how is navigation done when there is 8/8 cloud cover?

[Rjel]

4 minutes ago, MaxPower said:

I feel like I have some kind of magical power sometimes, what, with my ability to use networked computers to find information where others are helpless.  Mwahahaha.  Look on ye mighty and despair!
https://en.wikipedia.org/wiki/Okta

I usually prefer my meteorological information presented by a pretty young woman but thanks for the post. ☺️

[JG4_Deciman]

1 hour ago, geckoSOH said:

Wasn't aware of this tool, cool! But help me understand, are you pulling the instructions you posted previously from original sources, or somebody's documentation on how to use the flash DR2?
 

We (Jagdgeschwader4) had a flight school when flying 'Cliffs of Dover'
And 'Navigation' was a part of that school.

 

I ran through that school 2 times.
The first time I entered it at about the middle of the course.

The second time I started at the beginning.

And we had several very long discussions about navigation...

 

After my second pass of the entire school the game we used was changed from 'Cliffs of Dover' to 'BoX'

Meaning that almost everything had to be redone.
But most of the school content used during 'Cliffs' is needed for 'BoX'. The rest is not implmented there.

 

And when adjusting the former content (still relevant) to the new game the decision was made, not to perform such a school any more.

But the content of the school (even if not 'lived' any more) is still up to date.

 

There are also some further documents (from the 'real' time) available, providing other 'tables'

that reduce the 'calculation work with the DR2'.

They are all taken from the web (and seem to be authentic!)

 

If you want more information:
Just check the entire content linked here

https://jagdgeschwader4.de/index.php/navigationsschule

It's (nearly) our entire content of the former school, mentioning the differences between 'Cliffs' and 'BoX'.

And as 'Cliffs' had much more aspects the only difference is 'not needed in BoX' fore some of the contents.

 

I also know, this is (when trying to understand all) very comlex stuff.
But that is how the Luftwaffe made those calculation (and simplified them by using tables shown in the additional pages) at that time.

[JG4_Deciman]

To be continued...

 

I've studied a lot of original documents I found in the internet of that time.
There were in the later periods of war several tables to simplify the calculation.

There were also in the later periods tables to eleminate the errors in the gauges (speed) at different altitudes.

And everything discovered was used to make the calculation easier and more precise.

 

We could only take into account what we know.
But when using the tables available later in the war it was even possible, to calculate the speed during a climb (when passing several different altitudes and their influence).

I used these tables when creating my 'flight plan' for my test (Cliffs at that time), and the result was these calculations matched, so my flight plan was really good.

[AndyJWest]

OK, JG4_Deciman, you've figured out your flight plan, but what do you do once you've had to deviate from it?

 

Being able to navigate to your destination when you don't know where you are is a much more useful skill than being able to compile fancy flight plans that work on the assumption that you'll always follow them.

 

[JG4_Deciman]

Ok,

 

The basic thing was to 'navigate' with a closed coverage of clouds.
So no ground visibilty at all.

 

I that case you need a flight plan
and you have absolutely no chance to alter it due to no clue about where you are by ground view confirming your position.
Fly it or let it be.

 

In case you have to modify it: Good luck....

 

The only way to return safely in that case is:

Go to inverted course
Check your beacon
And hope that you receive a signal from any friendly airport within range.

And in that case: Follow the beacon to that airport, when reached go below the clouds.

Hope that there are no mountains or other obstacles you hit.

Hope that you see the airport and land....

 

PS:

You could also check your flight plan and see where you 'should' be (if you flew it exactly)
and then estimate a course to the next friendly airport.

But the rest will remain the same.
Hope for a beacon and pray for no obstacles and visibility when below the clouds...

Edited December 20, 2024 by JG4_Deciman

[AndyJWest]

Alternatively, you could abandon the attempt to navigate blind, with no back-up plan. In the real world, weather varies. In the real world, instruments have errors. In the real world, instruments fail. In the real world, people make mistakes. And in combat, your plan will likely become useless as soon as the enemy decides to intervene. Dead reckoning is a method for flying approximately towards somewhere you can get a fix - that's all it is. A route with no means to verify you are on it isn't a plan at all.

