|
|
#31
10-18-2013, 12:42 PM
|
|||
|
|||
Quote:
I'm gonna test this when I've got time, and if it works then there is potential fun in it, now that i've got the basics of level bombing (and the both of you Soldier_Fortune and KG26_Alpha gave me some hints here why I'm not hitting as good as i wished for -so thanks to the both of you) 
|
|
#32
10-26-2013, 04:32 AM
|
|||
|
|||
|
Howdy. I noticed and started reading this thread about a month ago. Then got extremely busy at work on some end of fiscal year projects that need to get out and just haven't had time to post anything. I don't want to butt in on your research so I won't say too much...you may be like me and love the challenge of figuring stuff out.
But I will say this....true altitude and indicated altitude are basically the same thing. The difference being true altitude would be what a tape measure placed between sea level and your plane would say and indicated altitude would be what your instruments tell you. With modern laser and radar equipment, the difference between the two could be mere inches. In addition to indicated altitude, there are 2 other altitudes you need to bomb accurately. Here's a list of the different altitudes.... http://www.meretrix.com/~harry/flyin...altitudes.html Also, you don't need adaptive bombing. There are definite formulas that are used, but some planes use slightly different values. Also, the IAS/TAS chart that's in the game is only giving you the partial equation...so the values for TAS are usually WAY off. That chart shows the aircraft's speed increasing linearly (on a straight line), but it actually increases on a curve. Fortunately, you don't need a differential equation to calculate it...a simple polynomial is all that's needed. In other words, basic mathematics. LOL And yes, OAT (Outside Air Temperature) is very important for calculating that curve. With OAT in mind, I recently noticed that the Free Air Temperature gauges on the G4M1-11 Betty are bugged. I've reported it to DT so hopefully it will get fixed. Having air temperature gauges that work properly come in quite handy.  Anyway, I've said enough...but if you guys would like some help, just let me know.
|
|
#33
10-26-2013, 10:09 AM
|
|||
|
|||
|
Hi Jeremiah. Thanks for your interest.
 As I already stated, in this sim there is not difference between Indicated Altitude (the altimeter reading) and True Altitude (altitude affected by local pressure and OAT at a given altitude). But True Altitude is modeled in other sims (i.e., LOMAC Flamming Cliffs 2). Will True Altitude be modeled in IL2 in a next future? Really I don't know. But if TD decides to model it, True Altitude will affect the level bombing. In any case, it can be easily calculated with an E6-B, as actually TAS and Ground Speed must be calculated for an accurate level bombing. Quote:
I personally am quite skillfull handling the E6-B and I have no difficulty solving all those equations with it while flying. But, at the same time, I know that may be many players would prefer to have something easier to handle, and I've made that set of graphic charts with that goal in mind (you can download it from the post #30 in this thread: I would like you test them, and then let us know your opinion). But also, in that post, I adress to a link to the 'Warbirds of prey' site where you will find a nice calculator to obtain all relevant data for an accurate manual level bombing, in a more friendly way (for many people, at least) without an E6-B : Ground Speed and bombsight elevation, taking in account OAT and wind. Quote:
But, until it is fixed, you always can calculate the OAT easily; for 'Betty' it is: OAT (ºC) = Tmap (ºC) - 0.0065 (ºC/m) * IALT (m) Quote:
|
|
#34
10-26-2013, 10:33 PM
|
|||
|
|||
|
Howdy SOF.
