Salut Mr. Tram!
Wall of text incoming, brace yourselves (hey, you asked for it )
First of all, you need to map a set of controls.
Most importantly, start with the bombsight:
increase/decrease bombsight distance, altitude and speed
toggle bombsight automation
Don't forget to also map keys to open and close the bomb bay doors.
To look into the bombsight scope you switch to the bombardier's position (another control to map) and use the same command you would use to get the gunsight view in fighters (default is shift-F1).
Distance essentially controls the angle (what you said about the scope pointing straight down). Altitude is your altitude over ground at the target area, so if you are flying at 4km and the target is on a hill 500m high, you need to input 3.5km in that one.
Speed is tricky, you need your speed over ground or ground speed (GS) for short. Start by referencing your indicated airspeed (IAS) to the charts near the end of the manual, you can find it in a PDF file in (your games folder)\steam\steamapps\il-2 sturmovik cliffs of dover\manual.
There is a metric chart, for Luftwaffe instrumentation, and an imperial one for RAF instruments so that you can bomb in the Blenheim.
The chart is a grid displaying various altitudes and IAS values. Match your altitude and IAS and where the line and column intersect you can read your true airspeed (TAS), which is IAS corrected for altitude.
Since air pressure drops the higher you go, less pressure registers on the pitot tube (the instrument sensing your speed relative to the outside air) and the gauges show a lower speed the higher you go, even if you are actually doing the same speed over ground.
The reason aircraft still fly by IAS even today, when we can easily get TAS and GS from GPS and other instruments, is that IAS is what the aircraft "feels". If the air is thin you will stall easier, if the air is thicker the airframe is stressed more at high speed. So, pilots prefer having an instrument that shows "incorrect" speed but gives correct stalling and overspeed information (ie, helps them prevent things that can break the aircraft )
In other words, TAS is what your airspeed gauge would read if you were suddenly teleported from your current altitude to sea level while doing the same ground speed and there was no wind.
And here is the tricky part, wind. GS is TAS corrected for wind. If you are doing 300km/h TAS but you have a 30m/h headwing, your GS is actually 270km/h.
In order for the automatic bombsight to perform an accurate drop, it needs to know the GS. Currently we have no instrument to measure wind and i don't know if all bomber types of the era even had something like this. I remember from flying B-17 II the mighty 8th years ago that the B-17 (and possibly other late war bombers) had drift meters: the navigator would measure drift due to wind, relay the value to the bombardier and he would input that into his automatic bombsight to correct for the effects of wind.
However, we can "reverse engineer" the correct value. A bombsight which is properly calibrated will track a single spot on the ground under the crosshairs once you engage bombsight automation. The scope automatically moves down as you get closer to the targeted point and releases bombs at the correct point. At the same time, the target point also moves to the bottom of your screen because you are getting closer to it. If all is calibrated properly, the crosshairs should move down at a rate equal to that of the target point doing the same, essentially keeping the crosshairs on the target as you get closer by angling the scope down the closer you get to it.
So, what you can do is input your TAS from the charts in the manual as a ballpark value for GS, input your altitude, use the increase/decrease distance controls to slew the scope up/down and once you see an easy to spot feature on the terrain, engage bombsight automation as the terrain feature is under the crosshairs.
The bombsight will now attempt to track your arbitrary target point and drop bombs on it. Don't worry, you can cancel bombsight automation by pressing the relevant key command a second time (just don't let the scope drift too far down, as it will release the bombs). If the scope has trouble tracking the arbitrary target point, then you know your speed value is incorrect (assuming that you used the correct altitude value of course).
If the scope moves down faster than the abritrary target point (the crosshairs is lower on your screen than the target point) it means it's trying to compensate for your bomber's forward speed more than it needs to, which means that the speed value you input into the bombsight is too high. On the other hand, if the arbitrary target point is "overtaking" the crosshairds as they both move do the bottom of your screen, it means the bombsight is compensating for your GS less than it has to, so the speed value you input into the bombsight is too low.
So, what you do is input the TAS that the charts give you for your current IAS and altitude, look into the scope, "lock" onto an arbitrary terrain feature and increase/decrease the bombsight's speed value until you get a more or less stationary sight picture: the crosshairs are moving downwards at a rate similar to that which the terrain does.