 

Which is probably why flying above 17/17ths cloud with nothing to get a fix on wasn't normal WW2 procedure. What exactly are you expecting to achieve up there?

[JG4_Deciman]

When flying above close coverage (so flying BLIND)
you need 2 things

 

A flight plan

and the possibility (according to the flight plan) to know, where (also according to the flight plan) you should be (assuming your calculation was correct and you flew it exactly).

 

If you matched both you should be able to know (not precise, but in the area) where you are at any time.
If you matched only one part... something arround where you should be at that time

If you matched nothing... feel happy to guess where you are!

 

Next thing is the golden rule:

Every flight plan (no matter how good it is)
will only work until the first enemy contact!

[geckoSOH]

Interesting resources Deciman, I'll have to check them out!

 

As said above, if you're flying above a white blanket of cloud and you don't know what direction, how fast, and how long you've been doing it, well, best of luck to you. The more of that information you can hang onto, and the more precisely you can do it, the better chance you have. But in that scenario you're really just hoping to pick up something on the ground visually without flying into a mountain.

 

As for changing mid flight - heading, distance, time. You can calculate your expected position on your route, note it, note the time and heading you took when you deviated from the planned route. In reality, it is no different than if you had planned it that way from the beginning, since you are working from the same information you had then, which normally, you've been able to confirm or correct while you did have an actual fix. It's a normal part of developing the dead-reckoning skill. Suppose you are flying along, weather deteriorating below you, but you hear over the radio your destination is clear, so you press on. Later, you get another report that weather has changed there and it's totally socked in. You're now over the overcast with no visual contact with the ground, but you hear an alternate airport is reporting improving weather, and decide to divert from your plan to try to get to this other airport. First, you give yourself time, and don't turn immediately. You pick a point 10 minutes ahead where you will start your diversion. Since you made and kept track of a dead reckoning plan, and marked it out on your map, you can determine the point you should be over in 10 minutes, and plot the new leg of your course to the new alternate airport from there, measure the distance, and calculate the appropriate heading and ETA. Then, you execute your new plan at the appointed time. If it goes south, as Deciman says, retrace your course. If you're careful, you won't be perfect, but you can still be close.

2 hours ago, AndyJWest said:

Alternatively, you could abandon the attempt to navigate blind, with no back-up plan. In the real world, weather varies. In the real world, instruments have errors. In the real world, instruments fail. In the real world, people make mistakes. And in combat, your plan will likely become useless as soon as the enemy decides to intervene. Dead reckoning is a method for flying approximately towards somewhere you can get a fix - that's all it is. A route with no means to verify you are on it isn't a plan at all.

 

Which is probably why flying above 17/17ths cloud with nothing to get a fix on wasn't normal WW2 procedure. What exactly are you expecting to achieve up there?

In the real world, pilots can, and do, dead-reckon accurately and consistently. It is nobody's plan A and NEVER should be (at least not the entire route), because it is subject to forecast accuracy and pilot discipline more than anything else. I don't think anyone is trying to argue that this would be normal procedure. But you train for when plan Z has just failed and it's all you've got left. Because, in the real world, radio and GPS navigation can fail, and they can fail over a solid cloud deck or at night over terrain with no lights. But if you didn't make a plan, or didn't keep track of the plan you made, or never learned how to make and use a plan in the first place, you've lost that option. It's a skill that is disappearing in the GPS age, but is still practiced by many, and it definitely got more emphasis during WWII than it does now.

 

Flying approximately towards somewhere you can get a fix is a step or two down from dead-reckoning. Dead-reckoning is careful calculations and disciplined flying to get you from a known, to a another known, though an area where you can't visually or electronically track your position, with the knowledge that factors outside your control can interfere with your result. That care and discipline give you the best chance to deal with the result you get once you're able to see more than clouds, and very often, that result will be right about on the money. 

P.S. I believe reporting cloud cover in octas was standardized sometime post WWII. I've seen a lot of WWII era references to cloud cover in 10ths, it's just not what is used today.