If you enjoy catching someone parked on an airfield 5000 meters below you or just like being able to drop an egg on your target and hit it, then you'll enjoy this. It looks like you already know these maps are somewhat based on ISA (International Standard Atmosphere) and also that temp rises by .0065 deg C per meter. Also, that 15 deg C is the temp at sea level for ISA normal, at least for one, so I don't really need to go into any detail about that. (I believe there is another ISA that starts at 0 deg C, but we'll ignore that one) So, on to one of the formulas. While looking at the IAS/TAS chart, I was able to derive a formula that came up with their numbers: (IAS * .0657 * (ALT/1000)) + IAS = TAS I quickly realized that this formula didn't take into account changes in OAT (Outside Air Temperature) and it wouldn't have been on a curve...so I modified it. What I came up with is this: ((IAS * .066 * (ALT/1000)) + IAS) * (1 + ALT/100,000) = TAS Using real numbers, let's say you had an IAS of 260kph and an (indicated) altitude of 4850m. The equation would look like this: ((260 * .066 * 4.850) + 260) * (1.04850) = TAS In operation, you would multiply the 260 by .066 then multiply that by 4.850, then add the 260 to arrive at a temporary airspeed. You would then multiply the temporary airspeed by the 1.04850 to arrive at your TAS. Now, here's the deal. The .066 factor is only for some planes, like the B5N1 Kate (my favorite bomber). Russian planes like the Pe-8, the IL-4 and some others use .084. The He-111 H-2 uses .026 and the H-6 uses .046. Also, this formula is used on other maps where the temperature is different (above or below ISA), but it's calculated differently. Namely, you'll be calculating for density altitude. But I'll get into that later on. I tested this formula by using the Gulf of Finland 1 (summer) map, since it was ISA normal. I used the Island of Lavansaari/Moschnyi as a base and put several air starts in grid AV-11 to the east of it, ranging from 1000m all the way up to 6000m. I also put a sizable group of cargo ships in grid AR-11 to the west and also placed a "destroy ground" icon in the middle so I could see it on the map well before I could see the ships. The distance gives you time to trim your plane (especially the rudder) and get it stable at altitude without any control inputs before kicking in "auto level". I also cut back on power and prop pitch...some planes not as much as others. Also, I found that as altitude increased, accuracy started to suffer, although not as much as you would expect. I'm still able to zero a freighter at 6000 meters alt with that big ole 5000 kilo monster the Pe-8 drops. Anyway, if you want, get set up on that map and get used to running the numbers on your way to the target. Then, when you're ready for temperature changes, let me know. Additionally, I think a calculator will do you much better than your E6B due to the variations in the velocity factor. (.084, .066, .046, .026, etc)
Last edited by Jeremiah_Weed; 10-27-2013 at 04:47 AM.
|
|
#35
10-27-2013, 05:30 AM
|
|||
|
|||
|
Also, I forgot to mention, if you're testing out the Lofte/Norden type bombsights there's a trick to them. Don't try to track your target forever. They aren't designed for that. Only track your target about 3 or 4 degrees at the most. For instance, if you find the bombs release around 35 degrees at a given altitude, manually move the bombsight angle no farther than 38 or 39 degrees. As your sight moves over the target, enter it into auto mode and let it do its job. If you don't try to track your target forever, they're just as accurate as the OKPB-1 sights.
You can also "tweak" it a bit before you enter into auto mode. If the actual TAS is 2 or 3 kph HIGHER than what you entered as the bombsight velocity, you can move the bombsight altitude DOWN 10 or 20 meters in elevation for fine adjustment. The reverse is also true. Note: The Betty uses this type of bombsight and its velocity factor is .046. Bombs away!
|
|
#36
10-28-2013, 07:09 PM
|
|||
|
|||
|
As time permits, I'll post a more sophisticated formula. The one I posted starts to become inaccurate above 6000 meters. The last factor needs to have a Delta/Rate of Change factor in it to slow down the rate of increase, which usually requires the use of exponential function. I've purposely avoided that because I'm not sure most players would enjoy having to (or be able to) work the equation.
