Interesting Information

H2S (answers credited to Mark Simpson & Gaz Greggson - FB Posts on Friends of 625 Squadron Group)

H2S is the code name for the onboard groundscanning radar carried by heavy bombers, used as a navigation aid, and a blind bombing aid for PFF squadrons. The aerial was housed in the bulge seen under heavy bombers. The phrase "'Y' Training" sometimes seen in Operational Record Books refers to navigational training flights carried out using H2S.  H2S was a ground radar system fitted to RAF aircraft from 1943 onwards. You may notice the pear shaped bulge beneath Stirlings, Lancasters and Halifaxes. It was able to show the ground terrain as an aid to bombing accuracy. 

Log Books

All crew members kept a log book from the first flight to their last in the RCAF or RAF.  The log book was kept by that crew member and checked periodically by the Commanding officers of his air force unit.  Most log books were kept by the crew member AFTER they finished their career but many were lost or destroyed after time.  There is no such thing as a master library where an individual airmen's log book is stored.

The "Erks" - Ground Crew (answer credited to 419 Squadron Website)

The aircrews of the mighty bombers of Bomber Command were an important part of the hammer that struck out against the Axis Powers.  Overcoming the fear and hardships of the flights over the Fortress Europe, time and time again.  Their bravery and devotion to duty was plain for all to see.  The newspapers and dispatches retold their exploits to the world at war.

Behind the scenes and not always fully rewarded for the work they did were the groundcrew members.  Who spent loving care on their aircraft, for the aircrews only borrowed the aircraft, the groundcrew were its sole owners in their own eyes.  It was also these men of the various trades who watched the takeoffs and remembered past crews who they had also watched leave and failed to return.  The deep emotions that sunk into these men as they watched and realized that their ship and crew were not among those that had returned to base.

Then there could be the shock and horror of helping medicals with removing the wounded and dead from the aircraft, men you knew and now the best you could do was help carry them out of aircraft.  And then the scene in the day light as they groundcrew returned to the bomber to start the repairs and the cleanup.

Each flight would have a Flight Sergeant in charge of 10 or so aircraft, the crew of an aircraft was headed by a Sergeant or Acting Sergeant, usually a Corporal.  Then there were riggers, fitters, armourers, instrument technicians, radar technicians, radio technicians and those who fueled the aircraft.  Riggers were responsible for the airframe and related parts, gaining their name from the original riggers on WWI bi-planes who worked on the cables, turnbuckles and wooden struts to “tune” the airframe.  Fitters, some times nick named “engine bangers” amongst other things were responsible for engines and other mechanical components.  Aircraft inspection would include checking all engine controls from cockpit to the engines themselves, all hydraulics and pneumatics all electrical systems, navigation and communication systems, lights, brakes and more items which had specific checks based on the number of hours of use on that part.  The air crew also would supply a list of items they wanted checked from previous flight.  Their would be engine checks while running up the engines on the ground to check for leaks, sticking valves, burning oil, and checking the output of the electrical generating device the magneto.  Oxygen systems, gun turret operation and intercoms were all essential to the safe operation of the aircraft while in the air.

The most common rank for the trades was LAC Leading Aircraftman, and never ever Aircraftsman, it was Aircraftman.  LAC was not really a rank in the true sense, they had no powers of discipline over subordinates.  LAC was a badge of accomplishment for having completed their trade training with high marks.  The first true rank would be Corporal.

The term Erks which seemed to come from RAF slang that flowed over to other air forces and was a general term to cover those below Corporal.  The Erks plied their trades out in the open air, hangers were for longer overhauls.  No matter what the weather was like the trades worked at repairing, tuning and testing engines or instruments, hydraulics, guns airframe repairs or modifications.  It was not a glamorous job in the least, the work went on until the job was done no matter how tired, cold or wet you were.  Depending on a number of things outside of Erks control they could get a 48 hour pass every month or on occasion a leave.

Always putting their best work into the job at hand to do their part to bring the crews home safely.  The ground crew members were not except from the harms of war or accidents which killed and injured many in their number.  Climbing up slippery wet or icy scaffolding, crawling across wings and fuselages under these same slippery conditions sometimes let to serious mishaps.  Even in the best attempts to work safely, working with heavy items such as engines, wheels or being in the wrong place could bring about deadly consequences. The cold and wet would also take their toll on the health of the tradesmen too devoted to the job not to continue when they should have been hospitalized.

For the most part the aircrews respected the work that the crews put in to keep the aircraft in top form.  Sometimes it was a simple “well done” to the Sergeant in charge from the officer signing off on the Form 700, the official form returning the aircraft to the aircrew for their journey into the hell over of the Fortress Europe.

Airframe Icing (answer provided by Jack Albrecht)

Airframe icing is usually encountered in cloud when an aircraft comes in contact with supercooled water droplets that freeze on contact with an aircraft’s surface. The rate of ice accumulation can vary from slow to extremely rapid. The latter occurring in cumulonimbus clouds (thunderstorms) or freezing rain. The build-up of ice can significantly upset the aerodynamics and stability of an aircraft’s flight characteristics.

