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Guest Rockcliffe

How did WW2 bombers navigate?

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I'm assuming they didn't use dead reckoning, as they cruised at heights of about 30,000 feet and they flew in IMC. Tristan

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Why would you assume that? The whole point of ded reckoning is that you have no outside references for periods of time. It's perfect for traveling through weather and across wide expanses of ocean. Pilotage and ded reckoning were the main ways they found their targets. The only radio navaids they could have counted on were those based in friendly territory or planted by special forces, and that made their use quite limited. Even then, they could have been subject to meaconing.

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Hello Tristan,There are quite a bunch of good movies and books about WW2 bombers, check them out if you are interested in the subject, I would recommend Memphis Belle or you could read Stephen E. Ambrose's Wild Blue. A navigator was a part of the crew apart from the 2 pilots and gunners. They navigated with the aid of maps and compasses along with landmarks. Also bear in mind that there were night bombings so it wasn't just dead reckoning.Regards

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>I've heard that celestial navigation was used too. A recognition of>main stars could allow for latitude and longitude calculations. A >sextant and accurate watch would be needed.In the late 50s and early 60s, my ANG fighter unit had one C-47. It had a plexiglass turret on top where the navigator could "shoot" the stars with a sextant. Well that's what I was told. By then the old Gooney Bird was equipped with a direction finder (albeit with a hand-operated directional antenna) and even a VOR system. I don't believe it had DME nor do I think it was ILS-capable.This is the end of the history lesson; carry on.R-

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Tristan- early dead reckoning navigation to bomb targets in Germany was notoriously inaccurate. Often the attacking planes were miles off target. Later investigations showed this to be a waste of planes and crews. And the weather over Europe often meant that the target was never visible to the bomber crew. By 1943, electronics had developed to allow radio beam navigation to targets. "Gee" was the first such system, followed by "Oboe" and then "H2S", which if I recall, was a radar bombing system. Still the accuracy was very poor- to hit a specific factory, the bomber had to be extremely precisely positioned. The Royal Air Force and the Royal Canadian Air Force took on the task of night area bombing, often in very poor met conditions. The US 8th Air Force with the Norden bombsight had the task of precision daylight bombing of specific targets- an extremely dangerous mission until the long range P51 Mustang fighter was available to escort the B17s. To improve night bombing accuracy, the very fast DeHavilland Mosquito bomber was used in Pathfinder squadrons to fly the Oboe and H2S radio beams, then visually locate specific targets and drop coloured flares to indicate to the following bomber fleet where to release their bomb loads. With hundreds of bombers following the beams in a steady stream, a raid could take up to an hour or so, with the Pathfinders hanging around and dropping flares amidst heavy smoke, cloud, radar controlled searchlights & anti-aircraft fire and German night fighters trying to break up the formations and drive the bombers off target. So to answer your question- Yes, dead reckoning was used-especially on the return trip when many aircraft were way off the usual flight paths. A scary propostion in the dark with perhaps an engine shot out, nothing to be seen below through the cloud and the North Sea waiting for you when you ran out of gas after miscalculating your DR position. But the AGE of ELECTRONIC NAVIGATION had arrived !!Alex Reid

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>>A navigator was a part of the crew apart from the 2 pilots and>gunners. They navigated with the aid of maps and compasses>along with landmarks. Also bear in mind that there were night>bombings so it wasn't just dead reckoning.>>Regards>Night bombing and overcast bombing required them to use pathfinding aircraft. The general bomber force was typically not equipped or trained to do anything beyond pilotage, ded reckoning and night star shooting. Pathfinders in Europe would use systems like H2X or Oboe to find the target and then mark it with their bombs or give the drop command to the force. H2X was an airborne groundmapping radar system while Oboe used ground stations in friendly territory.

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Dead reckoning was certainly used, and caused a lot of missions to end up bombing the wrong city by mistake.Later in the war the first long range radio navigation systems came into use, allowing aircraft to determine their position with some accuracy based on the relative signal strengths from a series of radio transmitters at known locations in England.