Edited December 20, 2024 by geckoSOH

[AndyJWest]

I'm not arguing against 'careful calculations and disciplined flying'. Just suggesting that having nothing else as an entire flight plan, which is what this discussion seems to be predicated on, isn't sensible. You seem to agree. I used the words 'approximately towards' because navigational skills include being able to estimate how accurate your route-following is likely to be, taking all the potential cumulative errors into account. How best to proceed depends on how accurately you know your position, and sometimes it is safer to assume you aren't accurate, and plan accordingly. If it's 1912, and while you are crossing the Channel in your Blériot XI (which apparently wasn't equipped with a compass), you run into a fog bank, you are better off 'dead reckoning' somewhat to the west of where you think Dover is than straight for it...

 

From a late-WW2 edition of the USAAF training command 'Air Navigation' manual (download here)

 

"Dead-reckoning is the art of determining, approximately, where the aircraft is or where it will be at a given time..."

 

Anyone seriously wanting to understand how WW2-era navigation was done would do well to read this manual.

[Stonehouse]

Veteran66 made a DR2 android app which is useful due to its convenience. I still have the file but the link in the thread below is dead - @Veteran66 perhaps you could rehost the app for those here please?

 

small Android tool for Navigation - 3rd Party Apps, Utilities, Tools and Other Content - IL-2 Sturmovik Forum

 

[Veteran66]

i find my "Navigator" App for PC, but how upload 150MB?

[geckoSOH]

On 12/21/2024 at 1:04 AM, AndyJWest said:

I'm not arguing against 'careful calculations and disciplined flying'. Just suggesting that having nothing else as an entire flight plan, which is what this discussion seems to be predicated on, isn't sensible. You seem to agree. I used the words 'approximately towards' because navigational skills include being able to estimate how accurate your route-following is likely to be, taking all the potential cumulative errors into account. How best to proceed depends on how accurately you know your position, and sometimes it is safer to assume you aren't accurate, and plan accordingly. If it's 1912, and while you are crossing the Channel in your Blériot XI (which apparently wasn't equipped with a compass), you run into a fog bank, you are better off 'dead reckoning' somewhat to the west of where you think Dover is than straight for it...

 

From a late-WW2 edition of the USAAF training command 'Air Navigation' manual (download here)

 

"Dead-reckoning is the art of determining, approximately, where the aircraft is or where it will be at a given time..."

 

Anyone seriously wanting to understand how WW2-era navigation was done would do well to read this manual.

There's a looser, more colloquial usage of the dead-reckoning, and there's a more technical usage as understood by pilots today, and the above excerpt makes allowance for both of them. Seems like we were just reading from different pages. Great resource by the way. It sounded to me like you were saying dead-reckoning was more or less useless as a precision tool, when that is not the case. In fact, there are real world scenarios where you'd be foolish not to check your visual navigation with dead-reckoning, and make decisions based on that unless there was a specific reason not to. But in the end, it is just one tool, and any time you find it is your only tool, you should seriously consider the wisdom of your plan. But if you're wondering how to navigate over 8/8ths cloud cover without ground based nav aids or GPS, there's the answer. The application is up to the individual.

[R33GZ]

On 12/21/2024 at 6:04 AM, MaxPower said:

I feel like I have some kind of magical power sometimes, what, with my ability to use networked computers to find information where others are helpless.  Mwahahaha.  Look on ye mighty and despair!
https://en.wikipedia.org/wiki/Okta

Well. There you go. I can now leave this forum feeling edumacated 

[IckyATLAS]

Mamma mia. What a complex thing.

I thought that having a Breitling Navitimer would solve everything. 😢

[R33GZ]

3 hours ago, IckyATLAS said:

Mamma mia. What a complex thing.

I thought that having a Breitling Navitimer would solve everything. 😢

With all the complex mathematical equations going on above, I must be some kind of idiot savant to be able to pretty much turn up on my waypoints, roughly when expected by simply looking at the map and picking a heading 😅

[unlikely_spider]

2 hours ago, R33GZ said:

With all the complex mathematical equations going on above, I must be some kind of idiot savant to be able to pretty much turn up on my waypoints, roughly when expected by simply looking at the map and picking a heading 😅

We're not flying 6, 7, or 8 hour missions at 30k feet with 60-70kt winds like they often were at the time.

