PDA

View Full Version : Blenheim High-Altitude Level Bombing Guide



Chuck_Owl
Mar-24-2014, 19:47
I did a small guide for Blennie pilots who want to do some high-altitude bombing.

https://drive.google.com/open?id=0B-uSpZROuEd3MDEwaDZXdmNSdnM&authuser=0

Edit: Version 2.0 available for nil wind conditions.

DRock
Mar-24-2014, 20:00
Brilliant, Chuck.:thumbsup:

Thanks for the work you put into this, it's fantastic.

That Gyro trick is useful, huh?


Cheers

Marmus
Mar-24-2014, 20:21
Looks like a great guide! Thanks for your efforts. I will have to read it in depth later on....I may be switching to Red side! I have never flown a Red plane before...but the Blem has always been enticing. Plus I hear lots of people mentioning it more and more.

ATAG_Freya
Mar-24-2014, 21:37
Nice going, Chuck! Well done :salute:



Looks like a great guide! Thanks for your efforts. I will have to read it in depth later on....I may be switching to Red side! I have never flown a Red plane before...but the Blem has always been enticing. Plus I hear lots of people mentioning it more and more.

You can even bring your gunner Fritz! He'll need his flak vest, that's for true. Just don't get caught with any schnapps or people might get suspicious..

Torric270
Mar-24-2014, 22:49
Very nice, will have to try the gyro setup.

Have found recently that the bombsight has a compass on it, I find it much easier to navigate with that then the pilot one.

:salute:

8581

FlatSpin
Mar-25-2014, 00:45
Great stuff. Thanks Chuck. This answers a lot of questions I had.

Chuck_Owl
Mar-25-2014, 01:13
Thank you al for your kind words. I really appreciate it.


Brilliant, Chuck.:thumbsup:

Thanks for the work you put into this, it's fantastic.

That Gyro trick is useful, huh?


Cheers

I'm only as good as my teacher taught me to be. ;)

Archie
Mar-25-2014, 03:22
Thanks! Have not tried the Blennie yet.

Roblex
Mar-25-2014, 03:22
A very good guide. All the things you need to know and nothing extra to confuse people :thumbsup:

One niggle though. When you tell people how to use the course setter you tell them to head South then put the arrow between the two parallel lines with the T heading towards you. This works for this one particular mission but you don't tell them how to align it correctly to avoid flying the reciprocal bearing by accident when flying other bearings. To make matters worse your close-up picture of the compass appears to show the course setter calibrated to '20' when the text says you have already set it to '179' (it is correct in the bigger picture) I think it is important to advise that the 'T' must be at the same end as the red 'N' on the course setter. It might seem obvious but I have seen a lot of people get confused and fly 180 degrees the wrong direction because they did not stop to think that there is a right way and a wrong way.

8582

Chuck_Owl
Mar-25-2014, 07:57
A very good guide. All the things you need to know and nothing extra to confuse people :thumbsup:

One niggle though. When you tell people how to use the course setter you tell them to head South then put the arrow between the two parallel lines with the T heading towards you. This works for this one particular mission but you don't tell them how to align it correctly to avoid flying the reciprocal bearing by accident when flying other bearings. To make matters worse your close-up picture of the compass appears to show the course setter calibrated to '20' when the text says you have already set it to '179' (it is correct in the bigger picture) I think it is important to advise that the 'T' must be at the same end as the red 'N' on the course setter. It might seem obvious but I have seen a lot of people get confused and fly 180 degrees the wrong direction because they did not stop to think that there is a right way and a wrong way.

8582

Ha ha, good eyes! I just wanted to show a zoomed-up picture of the compass (had to find one I took a while ago in my Spitfire) so they knew what the T actually was. In whole cockpit view, it's actually pretty hard to see.

ATAG_Lolsav
Mar-25-2014, 11:35
Good stuff Chuck. You only made me more proud of my "grasshoper". I believe this is how it works, you give and then the community gives you back. Proud you have chosen to contribute on your own way :thumbsup:

1lokos
Mar-28-2014, 11:21
Have found recently that the bombsight has a compass on it, I find it much easier to navigate with that then the pilot one.


In previous patch's this compass had much reflection, are barely readable, now with FXAA is a plus. :thumbsup:

The "trick" to use DG to fool Autopilot (Hope that someone remember to rename this "Kurssteurung" :dazed: in the next patch :D ) make the use
of Autopilot in Blenheim very ease.

A big THANK YOU. :clap:

Sokol1

EG14_Marcast
Mar-28-2014, 12:13
Outstanding guide! Downloaded and saved :thumbsup:

Deeside
Mar-28-2014, 15:13
Superb guide, very clear and well written.

Cheers
John

Bowsewr
Mar-28-2014, 16:09
Great Guide Chuck_Owl. I havent been playing long but i definately have felt the bomber force has been consistently higher lately, and that has been very exciting! This will surely pull more in to something way more fun than the pure fighter pilots may think it is ;)

ATAG_Septic
Mar-29-2014, 09:46
Thank you very much for constructing and sharing this brilliant resource Chuck_Owl.

Septic. :salute:

Ivank
Mar-30-2014, 19:52
Fantastic guide Bravo. I don't however understand why you are adjusting your main altimeter to take into account target elevation. Why not just adjust your Bombsight HEIGHT input to make it read Above Ground Level (AGL).... that is the way its designed to work.

EXAMPLE
Planned Bombing Altitude 17,000ft
TGT Altitude 150feet.
Therefore Release HEIGHT AGL is 17,000-150 = 16,850ft

Fly 17000ft on Default Altimeter pressure setting.
Set bombsight Height to 16,850ft. i.e. AGL value

In addition the Speed set in the sight should be Ground Speed not Indicated Airspeed.
So the bomb sight speed is IAS corrected to TAS then Wind applied to determine Ground Speed.

