High level bombing questions
 

Two questions about high level bombing.

Does anyone have a IAS/TAS conversion chart for the cold maps in IL2, like Moscow? Bombsight Table 2 and all the charts I can find seem to be calibrated for average spring/fall temperatures, but the Moscow map is much colder, which affects TAS calculations, which in turn affects bombing accuracy.

For example, on the Crimea map, at 3950m and an IAS of 270km/h the TAS is 340km/h, according to the wonder-woman view. But on the Moscow winter map, IAS of 270km/h at 3950m is 312km/h.

If someone had a chart, or at least a basic guideline for calculating TAS on winter maps, that'd be great.


My second question pertains to the Soviet bombsight on the Pe-2, Pe-8, and IL-4 (now also found on the single-engined Japanese bombers). I find it to be very precise but not accurate; it consistently drops bombs with the same error, depending on bomb type and plane type.

BFS Thor made a great level bombing manual with a chart to correct the Bombsight Table 2 program, but it does not include the IL-4 or the Pe-8, and the Pe-2 information is now inaccurate or was never accurate to begin with. Doing my own tests on the Crimea map, I found the following corrections are needed, all at 3950m:

Pe-2, 250kg bomb: go by the sight
Pe-2, 500kg bomb: go by Bombsight Table 2
IL-4, 250kg bomb: go by Bombsight Table 2 + 0.4 degrees
IL-4, 500kg bomb: go by the sight
Pe-8, 500kg bomb: go by Bombsight Table 2 + 2.0 degrees
Pe-8, 1000kg bomb: go by Bombsight Table 2

Does someone have a more complete chart, and is it possible to fix these inaccurate bombsigts in future patches?

Thanks,

WokeUpDead

HSFX has an option to show TAS in the speedbar.

What you need is PAL-HUDConfigHSFX6 mod for HSFX (I am guessing that you are using mods?), available here in JSGME package for HSFX 6 in DBS mods section.

Visit our DBS forums (link in my sig) for more info (not sure if I can post mod links here).


Alternatively you can do what I always do, since the bomb angle varies so much depending on the bomb size, use BombsightTable2 for IAS-TAS conversion and then input the accurate data into the OP-1 bombsight through in-game interface rather than dropping on a preset angle.

Thanks for the replies, I don't use mods though, and the servers I fly on may not allow that specific mod anyway.

"use BombsightTable2 for IAS-TAS conversion and then input the accurate data into the OP-1 bombsight through in-game interface rather than dropping on a preset angle"

Do you mean use BT2 to figure out the TAS, then ignore the angle BT2 gives and just line up the two needles on the sight? Unfortunately this does not always work, hence my problem from my first post. Different sizes of Soviet bombs do seem to fall differently, I think you found this yourself when you added different correction angles for the big bombs (BB) and medium bombs (MB) in your guide. But the OP-1 always gives the same angle given the same altitude and speed, regardless of the bomb size. And there also appears to be variation from plane to plane (Pe-2, IL-4, Pe-8)

To accurately bomb in those aircraft you need the target ground level altitude to calculate the bomb sight angle.

Or you will be long/short depending on the target alt from mean sea level.

I have never found it necessary to use any bombsite assistance programs the stock tables work perfectly well if you know the target alt :)







.

Target elevation (the correct term :) ) is very important when level bombing. You need to input the relative altitude above ground or AOG, not altitude above sea level or AOS for your target. In IL2, due to its terrain, those targets usually will not be above 200m AOS and that is rare since the terrain is mostly flat on all maps with very few exceptions. The highest target I ever bombed was MonteCassino on Italy map (600m AOS).

Could very well be so. Bear in mind that the angle value needed is a decimal number, i.e. in 1/3 that needs to be entered into the bomb sight. Depending on what the sight gives you. Three clicks are needed with OP-1 to switch to a higher angle. That may also be important.

Altitude deviations at airfields on a few of the common stock maps.

~@ Woke up Dead
Its important to know terrain elevation on parts of the maps you are intending to use altitude bombing.

Moscow
North 90m
South 140m

Crimea
South 200-240m

Smolensk
East 160m
North 90m
South 110m
West 40m

Stalingrad
North 200m
South 30m
East 50m
West 100m
Central 110m

Thanks again guys, but I think you're assuming I'm more of a novice at this than I really am. I'm aware of the importance of target altitude; for my recent tests I either targeted objects at the coast line or along rivers, or took target altitude into consideration.