This one is relatively simple and still allows you to hit your target the majority of the time and have some fun...and fun is what it's all about.
|
|
#37
10-29-2013, 08:08 PM
|
|||
|
|||
|
Hi again Jeremiah
I would like to coment some points of your posts: Quote:
In all of them the OAT decreases from the given free air temperature @MSL at a lapse rate of -6.5 ºC/km_altitude. It can be checked reading the OAT gauges in diferent planes, while flying whatever map. Under ISA, the lowest temperature of the troposphere is -56.5 ºC; and, for the standard condition (15ºC @MSL), that temperature is constant from 11,000 m up to 25,000 m. But, what if the OAT @MSL is not the standard? Well... if the OAT @MSL is greater than 15ºC you will find the lowest temperature at a higher altitude than 11,000 m; and if the OAT is smaller than 15ºC you will find the lowest tropospheric temperature at a lower altitude than 11,000 m. Since the OAT at a given altitude affects the air density, it also will affect the TAS. Quote:
Is it the kown IAS/TAS chart used since 6 years ago? - 2nd: Both of your equations give a TAS higher than that obtained with the ISA's equations, or than that measured in-game. I.e.: altitude = 5000 m; IAS = 250 km/h; OAT = -7.5 ºC (25 ºC @MSL) With your 2nd equation, TAS = 349 km/h With an E6-B, TAS = 320 km/h With the published IAS/TAS chart, TAS = 332 km/h With ISA equations: 319,5 km/h It's easy to check what TAS is right: at least there are 2 aircrafts equiped with TAS gauges: Me-262 and B-25J. Any pilot can ride them to fly at that altitude over Crimea, and read both IAS and TAS. 3rd: Regardless the mathematical method used to relate variables, constants of proporcionality found or made during the process must be consistent with what those variables are representing. That formal consistency must cover the measurement units also. ((IAS * .066 * (ALT/1000)) + IAS) * (1 + ALT/100,000) = TAS I gather 0.66 is measured in 1/km in the above equation, and 1000 is measured in m/km. In this way the first parenthesis gives outcomes in km/h, and it is consistent. Right? But... what does 100,000 within the second parenthesis mean? If ALT is measured in meters, 100,000 must be measured in meters also, because 1 in this case has not dimension. But then, why "100,000" and not any other arbitrary value? If "100,000" would mean "100,000 m", it is far beyond where our planes can fly... and I see no reason to consider a value of altitude unattainable for any aircraft, including the most modern ones. 4th: You've found diferent constans of proporcionality for diferent planes: 0.066 for B5N1; 0.084 for Russian bombers; 0.046 for G4M11; 0.026 for He-111 H2 and 0.046 He-111 H6... In few words: a diferent constant for each bomber, for one only map, and for altitudes below of 6000 m. Perhaps I'm unable to get your point but... why one should use so complicated methods instead of the more realistic and simple ISA equations, already implemented in any 'wizz wheel' or in the 'Warbirds of prey' calculator? And: will those constants be valid when you enter the wind? Quote:
 ) OK... You've been working very hard and I hope my comments are not offensive for you. But, under my own experience, I see you might be getting into a method of analysis which may give you more problems than solutions, despite its apparent simplicity.  See you soon.
Last edited by Soldier_Fortune; 10-29-2013 at 08:11 PM.
|
|
#38
10-30-2013, 05:08 PM
|
|||
|
|||
|
Howdy SOF
Let's see if I can clear up some confusion here. Regarding your question about the 100,000 figure. It is NOT a measure of any distance or altitude. It's simply a mathematical value that let's you know you are converting the altitude to a decimal to be used in the equation. Also, with regards to me perhaps over-complicating things, I'm actually attempting to do just the opposite. Take a second and look up the wiki article on the E-6B (whiz wheel) calculator. See the equations? For me, those are quite manageable...they're basic trigonometry. Something I have to use every day. But I don't think most players would enjoy number crunching them on their way to a target. While still on the subject of the E-6B, I'm assuming you have been unable to obtain good accuracy using it and that's what prompted this thread. Am I correct? In fact, I'm thinking the different values like .084, .066, .046, etc., are being used to PREVENT the use of an E-6B calculator. Also, I don't think the numbers my equations are coming up with are the actual TAS of the aircraft, it's just the numbers the game is using to drop bombs. I'm thinking they have taken "special liberties" with Newtonian physics (classical mechanics) in the game and that bombs don't precisely follow established flight paths based on actual physics. Also, why are you using a Crimea map? Remember, in