My guide/ideas here:
http://www.theairtacticalassaultgroup.com/wiki/doku.php?id=blenhiem_mkiv

Excerpt from above WIKI

Course Setting Bombsight Operation.

The Blenheim MKIV is equipped with the Course setting Bomb sight. This is a simple vector sight that provides an aiming reference for bomb release. The Bomb aimer inputs Bomb release HEIGHT and GROUND SPEED and drift. It is important to understand that the Bomb aimer must input Bomb Release HEIGHT not Altitude. Bomb Release Height = Altitude – Target Elevation. In addition the Bomb Aimer must determine the GROUND SPEED and input this to the sight. So the Bomb aimer needs to first determine TAS then apply the wind to determine the ground speed. In Nil wind conditions TAS = GROUND SPEED.

The Sight consists of a vertical post which combines as the Height scale and back sight. The back sight consists of an aperture with the Tgt Height Ref index pin on the right and left sides. A scale on the vertical arm shows the current Height set by the bomb aimer.

The sight also has a horizontal arm with attached Track reference wires. The Horizontal arm also has the foresight which consists of the Ground Speed Ref index pin. The horizontal arm has two ground speed scales. The White scale on the left (not visible with zero drift) has a mph scale. The Red scale on the right is also a Ground Speed scale but in “Minutes to fly 60 miles”. This is easily visible in most situations.

In the graphic below The Release Height is set to 7000ft. The ground Speed is set to 12Min to cover 60 miles i.e. 5 miles per minute or 300mph Ground Speed. To obtain the correct aiming reference the Bomb Aimer moves his Eye line to line up both the Ground Speed ref pin and the Release Height ref pin….i.e. Like with a Rifle he aligns the backsight with the foresight. In the Sim in bombsight view the eyeline is automatically set for you. With these Ref pins aligned the bomb aimers eyeline is now on the correct release angle sight line.

http://www.theairtacticalassaultgroup.com/wiki/lib/exe/fetch.php?media=wimperis_sight.jpg

With these settings the aircraft is then flown so the target passes through either the Left Aiming aperture or the right aiming aperture. (In the sim it needs to be the right aiming aperture)The Bombs are manually released as the target passes through and adjacent to the ref pins.

In Drift situations the Bomb aimer lays of the drift so that ground features are tracking directly parallel to to the horizontal arm and its drift wire reference lines. The aircraft is then flown to ensure the target tracks down the Drift wire guideline to the aiming aperture.

Red Minutes to fly 60 miles to Miles per Min and MPH.

30 = 2miles per min = 120mph
25 =2.4miles per min = 144mph
22 = 2.7 miles per min = 164mph
18 = 3.3 miles per min = 200mph
14 = 4.2 miles per min = 257mph
12 = 5miles per min = 300mph

Tip

In the Sim you can simply use the digital values of release height and ground speed to set the sight accurately rather than refer to the respective scales.

http://www.theairtacticalassaultgroup.com/wiki/lib/exe/fetch.php?media=rafsight.jpg

windigger
Apr-01-2014, 08:31
Hey Chuck , I just want to add my thanks here for the work you put in this guide. I didn't know about the protractor in this map til now.......:doh: You just helped me increase my survival rate in the Blenny.
Also want to thank both you and DRock for promoting interest in the Blenheim so we have more red team bomber pilots. I've left the server numerous times when I was the only one flying Blenny. It is a futile and wasted effort with only one bomber. With 2 bombers it's a bit more workable , albeit, still futile for map win.
Thank you guys for tapping the potential of the old Blenny bus and sharing your knowledge , and maybe get more people interested in this airplane.
I have definitely learned from you.

best regards,

Windigger

ATAG_Naz
Apr-01-2014, 09:35
I set up controls for the Blenny using DRocks Guide and managed to take off and land from Cantebury after work tonight using ChuckOwls guide. I haven't tried the high level bombing yet but will give It a quick go during the week.
Thanks to both of you for your guides, it was all very easy and painless to go through.

:thumbsup::thumbsup:

One more Blennie licenced driver available for your bomber raids gentlemen!
;;)

1lokos
Apr-01-2014, 09:52
IvanK,

This guide on Wiki for adjust Blenheim bombsight is a bit complicated with this "Ground Speed", "time to fly miles"... for the casual "bomber pilot".
I like "simulate", but fail in use this successfully. (IMO) he more scary than help potential bomber newbies.

Chuck_Owl guide work fine, in Blenheim use IAS to set the bombsight work well, after all we are not flying in real world, we are flying in "Dr.Who(leg) Wolrd". :)
That some have "peculiar" Physics Laws...

:thumbsup:

Sokol1

DRock
Apr-01-2014, 16:51
Chuck_Owl guide work fine, in Blenheim use IAS to set the bombsight work well...

I'm pretty sure the bombsight used in the Bristol Blenheim IV by the RAF figured out the TAS. It was up to the Bombadier to set the IAS. So this feature for the RAF is accurate.

Great job with the Blenheims, Guys. Blue no longer has the trump card on bombing, just by the overwhelming numbers of Red bombers I'm seeing now a days.

~S~

Ivank
Apr-01-2014, 18:01
I'm pretty sure the bombsight used in the Bristol Blenheim IV by the RAF figured out the TAS. It was up to the Bombadier to set the IAS. So this feature for the RAF is accurate.

Great job with the Blenheims, Guys. Blue no longer has the trump card on bombing, just by the overwhelming numbers of Red bombers I'm seeing now a days.