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If you're interested in celestial navigation, have a look at the bubble sextant for FS uploaded by Dave Bitzer and Mark Beaumount (dc3_bbsx.zip). It approximates the procedure of celestial navigation. I must admit, I tried it a few times, but soon learned to appreciate at GPS! Still, it's one of the most inventive addons for FS I've ever seen.BlairCYOW

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Wow..totally relying on DR would have lead to quite a bit of navigation error. I guess they had specialist navigators on the flight, but for DR you really need to have regular reference to ground features, i.e positive fixes. Flying over extensive cloud cover without reference to the ground for long periods would certainly have caused track error, especially if wind aloft differed some what from forecast. Tristan

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Incidently, in Martin Middlebrook's book on the Berlin bombing raids he mentions that the bomber stream was thrown completely off course on one of the missions when it encountered 100 knot winds aloft. No one could believe such high winds could exist. In fact, they had just discovered the jet stream!My Dad was an RCAF navigator so I've always had an interest in this.BlairCYOW

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Another sidelight to aerial navigation in WWII was the system used by the DamBusters to maintain altitude on their famous raid. They had 2 spotlights- fore and aft which combined into one spot on the water when flying over the dam reservoirs at the precise altitude needed for the mines(bombs) to deploy properly.You can sort of duplicate this feat in Flight Sim. Fly over a large body of water at night so there are no land lights showing. Turn on landing lights, then descend slowly until these lights show on the water. Now fly at a precise/constant speed and maintain altitude using ONLY the refection of these lights on the water."Bombs Away Skipper!"PS- in the raid, the pretty streams of white, red, orange and green arcing toward you were NOT fireworks !!!!Alex Reid

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They did use de'd reckoning (deduced reckoning) in conjuction with celestial navigation and during daylight with star shots on the sun using sextants. They also used wind drift meters, and other gadgets like dropping a smoking canister in the water and tracking how far off bearing the aircraft would drift over a given distance. They also used the white caps on the ocean to see which way the wind was blowing and how hard (mostly only good for lower altitude I assume). Dive bomber pilots on U.S. carriers even carried sextants. Amelia Earhart had reported over the radio to the navy ship in the area of Howland Island that they had taken a line of position on the sun. Most searches today looking for her aircraft look along that line of position.Today we use celestial navigation just as they and seafarers did hundreds of years ago except we call it GPS and the stars are ones we put up there. Exact same concept though. Miller

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Flight Simulator teaches us a lot of bad habits - and basic navigation is one where we skip the basics.Most of us never plot our intended course across a map, never check our time between waypoints and calculate our ground speed and drift due to winds.In the first 30 minutes of flight a navigator on an aircraft of that age has a feel for the winds, their impact upon the intended course, the aircraft speed.An accurate watch was an early pilot's friend. Knowing how long it was taking to fly between two visual waypoints was critical.But celestial navigation was something quickly adopted by the aviation community - once they figured out how to create bubble sextants and handle height reduction.When I was in my first US Navy squadron in 1974 - navigators in our A-3 Skywarrior jets, our P-3 turboprops and our C-121 aircraft all routinely used the sextant.Of course we were based in Guam and there is a lot of open water out of the range of navaids to get from Guam to anywhere.My cousin was a B/N in F-4 Phantom's in 1967 when they flew the squadron aircraft from El Toro to Chu Lai.For many legs they needed the KC-135 tankers as pathfinders - but his description of having to find Wake Island on the leg from Midway when the pathfinder was grounded is scary. Of the eight navigators who thought they had a good position, four put the flight of 16 aircraft north of Wake and four put the flight south of Wake.Understanding and being able to use DR is a skill modern pilots need, but the workload has been so tremendously reduced that specially trained navigators are not needed in commercial aviation.But as one fellow who flies cargo B747's across the Pacific put it a couple days ago."Water on the right, land on the left - that's how to find Alaska when flying from China."

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The book North Star Over My Shoulder by Bob Buck talks a lot about celestial navigation, first a civilian pilot with Transport Command and later as chief pilot for TWA. He describes one flight from Alaska to Midway where, as you might guess, navigation was critical.

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It has all been said! Try to watch the film "The Dambusters" and then recreate it in the sim: moonlit night, flying to the dams at treetop height all the way from the English coast in order to avoid German radar.vololiberista

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It has all been said! Try to watch the film "The Dambusters" and then recreate it in the sim: moonlit night, flying to the dams at treetop height all the way from the English coast in order to avoid German radar.vololiberista
Test your flying skills- try flying FS in total darkness over a large body of water. Turn on your landing lights and descend until the lights can be seen on the water- then maintain your altitude by watching the lights ONLY.That's how the "Dambuster" Lancaster bombers were able to fly at about 50' altitude to drop the mines(bombs) precisely behind the wall of the Ruhr dams.(They had special lights at nose and tail aimed so that when the two beams intersected on the water surface,the pilot knew he was at the exact height needed for the mine to skip along the surface, then finally sink to the bottom just behind the rear face of the dam.)Alex Reid

