Target elevation for level bombing

[357th_Esco]

Is there a way to get the target elevation in order to subtract it from your altitude when inputting the altitude in the bombsight? I never see the target elevation posted on multiplayer servers or single player campaigns, so most bombs land short/ long depending on the difference from sea level.  Some people I have asked say “You don’t have to worry about that in IL2.” Or “I don’t know.” but I find that to be false. Is there an easier way to get the elevation other than taking another plane to ground level and noting the elevation for the next trip in a bomber?

[busdriver]

Well historically almost all bombs fell short/long. I am unaware of any method of obtaining a target’s elevation to suit your needs. You are left estimating (albeit with potentially greater error) just like WWII aviators.

The mighty 8th AF bombing was far from precise.

[Elem]

From...

https://wiki.wwiionline.com/view/Level_Bombing

 

The targets Height (ASL) would be known to the mission planners.

Edited August 6, 2020 by Elem

[Lusekofte]

1 hour ago, Esco said:

say “You don’t have to worry about that in IL2.” Or “I don’t know.” but I find that to be false.

How do you find it not to be true?  
I stopped taking target altitude into account as long as we do not take Kuban mountains into the equation. 
I can hit a static tank from 5 k as long as I spot it, without taking 50 to 200 mtrs into the bombsite. I am afraid you put far more into it than needed.  As long as you get the wind correctly you get far more accurate bombing than RL ever gave

[RedKestrel]

2 hours ago, busdriver said:

Well historically almost all bombs fell short/long. I am unaware of any method of obtaining a target’s elevation to suit your needs. You are left estimating (albeit with potentially greater error) just like WWII aviators.

The mighty 8th AF bombing was far from precise.

I have it on good authority the Norden bombsight let you put a bomb in a pickle barrel* from 30000 feet!

*only applicable when bombing pickle barrel factories

[AndyJWest]

If you do the maths you'll find that when level bombing from historically-accurate altitudes, the error you might get from not having a correct target ASL figure is usually more or less insignificant, if you take into account other possible sources of error. A bomb from that height will typically be dropping at about 10-20 degrees from the vertical by the time it gets to the target.

 

If you assume a 15-degree angle, an AGL altitude error of 250 ft equates to a horizontal error of 67 ft. Which might sound a lot, but in comparison at 300 mph TAS, you cover 67 feet in 0.15 seconds, and I doubt many people can consistently time release that accurately. And this isn't taking into account any wind, which even if you have the figure for at your altitude, will still cause errors as it changes speed and direction as the bomb drops.

 

The Norden sight may well have been able to hit the proverbial pickle barrel in theory, but the theory seems to have been based on either having no wind at all, or a constant wind at all altitudes, which basically never happens. Level bombing small targets requires either big bombs, or lots of them. Or at least, it should. If IL-2 GB suggests otherwise, it is optimistic. 

 

Edit: Thinking about this some more, there are other factors than the final angle of descent that come into play if you get the target ASL wrong (e.g. the error this induces in the initial sight angle), though I don't think this really matters in practice. Not with all the other factors involved. 

Edited August 6, 2020 by AndyJWest

[Pict]

1 hour ago, RedKestrel said:

I have it on good authority the Norden bombsight let you put a bomb in a pickle barrel* from 30000 feet!

*only applicable when bombing pickle barrel factories

 

I think the word for that is "zonk", at least according to "Way to the Stars" (1945) https://archive.org/details/TheWayToTheStars

 

Quote is around the 50:15 mark. Good old movie, a classic.

[sergio_]

The way *I* would do it if I wanted to be more precise than level-bombing sea level would be to check the elevation in Google Earth.

 

It would make a good addition to the planning phase of your sortie.

 

I'm myself not that concerned because of the actual difference it would make in my bombing would be next to none compared to my human  precission, unless the target was in a high place in Kuban.

 

[busdriver]

1 hour ago, sergio_ said:

The way *I* would do it if I wanted to be more precise than level-bombing sea level would be to check the elevation in Google Earth.

I’ve done a bit of that on the BoBP map with the elevation of a few (not all) airfields in the southern sectors. In the small sample I researched, this technique was within 50 meters or so. Since game maps are not high fidelity, a 50-100 meter error is pretty good.
 