~S~

I am pretty sure it didnt thats why they provided Ground speed scale :)

DRock
Apr-01-2014, 18:36
I am pretty sure it didnt thats why they provided Ground speed scale :)

I stand corrected then. Thanks, Ivank.:thumbsup:

I thought the Ground speed scale was used more specifically to estimate time for drop based on weight of bomb. As these numbers would have varied based on weight and terminal velocity of bombs.

So, IAS to TAS was not automatic in the bombsight.

Ivank
Apr-01-2014, 18:42
No probs. Here is an image of the Airspeed input knob/scale labelled TAS. This from a RAF MKIXA Course setting Bombsight

http://i40.photobucket.com/albums/e215/zulu64/cOURSESETTINGbOMBSIGHT2_zps2c592f75.jpg

1lokos
Apr-01-2014, 22:03
4) In case your target is West (to the left) to
your home base, the number that pops up will
not be your heading. The proper heading will
be 360 minus the number that popped up.

To simplify, for waypoints on left side of quadrant trace the reference line from 1st waypoint to up (North).
So the angle in 2nd line pop-up is the course, no subtraction is needed.

Right side - 1st line to South
Left side - 1st line to North

Sokol1

1lokos
Apr-01-2014, 22:22
Fiddling with "Ground Speed/Red Minutes" scale found that it is just a more complicated way to do the same thing - like the "Lubber line" on P-8 Compass. :D

http://i58.tinypic.com/1411krt.jpg

When adjust Wimperis with IAS, the "ground speed/red minutes" scale is adjusted automatically. GS scale is hidden behind Altitude scale.

http://i58.tinypic.com/2vl778l.jpg

Above, enter a 200 MPH IAS (Altitude 11.800 foots), the index on "Red minutes" scale move to 18 and in "Ground speed" scale for 200.
On the map used (default wind) need a -0.5 slip adjust.

* What indicate that MG calibrated (CloD) Blenheim Wimperis for IAS, or the Ground Speed scale should show a different value and not 200.

;)

Sokol1

Ivank
Apr-01-2014, 22:30
Err but arn't the Blue Bombsight velocity values TAS ?

So IAS should be around 168mph at 11,800ft

1lokos
Apr-01-2014, 22:36
Yes, Lotfe need TAS (I use Colander Lotfe Assistant or VO101_Tom DR-2 disk including OAT).

British you know, are "kink", so IAS is fine.


So IAS should be around 168mph at 11,800ft

This I dont know, only know that I hit (+, -) the target. And if I input 168MPH instead 200MPH (plane instruments) I miss. :)

Sokol1

Ivank
Apr-01-2014, 22:53
Well when I use TAS I get hits :)

Torric270
Apr-02-2014, 21:47
With the talk about ground speed now that we have wind, I think I have reversed engineered a solution since we have to input IAS, not TAS into the bombsight.

Using a bomb run I did today as an example, I was able to (after the fact) calculate ground speed.

Flying from Eastchurch to Calais Mark I flew a course of roughly 125 @ 190 IAS @ 17000 feet. Using my pilot computer on my Iphone, this equals 255 TAS. With the wind from 270 @ 4 m/s (from the correction angle/groundspeed function) this gives me a groundspeed of 262 TAS. I then entered numbers into the IAS box (iphone E6B) until TAS equaled the 262, which was 196.

So , if I did this bomb run again, I would enter 200 instead of 190 mph into the bomb sight. Not s big deal when bombing an airfield but more exact when hitting something smaller.

Also for this run I used a - 1.5 slip to account for the wind and it seemed to do well. I will do some controlled tests to see how this comes out.

Ivank
Apr-02-2014, 23:48
....." since we have to input IAS, not TAS into the bombsight."

Why ? TAS is the way it is designed and it works.

There is a reason they put this table in the manual !

http://i40.photobucket.com/albums/e215/zulu64/clodtas_zpsd0a58f16.jpg

Entering TAS and dropping from 9800ft I am getting single bomb release impacts within 1 ship length of the target ... Entering IAS they impact miles away... as expected. This image prior to release showing the run in. I Pickle with the centre of the ships + in the sight aim window.

http://i40.photobucket.com/albums/e215/zulu64/BombTAS_zpsbadce153.jpg

I think the sight represents the first weapon impact, so if doing a manual multiple pickles a little allowance needs to be made to centre the Bomb stick on the target.

Torric270
Apr-02-2014, 23:56
....." since we have to input IAS, not TAS into the bombsight."

Why ? TAS is the way it is designed and it works.

There is a reason they put this table in the manual !

http://i40.photobucket.com/albums/e215/zulu64/clodtas_zpsd0a58f16.jpg

As you say, using TAS works for you. In my tests, I can only hit the target using IAS. I will include that when I test again.

1lokos
Apr-03-2014, 00:50
Flying from Eastchurch to Calais Mark I flew a course of roughly 125 @ 190 IAS @ 17000 feet. With the wind from 270 @ 4 m/s (from the correction angle/groundspeed function)...


Wrong: http://i58.tinypic.com/venqx3.jpg

http://i59.tinypic.com/oubio3.jpg

TRUE COURSE 123º @ 318KMH ~198 MPH - near the I-phone calc's "which was 196." ;)

If I set the wind direction correctly...

EDIT - the first picture have the wind set wrongly, the parallel ~~~ indicates TO wheres wind blow (the wind from 270º blow to 90º - the map standard).
A 125º heading plane under a wind come from 270º should be deviate for left, not for right.

The GREEN band indicates a favorable wind.
The RED band indicates a contrary wind.

:D

Sokol1

ATAG_Freya
Apr-03-2014, 01:07
Therefore, an I-phone travels 13mph slower than Sokol's wind angle calculator! :) But I don't own an i-phone. Can I have a link to that W.A.C. please! :D

edit: I need all the help with math that I can get!!

