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131-694: H2X , officially known as the AN/APS-15 , was an American ground scanning radar system used for blind bombing during World War II . It was a development of the British H2S radar , the first ground mapping radar to be used in combat. It was also known as the "Mickey set" and "BTO" for "bombing through the overcast" radar. H2X differed from the original H2S primarily in its X band 10  GHz operating frequency rather than H2S' S band 3 GHz emissions. This gave H2X higher resolution than H2S, allowing it to provide usable images over large cities which appeared as

262-495: A GPR on its underside to investigate the soil and crust of the Moon. Engineering applications include nondestructive testing (NDT) of structures and pavements, locating buried structures and utility lines, and studying soils and bedrock. In environmental remediation , GPR is used to define landfills, contaminant plumes, and other remediation sites, while in archaeology it is used for mapping archaeological features and cemeteries. GPR

393-520: A bomb load of 3,000 lb (1,400 kg) for 3,000 mi (4,800 km) with a maximum speed of 275 mph (445 km/h) at 15,000 ft (4,600 m); a maximum bomb load of 8,000 lb (3,600 kg) carried over shorter ranges was also required. Aviation firms entered heavy designs with new high-powered engines and multiple defensive turrets, leading to the production of the Avro Manchester and Handley Page Halifax . In May 1937, as

524-525: A comparison to P.13/36, George Volkert , the chief designer of Handley Page , put forward the concept of a fast, unarmed bomber. In 20 pages, Volkert planned an aerodynamically clean, medium bomber to carry 3,000 lb (1,400 kg) of bombs at a cruising speed of 300 mph (485 km/h). Support existed in the RAF and Air Ministry; Captain R. N. Liptrot, Research Director Aircraft 3, appraised Volkert's design, calculating that its top speed would exceed that of

655-417: A compartment under the cockpit floor with the breeches projecting into the bomb bay and the automatic bomb bay doors were replaced by manually operated bay doors, which incorporated cartridge ejector chutes. As a day and night fighter, prototype W4052 was equipped with AI Mk IV equipment, complete with an "arrowhead" transmission aerial mounted between the central Brownings and receiving aerials through

786-400: A considerable altitude was attained. The aircraft reached 220 mph (355 km/h), with the only problem being the undercarriage doors, which were operated by bungee cords attached to the main undercarriage legs,and remained open by some 12 in (300 mm) at that speed. This problem persisted for some time. The left wing of E-0234 also had a tendency to drag slightly to port, so

917-455: A cruising speed of 325 mph (525 km/h) at 26,500 ft (8,100 m) with a range of 1,500 mi (2,400 km) at 25,000 ft (7,600 m) on full tanks. Maximum service ceiling was to be 32,000 ft (9,800 m). On 1 March 1940, Air Marshal Roderic Hill issued a contract under Specification B.1/40, for 50 bomber-reconnaissance variants of the DH.98; this contract included

1048-503: A delivery rate far in advance of competing designs. Without armament, the crew could be reduced to a pilot and navigator. Whereas contemporary RAF design philosophy favoured well-armed heavy bombers, this mode of design was more akin to the German philosophy of the Schnellbomber . At a meeting in early October 1938 with Geoffrey de Havilland and Charles Walker (de Havilland's chief engineer),

1179-626: A design with a clear perspex bomb-aimer's position, to one with a solid nose housing four .303 machine guns and their ammunition. On 3 November 1940, the prototype aircraft, painted in "prototype yellow" and still coded E-0234 , was dismantled, transported by road to Hatfield and placed in a small, blast-proof assembly building. Two Merlin 21 two-speed, single-stage supercharged engines were installed, driving three-bladed de Havilland Hydromatic constant-speed controllable-pitch propellers . Engine runs were made on 19 November. On 24 November, taxiing trials were carried out by Geoffrey de Havilland Jr. ,

1310-442: A few centimetres. Ground-penetrating radar antennas are generally in contact with the ground for the strongest signal strength; however, GPR air-launched antennas can be used above the ground. Cross borehole GPR has developed within the field of hydrogeophysics to be a valuable means of assessing the presence and amount of soil water . The first patent for a system designed to use continuous-wave radar to locate buried objects

1441-419: A full-scale mock-up at Hatfield on 29 December 1939, the project received backing. This was confirmed on 1 January 1940, when Freeman chaired a meeting with Geoffrey de Havilland, John Buchanan (Deputy of Aircraft Production), and John Connolly (Buchanan's chief of staff). De Havilland claimed the DH.98 was the "fastest bomber in the world ... it must be useful". Freeman supported it for RAF service, ordering

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1572-502: A larger rudder tab. It continued to serve as a test machine until it was scrapped on 28 January 1946. 4055 flew the first operational Mosquito flight on 17 September 1941. During flight testing, the Mosquito prototypes were modified to test a number of configurations. W4050 was fitted with a turret behind the cockpit for drag tests, after which the idea was abandoned in July 1941. W4052 had

1703-477: A motion sensor for military guards and police. An overview of scientific and engineering applications can be found in: A general overview of geophysical methods in archaeology can be found in the following works: De Havilland Mosquito The de Havilland DH.98 Mosquito is a British twin-engined, multirole combat aircraft , introduced during the Second World War . Unusual in that its airframe