However in game play there is often a very large altitude error induced when changing your altimeter between the “Nearest friendly airfield” and “Standard altimeter.” It is not uncommon to see 300 meters difference. I did this several builds ago and found the variations greatest on winter maps.

I agree with @AndyJWest the are other factors that compound the problem. I’m not anywhere as smart with the maths. Your speed across the ground, and the vagaries (speed and direction) of the winds as the bombs fall typically have a greater influence than approximating target elevation. Winds are pretty benign in game compared to RL.

[JimTM]

Note that for each target, mission makers can include text (including the height ASL) that pops up when you mouse over the target icon. Combat Box has this text feature, but I don't believe they show heights...yet.  

[Gambit21]

The best way to level bomb I’ve found is to fly in formation with a buddy who knows WTF he’s doing and he tells me when to drop. ?

 

Fond memories of level bombing Henderson in Bettys in the old days.

[AndyJWest]

6 minutes ago, Gambit21 said:

The best way to level bomb I’ve found is to fly in formation with a buddy who knows WTF he’s doing and he tells me when to drop. ?

 

Fond memories of level bombing Henderson in Bettys in the old days.

 

Yeah, works well. As long as they tell you. I can remember years back doing a coop in the IL-2 '46 Pe-8, and asking how far it was to the target. "We dropped five minutes ago" came the helpful reply. I bombed some cabbages or something, and scuttled back to base. Or most of the way there, before I crashed in flames. Can't remember if it was flak, or a Hun taking advantage of a straggler for easy target practice.

 

And yes, useful details like where the target is, what the wind is doing etc, should probably be in the briefing. 

[RedKestrel]

16 minutes ago, AndyJWest said:

 

Yeah, works well. As long as they tell you. I can remember years back doing a coop in the IL-2 '46 Pe-8, and asking how far it was to the target. "We dropped five minutes ago" came the helpful reply. I bombed some cabbages or something, and scuttled back to base. Or most of the way there, before I crashed in flames. Can't remember if it was flak, or a Hun taking advantage of a straggler for easy target practice.

 

Will the plight of the humble cabbage farmer never end?

[AndyJWest]

2 minutes ago, RedKestrel said:

Will the plight of the humble cabbage farmer never end?

 

https://www.reddit.com/r/aww/comments/ctfujw/the_snow_leopard_attacks_its_natural_enemy/

[migmadmarine]

Career mode missions should have the target elevation listed in the briefing. 

[357th_Esco]

1 hour ago, migmadmarine said:

Career mode missions should have the target elevation listed in the briefing. 

I looked in scripted campaign and career. I did not see that information anywhere.

10 hours ago, busdriver said:

Well historically almost all bombs fell short/long. I am unaware of any method of obtaining a target’s elevation to suit your needs. You are left estimating (albeit with potentially greater error) just like WWII aviators.

The mighty 8th AF bombing was far from precise.

I would assume that information of that nature would have been known/ passed down thru intelligence to pilots prior to the mission.

[busdriver]

40 minutes ago, Esco said:

I looked in scripted campaign and career. I did not see that information anywhere.

 

 

40 minutes ago, Esco said:

I would assume that information of that nature would have been known/ passed down thru intelligence to pilots prior to the mission.

 

For level bombing by airplanes using a bombsight the navigator and/or bombadier would certainly use whatever elevation info they had for mission planning.

Edited August 6, 2020 by busdriver

[357th_Esco]

Thanks. I guess my sight is failing me.

[Lusekofte]

8 hours ago, Esco said:

Thanks. I guess my sight is failing me.

I drop short or too long from target sometime. Online when I am pretty sure I had the right settings I wonder if the game did not take my wind settings on that drop or it was a lagg. 
You need to look at your general drop statistic in order to see if you are doing something wrong. 
I sometimes go for a column of tanks. 
I try to line up with the road, 1 of 10 tryes I hit more than one tanks. 
maybe 4 of 10 only 1 and the rest are misses. 
Sometimes the target that showed as undamaged in sight pop up as ruins just when you dropped. I just figure that , I was ordered to drop there, I did, meaning I did my job. I go home. I count survival as a victory too

[Leon_Portier]

I usually drop bomb trains of at least 4 bombs, when I'm not sure of the elevation I just use the maximum intervall. That makes bombing surprisingly reliable for me.