Ivank
Apr-03-2014, 01:37
Just to add some more into the equation there is a 5Mph discrepancy between the Cockpit ASI and Bombardiers ASI.

trademe900
Apr-03-2014, 01:47
In my tests, I can only hit the target using IAS

+1

1lokos
Apr-03-2014, 02:00
Can I have a link to that W.A.C. please! :D


I find this Wind Angle Calculator in (RoF) Russian forum, have only the .html.
Translate the names and increase the speed scale from 150 t 355 KMH.
To use in MPH is need replace 1000/3600 with 1609.344/3600 on code
but dont find where change for True Course Speed...

http://www.sendspace.com/file/iqerjm

I think in the above calc the wind directions is wrong... (EDIT -Yes, "fix it").

Sokol1

EG14_Marcast
Apr-03-2014, 03:59
As you say, using TAS works for you. In my tests, I can only hit the target using IAS. I will include that when I test again.

If I use TAS all my drops fall short. On DRock's advice I use IAS+10mph and I can hit an airfield from 17000 ft., but I haven't yet tried on small targets.

DRock
Apr-03-2014, 07:17
If I use TAS all my drops fall short. On DRock's advice I use IAS+10mph and I can hit an airfield from 17000 ft., but I haven't yet tried on small targets.

+1

I use IAS and add 10 mph to my bombsight velocity when I climb over 15,000.

This gives me the accuracy I need.


~S~

DRock
Apr-03-2014, 10:48
Can someone explain the side slip on the bombsight, as well as how to account for wind.

I'm still not completely sure how this works.

I have been using my gut instinct to adjust for wind, but I'd like to know how to do it properly now that these maps have wind effects.

The info in this thread is amazing. Much appreciated.

Thanks, again.

Torric270
Apr-03-2014, 12:02
Can someone explain the side slip on the bombsight, as well as how to account for wind.

I'm still not completely sure how this works.

I have been using my gut instinct to adjust for wind, but I'd like to know how to do it properly now that these maps have wind effects.

The info in this thread is amazing. Much appreciated.

Thanks, again.

Not on gaming computer, but briefly explained here.

http://theairtacticalassaultgroup.com/forum/showthread.php?t=9638

ATAG_Knuckles
Apr-03-2014, 13:52
heres a question;;;; you mention to use magnetic deviation when working out your course


is magnetic deviation even modeled in this sim ????????

ATAG_Knuckles
Apr-03-2014, 13:58
also there has been dicussion on working out "true airspeed" which relies on "air density, temp, and pressure are these also modeled into this sim ??

if they arent isnt all this a moot point

just askin ???

DRock
Apr-03-2014, 14:07
heres a question;;;; you mention to use magnetic deviation when working out your course


is magnetic deviation even modeled in this sim ????????

Yes, add 10 degrees to course setter.

All maps.

ATAG_Colander
Apr-03-2014, 14:13
The bombsight expects TAS however, I don't think it takes into consideration bomb drag.
Because of the above, the bombs will slow down their horizontal speed dropping short.

I'm unsure if that sight was supposed to correct for drag.


Edit:
From Wikipedia:

Although a bomb's trajectory is roughly parabolic, when the bomb is dropped from high altitudes may reach terminal velocity before hitting the ground. This effects the final trajectory in a non-linear fashion, generally making the line of fall more vertical. To account for this a "trail screw" was added starting with the Mk. II version of the CSBS, which rotated the height bar forward. This had the effect of reducing the range angle, which accounted for the more vertical trajectory of the bombs. This effect only comes into play for high altitudes when the bomb has time to build up speed. Later models of the CSBS, starting with the Mk. VII, used a cam that was driven by both the altitude setting and the trail screw in order to automate the calculation of this effect. Additionally, each aircraft has a slightly different way of measuring altitude that needs adjustment, the CSBS accounted for this effect by including two altitude scales, a linear scale of altitude in orange on the right side of the bar, and any number of white scales on the back that could be clipped onto the sight. The two were used in combination to make adjustments for the altitude of the target over sea level.

Are we supposed to have an MKII in the game?

1lokos
Apr-03-2014, 14:47
also there has been dicussion on working out "true airspeed" which relies on "air density, temp, and pressure are these also modeled into this sim ??


Temperature is modeled, look at He 111 and Ju 88 thermometer - but if this affect TAS dont know...

And temperature varies during the day/night:

E-69 Vencejo/Tuckie test with CLoD 1st (2011) version - interesting things:


Aircraft: HE- 111 H
Map Channel
Base: Rosieres -en- Santerre
Weather: default

Plane on runway 25, engines OFF, magnetic heading 251 º .

Time / QFE / Temp. environment / Temp. water-oil left motor / Temp . water-oil Derch / ind motor. Gyroscope / /

1200/984/15/16-15/20-18/- / /
1300/984/13/15-15/19-18/- / /
1400/984/12/15-14/19-17/- / /
1500/984/11/14-14/18-17/- / /
1600/984/9.4/14-13/18-16/- / /
1610 ~ 1620 I turn on cabin lights / /
1700/984/7.5/13-13/17-15/101 / /
1800/984/5.6/13-12/16-15/120 / /
1900/984/3.5/12-12/15-14/140 / /
2000/984/1.2/11-11/15-13/161 / /
Sunset 2005 / /
2100/984/-1/11-10/14-13/181 / /
2200/984/-3.3/10-10/13-12/200 / /
Between 2200 and 2300 I realize that the battery is over / /
2300/984/-6.1/9-9/12-11/220 / /
2400/984/-9.1/8-8/11-10/244 / /
0100/984/-12/7-7/10-9/266 / /
From this time , until 0345 instruments impossible to see total lack of visibility / /
0400/984/-24/4-4/5-5/324 / /
0410 dawns / /
0500/984/-33/1-1/1-1/349 / /
0600/984/-40/0-0/0-0/011 / /
0700/984/-40/0-0/0-0/030 / /
0800/984/-40/0-0/0-0/051 / /
0900/984/-40/0-0/0-0/0/072 / /
Ripped 0900 motor passing ambient to -12 ° / /
1000/984/-5.5/0-0/-0-0/093 / /
1010/start flashing cockpit lights / /
1020/ cockpit lights maintain their light / /
1100/984/-4/0-0/0-0/114 / /
1105/Engines stop / /
1120/batteries charge end/ /
1200/984/-/0-0/0-0/135 / /
1215/start Engines / /
1225/cockpit lights come back / /

