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#1
10-02-2013, 03:55 PM
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Hi mate.
 First of all: my sincere thanks by your explanation about the parabolic motion... but I know the works of sir I. Newton also.  BTW, I must point out an error in your eq. 3. It must be written as: R = v . SQRT (2h/g) Basically we are talking about of 2 types of bombsight: the Norden/Lofte type(Allies/Germans), and the OKPB-1 type (Russians). Both need 2 settings: TAS (horizontal speed), and altitude. The difference between both types is the first allows automatic or manual release, and the second only allows manual release. But in both types normally the aiming angle is internally calculated (all that equations you've posted run behind the scene). The exception is the Norden/Lofte type when a player prefers the manual release; if so, he will must perform those calculations by himself (some players made an published their charts for manual release with the Norden/Lofte type, long before the patch 4.10). According to my tests carried out several weeks ago, it seems that all bombs have the same FM, regardless of size and country (IRL the bombs' shape and weight are relevant, as well as the launching altitude, GS, OAT, and the wind's speed & direction). As far as I can remember, when the atmosphere model had one only air temperature, the parabolic motion was almost perfect and it was very easy to adjust and to aim the bombsight, and to hit an intended target. But now we have an atmosphere with different OATs at SL which change with the altitude, thus changing the air density dinamically. I.e.: according to the AIS, if the OAT at SL is 25 ºC, we'll have: Altitude (m)___OAT (ºC)___Air density (kg/m3) 0____________25_________1.225__(1.225) 1000_________18.5_______1.115__(1.088 ) 2000_________12_________1.013__(0.966) 3000_________5.5________0.919__(0.858 ) 4000_________-1_________0.831__(0.762) 5000_________-7.5_______0.75___(0.676) 6000_________-14________0.675__(0.601) 7000_________-20.5______0.606__(0.533) * (The values into brackets are the air density at different altitudes considering a constant OAT = 0 ºC). We could supose that any bomb released from a given altitude (say 6000 m), when t = 0, will have a constant horizontal velocity v = TAS (a/c), and an increasing vertical velocity u which range from 0 up to its final value. But both velocities will change with air densitý as the bomb is falling. Therefore, its path will not be perfectly parabolic as we could expect in a 'Newtonian Universe'. Perhaps all bombs have the same in-game's FM... but they might work in a different fashion than that known before the patch 4.11. Another factor which produce offsets between the aiming point and the hit point is how leveled flies the aircraft. If the pilot flies with the Level Stabilizer engaged, the aircraft may be flying at a steady altitude... but if its elevator is trimmed to avoid the 'sinking', probably its Angle of Attack (AoA) is not 0. The pilot will not be noticed about how is the AoA (the pitch), because the artificial horizon doesn't work when the LS is on, and because we haven't an 'AoA gauge' like the modern aircrafts have. Thus, with that configuration, when the bombsite is at 0 º elevation, really it will be aiming at 'AoA' elevation. I.e.: if the AoA is +3º, this angle adds to the bombsight elevation. A bombardier aiming to a target with a BS elevation = 50º, really is like if he would be setting an elevation of 53º, and then he adjusts the TAS and/or altitude to fix the target under his crosshair according to that wrong angle... which will worsen the final outcome. A difference of 3º may seem a small thing; but if we make same calculations according to the equations you've posted: Wrong elevation = 53º (the bombardier believes the elevation is 50º) tan (53º) = 1.327 Right elevation = 50º (if the aircraft would be flying perfectly leveled) tan (50º) = 1.192 According to your eq 7, D(53) = 5000 x 1.327 = 6635 m D(50) = 5000 x 1.192 = 5960 m As you know, the most of players engage the Auto Release when the elevation is about 50º. Even if the crosshair is fixed over the target (what would be rare in this case), the bombs will fall about 675 m short because of the early release. ... Other unavoidable errors related with the type Lofte/Norden BS: This bombsite has not a 'coarse/fine' setting, but one only mode with 2 fixed rates: one for the TAS and the other for the altitude. The rate for altitude is 50 per keystroke, and that for TAS = 10 per keystroke. But, depending on the chosen bomber, we have the following combinations: - German bombers: TAS rate = 10 km/h; altitude rate = 50 m. - Allied bombers: TAS rate = 10 KTS; altitude rate = 50 ft. - Japanese bombers: TAS rate = 10 KTS; altitude rate = 50 m. Thus, 1 keystroke of TAS in an Allied bomber BS is almost equivalent to 2 keystrokes in a German bomber; and conversely, 1 keystroke of altitude in an German bomber BS is almost equivalent to almost 3 keystrokes in an Allied bomber. In short: German bombers allow more accurate TAS settings than the Allied, but the latter allow more accurate altitude settings than the German. Other errors come from the instrument readings: sometimes the pilot visually must interpolate between two marks, and can be difficult to decide if he's reading a value of 12,600, or 12,700, or 12,800... I'm wanting to emphasize that, even if the calculations were very accurate, the game interface makes it impossible to apply them exactly. ... This evening I'll try to perform more tests, as you've suggested: one with a Russian bomber, and other with a German bomber at least. See you later! 