Congratulations, you now have a calibrated bombsight. Disengage bombsight automation, slew the scope upwards and look for your real target this time. Once you spot it, engage bombsight automation again as the target is under the crosshairs. If you've done things correctly up to this point, the bombsight should automatically track the target and release the bombs at the correct time to ensure a hit.
But will they explode? And what about setting a nice pattern so that your bombs can cover the target in an effective manner? This is the job of the bomb distributor on your aircraft and that's what you need the relevant controls for:
salvo selection, bomb interval and arming switch
Salvo selection is just that, how many bombs will drop. Luftwaffe bombers and especially the 111 carry a few big ones and a whole lot of small, 50kg bombs. If you don't remember how many of them you have, just set this to the maximum allowable value. The reason you can opt not to drop everything at once is that during more "free form" missions (like skip bombing ships or even low level close air support, absurd i know, but i think 111s actually flew CAS sorties on the eastern front) you might have only a few big bombs that you might want to drop on specific targets.
For high altitude level bombing a la battle of Britain though, the norm is to drop them all in one go rather than extend away and do the whole bombsight thing again in the midst of flak and enemy fighters. So, just select the maximum salvo amount.
Bomb interval governs the spacing of the bombs in the selected salvo. This is not so much a time delay between individual bomb drops (it is, but that's not what you specify in the controls), it's the desired distance between bomb impacts on the ground and it's measured in meters.
It's easy to understand then, that for it to work as specified you need to have the correct altitude over target and GS values input into the bombsight. Otherwise, the bombsight calculates the wrong interval between bomb releases.
For tightly packed targets like a concentration of trains in a marshaling yard you would probably use a small value for this. For more spread out targets, like for example a big airbase, you would want to increase this in order to spread out your impact points and ensure you crater as much of the runways as possible and stand a chance of also hitting hangars and buildings on the periphery of the runways.
As for the arming switch is just that. Bombs are inert during the trip to the target, so that a fighter getting a lucky shot won't result in blowing up you, himself and half your formation and when you have fighters with 8 rapid firing machine guns facing you, that lucky shot is actually quite probable
Usually the bombs will be armed during the bomb run (the route between the final waypoint before the target called the IP, or initial point, and the actual target) a short time between dropping. I guess that once your sight is calibrated, "locked" onto the target and tracking it and you have opened your bomb bay doors, that would be a good time to arm them.
Finally, you need to map controls for the various compasses that govern the autopilot. The plane won't fly itself while you look through the bombsight scope you know...well it actually will, as long as you follow the correct steps
You can also click on the relevant instruments in the cockpit with the mouse, but it's one of those things that i prefer to have on keys so that i can adjust them while looking through the bombsight scope or while flying the aircraft.
These controls are:
increase/decrease course setter (optional, this is just a "remind me what heading to keep" dial that has no effect on the autopilot)
inc/dec directional gyro
course autopilot mode previous/next
course autopilot left/right
From here on out the autopilot is referred to as AP to save me typing, because my fingers are starting to hurt
Having the mouse cursor enabled helps a great deal here (default toggle key is F10), because of the tooltip pop-ups that give you instrument readouts.
In short, the AP works by comparing your actual heading (read from the gyrocompass, otherwise known as directional gyro or DG for short) to your intended heading which you set via the course AP left/right commands on a secondary compass card readout similar to the DG. The AP compares the two compass cards (DG and desired heading) and turns to match them.
Mind you this is no Airbus with bank limiters and angle of attack safety algorithms, if you engage the AP with a high offset between these two values the bomber will bank way too much and you'll end up in a diving spiral (if you don't collide with your wingmen first), so go easy on the corrections.
It's also where the final part of our troubles start: to prevent wild maneuvering upon engaging the AP, we first need to match our desired heading with the one displayed on the DG.
The entire sequence goes like this:
1) Once completing the turn from the IP to the target, adjust your power settings as desired and trim for level flight so that the bomber flies almost hands-off. You might want to let it settle a bit, pick up the speed it lost during the turn etc, retrimming as required.