Comment :

The atmospheric pressure has changed .

The ambient temperature varies about 1 º / hour.

Battery charge/discharge are modeled.

When the battery is discharged, cockpit lights, all indicators of temperature and bombsight stop working immediately. Fuel indicators stop working later.

With battery charged, all redials work again except engine temperature indicators that will not start work until they properly caught temperature.

Nice the effect of the lights when they want re-start, like a bad screwed bulb.

The gyroscope has an error of about 20 ° / hour = 5 º / 15 with plane stopped!

But: " By the way, the gyro error is normal, takes into account the rotation of the earth , so detuned with it ...

If you 're flying and we see that we can not turn the cabin lights , and/or the temperature of the engine begins to drop, and we have the bombsight, and if fuel gauges marked zero is that we do not have electricity.
The only caution is that we can not trust what they tell us thermometers water / oil engines, so I would open a little radiator and remove a point of gas, just in case .



Sokol1

Ivank
Apr-03-2014, 18:36
The bombsight expects TAS however, I don't think it takes into consideration bomb drag.
Because of the above, the bombs will slow down their horizontal speed dropping short.

I'm unsure if that sight was supposed to correct for drag.


Edit:
From Wikipedia:


Are we supposed to have an MKII in the game?

The real sight has an adjustment for bomb Terminal velocity and Bomb trail. Both these variables are used to set up the differrent ballistics for each type of bomb and as a consequence take into account drag.

In the real sight the bomb aimer entered TAS, Height above target, Bomb Terminal Velocity,Bomb trail (this allowed for different bomb type ballistics). This provided him with a nil wind solution. In a nil wind solution TAS = Ground speed.

He then removed the drift by offsetting the tracking wires (Slip skid controls in CLOD). The pilot then flies the aeroplane (based on bomb aimer directions "LEFT LEFT or RIGHT .... STEADY" etc to track the target parallel with the drift wires. The bomb aimer then calculated Ground Speed and adjusted the ground speed using the RED groundspeed (Minutes to fly 60nm) scale on the right arm or the white Ground speed reference on the left arm (cant be seen in CLOD due view restrictions). This then set the wind corrected aiming triangle up.

http://i40.photobucket.com/albums/e215/zulu64/CSBSGSscale_zps46b71814.jpg

I think the sight modelled in game is CSBS MKIXA

Knuckles Magnetic variation is modelled in the sim and is correct for 1940 in the SE UK at 10deg West.

1lokos
Apr-04-2014, 12:26
http://i40.photobucket.com/albums/e215/zulu64/clodtas_zpsd0a58f16.jpg



Some thoughts about MG IAS>TAS table.

Generally these online IAS>TAS (http://www.hochwarth.com/misc/AviationCalculator.html) converter use a .02 factor to make the conversion - some allow set a different index (http://www.csgnetwork.com/tasinfocalc.html).

MG table use a .016 factor - remember this is "Dr.Who(leg) World". :D

TAS = IAS + (IAS x (0.016 x altitude/1000).

Sample IAS 200 MPH @ 10000 feets = 200 + (200 x [0.016 x 10000/1000] = 200 + (200 x 0.16) = 200 + 32 = 232 MPH TAS

Since Clod altitude input is done in 100 (foots/meters) increments simplify to:

(IAS x 0.16) + IAS to match MG calculation for other speed/altitude not in table.

But my Wimperis still uncalibrated for TAS. :doh:

Sokol1

Torric270
May-03-2014, 18:39
@ Snapper. Can you sticky this?

ATAG_Snapper
May-03-2014, 19:15
@ Snapper. Can you sticky this?

Done! :salute:

I've actually taken the liberty of printing the IAS/TAS chart that IvanK kindly attached up further. It's darn handy and it's as precise as I will ever need as a Spittie pilot. :thumbsup:

Chuck_Owl
May-05-2014, 14:42
Updated guide to version 2.0 based on feedback received from you guys. Please take note that this 2.0 version is for nil wind conditions.

Roblex
May-05-2014, 16:58
I don't hold with these new-fangled Wind Angle Calculator thingamajigs, I use pencil and paper and draw a good old fashioned Triangle Of Velocities :-P

I have seen several people offset the wrong way using a WAC but as long as you use arrows in your Triangle Of Velocities then you can't get it arse about tit. On the other hand, I know which method I would rather use in a cramped cockpit :D

Roblex
May-06-2014, 16:51
Can someone explain what is wrong with my logic?

The guide recommends that when the target is 240ft higher than your own field (at 0ft) then you should first set your altimeter to read 240ft then when setting up the bombsight use the reading on the altimeter without any adjustments.

My brain tells me that this will mean that when your altimeter reads 17000ft you are actually only 16760ft above seal level and when you are over the target you are actually only 16520ft above the target yet you have told the bombsight you are at 17000ft.