I'm also aware that it takes multiple clicks to increment move the Soviet bombsight by angle integers. Not three, but five; increments of 0.2 degrees: 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, etc.

Given all this, I still can't get accurate results, even if I read my TAS from the wonder-woman view. I input the correct speed, correct altitude, match the two indicators on the bombsight, and still can't hit my target. The error is consistently the same if I use the same bombload and drop it from the same plane, but different if I take another bombload or another plane. For example, a FAB-500 dropped from a Pe-2 from 4000 may always fall a little bit long, but the same FAB-500 dropped from in IL-4 may always fall very long.

In other words, the Soviet bombsights in this version of the game are inaccurate, or to put it bluntly, screwed-up. I hope they get fixed for 4.13, in the meantime I may create a chart of corrections for the Pe-2, IL-4, Pe-8, and maybe the Japanese bombers as well.

I use the bombsite table as a guide to correct airspeed, but nothing beats experience in these situations, you need to experiment a bit with the sight and different speeds.

http://img.photobucket.com/albums/v1...ha1/KPHTAs.jpg

http://img.photobucket.com/albums/v1..._TAS_Chart.jpg


Using the Russian sight I drop the bombs at the start of the target they then hit the middle allowing for altitude deviation at ground level.

Just done a 3930m drop with

Pe2 (1942)
FAB 500's x 2
IAS 270kph
TAS 330kph
Target altitude (elevation) 30m

Perfect drop with a direct hit on the target using the @ 60kph speed difference as indicated on the bombsite table above.

Track attached.

Do you have wind on the maps you tested (I presume not)? In todays IL21946 it plays a key role when level bombing.

No Alpha, you clearly missed. You released the bombs when the bombsight was over the nearest plane, but the bomb hit the ground and destroyed the middle/farthest planes on the airfield. The nearest two planes remained intact.

Perhaps it's because you didn't input the correct TAS: you put in 330km/h, but the TAS at the time of your drop according to the wonder woman view on your track was 345km/h.

Your track is inconclusive.

I made my own tracks of a similar target in Crimea. The target is about 20m above sea level, I'm always aiming for the nearest (easternmost) plane, and I always used the TAS according to wonder woman.

My first run was in a Pe-2 with 2x500 bombs. I had the speed, altitude, and angle pretty much perfect, yet the bombs dropped long, the first plane was not damaged.

My second run was also in a Pe-2 this time with 2x500 bombs. Again everything was as close to perfect as I could get it, and this time the bombs were almost on target. Just a bit long, but still close enough to destroy that first plane.

My third run was in an IL4 with one 500kg bomb. It's steadier than the Pe-2 so I think my altitude and speed were closer to perfect than in the first two runs, but the bomb went way, way, waaaaayyy long. I didn't even hit the rectangular tarmac. In fact, I think the tarmac could have been twice as long, and the bomb would still have missed it. Check for yourselves:

:rolleyes:

I missed ?

I hit where I aimed :)

Its simple 270kph ias @ 3900m = TAS 330kph whats wonder woman TAS got to do with anything just use the bombsite table settings and it works :)

The bombs dropped in the center of the target that's the way I use the sight and have for years the TAS is correct that's why I hit the middle of the target.

The point of aim is between the 0 and 5 indicator 2.5 being the target center.

NB

All consideration taken from actual pilots using these crude bombsites back in WW2 we do better than they probably ever did,
they were never designed to be precision bombing devices just a general aiming sight.

Those charts don't take temperature into account, so on a very cold map like Moscow they won't show the right TAS. Wonder-woman view shows the correct TAS.

Since when is 2.5 target center?

Try your technique with a 2x250 FAB load, or a 1x500 FAB in an IL4, or 2x500 FAB in a Pe-2 on the Moscow winter map.

Well I hit the target perfectly well every time not using "WW" views TAS reading.

I use the charts and have done for years taking into account the target altitude (elevation) it works for me.

Continue your method and keep missing.

Have fun.

No need to get pissy. I tried several planes, several bomb loads, on several maps and I think something is not right. You try one drop and say everything is fine.

OK, let's use your method then:

First track:
IL4, 1x500FAB, Crimea, IAS 270km/h, TAS set to 330km/h according to your chart, dropped from 3930m, took target altitude of 30m into account, dropped at the 2.5 mark above the bubble, aimed for first plane. Result: waaaaaaay long.

Second track:
Pe2, 2x250FAB, Crimea, IAS 270km/h, TAS set to 330km/h according to your chart, dropped from 3930m, took target altitude of 30m into account, dropped at the 2.5 mark above the bubble, aimed for first plane. Result: short enough to not damage the target.

