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Author Topic: Will this calculator help bombardiers who love level bombing?  (Read 6117 times)
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KU_jijii
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« on: January 28, 2012, 12:55:47 AM »

I made a calculator for bombers when we do formation level bombing in manually-operated, without automatic bomber site.
http://www1.bbiq.jp/~zhukov/calc/calc.html
Il-2 game does not seem to calculate air resistance.
An angle include air resistance is optional when the dropping bomb model with air resistance come out in future.
By the way, I want to know the temperature of each maps, so I made a script to read the map attributes from load.ini files.
I unpacked fb_maps*.SFS and up_maps*.sfs files, but it seems all load.ini files do not exist in there.
This table.
http://www1.bbiq.jp/~zhukov/calc/T_Il2_MapAttr.html
Where are the load.ini files of MOD maps?
I posted same question to the Ultr@Pack forum a few days ago, but I did not receive a answer.
Do someone know the answer of my question?

Edited...made into a sticky for you KU_jijii
« Last Edit: January 30, 2012, 08:13:00 AM by RAF238thGunRunner » Logged
wespe
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« Reply #1 on: January 28, 2012, 08:18:03 AM »

Interesting work, Jijii, very interesting work.
  I've spent about three hours now playing with your calculator comparing numbers.  Very nice, Sir.
  Map temperatures:  I was never really able to get into the files... about the best I could do was to put a bomber on the ground and read the gauge.  Odd thing.  For Pacific theater maps both the He111 and Ju88 read 25c degrees for ground temp, but at 5,000m altitude, the He111 reads -10c and the Ju88 reads -3c.  What's worse, the Bf110 reads -25!
  It's a shame there is so much inconsistency with some of the data and planes in this sim.  Like the SM-79...  the air speed indicator in the cockpit reads, if I remember correctly, 10kph different than what it shows in the bombardier's position.  The only way to get good bomb data for that plane would be through trial and error as to which gauge is the accurate one.
Quote
Il-2 game does not seem to calculate air resistance.
  It does to a degree.  There's more resistance for an external load of two 500kg bombs compared to one 1,000kg bomb, but if you mean does the sim take into account the different air densities at altitude and how it affects the trajectory of the falling bomb I don't know.  A load of 60kg or 100kg bombs will scatter more laterally when dropped from higher altitudes, but I'm sure you know that. 
  Does wind cause an effect on bombs?  I don't know.  I've never taken the time yet to run tests, mostly because if it did, I'd probably be unable to work out a way to consistently compensate for that effect.

  Anyway...
  Very good work, Jijii.
  I've built a nice shrine in your honor here on my desk.       
 
     



 
 
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KU_jijii
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« Reply #2 on: January 28, 2012, 09:36:45 AM »

Salute Sir Wespe, thanks for replying.
I am glad it helps you, and I thank you tested it at the cost of your precious time.
I am interested that each planes indicate different numbers, I did not know that.
About air resistance, I tried the angles with air resistance a few times, but all bombs missed.
In fact, the air resistance drag coefficient will be more larger, for examples it is 0.24 at the skydiving.
Though I do not know coefficient of the bomb, a drag coefficient of P38 is about 0.0268, as far as I looked up.
About wind, I could not examine it yet, but I will do sometime.

I am grateful you are interested in my calculator, Arigatou Gozaimasu!
Best regards,
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saipan
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« Reply #3 on: January 28, 2012, 11:19:20 AM »

pretty comparable to bombtable 2 isnt it?
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78thFG_Yoshi
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« Reply #4 on: January 28, 2012, 12:41:55 PM »

pretty comparable to bombtable 2 isnt it?

Yes, but better.
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RAF238thGunRunner
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« Reply #5 on: January 28, 2012, 12:42:18 PM »

pretty comparable to bombtable 2 isnt it?

Sounds like it!  We used to use this all the time.
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Sorbifer
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« Reply #6 on: January 28, 2012, 12:56:33 PM »

If I get the time I will compare it with Il2 Shturman tool, that also uses temperature, bomb loadout/weight and the target altitude, and seemed always better than BT2, but it might be a personal feeling only, no proof. I do appreciate your work, definitely a lot of, but is it possible that you will share your equations, and the calculations you are using?
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OstBlock.
Sorbifer.
Kiepsky.

Dogfight2: Shoot down enemy aircraft and destroy ground forces to progress. Avoid enemy fire and flying into the ground.
wespe
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« Reply #7 on: January 28, 2012, 01:07:28 PM »

  Bomb Table 2 is inaccurate as it doesn't take into account the air temperature differences between maps.  Changes in air density affect the indicated/true air speed ratios ... which is what is used to get the bomb drop angle.
 
  I mean... It's nice if you just want to fly over a city and throw bombs down at it but that's about it.

  Here's some info I posted for a Bomber Night mission a year or so ago. 