In stabilized level flight there is equilibrium between two pairs of opposing forces: lift and weight, thrust and drag.

Air frame icing has the potential to negatively impact all four forces simultaneously. Ice on the wings disturbs the laminar flow that creates lift, increasing the stall speed. Increase in weight and drag are obvious with increase in mass and turbulence. Thrust will be affected as air intake for combustion is obstructed.

Once icing conditions are encountered it is critical that remedial measures are taken before the aircraft becomes an uncontrollable ice cube—the urgency depending on the rapidity of build-up. Most critical is to exit the local conditions that caused the problem, by climbing, descending or course reversal, lighten the load by jettisoning bombs or fuel and maintain control with fingers crossed that the weight and balance have the centre of gravity within limits. The worst case scenarios would be to stall the aircraft with a Centre of Gravity" aft of limits, resulting in an unrecoverable flat spin or overstressed airframe and inflight break-up.

During the Bomber Command campaign, one raid would go down in the annals as the night of ice and it would take a devastating toll on the R.C.A.F. crews of Group 6, in particular Squadrons 420, 425 and 426. For five crews, possibly seven, the March 5/6 1945 raid on Chemnitz would bring an abrupt end to their operational tours before they had cleared the English coast.

The met briefing for all Group 6 squadrons was not particularly ominous: seven-tenths to ten-tenths stratocumulus from 1,000 to 3,000 feet and altocumulus from 8,000 to 9,000 feet. Likelihood of icing was moderate and no embedded surprises, such as cumulonimbi (CBs - thunderstorms), with their risk of severe icing or structure popping up and down drafts. It would not take long to prove that this forecast underestimated the cloud thickness, risk of icing and that in this part of the sky, lurking, embedded cumulus or CBs had developed.

Where did Lancaster training take place? (answer provided by Christopher Dean and Mike Wainwright)

In the UK. Although some pilots and navigators gained their flying badges in Canada, they returned to the UK for crewing up and training to fly the bombers. Very often, the crews learned to fly four - engine heavies on Stirlings and Halifaxes before carrying out a quick conversion to Lancasters on the Lancaster Finishing Schools (LFS). That all said, of course, the training routes changed during the War and there were some subtle variations with the naming of the various training unit types. Generally, the crews began bomber training on twin engine aircraft (typically, but not exclusively on the Wellington) at an Operational Training Unit (OTU) before moving to a Heavy Conversion Unit (HCU) to learn four - engine aircraft. Then to the afore mentioned LFS and finally their squadron.  Aircrew also trained in South Africa.  It was only right at the end of training that a crew flew in Lancasters though, known as LFS, in the UK.

Interview with 2 Members of a Lancaster Crew from the Pathfinders #7 Squadron, F/L Edwin "Bud" Cy, Pilot, DFC and F/Eng. Frank Pointer  

The interview took place in 1995, 50 years after their discharge.  The interview was conducted at the Bomber Command Museum in Nanton, Alberta, Canada.  The interview describes the flying procedures that were used to fly the Lancaster on bombing sorties.  The interview is absolutely fascinating and describes in great detail how the aircraft was flown.  The degree of detail that is exhibited in the interview from the two crew members is simply amazing.  It's as if they had just flown the day before the interview.  Click here to launch the interview.

Roles of the Wireless Operator (information provided by Jim Hocking)

In a Lancaster bomber crew, the wireless operator was responsible for transmitting and receiving radio messages, acting as a reserve gunner, and monitoring equipment like "Monica" or "Fishpond". 

Primary Duties:

• Radio Communication: The wireless operator transmitted and received messages to and from the aircraft to base, though operations were often conducted in wireless silence. 

• Reserve Gunner: In addition to their radio duties, the wireless operator was also trained to act as an air gunner in an emergency.

• Equipment Monitoring: They were also responsible for monitoring the "Monica" or "Fishpond" equipment, which were used for navigation and radar. 

• Distress Signals: If the aircraft got into difficulties or had to ditch into the sea, the wireless operator had to remain at his post to send out a distress signal.

Location:

The wireless operator's position was located just after the navigator's position on the port side of the aircraft. It was the warmest position in the aircraft – next to the heater!

Other Responsibilities:

• Discharging "Window": They were also tasked with discharging "Window," which was a type of chaff used to disrupt enemy radar.

How did Navigators on Lancaster Bombers Navigate to the Target and Back to their Station?

During World War II, the RAF’s Bomber Command relied on a sophisticated array of navigational systems and tools to guide bombers such as the Avro Lancaster through the often challenging conditions of wartime operations. These systems evolved significantly between 1940 and 1945 and were the result of rapid technological innovation under pressing wartime demands. Below is a detailed overview and explanation of the principal systems and tools used during that period:

1. Traditional Navigation Methods

Dead Reckoning and Pilotage

• Dead Reckoning:
  Early in the war, and even throughout it as a backup method, navigators would determine their position by calculating the aircraft’s course, speed, time, and estimated winds. This involved plotting a course on a map and updating position estimates as the flight progressed.