Let's try that again with smaller numbers to make it clearer:-

You want to drop your bomb at 500ft so you put that in your bombsight
Before you have even taken off from Shoreham (0ft), your altimeter says you are already at 240ft
You take off and climb to an indicated 500ft but that means you only climb 260ft at take-off i.e. you are only 260ft above the sea as you cross to France.
You arrive at your target field but as the field is 240 ASL then you are only 20ft above the target field!
Your bombsight thinks you are 500ft above the target i.e. it is out by 480ft!

Chuck_Owl
May-06-2014, 17:28
Can someone explain what is wrong with my logic?

The guide recommends that when the target is 240ft higher than your own field (at 0ft) then you should first set your altimeter to read 240ft then when setting up the bombsight use the reading on the altimeter without any adjustments.

My brain tells me that this will mean that when your altimeter reads 17000ft you are actually only 16760ft above seal level and when you are over the target you are actually only 16520ft above the target yet you have told the bombsight you are at 17000ft.

Let's try that again with smaller numbers to make it clearer:-

You want to drop your bomb at 500ft so you put that in your bombsight
Before you have even taken off from Shoreham (0ft), your altimeter says you are already at 240ft
You take off and climb to an indicated 500ft but that means you only climb 260ft at take-off i.e. you are only 260ft above the sea as you cross to France.
You arrive at your target field but as the field is 240 ASL then you are only 20ft above the target field!
Your bombsight thinks you are 500ft above the target i.e. it is out by 480ft!

Roblex: It was a mistake on my part. It's fixed in version 2.0. Pages 11 and 12 got it explained just like you said.

1lokos
May-06-2014, 18:24
You arrive at your target field but as the field is 240 ASL then you are only 20ft above the target field!


LOL. Fortunately the trees are "virtual". :D

Sokol1

Roblex
May-07-2014, 02:06
Roblex: It was a mistake on my part. It's fixed in version 2.0. Pages 11 and 12 got it explained just like you said.

OK. I used the version in your dropbox account because I refused to subscribe to SCRIBD :-)

Where there any other changes in V2? It is not worth me downloading the latest version just for that one change.

Chuck_Owl
May-07-2014, 02:47
I corrected some (very stupid) mistakes and oversights.

I corrected the procedure to take into account target elevation (and I re-did the drawing showing it). I corrected the bombsight input values so they used TAS rather than IAS. I included IvanK's chart to get a rough estimate of TAS. I improved the magnetic compass tutorial to find a proper heading. Corrected some typos. Fixed some graphical glitches.

That sort of stuff...

1lokos
May-14-2014, 12:04
The manual IAS-TAS table expanded, limited to ranges (common) used in Blenheim, 3000 to 2000 feet, 150-250 MPH.

9612

And why not include a box for IAS/TAS conversion in Lotfe Assistant, since people are using TAS for high altitude bomber. :thumbsup:

Sokol1

SG1_sandokito
May-15-2014, 13:45
Hi all.

frist. on cod outside temperature affects to calculate the tas, then i use e6b to calculate the wind drift grades.

usin this you can destroy target whit 20m/s of wind.
but if the wind is 4 m / s or less, my recomendation on he111h2 is. Insert ias calculate wind drift grades, and use altitude to set target. you can destroy target on 98% of case.

1lokos
May-15-2014, 15:35
frist. on cod outside temperature affects to calculate the tas,

Probable this explain the variation of the factor in the above table. :thumbsup:

Sandokito,

What is the function used to get "ias calculate wind drift grades", in this E6-B emulator:

http://www.csgnetwork.com/e6bcalc.html

Sokol1

SG1_sandokito
May-15-2014, 16:11
The 3 or 4 option.

And I have downloaded cr3 on my phone. And I use this tool to to calculate angle correction.

1lokos
May-15-2014, 16:35
And I have downloaded cr3 on my phone. And I use this tool to to calculate angle correction.

You can explain more this?

If prefer, write in Spanish.

Sokol1

AKA_Recon
May-15-2014, 16:48
So, I'll plead ignorance here but...

In my offline bombing attempts at 10,000 on Calaise Mark I was nearly dead center using IAS (200-210) vs. TAS (230-240) - with IAS I was nearly dead on, TAS always hit short of target.

SG1_sandokito
May-15-2014, 17:17
You can explain more this?

If prefer, write in Spanish.

Sokol1

Yes. you have on android marquet, one aplication callet CR3 flight Computer.now in spanish.

En esta aplicacion tienes una opcion, que es wind.

Metes tu rumbo al obj, la Tas , de donde pega el viento, y la velocidad del mismo y me da el rumbo que tendría que llevar y la tas con la correccion correcta.
ejemplo.

course to target 354
Tas 350
wind heading(from) 120
wind Speed 72KM/h (20m/s)

resultado
heading 4
Etas 345

ahora de 354 a 4, deduzco que para ir al obj tengo que ir 10 grados a la derecha, con lo que en la mira programo 10 a la izquierda.

SG1_sandokito
May-15-2014, 17:20
So, I'll plead ignorance here but...

In my offline bombing attempts at 10,000 on Calaise Mark I was nearly dead center using IAS (200-210) vs. TAS (230-240) - with IAS I was nearly dead on, TAS always hit short of target.

But one cuestion. You need correct on your tas wind influence

1lokos
May-15-2014, 18:27
So, I'll plead ignorance here but...

In my offline bombing attempts at 10,000 on Calaise Mark I was nearly dead center using IAS (200-210) vs. TAS (230-240) - with IAS I was nearly dead on, TAS always hit short of target.
But one cuestion. You need correct on your tas wind influence.


Considering map default wind of 3 m/s ~7 MPH to 90 (FROM 270), the influence over TAS (232 - IAS 200@10000 game charts) is minimal in resultant CAS... ~7 MPH more or less (if fly 270 or 90).