Edited December 23, 2024 by unlikely_spider

[AndyJWest]

59 minutes ago, unlikely_spider said:

We're not flying 6, 7, or 8 hour missions at 30k feet with 60-70kt winds like they often were at the time.

 

Today's weather. Good luck to anyone dead reckoning that. Or trying to level bomb from that altitude...

 

Not much better over Europe. 140 kt wind from the north at 30,000ft over England and France. 

[Stonehouse]

On 12/22/2024 at 4:26 PM, Veteran66 said:

i find my "Navigator" App for PC, but how upload 150MB?

Probably have to get an account with dropbox or mediafire or meganz - as far as I know all have a free account available that gives you a few gigs of hosting space. 

[AndyJWest]

1940s tech to calculate 'Air Mileage'.

 

Fitted to Lancasters during WW2. Later marks were still in use up to the 1960s.

 

Even with all that, you still need to know winds aloft to estimate your position. Apparently late-war RAF practice was for H2S-equipped aircraft at the front of the bomber stream to measure drift and thus calculate wind speeds, to transmit back to non-H2S aircraft behind. 

[JG4_Deciman]

On 12/22/2024 at 6:26 AM, Veteran66 said:

i find my "Navigator" App for PC, but how upload 150MB?

 

Sent you a link to my dropbox.

Maybe you can upload it there...

 

Deci

[Veteran66]

dropbox don`t work for me

 

hier he link:

 

https://www.file-upload.net/en/download-15430999/Navigator1.4.rar.html

 

[Stonehouse]

7 hours ago, Veteran66 said:

dropbox don`t work for me

 

hier he link:

 

https://www.file-upload.net/en/download-15430999/Navigator1.4.rar.html

 

 

Thanks that's an interesting one too but I actually meant your DR2 app for android phones. It is very handy to have your DR2 on your phone so you can easily use it during a mission.

[Veteran66]

12 hours ago, Stonehouse said:

 

Thanks that's an interesting one too but I actually meant your DR2 app for android phones. It is very handy to have your DR2 on your phone so you can easily use it during a mission.

 

 

here what i find on my android tablet

 

 

https://www.file-upload.net/download-15431351/Fliegeruhr.apk.html
https://www.file-upload.net/download-15431354/Navigator1.0.0.apk.html
https://www.file-upload.net/download-15431350/DR5_1.0.0.apk.html

[LLv44_Damixu]

On 12/15/2024 at 7:00 PM, JG4_Deciman said:

That is not enough...

 

Your instruments show IAS (indicated air speed), so how fast is your plane moving through the surrounding air.
This is absolutely nessassary to know if your plane is able to perform any manouvers and able to stay in the air.
But for navigation you need the 'speed over ground'.
And this speed is much more different from the 'IAS' when flying at higher altitudes or with wind and even effected by the temperature in that altitude...

You also need a course to fly (read from the compass).
This course is also affected by 'deviation' (not implemented in BoX), 'declination (not mplemented in BoX) and wind (IMPLEMENTED)

 

So steering a course of 0 degrees, taking the speed from the gauges, flying at 7000m and having wind from 90 degrees with 20 m/s

and then doing the base calculation without any recalculation for altitude, wind, temperature
will lead you somewhere when flying a course at a speed for a time, but NEVER where you want to go

(except you are flying at ground level with no wind)

 

 

Deci

And simply, to take only the wind....

You manage so start in a PO2 and head to the north, flying for an hour with 120km IAS on your gauges
The wind is blowing with 120 km/h from the north

Where will you be after 1 hour of flight?

 

Exactly where you started

 

(Even if I know that this scenario is impossible because you'l never make it to manage the take off)

But you don't a luxury to have the information of Ground Speed (GS) with WWII aircrafts so only information is IAS gauge to plan the course.

 

[JG4_Deciman]

1 hour ago, LLv44_Damixu said:

But you don't a luxury to have the information of Ground Speed (GS) with WWII aircrafts so only information is IAS gauge to plan the course.