1834-451: A number of additional reinforcements and special details. Spruce and plywood ribs were connected with gusset joints. Some heavy-duty ribs contained pieces of ash and walnut, as well as the special five ply that included veneers laid up at 45°. The upper skin construction was in two layers of 0.25-in five-ply birch, separated by Douglas fir stringers running in the span-wise direction. The wings were covered with madapollam fabric and doped in

1965-408: A radar signal travels is dependent upon the composition of the material being penetrated. The depth to a target is determined based on the amount of time it takes for the radar signal to reflect back to the unit’s antenna. Radar signals travel at different velocities through different types of materials. It is possible to use the depth to a known object to determine a specific velocity and then calibrate

2096-435: A range of 1,500 mi (2,400 km) carrying a 4,000 lb bomb load, with a maximum of 260 mph (420 km/h) at 19,000 ft (5,800 m), and a cruising speed of 230 mph (370 km/h) at 18,000 ft (5,500 m). De Havilland believed that a compromise, including eliminating surplus equipment, would improve matters. On 4 October 1938, de Havilland projected the performance of another design based on

2227-521: A range of 3,000 mi (4,800 km) with a 4,000-lb bomb load. To appease the ministry, de Havilland built mock-ups with a gun turret just aft of the cockpit, but apart from this compromise, de Havilland made no changes. On 12 November, at a meeting considering fast-bomber ideas put forward by de Havilland, Blackburn , and Bristol , Air Marshal Freeman directed de Havilland to produce a fast aircraft, powered initially by Merlin engines, with options of using progressively more powerful engines, including

2358-474: A receiver. The travel time of the reflected signal indicates the depth. Data may be plotted as profiles, as planview maps isolating specific depths, or as three-dimensional models. GPR can be a powerful tool in favorable conditions (uniform sandy soils are ideal). Like other geophysical methods used in archaeology (and unlike excavation) it can locate artifacts and map features without any risk of damaging them. Among methods used in archaeological geophysics, it

2489-486: A sectional (profile) view of the subsurface. Multiple lines of data systematically collected over an area may be used to construct three-dimensional or tomographic images. Data may be presented as three-dimensional blocks, or as horizontal or vertical slices. Horizontal slices (known as "depth slices" or "time slices") are essentially planview maps isolating specific depths. Time-slicing has become standard practice in archaeological applications , because horizontal patterning

2620-513: A shorter 3 cm "centimetric" wavelength (10 GHz frequency) than the H2S, giving a higher angular resolution and thus a sharper picture, which allowed much finer details to be discerned, aiding in target identification. H2S subsequently also adopted 3 cm in the Mark III version entering operational service on 18 November 1943, for " Battle of Berlin "). H2X is not known to have ever been spotted by

2751-404: A similar manner to the fuselage. The wing was installed into the roots by means of four large attachment points. The engine radiators were fitted in the inner wing, just outboard of the fuselage on either side. These gave less drag. The radiators themselves were split into three sections: an oil cooler section outboard, the middle section forming the coolant radiator and the inboard section serving

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2882-464: A single 2,000 hp (1,500 kW) Napier Sabre, with a wingspan of 47 ft (14 m) and capable of carrying a 1,000 lb (450 kg) bomb load 1,500 mi (2,400 km). On 20 September, in another letter to Wilfrid Freeman, de Havilland wrote "...   we believe that we could produce a twin-engine bomber which would have a performance so outstanding that little defensive equipment would be needed." By 4 October, work had progressed to

3013-499: A single blob on the H2S display. The Royal Air Force (RAF) initially considered using H2X as well, but would instead develop their own X band system, the H2S Mk. III. The RAF system entered service in late 1943, before the first use of H2X in early 1944. The desire for even higher resolution, enough to image individual docks and bridges, led to a number of variations on the H2X system, as well as

3144-465: A single prototype for an unarmed bomber to specification B.1/40/dh, which called for a light bomber/reconnaissance aircraft powered by two 1,280 hp (950 kW) Rolls-Royce RM3SM (an early designation for the Merlin 21) with ducted radiators , capable of carrying a 1,000 lb (450 kg) bomb load. The aircraft was to have a speed of 400 mph (640 km/h) at 24,000 ft (7,300 m) and

3275-431: A slight change in the angle of the wing was carried out before further flights. On 5 December 1940, the prototype, with the military serial number W4050 , experienced tail buffeting at speeds between 240 and 255 mph (385 and 410 km/h). The pilot noticed this most in the control column, with handling becoming more difficult. During testing on 10 December, wool tufts were attached to suspect areas to investigate

3406-521: A steel-tube frame. The idea of a small, fast bomber gained support at a much earlier stage than is sometimes acknowledged, though the Air Ministry likely envisaged it using light alloy components. Based on his experience with the Albatross, Geoffrey de Havilland believed that a bomber with a good aerodynamic design and smooth, minimal skin area, would exceed the P.13/36 specification. Furthermore, adapting