Using the E6-B emulator (http://www.csgnetwork.com/e6bcalc.html), (his OAT factor 2 is above game charts) the CAS is 247 or 233 MPH (downwind or against)...

200 MPH @ 10000 > TAS 240 > CAS (wind 3 m/s ~7 MPH) = 247 or 233.

BTW - At 10000 fts (~3.000) meters) the temperature in middle of Channel is -3.5 degrees (He 111 thermometer).
Is -6.8 at 3.500 and 3.2 at 2.000 meters.

This CAS>TAS allow enter the temperature, but the result is similar to CloD tables.

http://www.kilohotel.com/cgi-bin/cas2tas.py

The matter still confuse... :)

Sokol1

1lokos
May-15-2014, 18:35
Bomber Calculator for il-2('46) - with adjusts for "Dr.Who'leg World". :D

http://www1.bbiq.jp/~zhukov/calc/calc.html
http://www1.bbiq.jp/~zhukov/calc/calc_wind.html

The result TAS is similar to CloD charts.


course to target 354
Tas 350
wind heading(from) 120
wind Speed 72KM/h (20m/s)

resultado
heading 4
Etas 345

ahora de 354 a 4, deduzco que para ir al obj tengo que ir 10 grados a la derecha, con lo que en la mira programo 10 a la izquierda.

Sandokito,

These data show that you are talking about He111/Ju88 (TAS 350), here is discussed Blenheim, that see use different (Dr.Who'leg) rules. :thumbsup:

Sokol1

SG1_sandokito
May-15-2014, 18:58
The AO squad confirmed that it works with blemmheim.

postd by armanGT
Bueno Sando la trasnochada de ayer sirvió para algo, te confirmo todo lo que hablamos ayer, después estuve haciendo pruebas a 14.000 pies con el mismo objetivo y viento, entrándole en 3 rumbos diferentes (viento de cara, viento de cola y viento totalmente lateral) e hice blanco de lleno en las 3 pruebas, eso sí, en los tres utilicé la TAS y no la IAS, así que la TAS si esta implementada. Resumiendo, calculamos la TAS la corregimos con los valores de viento (sumándolo, restándolo o desviando la mira con los grados del calculador que te pasé), e introduzco en la mira la altitud - 100 pies - altura de objetivo y en la velocidad la TAS resultante - 10 mph y PREMIO!..

Gix
May-16-2014, 04:06
Can someone explain how to use the side slip angle ? I saw in vid you fine tune it (while looking slip indicator ?).
In the lofte7 or Blenny stuff, what in fact this adjustment do ?
In calculator, it gives a value also. For example if calculator gives +2°, how do you use this info ?

1lokos
May-16-2014, 11:16
Influence of Altimeter adjust in TAS, accord the "Bomber Calculator". Not that help for something... :D

- The CloD map temperature at ground level - He 111 thermometer in Lympne - is 12º C between 6:00 and 19:00 hs (no more change across the day like in "release" version...)

Blenheim Altimeter with default adjust - 1013 Mbar (1013 hPa or 759mmHG on Bomber Calculator) what is set for Altitude = 900 feet.
200 MPH @ 10.000 > TAS = 232 MPH (match with chart on manual).

Altimeter adjusted for 995 Mbar - Altitude = 0 feet (sea level).
200 MPH @ 10.000 > TAS = 234 MPH

Altimeter adjusted for 940 Mbar - minimum adjust, Altitude = -1000 feet... :S
20.000 MPH @ 10.000 > TAS = 240 MPH

Sokol1

SG1_sandokito
May-16-2014, 11:53
Can someone explain how to use the side slip angle ? I saw in vid you fine tune it (while looking slip indicator ?).
In the lofte7 or Blenny stuff, what in fact this adjustment do ?
In calculator, it gives a value also. For example if calculator gives +2°, how do you use this info ?

if your course to target is 5, and on calculator you have +2. You need put 7 course. and you need adjust de bomb sigh 2 grades to the left.

1lokos
May-16-2014, 12:05
Can someone explain how to use the side slip angle ? I saw in vid you fine tune it (while looking slip indicator ?).
In the lofte7 or Blenny stuff, what in fact this adjustment do ?
In calculator, it gives a value also. For example if calculator gives +2°, how do you use this info ?


Gix,

"Side Slip" is to compensate the wind influence in your heading.

Taking the Sandokito example:

Course to target = 354
TAS = 350
Wind heading (from) = 120
Wind Speed = 72KM/h (20m/s)

After input this data on CR-3 Flight Computer emulator, give:

Heading = 4 <<< This is the actual heading that plane should fly under a wind coming from Right/back - that drift the plane for left and increase his speed - to maintain the pretend 354 course.
ETAS = 345 <<< This is the TAS correct with wind influence, the "Ground Speed" on Blenheim bombsight - the scale hidden behind Altitude scale (visible if you adjust drift +10 or -10 degrees).

"ahora de 354 a 4, deduzco que para ir al obj tengo que ir 10 grados a la derecha, con lo que en la mira programo 10 a la izquierda. "

He say that need steer the plane 10 degrees for right (from 354) to maintain a true 354 heading, and due this adjust the "Side Splip" 10 degrees for left to maintaim the aim point.

You can do this adjust visually, aim for some point in the scenery ahead in your path and adjust "Side Slip" until the point slide between the black and white lines on bombsight.

On He 111/Ju 88 to adjust "Side Slip" engage the bombsight automation, the cross should remain static on aim point - Caution, if are done this before the target dont let the cross move all the way down, or you
drop the bombs on some poor cows. :D

Using the "Flight Computer" emulator, E6-B, CR-3, DR-2... you simplify this.