 

 

I fully agree with that.

Just Continue reading my later posts and they'll show you how the ground speed can be (and was) calculated in that period...

 

Merry Chrismas

Deci

[czech693]

You can calculate your ground speed in pre-flight, but it can become of lesser value if you don't have winds aloft information.  We have that info today, but back then they didn't and it so navigating above a cloud deck was still best guess.

[AndyJWest]

1 hour ago, czech693 said:

You can calculate your ground speed in pre-flight, but it can become of lesser value if you don't have winds aloft information.  We have that info today, but back then they didn't and it so navigating above a cloud deck was still best guess.

 

Rather depends on how you define 'then'. For WWI, information regarding winds aloft was likely to be of limited accuracy, though a competent meteorologist could do better than pure guesswork. Soon after though, radio navigation aids of various sorts, along with e.g. celestial navigation tools made measuring such things in the air possible, and as the accuracy and range of such technology improved, so did the accuracy of wind forecasting. By early WW2, the allies were routinely despatching aircraft solely to gather meteorological data. 

 

 

[AEthelraedUnraed]

12 hours ago, AndyJWest said:

[...] so did the accuracy of wind forecasting. By early WW2, the allies were routinely despatching aircraft solely to gather meteorological data.

Yes, but that's not quite enough. For long flights deep into Germany, you're looking at a delay of 4 to 5 hours between takeoff and reaching the target, and a distance of 1000km. Even with perfect weather data, you can't be sure that still applies 4 hours later, and even with perfect local weather forecasts, you can't be sure your forecasts for Germany are accurate until you send an aircraft there.

 

That's why until late in the war when more advanced aids (e.g. ground radar) became available, you were very lucky if your bombs hit a target as large as a big city.

[JG4_Deciman]

1 hour ago, AEthelraedUnraed said:

Yes, but that's not quite enough. For long flights deep into Germany, you're looking at a delay of 4 to 5 hours between takeoff and reaching the target, and a distance of 1000km. Even with perfect weather data, you can't be sure that still applies 4 hours later, and even with perfect local weather forecasts, you can't be sure your forecasts for Germany are accurate until you send an aircraft there.

 

That's why until late in the war when more advanced aids (e.g. ground radar) became available, you were very lucky if your bombs hit a target as large as a big city.

If you miss the course you should be flying by only 1 degree (wind or not correctly beeing able to hold the course)
you'll miss your destination by 17.4m to the side for every Km of flown distance...

100 Km -> 1.74 Km

1000 Km -> 17.4 Km

And with stonger crosswinds there could be couse adjustment of 5 degrees or more.
 

Edited December 29, 2024 by JG4_Deciman

[AEthelraedUnraed]

46 minutes ago, JG4_Deciman said:

If you miss the course you should be flying by only 1 degree (wind or not correctly beeing able to hold the course)
you'll miss your destination by 17.4m to the side for every Km of flown distance...

100 Km -> 1.74 Km

1000 Km -> 17.4 Km

And with stonger crosswinds there could be couse adjustment of 5 degrees or more.
 

Yup... and while you can compensate for known crosswinds by using flight computers and accurate flying, you cannot compensate if the wind at 10km altitude over Germany is 6kph faster than your meteorologist predicted back in Britain 5 hours ago (with 6kph roughly corresponding to the 1 degree of your example).

 

Good calculations of ground speed and direction are very important to obtain the best guess of one's position - but it remains a guess.

[JG4_Deciman]

12 minutes ago, AEthelraedUnraed said:

Yup... and while you can compensate for known crosswinds by using flight computers and accurate flying, you cannot compensate if the wind at 10km altitude over Germany is 6kph faster than your meteorologist predicted back in Britain 5 hours ago (with 6kph roughly corresponding to the 1 degree of your example).

 

Good calculations of ground speed and direction are very important to obtain the best guess of one's position - but it remains a guess.

But without good calculations (even if there is a bit of a guess always included) you want to fly to Bremen and end up in Hamburg...

