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MOH_GUMBY
01-05-2005, 02:29 PM
Gents...
Does anyone know how to correct the error that is in the B25 bombsight so that one can input the data and have it drop on target?

Gumby

MOH_GUMBY
01-05-2005, 02:29 PM
Gents...
Does anyone know how to correct the error that is in the B25 bombsight so that one can input the data and have it drop on target?

Gumby

antifreeze
01-05-2005, 08:20 PM
There is no error as far as I'm aware.
The bombsight uses feet and mph, rather than meters and kmph.

If you assign a key for 'toggle speedbar', pressing it during the game will toggle through metric/nautical/imperial measurements.

Eg. the speedbar shows:
3000m = 9840feet
250kmph (Indicated Air Speed) = 135 mph (IAS)

But then you need to get the True Air Speed, which is always a little more than the corresponding IAS. How can you convert mph IAS to mph TAS (as the conversion chart that comes with the game on CD2 is only in kmph)?

method 1
White Tigers Squad made a little program that does the conversion for you. Get it here:
http://wtigers.wz.cz/ -->VSTUTPE -->DOCUMENTY (left nav)-->DOWNLOADS (top nav)-->bombsight table
I noticed that the kmph to mph conversion is actually kmph to knots, but that's ok, because the bombsight seems to work with nautical miles per hour too! Although it seems to like an additional 10 or 20 knots added to the converted figure that the WTBT gives you.

method 2
There is a dial in the cockpit that seems to show IAS in mph. But I don't think this is useful, because the bombsight seems to work with knots. Anyway, it doesn't seem very accurate and it even looks as though the modeller messed up the graduations a little(?). Best to get mph from the speedbar if you have it enabled, although if the bombsight uses knots then there is no reason to know the mph IAS.

method 3 (I use this method)
Don't bother converting.
Dial in the IAS in knots (using the speedbar reading), and add about 40 knots. Press 'auto' when the reticule is over the target. If the reticule starts moving down from the target, decrease the dialled speed a little until the sight tracks on target again. If the reticule starts moving up from the target, increase the dialled speed a little until the sight tracks on target again. Try to get it steady and then leave the dialled speed alone long before the bombs actually drop. Nevermind that the speed you dial may not correspond with a speed given on a chart. As long as you have worked out the average speed well before the bombs drop, the auto-drop will calculate the angle to release at.

I find that height matters much more when your target is inland, especially on a mountainside. Usually I'll roughly guess the dialled speed and leave it alone, instead changing the height to keep the reticule on target. Again, I don't worry if the height is nowhere near my speedbar height.

MOH_GUMBY
01-05-2005, 08:44 PM
antifreeze...

Sir, I do use feet instead of metric, and I also use the bombsight table program. I am sure that I am setting the alt, speed etc correctly as when I fly the HE I can drop the bombs where I intend.

But in the B25 they are very erratic and most often fall short. Before the 3.03 the sight had a bug and it must still be there.

Gumby

J_Weaver
01-05-2005, 08:46 PM
Check out www.airwarfare.com (http://www.airwarfare.com) it has a nice guide and a great manuel bombing chart.

AWL_Spinner
01-06-2005, 03:23 AM
You're not going mad, I agree, the B25 bombsight is wonky.

It's been said on here before that the correct TAS input for the B25 is actually about TAS minus 10%.

This seems to work.

For instance, 13,000ft at 200mph IAS the TAS should be about 250mph but for accurate strikes it's actually about 230mph.

It's not ideal, but it's a working solution.

I've mentioned this in my guide (see sig) together with a TAS correction table.

Its possible it is working in Knots rather than MPH as it should.

antifreeze
01-06-2005, 06:24 PM
Hmmm.. after testing using the conversion method:

If you use knots rather than mph, the B25 bombsight seems to be just as accurate as the HE111. You have to adjust the B25 sight a little, but in the HE111 I also find myself adjusting 10-20kmph away from the given conversion to keep the sight on target.
However, I did note that whilst the HE111 usually required a decrease from the given TAS, the B25 more often required an increase fromthe given KTAS.

Strangely, I think the problem might be that the HE111 bombs have a different 'flight model' and possibly a different damage model to the B25 loadout.
I repeated the same mission about 20 times in the B25; set-up and release was almost exactly the same each time, but the bomb's flight-path was not consistent; they fell quite unpredictably within a 75m-100m radius from 5000m high.
The HE111 bombs were more consistent, and on top of that near-misses seemed to damage ships more than the B25 near-misses did.

