly and throw their aim off to the left or right

[Kingpin]

I have enjoyed reading this discussion!

...when at half "convergence" (harmonization?) the bullet streams are hitting below the center point of the crosshairs leading one to conclude that they would have to aim slightly above the target, if going by the piper, correct?

Yes, I am using the term convergence (rather than harmonization), because that is what the game calls it.  You are correct that there is more of a convergence zone/pattern/area, even when you have all guns set to the same distance.  This is one reason I had players in the video fire at the target, at convergence distance, while sitting on the ground -- just to give the an idea of how big their bullet dispersion pattern is without any flight control inputs.

At "half convergence" (using a 325 convergence in the Corsair) the bullets have only risen about halfway to the level of the pipper, so you must aim higher when firing in close.  This is what that section of the course is meant to demonstrate, so you got it.

Also to be noted, at half convergence with wing-mounted guns, your two bullet streams have yet to meet but the bullet dispersion patterns are tighter.  Essentially, you have two very effective bullet streams, if you know how/where to place them.

Important note: This will all vary from 1) aircraft to aircraft 2) from gun-package to gun-package and 3) with different convergence settings.  The purpose for that part of the course is not to show how to shoot/aim with the Corsair, but really to demonstrate how to test and see what your bullet stream looks like at various ranges, depending on your convergence settings, for ANY aircraft/gun-package in the game -- because they will all be slightly different.

For example, if you have a 109K4 with a convergence set to 600 yards (as Shida was mentioning in this thread) and you are firing at half convergence distance (300 yards) do you aim high or low...?    (Answer below!)

Yet we are also talking about "Holding Under," does this mean at some point you should aim thd piper below the enemy? Just looking for clarification

Yes, there are cases when you should aim below, like firing at a target going straight vertical, as Shida is discussing in this thread.

Another example would be in a 109K4 with a convergence set to 600 yards when firing at a target 300 yards out -- you need to aim low.  The 30mm must be arced so high to get it out to 600 yards at pipper level that it is well above the pipper at half convergence.  If you test this with the .target command, you will see two distinct bullet patterns at 300 yards for the MGs and the 30mm (tater) -- with the 30mm impacting about 10 feet ABOVE the pipper on a target 300 yards away.  So, assuming you are trying to hit with the 30mm, you would need to aim about 10 feet below your target. 

Note: Some of this is also dependent on altitude.  The results discussed above were tested at and under 10K.  As you reach higher altitudes there is less air density and you will see this has an effect on bullet drop.  If you plan on bomber-hunting at altitudes of 25K or higher, you may want to test your bullet stream(s) at altitude (there is a nice 30K base in the TA for this).  You will notice less bullet drop at higher altitudes, which especially affects your aim for long range sniping.

Hope this info helps!

<S>