3537-602: A system to determine whether landmines are present in areas using ultra wideband synthetic aperture radar units mounted on blimps . In Pipe-Penetrating Radar (IPPR) and In Sewer GPR (ISGPR) are applications of GPR technologies applied in non-metallic-pipes where the signals are directed through pipe and conduit walls to detect pipe wall thickness and voids behind the pipe walls. SewerVUE Technology, an advanced pipe condition assessment company utilizes Pipe Penetrating Radar (PPR) as an in pipe GPR application to see remaining wall thickness, rebar cover, delamination, and detect

3668-423: A twin-engined light bomber with a wingspan of 51 ft (16 m) and powered by Merlin or Griffon engines, the Merlin favoured because of availability. On 7 October 1939, a month into the war, the nucleus of a design team under Eric Bishop moved to the security and secrecy of Salisbury Hall to work on what was later known as the DH.98. For more versatility, Bishop made provision for four 20 mm cannon in

3799-605: Is always a trade-off between resolution and penetration. Optimal depth of subsurface penetration is achieved in ice where the depth of penetration can achieve several thousand metres (to bedrock in Greenland) at low GPR frequencies. Dry sandy soils or massive dry materials such as granite , limestone , and concrete tend to be resistive rather than conductive, and the depth of penetration could be up to 15 metres (49 ft). However, in moist or clay-laden soils and materials with high electrical conductivity, penetration may be as little as

3930-558: Is often the most important indicator of cultural activities. The most significant performance limitation of GPR is in high-conductivity materials such as clay soils and soils that are salt contaminated. Performance is also limited by signal scattering in heterogeneous conditions (e.g. rocky soils). Other disadvantages of currently available GPR systems include: Radar is sensitive to changes in material composition; detecting changes requires movement. When looking through stationary items using surface-penetrating or ground-penetrating radar,

4061-401: Is one method used in archaeological geophysics . GPR can be used to detect and map subsurface archaeological artifacts , features , and patterning. The concept of radar is familiar to most people. With ground penetrating radar, the radar signal – an electromagnetic pulse – is directed into the ground. Subsurface objects and stratigraphy (layering) will cause reflections that are picked up by

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4192-428: Is pleasant to fly ... aileron control light and effective   ..." The maximum speed reached was 388 mph (624 km/h) at 22,000 ft (6,700 m), with an estimated maximum ceiling of 34,000 ft (10,000 m) and a maximum rate of climb of 2,880 ft/min (880 m/min) at 11,500 ft (3,500 m). W4050 continued to be used for various test programmes, as the experimental "workhorse" for

4323-547: Is rather small (20–30 cm), but lateral resolution is enough to discriminate different types of landmines in the soil, or cavities, defects, bugging devices, or other hidden objects in walls, floors, and structural elements. GPR is used on vehicles for high-speed road survey and landmine detection. EU Detect Force Technology, an advanced soil research company, design utilizes X6 Plus Grounding Radar (XGR) as an hybrid GPR application for military mine detection and also police bomb detection. The "Mineseeker Project" seeks to design

4454-534: Is the case with seismic energy. The electrical conductivity of the ground, the transmitted center frequency , and the radiated power all may limit the effective depth range of GPR investigation. Increases in electrical conductivity attenuate the introduced electromagnetic wave, and thus the penetration depth decreases. Because of frequency-dependent attenuation mechanisms, higher frequencies do not penetrate as far as lower frequencies. However, higher frequencies may provide improved resolution . Thus operating frequency

4585-441: Is unique both in its ability to detect some small objects at relatively great depths, and in its ability to distinguish the depth of anomaly sources. The principal disadvantage of GPR is that it is severely limited by less-than-ideal environmental conditions. Fine-grained sediments (clays and silts) are often problematic because their high electrical conductivity causes loss of signal strength; rocky or heterogeneous sediments scatter

4716-407: Is used in law enforcement for locating clandestine graves and buried evidence. Military uses include detection of mines, unexploded ordnance, and tunnels. Borehole radars utilizing GPR are used to map the structures from a borehole in underground mining applications. Modern directional borehole radar systems are able to produce three-dimensional images from measurements in a single borehole. One of

4847-544: The AN/APQ-13 became the first military radar converted to a domestic peacetime application as a storm warning radar. About thirty systems were converted and installed on military bases. It was replaced by the AN/CPS-9 system in 1949. Ground scanning radar GPR uses high-frequency (usually polarized) radio waves, usually in the range 10 MHz to 2.6 GHz. A GPR transmitter and antenna emits electromagnetic energy into

4978-554: The Bristol Beaufighter night fighter. During its trials on 16 January 1941, W4050 outpaced a Spitfire at 6,000 ft (1,800 m). The original estimates were that as the Mosquito prototype had twice the surface area and over twice the weight of the Spitfire Mk.II , but also had twice its power, the Mosquito would be 20 mph (30 km/h) faster. Over the next few months, W4050 surpassed this estimate, easily beating

5109-457: The Far East . At first, these were thought to be a result of wing-structure failures. The casein glue, it was said, cracked when exposed to extreme heat and/or monsoon conditions. This caused the upper surfaces to lift from the main spar. An investigating team led by Major Hereward de Havilland travelled to India and produced a report in early December 1944 stating, "the accidents were not caused by