Possible?

MOH_GUMBY
01-06-2005, 08:36 PM
Spinner...

Sir: When you that you think the B25 is in knots... Do you mean the cockpit gauges read MPH when in fact they are knots or do you mean that only the bomb sight input speed is registering in knots instead of MPH?

Gumby

WWSensei
01-06-2005, 09:05 PM
Yes, despite the fact the speed indicator says MPH and the input should be MPH for the B-25 it seems there was an error and you must input KNOTS instead.

CSS_Hayzee
01-06-2005, 11:11 PM
I've been having the same problem with the He-111 since PF....bombing at set altitude with TAS from chart....and dropping short. Before PF could put it in a pickle barrel every time.
http://forums.ubi.com/images/smilies/354.gif

AWL_Spinner
01-07-2005, 03:55 AM
Gumby,

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>When you that you think the B25 is in knots... Do you mean the cockpit gauges read MPH when in fact they are knots or do you mean that only the bomb sight input speed is registering in knots instead of MPH? <HR></BLOCKQUOTE>

I mean the cockpit gauges read correctly in MPH. The sight says it's input is in MPH but given the fact it's circa 10% off at altitude I think it likely that it's taking input in Knots (a Knot being about 0.87 of a MPH).

That seems to work reasonably well anyways. It'll be a shock if they "fix" it in 3.04!

VO1-VC
01-07-2005, 06:06 AM
Statute mile vs Nautical Mile.

The following information may be useful for those who fly bombers. I fly the B-25 for the most part, and the bomb sight is quite accurate when you input the data in feet and knots as previously described by Antifreeze

REF: http://www.aerospaceweb.org/question/history/q0139.shtml

"The mile most of us are familiar with goes by the more official name of land mile or international mile. By an international agreement made in 1959, it is defined to be precisely 5,280 international feet, 1,609.344 meters, eight furlongs, or 1,760 international yards in length. The US also makes use of a "survey mile" or "statute mile" that is equal to 5,280 survey feet and is longer than the international mile by only a quarter of an inch. The US statute mile was enacted by Congress before the international mile had been established and has been retained by the U.S. Coast and Geodetic Survey. The term "statute mile" comes from the fact that its length is specified by law. The term originated in England when the definition of the modern mile was decreed by Queen Elizabeth I, who redefined the mile from 5,000 feet to its present length of 5,280 feet."

"The nautical mile is almost exactly the same concept, except that it is equal to one minute of arc along a great circle of the Earth. A great circle is a circle on the surface of a sphere that has the same diameter as the sphere. What does that mean? The Earth itself is an imperfect sphere since it is slightly flattened at the poles. If you were to measure its diameter at the equator and its diameter at the poles, you'd find that the equatorial distance is greater by about 142,181 feet. Because of this difference, a geographical mile along the equatorial circumference would be 6087 ft long but the same mile along the polar circumference would be only 6066 ft in length. The great circle of Earth instead assumes that the Earth is actually a perfect sphere, and the differences between the equatorial and polar circumferences are averaged out."

Ok, for IL2 and other sims keep in mind that most maps show statute miles, the unit of measurement for distances on land. Distances at sea and in the air are most often measured in nautical miles. It makes navigation much easier. However, when you mix nautical and statute with metric, it can get quite confusing. You can convert statute miles to nautical miles by dividing the number of statute miles by 1.1508.

VO1-VC/Nominal

MEGILE
01-07-2005, 06:14 AM
Interesting read gents.
As someone who is new to using the bombsight, I had found the bombsight to move faster than the target in the B-25, but not in the HE-111.. and you have presented the explanation http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Zayets
01-07-2005, 06:27 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Antifreeze:
There is no error as far as I'm aware.
The bombsight uses feet and mph, rather than meters and kmph.

If you assign a key for 'toggle speedbar', pressing it during the game will toggle through metric/nautical/imperial measurements.

Eg. the speedbar shows:
3000m = 9840feet
250kmph (Indicated Air Speed) = 135 mph (IAS)

But then you need to get the True Air Speed, which is always a little more than the corresponding IAS. How can you convert mph IAS to mph TAS (as the conversion chart that comes with the game on CD2 is only in kmph)?

_method 1_
White Tigers Squad made a little program that does the conversion for you. Get it here:
http://wtigers.wz.cz/ --&gt;VSTUTPE --&gt;DOCUMENTY (left nav)--&gt;DOWNLOADS (top nav)--&gt;bombsight table
I noticed that the kmph to mph conversion is actually kmph to knots, but that's ok, because the bombsight seems to work with nautical miles per hour too! Although it seems to like an additional 10 or 20 knots added to the converted figure that the WTBT gives you.