[thepiespy]

I would imagine the majority of the forward movement of a bomb, especially from high altitude, is already accounted for by the bombsight from the aircraft's airspeed. A bomb from high altitude impacts at a much steeper angle in relation to the ground than say a lower trajectory round from a field gun or howitzer, or a glidebombing approach. Speaking from indirect fire experience side of things, the steeper the trajectory of the bomb/projectile, the smaller the error in range will given the same error in altitude. Consider the elevation for Stalingrad is only around 80m ASL. 

 

[Gambit21]

13 hours ago, [N.O.G.F]Leon_Portier said:

I usually drop bomb trains of at least 4 bombs, when I'm not sure of the elevation I just use the maximum intervall. That makes bombing surprisingly reliable for me.

 

If the bottom of your aircraft isn't scuffed and scratched from the tops of the fir trees then you're doing it wrong.

 

[RAAF492SQNOz_Steve]

5 minutes ago, Gambit21 said:

 

If the bottom of your aircraft isn't scuffed and scratched from the tops of the fir trees then you're doing it wrong.

 

 

Did that during a ground strafing attack...........

The loud bang that I heard suggested that I did more than scuff the bottom of the aircraft ?

Had an instantaneous thought of "How did I survive that".............. 

The subsequent almost total loss of control surfaces proved that I didn't, was just a dead man flying ?

 

Great fun and I got what I deserved!

[migmadmarine]

I always love when I bounce the tail wheel off the ground after a gun pass in the Hs-129

[jojy47jojyrocks]

Really wish we could change the waypoint and approach pattern even if we are not the Flight lead....SP setup.

 

Kinda hard to bomb supply depots, coz planning through the briefing and how the alignment is in relation to our target is a bit hard at the current interface.

Edited August 10, 2020 by jojy47jojyrocks

[Leon_Portier]

4 hours ago, Gambit21 said:

 

If the bottom of your aircraft isn't scuffed and scratched from the tops of the fir trees then you're doing it wrong.

 

 

I see you are a man of culture as well!

[[CPT]milopugdog]

I just want to be the one to point out that your plane's altimeter is automatically tuned to the airfield you spawn at. Then, there's also a command to change it to the setting at the nearest friendly base to you.

 

So, taking into account the fact that most actions in this game are happening over flat maps with rolling hills varying in heights of... probably 100-300m at most; I'd have to agree, it does not matter that much.

[FTC_Frederf]

No it isn't. The altimeter defaults to 760mm Hg "QNE" setting which just shows pressure altitude. It will neither read the airfield elevation nor zero when on the ground. At 4000m altitude on a cold day the altimeter can easily read 4700m. At the moment you select "nearest airfield" calibration then it changes the setting such that it will read zero when you're at that airfield. It won't update in future automatically but will stay at this altimeter setting.

 

The altimeter in the bomb sight is 100% independent of the concept of air pressure, temperature, density, lag, etc. It's a complete cheat altimeter that shows your exact vertical position relative to sea level at all times and has no adjustment. It's a "true altimeter" in that it only shows true altitude and nothing else at all times.

 

Almost always it is best to ignore the barometric cockpit altimeter when level bombing and use the true altimeter in the bomb sight view. From that value subtract the target elevation which in a lot of Stalingrad is 80~120m ASL so I take off 100m from the bomb height dial every time. The only way to know target elevation is to be told or look it up somehow. Putting the camera at the target in the mission editor you can read off the position of the camera. You can also use Google maps to check elevation which should be quite close to in-game. Overall you can consider the angle how bombs fall against the ground about 30 degrees from vertical which means for every 2m of elevation error there is 1m of range error. Usually this is small compared to errors in speed, especially at high altitude where speed matters a lot and bombs fall steeply so elevation matters a little.

 

Best training tool in IL-2 is to use "bombing assist" cheat option and have this bound to a key to toggle on and off. Fly in some manner and do your best estimate of all parameters of sight with bomb assist toggled off. When you think it is correct turn on bomb assist marker and see if you were right or not. You can change for example small adjustments in wind or height or speed and see how solution moves around relative to perfect marker solution. You will learn that sometimes it is impossible to perfectly match solution because input values cannot be set in between available values. In this case you accept the inaccuracy.