the scientific method you need to establish a control group and establish some baseline figures. To do that, you need an ISA neutral map (15 deg C) that allows bombing at sea level. There were only a couple of maps that allowed that; Gulf of Finland 1 and a generic Island map. The Crimea map is 25 deg C which is 10 deg C above ISA and you would need to factor in the difference in density altitude...which can be done with my equation. (But I haven't revealed how yet.) I am curious however. I'd love it if you set up for bombing on an ISA neutral map (15 deg C) with your targets at sea level just to see if you get any accuracy using your E-6B with various types of aircraft. Also, your comments are not offensive. Not even slightly. So don't worry about that. As for my method, I have a background in engineering, applied science and production engineering, and geology. I work for a company that provides technical and material assistance to the mining industry. I spend a large portion of any given month conducting failure analysis, so trust me, my methods are geared towards finding out why things aren't working properly and finding simple solutions rather than over-complicating things. There's a method used in engineering called the KISS method....it means Keep It Simple, Stupid. LOL And I live by it. Anyway, back to work. Things will be quite hectic from now until end of the year, but I'll try to re-work that equation to add a Δ (Delta) factor in which will slow down its rate of increase...and avoid trig or calculus. Also I'm thinking the factors like .084, .066, .046, etc., may be the factor that needs to change with density altitude. But we'll see. Oh, I almost forgot, the IAS/TAS chart I'm looking at is the one supplied with the game. It should be in the main folder as a .pdf file. You can also view a copy of it online. While running the numbers, I also noticed that things started to change once you reached 10,000 meters altitude, so I quickly realized they were taking into account changes that occur once you start entering the stratosphere. Anyway, if you can, please let me know what you find out using an E-6B on an ISA neutral map. I am curious about that. Last edited by Jeremiah_Weed; 10-30-2013 at 06:04 PM.
|
|
#39
10-30-2013, 08:15 PM
|
|||
|
|||
|
Quote:
I was waiting for an official reply from TD but I'm not sure there will be one or if they understand whats going on in the game. . Last edited by KG26_Alpha; 10-30-2013 at 08:23 PM.
|
|
#40
10-31-2013, 05:17 AM
|
|||
|
|||
|
Howdy Alpha.
Thanks for joining back in. I was wondering if anyone had come to that conclusion. Also, it looks like you are unable to get satisfactory accuracy across the board with all types of planes using the E-6B, or in your case, the Pilotwiz. During a break at work today I was pondering this issue. I came up with an idea to test if the game is actually using classical mechanics when it comes to dropping bombs. It won't tell you that it is using classical mechanics, but it will tell you right off if it isn't. (The only way to know that it IS using classical mechanics is to measure precisely the distance from drop point to target and the time from drop to impact.) Here's the test: Set up a map with 3 or 4 bombers of different types spawning at the same altitude and speed, all following a parallel course in the same direction. The target for each would be a ship, which would also be placed even with each other (abreast, juxtaposed) along the planes flight path. I'm thinking the skill level for the pilot/bombardier should also be set to ace. The planes would need to use different factors. I know the B5N1 and the Pe-2 use .066. All the other Russian bombers use .084. I think the Betty uses .046. And I think I listed some of the others above. Anyway, so you'd have one of each. So maybe a Betty, a Pe-8, an He-111, and maybe a Ju-88. Now, in classical mechanics certain things would be inevitable. You would not need to move the ships out of being in a line abreast in order for the bombs to drop at the same time...since they would all follow the same flight path, AND, they would all hit at the same time since gravitational acceleration (constant) would be the same. There are only a few things that could cause a different flight path: increased drag, something like a rocket motor applying thrust, and/or control surfaces. So unless you're dropping a para-bomb or one of the FritzX types, this should be a good test. If you have to move the ships or they (the bombs) don't hit at the same time, then the gig is up. I won't be able to try this until this weekend, but hey, if you have a chance and the time, give it a whirl and post the results. Maybe this is an unreported bug, but my gut tells me they did it on purpose. Again, thanks for posting in with your info.
|
 |
|
|
Linear Mode
