How did WW2 bombers navigate?

[vololiberista 205]

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

[january 19]

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

[vololiberista 205]

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

[mgh 89]

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.

[Alan_A 1,650]

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

[Chock 17,769]

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

[mgh 89]

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.

[Peter Clemenko 0]

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.

[teson1 0]

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."

[teson1 0]

And the following notes of a a WWII B-17 navigator may be of interest:http://www.stelzriede.com/warstory.htmGunter