 



  What I posted was good enough to hit a 10m wide target (Bf109) from 5,000m altitude and would be good for any map with a sea level temp of +15 degrees.  This data would not get the same results on a different map.
  For example:  At 5,000m, the Slovakia Summer map has an outside temp of -18 degrees.  Slovakia Winter has a temp of -30 degrees.  If you keep the indicated air speed the same when flying both maps, the true air speeds will be different... and it's from the true air speed that you calculate the bomb release angle.   Is it a big difference?  No, maybe 10 kph or so, but if your target is say, a port city, it's enough to make a difference between hitting an oil storage yard or throwing your bombs harmlessly into the harbor.

  To further illustrate:  I just put in the numbers from the pic above into Bomb Table 2 and received a Bomb Drop Angle of 32.43 degrees.  If I dropped at this angle, instead of the 30 degrees that I have listed, the bombs would fall about 200m short of the aiming point... in this case, right into the ocean.

  Like I said, it's a good tool... good for those who aren't too worried about hitting an orphanage instead of a munitions warehouse.
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saipan
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« Reply #8 on: January 28, 2012, 02:39:50 PM »

i always gor for playgrounds and orphanages first.  where do u get the info for air temp?
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78thFG_Yoshi
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« Reply #9 on: January 28, 2012, 02:42:58 PM »

i always gor for playgrounds and orphanages first.  where do u get the info for air temp?

From the map files, I believe.

Although there is a link on the calculator page to this nice collection:  http://www1.bbiq.jp/~zhukov/calc/T_Il2_MapAttr.html
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wespe
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« Reply #10 on: January 28, 2012, 03:41:54 PM »

  To find temperatures, go into Full Mission Builder and bring up the map for the mission in question. 
Example: To find data for the Bansei mission go to the stats page here and click on "missions".  Click on "Bansei" and the new page will show that the map used is Kyushu.  In Full Mission Builder bring up the Kyushu map and build a mission where you spawn in a He111 on a beach or runway who's altitude is close to sea level and read the temperature gauge in the plane.  (I use an He111 as the Bettie, Sally, etc, doesn't have a temp gauge)

  For temperatures at different altitudes, spawn in at say, 5,000m.  Note the temperature there and then start descending, noting the different temps as you lose altitude.     
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VRStick
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« Reply #11 on: January 29, 2012, 07:39:24 AM »

This looks great.  I assume this needs to be run on a web page.  This is a no go for me when flying as alt-tab screws up FFB.  Is there a possibility of making this into an executable that can be pulled up or hid (like BST2) while in the game?
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KU_jijii
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« Reply #12 on: January 30, 2012, 07:08:40 AM »

Salute all pilots, in particular to bomber lovers.
About wind, Wind seems to influence falling bombs. I tried to create a mission with wind of direction 0 degree and velocity 15m/s.
I dropped a 800kg bomb from 6000m, the bomb missed to about 100 meter south. (the distance may not be correct.)
Sir Sorbifer, about a equations, its ok, I will share the formulas.

But these are not my work, I just looked for and collected from the university's site and wikipedia.
Sir VRStick, about an executable program, in fact, I did not know about "Bombsight Table" until heard in here.
I made a simple tool executable one followed BT2.
http://www1.bbiq.jp/~zhukov/calc/BombersCalc.zip
But I do not have confidence in this program. Please read "README.txt" well.
I made also a table generator for bombers.
http://www1.bbiq.jp/~zhukov/calc/calc_create_table.html
It is more safety you print out this table to papers than you use this program.
Anyway, let's enjoy flying and bombing.

Best regards,
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RAF238thGunRunner
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« Reply #13 on: January 30, 2012, 08:08:03 AM »

When you have sorted the whole thing out and it is the final version, we should post it as a sticky on our site in the INFO Centre .

I have made this a sticky in the Pilots Lounge until then.
« Last Edit: January 30, 2012, 08:10:49 AM by RAF238thGunRunner » Logged

KU_jijii
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« Reply #14 on: February 06, 2012, 06:17:21 AM »

Salute all pilots, in particular to bomber lovers.
Thanks for good advice,Sir RAF238thGunRunner.
I made a film for an example of level bombing in wind.
http://www.youtube.com/watch?v=7Y-1XmKOYwU
Using this executable tool.
http://www1.bbiq.jp/~zhukov/calc/BombersCalcWind.zip
This program seems not to work well on windows7 and Radeon video.
On windows7, run-time error 13 happens, this problem sometimes solves using a Vista compatible mode.(not XP mode. I do not know why.)
On radeon video, this tool window could not show over the game, this problem can solve turning the game drawing from the OpenGL to the DirectX mode.
About the my first question of the maps' attributes, it was solved by advice of Hey_Joe and Goanna at the Ultr@Pack forum.
The maps' attribute table came perfect.
http://www1.bbiq.jp/~zhukov/calc/T_Il2_MapAttr.html

By the way, how can I post a new topic at the INFO center?
A button for new post does not seems to exist there.

Best wishes,
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