2) Look to your right, on the starboard cockpit wall you'll see the magnetic compass. With your aircraft flying steady, straight and level, hover your mouse over it to get a tooltip telling you your magnetic heading.
3) Using the inc/dec DG controls, turn your DG's compass card so that it matches the heading displayed by the magnetic compass. Up to this point, this is a drill you should be doing anyway throughout the flight, because the DG is easier to read. It needs readjustment every 10-15 minutes or after violent maneuvers because the gyros suffer from precession but it's definitely worth it. So, calibrate your DG once before takeoff and then every 15 minutes during the entire flight
Important: If you are accelerating or exerting any kind of substantial force on the airframe the magnetic compass is affected too and you'll get wrong indications. This is especially true if applying throttle and stepping on the brakes while on the ground, you can see the needle going crazy. So calibrate your DG when your aircraft is more or less steady. Calibrating while in a steady climb with wings level is ok, while barrel rolling it's not.
Absolute precision is neither possible nor necessary, just get it within 5 degrees or so and cross-reference your course with landmarks on your map and outside the aircraft.
4) You should now have a calibrated DG. Now use the course AP left/right controls to match the desired heading to the DG, so that when you engage the AP it won't start banking like mad.
There's an important note here and i don't know if it's a bug or a realistic feature: the desired heading and the DG compass cards are not completely aligned, they have a 5-7 degrees offset.
So, if you are flying due north and set both to 0 degrees, instead of flying straight like expected the bomber will slightly bank left and right, finally settling on a heading between 5 and 7 degrees off (heading specified by the DG not the magnetic compass).
To correct for this you can apply a correctional offset yourself. In the below schematic the top row is the DG compass card and the bottom row is the desired heading compass card that the AP will try to achieve, it should look like this:
---N---
------N---
If the instrument is reversed in-game (i don't really remember which compass card is which right now), then reverse your inputs as needed. I'm not entirely sure about the direction the offset should be since it's been a while since i last tested it, but you can click on my nickname and search my posts with the keyword "level stabilizer" and "gyrocompass" for another thread where i explain it correctly. I'll probably edit this post tomorrow and get it all right once i have a chance to test it.
5) You should now have a properly calibrated DG and your desired heading should be aligned with it, correctional offset included. Go ahead and use the course AP mode previous/next commands to finally engage the AP.
This switch has three functions: AP off, course AP (displayed with its proper German name) and R31 (or a similar abbreviation).
The first just turns it off, the second is what we want. As for the third, i have a hunch it's got something to do with the Lorenz blind landing system and/or radio guidance for night raids. In other words, until a mission builder comes up with a night raid mission that features radio navigation transmitters i can't really test it out (i'm not that good with the FMB).
Provided you did things correctly up to this point (NEVER skimp on trimming the aircraft, it's probably the most important step), the AP should engage as soon as you set it to course mode, the bomber might wiggle slightly left and right while the gyroscopes in the system stabilize and then you'll be flying via autopilot.
6) Go to the bombardier's position.
7) Configure your bomb distributor settings like we explained above.
8 ) Calibrate your bombsight like we also explained above.
9) Spot your target. More likely than not, you won't be right on course.
10) Use course AP left/right commands (the same ones we used to align the desired heading compass card) to make small course corrections (a couple degrees at a time, nothing drastic) and line up with your target (vertical line of the scope crossing the target area).
11) Slew the scope up/down with the inc/dec bombsight distance controls until the crosshairs is on the target.
12) Engage bombsight automation, open bomb bay doors, arm your bombs and wait.
If you've done everything correctly up to this point, the bombsight will automatically release bombs, you close your bomb bay doors, turn for home and some time later (depending on how high you were) you'll see the fireworks.
Hope it helps. Phew, that's another one for the FAQ
P.S. This is for almost full realism settings (in total full real you can't switch to other crewmen's positions, you're supposed to have other human players operating those in multiplayer). If i'm not mistaken, you can skip at least the bombsight's speed calibration if you turn off realistic bombing in the options, then you only need to input your IAS straight from your airspeed dial and it will work out things on its own.