5240-548: The Handley Page H.P.42 and other biplanes it was replacing. The wooden monocoque construction not only saved weight and compensated for the low power of the de Havilland Gipsy Twelve engines used by this aircraft, but also simplified production and reduced construction time. On 8 September 1936, the British Air Ministry issued Specification P.13/36, which called for a twin-engined medium bomber capable of carrying

5371-603: The Lockheed P-38 Lightning could fulfill the same duties. However, Arnold urged the United States Army Air Forces (USAAF) to evaluate the design even if they would not adopt it. On 12 December 1941, after the attack on Pearl Harbor , the USAAF requested one airframe for this purpose. While timber construction was considered outmoded by some, de Havilland claimed that their successes with techniques used for

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5502-567: The Pacific War . During the 1950s, the RAF replaced the Mosquito with the jet-powered English Electric Canberra . By the early to mid-1930s, de Havilland had built a reputation for innovative high-speed aircraft with the DH.88 Comet racer. Later, the DH.91 Albatross airliner pioneered the composite wood construction used for the Mosquito. The 22-passenger Albatross could cruise at 210 mph (340 km/h) at 11,000 ft (3,400 m), faster than

5633-578: The Rolls-Royce Griffon and the Napier Sabre . Although estimates were presented for a slightly larger Griffon-powered aircraft, armed with a four-gun tail turret, Freeman got the requirement for defensive weapons dropped, and a draft requirement was raised calling for a high-speed, light-reconnaissance bomber capable of 400 mph (645 km/h) at 18,000 ft. On 12 December, the Vice-Chief of

5764-516: The Supermarine Spitfire , Hawker Hurricane fighter, Vickers Wellington , Armstrong-Whitworth Whitley , and Bristol Blenheim bombers. Work on the DH.98 prototype stopped. Apparently, the project shut down when the design team were denied materials for the prototype. The Mosquito was only reinstated as a priority in July 1940, after de Havilland's general manager, L.C.L. Murray, promised Lord Beaverbrook 50 Mosquitoes by December 1941. This

5895-473: The strength-to-weight ratio of wood is equal to or better than light alloys or steel, hence this approach was feasible. A follow-up letter to Freeman on 27 July said that the P.13/36 specification could not be met by a twin Merlin-powered aircraft and either the top speed or load capacity would be compromised, depending on which was paramount. For example, a larger, slower, turret-armed aircraft would have

6026-525: The "main tanks" and the total internal fuel load of 452 imp gal (545 US gal; 2,055 L) was initially deemed appropriate for the type. In addition, the FB Mk. VI could have larger fuselage tanks, increasing the capacity to 63 imp gal (76 US gal; 290 L). Drop tanks of 50 imp gal (60 US gal; 230 L) or 100 imp gal (120 US gal; 450 L) could be mounted under each wing, increasing

6157-420: The Air Ministry showed little interest, and instead asked de Havilland to build wings for other bombers as a subcontractor. By September 1939, de Havilland had produced preliminary estimates for single- and twin-engined variations of light-bomber designs using different engines, speculating on the effects of defensive armament on their designs. One design, completed on 6 September, was for an aircraft powered by

6288-561: The Air Staff , Director General of Research and Development, and the Air Officer Commanding-in-Chief (AOC-in-C) of RAF Bomber Command met to finalise the design and decide how to fit it into the RAF's aims. The AOC-in-C would not accept an unarmed bomber, but insisted on its suitability for reconnaissance missions with F8 or F24 cameras . After company representatives, the ministry, and the RAF's operational commands examined

6419-613: The Albatross and the new all-metal DH.95 Flamingo , de Havilland settled on designing a new aircraft that would be aerodynamically clean, wooden, and powered by the Merlin, which offered substantial future development. The new design would be faster than foreseeable enemy fighter aircraft , and could dispense with defensive armament which would slow it and make interception or losses to antiaircraft guns more likely. Instead, high speed and good manoeuvrability would make evading fighters and ground fire easier. The lack of turrets simplified production, reduced drag, and reduced production time, with

6550-720: The Albatross principles could save time. In April 1938, performance estimates were produced for a twin Rolls-Royce Merlin -powered DH.91, with the Bristol Hercules ( radial engine ) and Napier Sabre ( H-engine ) as alternatives. On 7 July 1938, de Havilland wrote to Air Marshal Wilfrid Freeman , the Air Council's member for Research and Development, discussing the specification and arguing that in war, shortages of aluminium and steel would occur, but supplies of wood-based products were "adequate." Although inferior in tension ,

6681-458: The Albatross, powered by two Merlin Xs, with a three-man crew and six or eight forward-firing guns, plus one or two manually operated guns and a tail turret. Based on a total loaded weight of 19,000 lb (8,600 kg), it would have a top speed of 300 mph (480 km/h) and cruising speed of 268 mph (431 km/h) at 22,500 ft (6,900 m). Still believing this could be improved, and after examining more concepts based on

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6812-451: The DH 91 Albatross could lead to a fast, light bomber using monocoque-sandwich shell construction. Arguments in favour of this included speed of prototyping, rapid development, minimisation of jig-building time, and employment of a separate category of workforce. The ply-balsa-ply monocoque fuselage and one-piece wings with doped fabric covering would give excellent aerodynamic performance and low weight, combined with strength and stiffness. At