You can use these online emulator in flight (online/offline) open his page in STEAM browser (Shift+Tab) over the game. :thumbsup:

BTW - All this is "theory" in practice my bomb result is like this (http://cdn1.spiegel.de/images/image-335110-galleryV9-jmnw.jpg). :D

Sokol1

AKA_Recon
May-17-2014, 11:55
using the IAS + 10 methodology... I had some good success last night on ATAG.

1. there was a 6 knot wind from the SE
2. I slight bombed 'long' from my direction, and applied slight side slip
3. first run at 10k, second run at 13k

Was dead on - on a thin airfield strip.

Still experimenting and I need to get back to you on the wind I used in my test mission

1lokos
May-21-2014, 01:11
Testing offline, using IAS +10, ~10 degrees of flap, ~2.200 RPM.

http://i61.tinypic.com/wtsjvd.jpg
Point aimed, the road in 1st and roads X on 2nd, drop when target pass on black box on bombsight.

Autopilot in mode 22 without oscillation - just engaged when Variometer is near 0.

If convert to IAS>TAS will use 170, this dont cause the bomb hit more ahead?

Wind default on QM - probable 3 m/s to 90.

Sokol1

armanGT
May-21-2014, 09:05
The AO squad confirmed that it works with blemmheim.

postd by armanGT
Bueno Sando la trasnochada de ayer sirvió para algo, te confirmo todo lo que hablamos ayer, después estuve haciendo pruebas a 14.000 pies con el mismo objetivo y viento, entrándole en 3 rumbos diferentes (viento de cara, viento de cola y viento totalmente lateral) e hice blanco de lleno en las 3 pruebas, eso sí, en los tres utilicé la TAS y no la IAS, así que la TAS si esta implementada. Resumiendo, calculamos la TAS la corregimos con los valores de viento (sumándolo, restándolo o desviando la mira con los grados del calculador que te pasé), e introduzco en la mira la altitud - 100 pies - altura de objetivo y en la velocidad la TAS resultante - 10 mph y PREMIO!..

Yo al final me líe escribiendo el post con tantas pruebas y demás, en el Blenheim se usa la IAS, correcto, la TAS no funciona.

SG1_sandokito
May-21-2014, 09:23
Armand Gt posted,
He wrong to write, and you need use the CR3 using ias. sorry all for confusion

1lokos, yes if you no edit this on a mission, the wing is 3m/s to 90

1lokos
May-21-2014, 11:32
The scale on left side of Wimperis is for set the Ground Speed (TAS + wind correction),
but seems the MG calibrated for IAS...

http://i60.tinypic.com/xvwww.jpg

The puzzling is that some "swear" that using TAS hit better ... :S :D



He wrong to write, and you need use the CR3 using ias. sorry all for confusion


Sandokito.

OK. ArmanGT inform that he mistake TAS with IAS on report, and in tact are using IAS, correct?

And you advise use IAS on CR-3 computation to determine wind influence?

Thank you.

Sokol1

Decay
Sep-11-2014, 02:32
Hi All,

Here comes My tuppence:

11453

This picture is the CLOD Manual data copied into a spreadsheet and averaged for the values in between.


Now THIS is the same chart calculated using the 2% per thousand foot altitude rule-of-thumb.


11454


And there are some differences.


This next chart shows how much the calculated values differs from the printed values.
It's colour coded to show just how much different the calculations are from the manual.

11455

Okay so something is making the TAS different for different speeds.

The temperature gradient through the atmosphere looks like this:11456

So up to 30,000' the temperature drops from 15 degrees C down to -38 degrees C.
Now colder air is denser air, which should make the IAS indicate HIGHER for a given true TAS.

But the problem (for me) is that the amount of difference between the Manual and the Calculated TAS is not consistent.


Does anyone know how the developers came up with the values for the table?
Does anyone know what formula they are using (in-game) to adjust TAS for height and temperature?

And YES Virginia I am making a Bombing calculator.
I know the LOTFE one is very good, I am trying to do similar for the allies.
https://dl.dropboxusercontent.com/u/24241061/Bomb%20Calculator.xlsx

1lokos
Nov-21-2014, 12:27
Now THIS is the same chart calculated using the 2% per thousand foot altitude rule-of-thumb.

11454



Yes, the 2% general rule don't prevail for "Dr.Who'leg world" - the factor used there is less and varies with altitude... :S

http://theairtacticalassaultgroup.com/forum/attachment.php?attachmentid=9612&d=1400083251

BTW - the Dropbox link is dead.

Sokol1

_OD_
Mar-17-2015, 12:13
This is fantastic! Thanks a lot, I'll be making use of this!

OD

69th_Damon
Mar-24-2016, 11:11
This was great and answered so many question I have had.

Thanks for all the work.
Damon

1lokos
Jun-08-2019, 13:09
Interesting video about Wimperis Mk.IX - although not the exact model of bombsight, show how CloD Blenheim bombsight is poor implemented, they just loose time make the thing in 3D... for ending use the IL-2:46 bombsight "HUD" operation. :doh:

The "compass" at base of bombsight is not a "repeater compass" as modeled in CloD, but wind angle adjust ( 6:00 ) drift calculator.

Curious is that in IL-2:Bo'X, with their simplified "Android screen" bombsight - that convert IAS to TAS automatically, the wind angle need be adjusted.


https://www.youtube.com/watch?v=L0GH8bmW59I

"...red over red". :D

Wimperis Mk.IX technical manual: http://canadianflight.org/files/bombsight1.pdf

1lokos
Jun-12-2019, 11:22
Description of Wimperis Mk.I bombsight operation - basically the same for latter models.

39537

Double click over image for see full size.