_method 2_
There is a dial in the cockpit that seems to show IAS in mph. But I don't think this is useful, because the bombsight seems to work with knots. Anyway, it doesn't seem very accurate and it even looks as though the modeller messed up the graduations a little(?). Best to get mph from the speedbar if you have it enabled, although if the bombsight uses knots then there is no reason to know the mph IAS.

_method 3_ (I use this method)
Don't bother converting.
Dial in the IAS in knots (using the speedbar reading), and add about 40 knots. Press 'auto' when the reticule is over the target. If the reticule starts moving down from the target, decrease the dialled speed a little until the sight tracks on target again. If the reticule starts moving up from the target, increase the dialled speed a little until the sight tracks on target again. Try to get it steady and then leave the dialled speed alone long before the bombs actually drop. Nevermind that the speed you dial may not correspond with a speed given on a chart. As long as you have worked out the average speed well before the bombs drop, the auto-drop will calculate the angle to release at.

I find that height matters much more when your target is inland, especially on a mountainside. Usually I'll roughly guess the dialled speed and leave it alone, instead changing the height to keep the reticule on target. Again, I don't worry if the height is nowhere near my speedbar height. <HR></BLOCKQUOTE>

I remember there was even a formula back then when Oleg gave us the He-111. I lost it somewhere between formats. It was something calculated with the height and speed and that gave the angle of the sight when you should release. That will be a good adition to this thread.Maybe someone remembers?

VO1-VC
01-07-2005, 06:59 AM
1. Read your indicated airspeed (IAS) on your airspeed indicator.

2. Get your altitude above Mean Sea Level (MSL) on your altimeter.

3. Mathematically increase your indicated airspeed (IAS) by 2 % per thousand feet of altitude to obtain the true airspeed (TAS).

Example:
The indicated airspeed (IAS) at 8,000 ft. MSL is 170 knots.
2 % of 170 kt. = 3.4 kts.
The calculated TAS at 8,000 ft. is 170 kts. + (8 x 3.4 kts.) = 197.2 knots.

Here is a Java calculator site where I got the above info:
http://www.csgnetwork.com/tasinfocalc.html

VO1-VC/Nominal

Zayets
01-07-2005, 02:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by VO1-VC:
1. Read your indicated airspeed (IAS) on your airspeed indicator.

2. Get your altitude above Mean Sea Level (MSL) on your altimeter.

3. Mathematically increase your indicated airspeed (IAS) by 2 % per thousand feet of altitude to obtain the true airspeed (TAS).

Example:
The indicated airspeed (IAS) at 8,000 ft. MSL is 170 knots.
2 % of 170 kt. = 3.4 kts.
The calculated TAS at 8,000 ft. is 170 kts. + (8 x 3.4 kts.) = 197.2 knots.

Here is a Java calculator site where I got the above info:
http://www.csgnetwork.com/tasinfocalc.html

VO1-VC/Nominal <HR></BLOCKQUOTE>

You are 100% right , but what I meant is that there was a formula giving the sight angle when to release calculated by speed and height. I know I have seen this formula (although I don't use it when doing bombing runs) and is pretty useful when you wanna get a feel about your aircraft.Practicing , all that stuff.

Zayets
01-09-2005, 07:26 AM
Therefore,nobody knows or remember.Guess I have to dig up a lot in the forums achive.

MOH_GUMBY
01-09-2005, 09:17 PM
Gents....

OK.... I have been using that little bombsight program and converting the tas to knots for use in the bombsight, but I still cannot get good accuracy.

At 15000 feet and 180 ias what should I set the speed at in the bombsight?

Gumby

WWSensei
01-09-2005, 10:30 PM
~265 knots.

UPDATE: I replied with the TAS in mph when it should have been the TAS in knots. 234 knots TAS is the correct answer.

StellarRat
01-09-2005, 11:56 PM
Sensai is wrong. Set it to 230 or 240. If you put 260-270 in there I guarantee you'll hit way short of the target.

ZG77_Lignite
01-10-2005, 09:24 AM
I don't mean to hijack the thread, but what would be considered historically correct accuracy for medium and/or heavy bombers from 15000-25000ft? (or an 'high' altitude).

MOH_GUMBY
01-10-2005, 10:13 AM
Gents..

LOL... no wonder I am confused, so many different thoughts...