6943-521: The GPR signal, weakening the useful signal while increasing extraneous noise. In the field of cultural heritage GPR with high frequency antenna is also used for investigating historical masonry structures, detecting cracks and decay patterns of columns and detachment of frescoes. GPR is used by criminologists, historians, and archaeologists to search burial sites. In his publication, Interpreting Ground-penetrating Radar for Archaeology , Lawrence Conyers, one of

7074-576: The German FuG 350 Naxos radar detector , due to that receiving device's specific purpose being to spot the original British H2S equipment's lower frequency, 3 GHz emissions. The first H2X-equipped B-17 's arrived in England in early October 1943, and were first used in combat on 3 November 1943 when the USAAF VIII Bomber Command attacked the port of Wilhelmshaven. Those missions where bombing

7205-520: The Germans would produce fighters that were faster than had been expected. and suggested the incorporation of two forward- and two rear-firing machine guns for defence. The ministry also opposed a two-man bomber, wanting at least a third crewman to reduce the work of the others on long flights. The Air Council added further requirements such as remotely controlled guns, a top speed of 275 mph (445 km/h) at 15,000 ft on two-thirds engine power, and

7336-587: The Institute had used GPR to locate suspected unmarked graves in areas near historic cemeteries and Indian Residential Schools. On May 27, 2021, it was reported that 215 unmarked anomalies (possibly children's graves) were found using GPR at a burial site at the Kamloops Indian Residential School on Tk’emlúps te Secwépemc First Nation land in British Columbia. In June 2021, GPR technology

7467-667: The Mosquito by holding to Major de Havilland's initial investigation in India that the accidents were caused "largely by climate" To solve the problem of seepage into the interior, a strip of plywood was set along the span of the wing to seal the entire length of the skin joint. The fuel systems gave the Mosquito good range and endurance, using up to nine fuel tanks. Two outer wing tanks each contained 58 imp gal (70 US gal; 260 L) of fuel. These were complemented by two inner wing fuel tanks, each containing 143 imp gal (172 US gal; 650 L), located between

7598-578: The Mosquito family. In late October 1941, it returned to the factory to be fitted with Merlin 61s , the first production Merlins fitted with a two-speed, two-stage supercharger. The first flight with the new engines was on 20 June 1942. W4050 recorded a maximum speed of 428 mph (689 km/h) at 28,500 ft (8,700 m) (fitted with straight-through air intakes with snow guards, engines in full supercharger gear) and 437 mph (703 km/h) at 29,200 ft (8,900 m) without snow guards. In October 1942, in connection with development work on

7729-461: The Mosquito had become one of the world's fastest operational aircraft. It ordered 19 photo-reconnaissance (PR) models and 176 fighters. A further 50 were unspecified; in July 1941, these were confirmed to be unarmed fast bombers. By the end of January 1942, contracts had been awarded for 1,378 Mosquitoes of all variants, including 20 T.III trainers and 334 FB.VI bombers. Another 400 were to be built by de Havilland Canada . On 20 April 1941, W4050

7860-629: The Mosquito's use evolved during the war into many roles, including low- to medium-altitude daytime tactical bomber , high-altitude night bomber , pathfinder , day or night fighter , fighter-bomber , intruder , maritime strike , and photo-reconnaissance aircraft. It was also used by the British Overseas Airways Corporation as a fast transport to carry small, high-value cargo to and from neutral countries through enemy-controlled airspace . The crew of two, pilot and navigator, sat side by side. A single passenger could ride in

7991-560: The NF Mk.XV, W4050 was fitted with extended wingtips, increasing the span to 59 ft 2 in (18.03 m), first flying in this configuration on 8 December. Fitted with high-altitude-rated, two-stage, two-speed Merlin 77s, it reached 439 mph (707 km/h) in December 1943. Soon after these flights, W4050 was grounded and scheduled to be scrapped, but instead served as an instructional airframe at Hatfield. In September 1958, W4050

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8122-609: The Spitfire Mk.II in tests at RAF Boscombe Down in February 1941, reaching a top speed of 392 mph (631 km/h) at 22,000 ft (6,700 m), compared to a top speed of 360 mph (580 km/h) at 19,500 ft (5,900 m) for the Spitfire. On 19 February, official trials began at the Aeroplane and Armament Experimental Establishment (AAEE) based at Boscombe Down, although

8253-498: The U.S. military ordered ground-penetrating radar system from Chemring Sensors and Electronics Systems (CSES), to detect improvised explosive devices (IEDs) buried in roadways, in $ 200.2 million deal. A recent novel approach to vehicle localization using prior map based images from ground penetrating radar has been demonstrated. Termed "Localizing Ground Penetrating Radar" (LGPR), centimeter level accuracies at speeds up to 100 km/h (60 mph) have been demonstrated. Closed-loop operation

8384-450: The aircraft had been exposed to monsoon conditions or termite attack. The investigators concluded that construction defects occurred at the two plants. They found that the "...   standard of glueing ... left much to be desired." Records at the time showed that accidents caused by "loss of control" were three times more frequent on Mosquitoes than on any other type of aircraft. The Air Ministry forestalled any loss of confidence in