• Pilotage:
  Pilots and navigators also relied on visual references to terrain, landmarks, and airfields—a method known as pilotage. However, its usefulness was diminished at night or in poor weather, underscoring the need for more reliable electronic systems.

2. Radio Navigation Systems

Gee Navigation System

• Concept and Operation:
  Gee was one of the earliest and most widely used radio navigation systems. It worked on the principle of time-delay measurement between signals sent from pairs of ground-based transmitters.

• How It Worked:
  A Lancaster bomber was equipped with receivers that picked up pulsed signals from several synchronized transmitter stations. By measuring the difference in the arrival times of these pulses, navigators could determine their distance from each transmitter. With signals from at least two stations, a position could be triangulated.

• Advantages and Limitations:
  Gee was highly effective for establishing a bomber’s position, especially over the relatively flat terrain of parts of Europe. However, its accuracy was affected by factors such as signal reflection (multipath effects) and limited range.

Oboe System

• Purpose and Precision:
  Developed later in the war for increased bombing accuracy, Oboe was a precision radio navigation and blind-bombing system. It was used on select operations to mark targets precisely.

• Operational Details:
  The system used two ground stations. One station transmitted a signal that was then received and retransmitted by the aircraft’s Oboe equipment. The ground operators measured the time delay of the return signal, and through careful timing and coordination, controlled the bomb run to ensure the aircraft reached the exact point in space designated as the target.

• Challenges:
  While highly accurate, Oboe was complex and required a high level of coordination between the ground station and the aircraft. Its use was generally limited to missions where high precision was critical.

3. Radar Systems

H2S Radar

• Innovation in Aerial Navigation:
  As electronic warfare evolved, radar emerged as a critical tool not only for detecting enemy aircraft but also for navigation. H2S was the first ground-mapping radar fitted to British bombers.

• How H2S Worked:
  Mounted in the nose of the Lancaster, H2S emitted microwave pulses towards the ground and analyzed the time delay of the reflected signals. This allowed it to produce images (radar "maps") of the ground below.

• Key Benefits:

  • All-Weather Capability: H2S was particularly valuable for navigation in adverse weather conditions, low visibility, or during night missions when visual landmarks were not available.

  • Target Identification: The radar image could reveal coastlines, rivers, roads, and even large buildings, assisting navigators in correlating radar returns with map features.

• Operational Impact:
  The H2S system greatly enhanced the accuracy of bombing runs, reducing the reliance on less accurate methods such as dead reckoning and visual pilotage during critical phases of the mission.

4. Integration and Crew Coordination

The Role of the Navigator

• Multi-System Integration:
  Navigators in Lancaster bombers were trained to integrate information from several sources. A typical crew member would simultaneously compare readings from dead reckoning, Gee, and, where available, H2S radar displays.

• Procedural Cross-Checks:
  Mission protocols often required navigation to be checked at various waypoints using different systems. This redundancy ensured that if one system was compromised or gave erroneous data—due, for example, to enemy jamming or atmospheric interference—the others could provide a corrective check.

• Impact on Bombing Accuracy:
  These layered navigation systems enabled Bomber Command to reach targets with significantly improved precision over the early war years. The integration of radio and radar navigation allowed for more effective bombing strategies and was a key factor in the evolving air campaign.

5. Technological Evolution and Operational Challenges

• Rapid Innovation Under Pressure:
  The period from 1940 to 1945 saw rapid improvements. Early reliance on traditional methods gradually shifted towards a heavier dependence on electronic aids as these systems matured.

• Countermeasures and Electronic Warfare:
  As the Allies developed advanced navigation aids, the Axis powers began to deploy countermeasures. The continual improvement of systems like Gee, Oboe, and H2S was partially driven by the need to overcome enemy jamming and deception tactics.

• Crew Training and Adaptability:
  Effective use of these systems required extensive training. Navigators and bomber crews underwent rigorous instruction to master both the technical aspects of the equipment and the tactical procedures necessary for wartime missions.

Conclusion

The navigational systems used on Lancaster bombers during the period of 1940 to 1945 represent a remarkable blend of traditional navigation techniques with cutting-edge electronic aids. Systems such as Gee and Oboe provided essential radio navigation capabilities, while H2S radar offered a revolutionary means of acquiring ground images for navigation and target identification. Together, these technologies not only improved the accuracy of bombing missions but also exemplified the rapid pace of innovation driven by the exigencies of war.

These combined efforts in technological development and crew training were pivotal in shaping the air war strategy of Bomber Command, ensuring that Lancaster bombers could perform precision strikes under extremely challenging conditions.