15000 at 180 ias using this page http://www.csgnetwork.com/tasinfocalc.html equals a tas of 234 and converted to knots (mph x .87) equals a bombsight setting of 203. At least that is what my understanding of how to use the buggy sight. Do you guys concur???

Gumby

WWSensei
01-10-2005, 10:40 AM
Are you reading 180 mph IAS or 180 knots IAS? A 180 knots IAS would be 269 mph TAS or 234 knt TAS.

MOH_GUMBY
01-10-2005, 10:49 AM
Sir..

I am readying 180 MPH IAS then figuring the TAS in MPH and coverting that to Knots to input in the bombsight... Should I be doing everything in knots? Guess I am confused on which speed to read or convert to knots..

Gumby

AWL_Spinner
01-10-2005, 12:19 PM
Gumby, at 180 IAS I'd estimate 210 on the B25 bombsight at that altitude so your estimation seems reasonable. Generally I aim for 200mph and I'd be using 230/240.

As to your post above, yeah, you have it correct (read IAS MPH; convert to TAS MPH; convert MPH to KTS for input). Alternatively subtract approx 10%. As the increments on the sight are quite large (10MPH/KTS) it's only an approximation anyway.

The easiest way to check is to lock up your target early (50-60 degrees elevation) and watch how it tracks. If it's tracking too fast (i.e. if the sight is dropping faster than the target moves toward you) then your input is high, try dropping by 10mph (knots!) and see if that improves things. The reverse is also obviously true.

If your sight is tracking true with your target then you should be bang on the money.

antifreeze
01-10-2005, 05:43 PM
Regarding the white tiger's bombsight program...

In my first post I tried to briefly explain that when the White Tigers wrote the program, they had already figured out that the B25 bombsight used nautical miles per hour (knots) rather than statue mph. So their program also uses knots, even though they have labelled it 'mph'.

However, the cockpit dial shows statue miles per hour, so it easier not to use it. Instead toggle the speedbar until it reads 'KIAS'. This is the speed that you will use in the white tiger program; dial that speed into the field labelled 'IAS mph'.

Then dial the corresponding red number (labelled TAS mph) into the B25 bombsight. All you've done is convert IAS knots into TAS knots.

Using your example:
height=15000 feet (above sea level)
speedbar=180 KIAS (which means 'IAS knots')
whitetigers input=180 IAS mph (which is really 'IAS knots')
whitetigers output=232 TAS mph (which is really 'TAS knots') &lt;-- dial this into the B25 bombsight

Note that you have found the correct KTAS for your height above sealevel. But that is not the height that the bombsight wants. It wants the height above the target. If the target is inland, you will have to subtract the estimated height of the land away from the height above sea level, and dial the result into the bombsight.

Personally I think they've modelled the B25 bombsight and/or bombs differently from the HE111. I discovered for instance that the equivilent HE111 bombs are much more powerful (I was comparing the height of the water-spray; much bigger/taller). So if this is different, maybe the bomb-release and 'spread' are different too. I don't think that necessarily means the bombsight is 'porked' though.

MOH_GUMBY
01-10-2005, 09:07 PM
Antifreeze...

Sir:
Thanks for the explanation in your last post. Flying at sea level 15000 feet and about 160 kias I have been getting good results. Sometimes I have to adjust up one click the bombsight speed but not always.

Now to try it in the heat of battle online.

Thanks again for your valuable help.

Gumby

VO1-VC
01-11-2005, 04:56 AM
I have good results with the B-25 Bombsight.

First, make sure the altitude in the sight is exact. Otherwise, the bomb will release early or late - regardless of what else you do.

Second, when the auto-sight is engaged, the cross hairs have to be stationary on the target. Use the bombsight speed setting to "tweak" the cross-hairs to remain stationary on the target.

Then, watch the training video on the He-111 until you understand the importance of having your plane trimmed so the speed is constant, and altitude is constant. They also discuss how to keep the cross hairs stationary on the target.

Last, practice - practice - practice in single player mode. Set up quick missions in the B-25 with no AAA or enemy planes. Once you start hitting bridges and other stuff from way up, the bomber addiction gets worse - lol.

Capt_Pepper
01-12-2005, 08:57 AM
Howdy MOH Gumby......

I will be glad to share what I have learned thanks to input from a few of our mates who are some of the best at this. It's much easier if we go through it on T/S. Please just give me a holler the next time you see me online. I'm very confident that I can help.

If you have a specific time you'd like to meet, just let me know.

Thanks,
Pepper