8515-480: The aircraft's bomb bay when necessary. The Mosquito FB Mk. VI was often flown in special raids, such as Operation Jericho (an attack on Amiens Prison in early 1944), and precision attacks against military intelligence, security, and police facilities (such as Gestapo headquarters). On 30 January 1943, the 10th anniversary of Hitler being made chancellor and the Nazis gaining power, a morning Mosquito attack knocked out

8646-489: The airplane that looks fast usually is fast, and the Mosquito was, by the standards of the time, an extremely well-streamlined airplane, and it was highly regarded, highly respected." The trials set up future production plans between Britain, Australia , and Canada . Six days later, Arnold returned to America with a full set of manufacturer's drawings. As a result of his report, five companies (Beech, Curtiss-Wright , Fairchild , Fleetwings, and Hughes) were asked to evaluate

8777-552: The armament of subsequent variants might be regarded as primarily offensive. The most-produced variant, designated the FB Mk. VI (Fighter-bomber Mark 6), was powered by two Merlin Mk.23 or Mk.25 engines driving three-bladed de Havilland hydromatic propellers. The typical fixed armament for an FB Mk. VI was four Browning .303 machine guns and four 20-mm Hispano cannons, while the offensive load consisted of up to 2,000 lb (910 kg) of bombs, or eight RP-3 unguided rockets. The design

8908-503: The ball turret, being made retractable as the ball turret was for landing on the Liberator. The operators panel was installed on the flight deck behind the co-pilot (where the radio operator's normal position was). In combat areas the Mickey operator directed the pilot on headings to be taken, and on the bomb run directed the airplane in coordination with the bombardier . The first use of Mickey

9039-500: The balsa core. The main areas of the sandwich skin were only 0.55 in (14 mm) thick. Together with various forms of wood reinforcement, often of laminated construction, the sandwich skin gave great stiffness and torsional resistance. The separate fuselage halves speeded construction, permitting access by personnel working in parallel with others, as the work progressed. Work on the separate half-fuselages included installation of control mechanisms and cabling. Screwed inserts into

9170-561: The cabin heater. The wing contained metal-framed and -skinned ailerons , but the flaps were made of wood and were hydraulically controlled. The nacelles were mostly wood, although for strength, the engine mounts were all metal, as were the undercarriage parts. Engine mounts of welded steel tube were added, along with simple landing gear oleos filled with rubber blocks. Wood was used to carry only in-plane loads, with metal fittings used for all triaxially loaded components such as landing gear, engine mounts, control-surface mounting brackets, and

9301-407: The de Havilland test pilot . On 25 November, the aircraft made its first flight, piloted by de Havilland Jr., accompanied by John E. Walker, the chief engine installation designer. For this maiden flight, E-0234 , weighing 14,150 lb (6,420 kg), took off from the grass airstrip at Hatfield. The takeoff was reported as "straightforward and easy" and the undercarriage was not retracted until

9432-421: The de Havilland data. The report by Beech Aircraft summed up the general view: "It appears as though this airplane has sacrificed serviceability, structural strength, ease of construction and flying characteristics in an attempt to use construction material which is not suitable for the manufacture of efficient airplanes." The Americans did not pursue the proposal for licensed production, the consensus arguing that

9563-521: The de Havilland representative was surprised by a delay in starting the tests. On 24 February, as W4050 taxied across the rough airfield, the tailwheel jammed leading to the fuselage fracturing. Repairs were made by early March, using part of the fuselage of the photo-reconnaissance prototype W4051 . In spite of this setback, the Initial Handling Report 767 issued by the AAEE stated, "The aeroplane

9694-484: The defence of the UK decided no production capacity remained for aircraft like the DH.98, which was not expected to be in service until early 1942. Beaverbrook told Air Vice-Marshal Freeman that work on the project should stop, but he did not issue a specific instruction, and Freeman ignored the request. In June 1940, however, Lord Beaverbrook and the Air Staff ordered that production should concentrate on five existing types, namely

9825-557: The depth calculations. In 2005, the European Telecommunications Standards Institute introduced legislation to regulate GPR equipment and GPR operators to control excess emissions of electromagnetic radiation. The European GPR association (EuroGPR) was formed as a trade association to represent and protect the legitimate use of GPR in Europe. Ground-penetrating radar uses a variety of technologies to generate

9956-497: The deterioration of the glue, but by shrinkage of the airframe during the wet monsoon season". However, a later inquiry by Cabot & Myers firmly attributed the accidents to faulty manufacture and this was confirmed by a further investigation team by the Ministry of Aircraft Production at Defford , which found faults in six Mosquito marks (all built at de Havilland's Hatfield and Leavesden plants). The defects were similar, and none of

10087-408: The direction of airflow. The conclusion was that the airflow separating from the rear section of the inner engine nacelles was disturbed, leading to a localised stall and the disturbed airflow was striking the tailplane, causing buffeting. To smooth the air flow and deflect it from forcefully striking the tailplane, nonretractable slots fitted to the inner engine nacelles and to the leading edge of

10218-419: The equipment needs to be moved in order for the radar to examine the specified area by looking for differences in material composition. While it can identify items such as pipes, voids, and soil, it cannot identify the specific materials, such as gold and precious gems. It can, however, be useful in providing subsurface mapping of potential gem-bearing pockets, or "vugs". The readings can be confused by moisture in