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Test your flying skills- try flying FS in total darkness over a large body of water. Turn on your landing lights and descend until the lights can be seen on the water- then maintain your altitude by watching the lights ONLY.That's how the "Dambuster" Lancaster bombers were able to fly at about 50' altitude to drop the mines(bombs) precisely behind the wall of the Ruhr dams.(They had special lights at nose and tail aimed so that when the two beams intersected on the water surface,the pilot knew he was at the exact height needed for the mine to skip along the surface, then finally sink to the bottom just behind the rear face of the dam.)Alex Reid
I have already done that! The story of the Dambuster raid is well known and part of UK history. I have somewhere the original routings and it's challenging even in daylight. I have many years ago also had the priveledge of having a ride in the Lancaster during Air Show practice at Biggin Hill. It is noisy (understatement)The vibration is better than any massage you will ever have in your life (whoever she may be)!! The sound of four RR Merlins (only challenged by four RR Conways)!!!vololiberista

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I'm assuming they didn't use dead reckoning, as they cruised at heights of about 30,000 feet and they flew in IMC. Tristan
Initially they used dead-reckoning. The RAF began to use GEE - a crude form of LORAN - in 1942. Later the RAF used H2S - the first airborne ground-mapping radar - in 1943. The USAAF developed this into H2X.The need for navigation aids was made clear in the British Butt Report which showed that in 1941 only between 1 in 3 and 1 in 10 of the aircraft that claimed to have attacked its target actually got within 5 miles of it. During the early part of the war, 49% of the bombs the RAF dropped fell on open country, completely missing their targets.

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Another great source on WWII bomber navigation is Harry Crosby's memoir, A Wing and a Prayer. Crosby was group navigator of the 100th Bomb Group ("Bloody 100th"), 8th Air Force and also an excellent writer (he wound up as director of the writing program at Harvard). He goes into a lot of detail about how navigation was done and also the working life of the group - for example, the roles of group navigators, navigators in squadron lead planes and "rank and file" navigators, which is where he started. There's a really funny account of how he stumbled on Trondheim in his first big raid almost by accident - also some harrowing stuff about the Regensburg half of the Schweinfurt-Regensburg mission and a lot of atmosphere - you get a real sense of what it was like to be there. Really worth tracking down.Alan