Last edited by Soldier_Fortune; 10-02-2013 at 05:18 PM. 
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#2
10-03-2013, 02:18 PM
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In short................
Something don't add up with current Bombsite data/settings/interface. Some TD input would be favorable as to what they did or didn't do. Good luck with the Russian Bombsite testing.
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#3
10-03-2013, 07:23 PM
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I don't know much about Bombsights, but wouldn't they at least include some kind of water level to allow for the bombardier to set it facing downwards -no matter what AoA the plane has?
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#4
10-04-2013, 11:24 AM
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Well... I've performed two tests: one with a Pe-8 and other with a He-111, flying in the Moscow 1 (winter) map.
Both tests confirm all what I was telling until now: the TAS, when used as settings for the BS, are different than those indicated by the actual charts, and they regards on the OAT and the altitude. The attached file contains tracks of both tests. Quote:
It doesn't add up if you compare the tests' outcomes with the actual charts. But these tests show the internal consistency of the in-game's atmosphere model. BTW, I've found the actual charts are not completely useless after all. Yesterday, checking speeds at different altitudes higher and lower than the range from 4000 to 5000 m, calculating them with the wizz wheel and comparing my results with the charts, I realized that those charts were made for an OAT = 25 ºC @ MSL. Thus, they may be used only with the following maps: Iasi (on line) Crimea Kiev Balaton Hawaii Midway Kuyshu Net 8 Islands The bad news is that there are other 56 maps in the game, covering a range from -20 upt to +30 ºC. If the new charts were made for starting OATs from -20 up to +30 in steps of 5ºC each, it would mean 11 charts to cover all the maps (plus other maps included in some mods). But then it would be necessary to considere all the Altitud/IAS/TAS combinations: - Altitude in m and IAS/TAS in km/h (Germans, Russians, Italians) - Altitude in ft and IAS/TAS in mph and kts (Allies) - Altitude in m and IAS/TAS in kts (Japanese) This gives us... 33 different charts!!  Do you really think the players would feel comfortable managing so many papers? IMHO, perhaps it would be better and easier to learn how to use the E6-B, or an app like pilotwizz.  Back to my last tests: the bombs fell faily close to the target. At this point I'm considering that perhaps the altitude (used as input for the BS) should be corrected by OAT, instead of using directly the indicated altitude, to get a better accuracy. Which leads us back to the question with wich I started this treath: What should we use: the indicated altitude, or the corrected ('true') altitude? It's very easy to check the TAS: we have some aircrafts with IAS/TAS guages. But we haven't other than the barometric altimeter... so, if TD doesn't fire a starshell for us, more testing will be needed.  ..................... Edit: The page doesn't let me to upload the zip file containing the tracks. Perhaps tomorrow... 
Last edited by Soldier_Fortune; 10-04-2013 at 06:38 PM.
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#5
10-04-2013, 11:59 AM
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Quote:
The OKPB-1 Bombsight (Russian) has a bubble in its centre, wich indicates whether the aircraft is flying flat and leveled or not. The other bombisghts don't have a similar device. The real Norden BS had an autopilot wich, when it was engaged, kept the bomber on the right path. In-game, that autopilot is not modeled. Instead, the Level Stabilizer helps the player with respect to that. But the LS shouldn't be considered a 'solution' to level a bomber from any situation, but just a help. This means the player must be sure that the bomber is flying flat and leveled at the right speed, altitude and heading, before engaging the LS to lock the airctraft on the desired configuration. To achieve this, the player must know the behavior of his bomber at any altitude and must to know how to trim it properly.
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#6
10-05-2013, 11:06 AM
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I've already stated the charts are not totally inaccurate,
but using Bombsite data even with a wizz wheel or Pilotwizz the bombs still drop longer/shorter than they should, even when you taken have in to account ground elevation of the target, I still have to use a "feeling" of where the bombs "might" hit instead of accurate an bombing solution with the correct input data. Tested ac: Pe2 IL4 The payloads on these aircraft all drop long as pointed out in an earlier thread >> http://forum.1cpublishing.eu/showthread.php?t=40740 He111 Payload drops short of aiming point, where as they used to run in from the start point of the bombsite. The SC50 track is interesting as it hits before the aiming point and then long as you would expect from 32xsc50's But as I have already said also, these bombsite shouldn't be too accurate, but some explanation the payload drops inconsistency would help matters, be it the air density changes or other factor. . Last edited by KG26_Alpha; 10-05-2013 at 12:07 PM.
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#7
10-06-2013, 07:31 AM
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Hi...!
Finally I could upload my last tests: one with a Pe-8 and other with a HE-111. Today I may not see your tests because I haven't IL2 installed in this computer (perhaps tonight or tomorrow). BTW: what maps have you used? It is importan to know it.
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#8
10-07-2013, 12:52 PM
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Quote:
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Hybrid Mode