10349-451: The field remained sparse until the 1970s, when military applications began driving research. Commercial applications followed and the first affordable consumer equipment was sold in 1975. In 1972, the Apollo 17 mission carried a ground penetrating radar called ALSE (Apollo Lunar Sounder Experiment) in orbit around the Moon. It was able to record depth information up to 1.3 km and recorded

10480-408: The fighter prototype, W4052 , was also carried out at Salisbury Hall. It was powered by 1,460 hp (1,090 kW) Merlin 21s, and had an altered canopy structure with a flat, bullet-proof windscreen; the solid nose had mounted four .303 British Browning machine guns and their ammunition boxes, accessible by a large, sideways hinged panel. Four 20-mm Hispano Mk.II cannon were housed in

10611-444: The fighter version should have dual or single controls, or should carry a turret, was still uncertain, so three prototypes were built: W4052 , W4053 , and W4073 . The second and third, both turret armed, were later disarmed, to become the prototypes for the T.III trainer. This caused some delays, since half-built wing components had to be strengthened for the required higher combat loading. The nose sections also had to be changed from

10742-447: The fillet some 10 in (250 mm) behind the wing's trailing edge; this meant the flaps had to be divided into inboard and outboard sections. With the buffeting problems largely resolved, John Cunningham flew W4050 on 9 February 1941. He was greatly impressed by the "lightness of the controls and generally pleasant handling characteristics". Cunningham concluded that when the type was fitted with AI equipment, it might replace

10873-846: The first archaeological specialists in GPR, described the process. Conyers published research using GPR in El Salvador in 1996, in the Four Corners region Chaco period in southern Arizona in 1997, and in a medieval site in Ireland in 2018. Informed by Conyer's research, the Institute of Prairie and Indigenous Archaeology at the University of Alberta , in collaboration with the National Centre for Truth and Reconciliation , have been using GPR in their survey of Indian Residential Schools in Canada . By June 2021,

11004-537: The first version of the Youngman Frill airbrake fitted to the fighter prototype. The frill was mounted around the fuselage behind the wing and was opened by bellows and venturi effect to provide rapid deceleration during interceptions and was tested between January and August 1942, but was also abandoned when lowering the undercarriage was found to have the same effect with less buffeting. The Air Ministry authorised mass production plans on 21 June 1941, by which time

11135-440: The fitments and transmitted the aerodynamic loadings for the tailplane and rudder. The fuselage had a large ventral section cut-out, strongly reinforced, that allowed the fuselage to be lowered onto the wing centre-section at a later stage of assembly. For early production aircraft, the structural assembly adhesive was casein -based. At a later stage, this was replaced by " Aerolite ", a synthetic urea-formaldehyde type, which

11266-477: The floor (much like the earlier P-38 "Droop Snoot" bomber-leader variants, but with a radome instead of a glazed nose). These missions were to obtain radar maps of German targets but plans to produce the variant in quantity never materialized. In the Pacific theater , B-29 ’s were equipped with the improved H2X radar called the AN/APQ-13 , a ground scanning radar developed by Bell, Western Electric, and MIT. The radome

11397-444: The forward half of the bomb bay , under the cockpit, firing via blast tubes and troughs under the fuselage. The DH.98 was too radical for the ministry, which wanted a heavily armed, multirole aircraft, combining medium bomber, reconnaissance, and general-purpose roles, that was also capable of carrying torpedoes. With the outbreak of war, the ministry became more receptive, but was still sceptical about an unarmed bomber. They thought

11528-436: The forward sweep of the trailing edges of the wings, this rear spar was one of the most complex units to laminate and to finish machining after the bonding and curing. It had to produce the correct 3D tilt in each of two planes. Also, it was designed and made to taper from the wing roots towards the wingtips. Both principal spars were of ply box construction, using in general 0.25-in plywood webs with laminated spruce flanges, plus

11659-515: The ground and they can't separate gem-bearing pockets from non-gem-bearing ones. When determining depth capabilities, the frequency range of the antenna dictates the size of the antenna and the depth capability. The grid spacing which is scanned is based on the size of the targets that need to be identified and the results required. Typical grid spacings can be 1 meter, 3 ft, 5 ft, 10 ft, 20 ft for ground surveys, and for walls and floors 1 inch–1 ft. The speed at which

11790-533: The ground. When the energy encounters a buried object or a boundary between materials having different permittivities , it may be reflected or refracted or scattered back to the surface. A receiving antenna can then record the variations in the return signal. The principles involved are similar to seismology , except GPR methods implement electromagnetic energy rather than acoustic energy, and energy may be reflected at boundaries where subsurface electrical properties change rather than subsurface mechanical properties as

11921-433: The inner skins that would be under stress in service were reinforced using round shear plates made from a fabric-Bakelite composite. Transverse bulkheads were also compositely built-up with several species of timber, plywood, and balsa. Seven vertically halved bulkheads were installed within each moulded fuselage shell before the main "boxing up" operation. Bulkhead number seven was especially strongly built, since it carried