[AndyJWest]

2 hours ago, AEthelraedUnraed said:

Yes, but that's not quite enough. For long flights deep into Germany, you're looking at a delay of 4 to 5 hours between takeoff and reaching the target, and a distance of 1000km. Even with perfect weather data, you can't be sure that still applies 4 hours later, and even with perfect local weather forecasts, you can't be sure your forecasts for Germany are accurate until you send an aircraft there.

 

That's why until late in the war when more advanced aids (e.g. ground radar) became available, you were very lucky if your bombs hit a target as large as a big city.

 

Yup. The point I was responding to though was the suggestion that they had 'no information' about winds aloft. They put a lot of effort into collecting such information, so it was clearly useful.

 

As I noted earlier, one of the techniques the RAF used was to use H2S (and before that, GEE) in the early aircraft in a bomber stream to (hopefully) find the target, and mark it so that later aircraft could see it. For that to work, the non-H2S/GEE aircraft didn't need precision location, but they needed to be somewhere close enough to see the target (or at least, the glow through clouds). Sometimes this worked, sometimes it didn't. For it to work at all in typical European weather conditions, you needed all the information you could get.

 

 

[JFS4_Eisbaer]

Training with the triangular calculator (1942)
 

 

[Crious]

E6BX is your friend if you want to give it a little time before take off. Remember to convert ias to tas for the altitude you expected to fly and use the metric system for all values. Remember also to covert m/s to km/h for the wind speed. Then you are the blind man shooting at the world and ... wait for the ricochet.

Edited December 29, 2024 by 335th_GRAlbatros74

[MaxPower]

On 12/22/2024 at 12:30 PM, R33GZ said:

Well. There you go. I can now leave this forum feeling edumacated 

Give a google to a man / teach a man to google etc etc.

Edited January 4 by MaxPower

[[CPT]Crunch]

Memorize the maps, than use the force Luke, you'll never go wrong. 

[R33GZ]

4 hours ago, [CPT]Crunch said:

Memorize the maps, than use the force Luke, you'll never go wrong. 

this is the way, the truth and the light. This man speaks the truth

[JFS4_Eisbaer]

E6-B Manual link, link to a old original online version and link to a modern version.

 

https://mediafiles.aero.und.edu/aero.und.edu/aviation/trainers/e6b/?q=sliderule&q=sliderule

 

Link to modern online version:  https://e6bx.com/e6b/

 

 

 

 

 

 

 

 

Edited January 5 by JFS4_Eisbaer

[JFS4_Eisbaer]

Manual for Dreieckrechner DR 2 (German Luftwaffe)

 

Link to online version of Dreieckrechner DR 2

 

https://www.pumaszallas.hu/Private/VO101_Tom/Flash-DR3/DR3v10.htm
 

 

 

Dreieckrechner DR 2.zip

Edited January 13 by JFS4_Eisbaer

[JG4_Deciman]

On 1/13/2025 at 3:42 PM, JFS4_Eisbaer said:

Manual for Dreieckrechner DR 2 (German Luftwaffe)

 

Link to online version of Dreieckrechner DR 2

 

https://www.pumaszallas.hu/Private/VO101_Tom/Flash-DR3/DR3v10.htm
 

 

 

Dreieckrechner DR 2.zip 1.31 MB · 5 downloads

 

Thanks to Eisbär for these manual!

 

And as mentioned before
 

There IS a difference in the terms used...

Germans used 'Grundgeschwindigkeit' in their manuals (and during calculation)

And the 'direct' translation would be something like 'ground speed', which is NOT was it was.

 

The (german) 'Grundgeschwindigkeit' is the IAS (so speed read from the gauges) corrected by wind ONLY!
I guess that would match the TAS, but I'm not sure!

 

The important speed for navigation is the 'speed over ground'
And that speed results in IAS -> modify by wind -> modify by altitude, air pressure and temperature
or in the german way to calculate:

IAS -> modify by wind -> Grundgeschwindigkeit

Grundgeschwindigkeit -> modify by altitude, pressure and temperature -> Speed over Ground (Eile über Grund)

 

Deci