Third track
Pe2, 2x500FAB, Moscow winter, IAS 270km/h, TAS set to 330km/h according to your chart, dropped form 4000m, took target altitude of 90m into account, dropped at the 2.5 mark above the bubble, aimed for middle plane at the far end of the tarmac. Result: way short, no damage to target (destroyed planes at the near end of tarmac)

Tell me what I'm doing wrong.

I also replicated the drop you did (Pe2, 2x500FAB, Crimea) and hit my target, so I can confirm that yes, on that map, that plane, that loadout, your method is accurate, if we assume 2.5 above the bubble to be the target center.

I guess I have been bombing on instinct and feeling for a long time, as some of the numbers you are quoting seem to be off.

I have a few rules for the bombsites and bomb types, subconsciously I suppose I have learnt the method to apply different loads and conditions for successful bombing without realizing it.

More testing............



.

Possibly. I try to go by the book and get frustrated with results that are bad but consistently the same: always long with Plane A bomb B, or always short with Plane C bomb D. No matter the book either: your charts, wonder woman TAS, Bombsight Table 2, Thor's book, IL2 Shturman, nothing seems to work for all the soviet planes and bombs.

If you're going by your instinct, I'd bet the IL4 will make you miss since it's a new plane and you may have not flown it much.

The initial problem is the sight its self as in HSFX its a smaller zoomed out optic and looks totally different from the stock one in v4.12.1 (HSFX being my main choice, maps etc)

Given that, the IL4 is a perfect example of a plane I have not bombed with until testing in this thread, that said the same problem exists in HSFX as in the stock version, the bombsite remains the same as is the method using it, so any corrections would be the same.

I have dealt with it in the game, as I already suggested, by unconsciously adjusting the sight for the difference without really making a conscious effort and referring to external devices for reference,
I kind of just got on with it.
In some places the settings touch the bombsite tables suggestions and in other areas its off so its inconsistent at its best and just plain wrong at its worst.

I'm not a good candidate for "by the book" testing as I have been at this too long and have probably picked up too many bad habits using bombsites and blowing stuff up :)

Maybe someone will pop up in here regarding the bomb weighting ............

:(






.

Hi all.

I'm performing several tests since de patch 4.12 about flying navigation an level bombing, watching two important effects: the wind speed and the free air temperature.

Wind speed and its direction have effects on your true heading in order to flight following a preplaned true course to your target. But also the wind affects your Ground Speed.
If in your mission there is wind with a non "zero speed", you shouldn't use TAS to set your bombsight up, but the Ground Speed. This must be solved knowing your TAS and the wind speed at a given altitude, as well as your course and the wind direction.
To find the Ground Speed (GS) you can use the "Cosin's Theorem", or solving the vectorial sum between TAS and Wind Speed (WS)... or using the back side of an E6-B Flight Computer (as I do :cool:). So, TAS may be used only when there is not wind (in such case, GS = TAS as it was before the patch 4.12).

The free air temperature affects both the TAS and the True Altitude (TA): when the air is colder it is denser, and your TAS will be slower than that measured in your TAS gauges, or that computed for any given warmer temperature. The same is for the altitude: in colder air your real altitude may be a bit lower than that indicated by your altimeter... or a bit higher if the free air is warm.
In air navigation it's admitted that the free air temperature decrease -6.5ºC each 1000 meters ASL. At sea level (for air navigation) the standard temperature is 15ºC; and from 11,000 m to 20,000 it's accepted the air temperature has a constant value of -56.5 ºC.

But, what if the air temperature on the ground level is not the standard value of 15 ºC?
The step of -6.5 ºC each 1000 m ASL doesn't change... but it means that you will find the limit of -56.5 ºC below of 11,000 meters (i.e., in a winter map), or above of 11,000 m (i.e., in a summer map).

So, the free air temperature at a given altitude affects the True Altitude and the TAS. And if there is wind, also it affects your GS. All together are combined and must be taken in account for the right setting of your bomb sight. Always I compute all these values with my E6-B and normally I find good results... and in any cases I've obtained the same bias with the same bombers using different bombs. Of course, I must perform more tests for to obtain a conclusion... but till now it seems that TD has implemented a very realistic atmospheric behavior. :grin:

About the bombs' FM, my tests let me guess that the FM is the same for all bombs, regardless of their sizes and their countries.

I hope this spots the new challenges of IL2-1946 propossed by TD. :cool:

The problem existed before v4.12 & v4.12.1