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I too would recommend ready Harry H Crosby's On a Wing and a Prayer. It actually has quite a lot of useful info on navigational tricks that you could still make use of today.Crosby was undoubtedly a talented navigator, but he openly admits in his book, that it was operational experience, and not natural talent which made him so. As mentioned in an above post, Crosby kind of blundered into becoming the lead navigator for the group, when a series of lucky coincidences made people think he was a a whizzkid. As a result, he had to raise his game to live up to the reputation he gained by that luck, and fortunately, he was also lucky enough to survive long enough to manage that.To elaborate on how he got lucky, he was asked at the start of his tour of operations, to fill in for the group's lead navigator, who was unable to fly that day. The mission was to Trondheim, and Crosby made a lot of mistakes owing to his inexperience, but these mistakes ended up making the raid more successful. For example, he forgot to make several radio calls reporting his position, but in doing so, the enemy aircraft patrolling the area could not home in on radio signals, and only two aircraft managed to intercept the raid, both of these being shot down. He also got a little bit lost and had to fly up the enemy coast to find a recognisable geographical feaure, as a result, the raid came over the target and dropped its bombs on a factory when the local population were switching shifts, so not civilians were hit. The resistance thought that was deliberate and were full of praise for what they presumed was the raid navigator's cunning ploy! On the return leg, Crosby could not find an accurate heading for a return to the UK, and so he turned the formation well to the north so that when he hit the UK coast, he would know that flying south down the coast would take him the right way to get back to base, as a result of that, patrolling enemy fighters were too far south to intercept the raid and completely missed it. As a result of several other such happy mishaps along those lines, Crosby was regarded as a 'wonderkid', and that's how he ended up being earmarked as a potential lead navigator for the group.Being in the lead plane of a B-17 formation was generally not a healthy place to be, since Luftwaffe fighters tended to go for that aircraft so that the raid's coherence was affected. Most navigators further back in the formation were in large part not required to do much other that keep a log, since the aircraft would merely keep formation with the others, who would all be following the lead aircraft.Crosby points out that although he would sometimes use an E6B, often he would simply throw in doglegs based on predicted winds in order to make rendezvous on time, and he did eventually develop a real talent for doing those with split-second accuracy. As the war progressed, such weather reports got better, making navigation easier, but even before that was the case, daylight bombers could do something which night bombers could not, and that was dropping smoke bombs to observe the drift through a sight in the floor of the aircraft. since daylight raids relied on good weather most of the time in order to be able to see the target, the chances were also good that sightings of the terrain could be used to assist with determinging position, although later in the war, many raids used H2S radar to bomb through the cloads layer, so it wasn't always an option.Both the Allies and the Axis made use of radio beacons to assist with navigation. Initially, the Germans used a system called 'knickbein' (literally translates as 'crooked leg'), which was essentially a pair of radio beacons widely spaced apart which could send directional signals (this is basically how we would navigate today using a could of VOR beacons to fix our position where the radials cross one another). With knickbein, both beacons would be aimed at a target city. The bombers would fly along one of the beams, when they got to the point where they crossed the other beam, a clockwork timer would start and a few seconds later, the bombs would be automatically released, enabling fairly accurate nighttime bombing of cities in the UK to be done. However, since the radio beacons would be tested earlier in the day, and then switched on for the raid at night, the UK's air defence intelligence people were often well aware of where a raid would be taking place that evening and could put up a screen of night fighters to patrol the route into the target.The Allied version of that kind of system was a somewhat more sophisticated, and was called GEE. GEE worked essentially in the same way as GPS does, although using ground based transmitters rather than the satellites which GPS uses. There were a number of GEE 'master' stations at varius locations in the UK, each of which would have a pair of slave stations some distance away. These would transmit timed pulses, and the GEE box in the aircraft could decode the pulses. Based on calculating the timing differential of the master and slave signals, an oscilloscope in the bomber would display a specific pattern on screen. These patterns could be compared to a sheet with illustrations of what pattern the scope would display when the aircraft was at various locations. Effectively, this is very similar to how GPS works, although of course we have a nice moving map rather than a pattern on an oscilloscope to deciopher. GEE was in fact accurate enough at short range to be used to make blind landings if the GEE operator was skilled enough, but in practice, it tended to be accurate to perhaps a coule of miles when a long way over enemy territory.Al

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Knickebein was developed from the Lorenz blind landing sustem. The airborne Kickebein equipment was made to look like the Lorenz equipment to fool the British should an aircarft be captured. Fortunately when one was, the investigators realised it was far to sensitive than needed simply for ILS!The main Knickebein transmitter was effectively a high powered ILS localiser which the aircraft flew away from. It transmitted two beams one giving a series of dots to the left of the centreline and a the other a series of dashes to the right. The two beams overlapped along a relatively narrow centreline where the received strengths of the dashes matched those of the dots to give a continuous signal. The idea was that aircraft would fly along the centre line until they intercepted an other, crossing, beam which was the signal to initiate the bombing sequence, as has already been said. The British were eventually able to "bend the beam" by transmitting spurious dots at the correct times so that the aircraft drifted away from the centre-line of the origanal beam. Because the Germans relied almost entirely on the beams for navigation and neglected the need for dead reckoning, their aircraft then tended to become lost and sometimes unable to navigate back to Germany. The Germans went on to develop X-Geraet and and Y-Geraet and the British responded with counter-measures. Google "Battle of the Beams" for more detailsGEE used sets of three stations, one master and two slaves all of which transmitted pulses at timed intervals. The time differences between the pulse were shown a a CRT and the navigator was provided with a map overprinted with hyperbolic curves. Each curve represented a line of constant time difference between the master and a slave station. The navigator had to find the intersection of the two curves representing the two slave stations to determine position. GEE could also be jammed simply by transmitting surplus pulses.

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Dead reckoning and map and compass were what they used. That's why a lot of WWII bombers got lost and never saw again on missions, especially in bad weather and at night.

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The following article gives an overview of navigation methods, including during WW2:http://www.airforce-magazine.com/MagazineArchive/Pages/1984/December%201984/1284navigation.aspxWhile radio and radar methods mentioned earlier greatly improved success of bombing missions, classic navigation methods (DR, celestial) were widely employed, in particular during the first years of WW2.AAF Advanced navigation training manual 1944:http://aafcollection.info/items/list.php?item=000198"Navigation contains one basic element, dead reckoning, which is supplemented by three aids: map-reading, radio and celestial."

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