12052-444: The lead bomber did. The ventral hemispherical radome for the H2X's rotating dish antenna replaced the ball turret on B-17 Flying Fortress Pathfinders, with the electronics cabinets for the "Mickey set" being installed in the radio room just aft of the bomb bay. The system was used extensively by The 91st Bomb Group in 1945 with occasional excellent but generally inconsistent results. The H2X on later B-24 Liberators also replaced

12183-734: The main Berlin broadcasting station while Hermann Göring was speaking, taking his speech off the air. The Mosquito flew with the Royal Air Force (RAF) and other air forces in the European , Mediterranean , and Italian theatres. The Mosquito was also operated by the RAF in the Southeast Asian theatre and by the Royal Australian Air Force based in the Halmaheras and Borneo during

12314-498: The more advanced AN/APQ-7 "Eagle" system. All of these were replaced in the post-war era with systems customized for the jet powered strategic bombers that entered service. H2X was used by the USAAF during World War II as a navigation system for daylight overcast and nighttime operations. It was introduced as an improvement of the earlier H2S set, which had been supplied to the US to aid in

12445-616: The most detailed at Salisbury Hall, where E-0234 was later constructed. Initially, the concept was for the crew to be enclosed in the fuselage behind a transparent nose (similar to the Bristol Blenheim or Heinkel He 111 H), but this was quickly altered to a more solid nose with a conventional canopy. Work was cancelled again after the evacuation of the British Army from France , when Lord Beaverbrook , as Minister of Aircraft Production , concentrating production on aircraft types for

12576-484: The new Supermarine Spitfire , but counter-arguments held that although such a design had merit, it would not necessarily be faster than enemy fighters for long. The ministry was also considering using non- strategic materials for aircraft production, which, in 1938, had led to specification B.9/38 and the Armstrong Whitworth Albemarle medium bomber, largely constructed from spruce and plywood attached to

12707-517: The new standard". Radioglaciology is the study of glaciers , ice sheets , ice caps and icy moons using ice penetrating radar . It employs a geophysical method similar to ground-penetrating radar and typically operates at frequencies in the MF , HF , VHF and UHF portions of the radio spectrum . This technique is also commonly referred to as "Ice Penetrating Radar (IPR)" or "Radio Echo Sounding (RES)". Individual lines of GPR data represent

12838-444: The optimum speed for obtaining maximum range was 200 mph (320 km/h) at 17,000 lb (7,700 kg) weight. The Mosquito had a high stalling speed of 120 mph (190 km/h) with undercarriage and flaps raised. When both were lowered, the stalling speed decreased from 120 to 100 mph (190 to 160 km/h). Stall speed at normal approach angle and conditions was 100 to 110 mph (160 to 180 km/h). Warning of

12969-539: The other 30 were delivered by mid-March 1942. During the Battle of Britain , interruptions to production due to air raid warnings caused nearly a third of de Havilland's factory time to be lost. Nevertheless, work on the prototype went ahead quickly at Salisbury Hall since E-0234 was completed by November 1940. In the aftermath of the Battle of Britain, the original order was changed to 20 bomber variants and 30 fighters. Whether

13100-435: The other main applications for ground-penetrating radars is for locating underground utilities. Standard electromagnetic induction utility locating tools require utilities to be conductive. These tools are ineffective for locating plastic conduits or concrete storm and sanitary sewers. Since GPR detects variations in dielectric properties in the subsurface, it can be highly effective for locating non-conductive utilities. GPR

13231-457: The otherwise successful Mosquito reconnaissance aircraft, and were severely curtailed after 19 February 1945. Three were lost to enemy action and one was shot down by friendly fire from a Ninth Air Force P-47 . In Europe several P-38 fighters were also converted to carrying H2X radar in the nose, along with an operator/navigator in a cramped compartment in the nose behind the radar dish, provided with small side windows and an access/exit hatch in

13362-417: The outer wing tips, and it was painted in black RDM2a "Special Night" finish. It was also the first prototype constructed with the extended engine nacelles. W4052 was later tested with other modifications, including bomb racks, drop tanks, barrage balloon cable cutters in the leading edge of the wings, Hamilton airscrews and braking propellers, and drooping aileron systems that enabled steep approaches and

13493-469: The outside of the shells. The half bulkheads of each shell were bonded to their corresponding pair in a similar way. Two laminated wooden clamps were used in the after portion of the fuselage to provide supports during this complex gluing work. The resulting large structural components had to be kept completely still and held in the correct environment until the glue cured. For finishing, a covering of doped madapollam (a fine, plain-woven cotton) fabric

13624-458: The presence of voids developing outside the pipe. Wall-penetrating radar can read through non-metallic structures as demonstrated for the first time by ASIO and Australian Police in 1984 while surveying an ex Russian Embassy in Canberra . Police showed how to watch people up to two rooms away laterally and through floors vertically, could see metal lumps that might be weapons; GPR can even act as

13755-672: The problem and were used in the PR.VIII, B.IX, and B.XVI variants. This increased speed performance in the B.IX alone by 10 to 13 mph (16 to 21 km/h). The oval-section fuselage was a frameless monocoque shell built in two vertically separate halves formed over a mahogany or concrete mould. Pressure was applied with band clamps . Some of the 1/2—3/4" shell sandwich skins comprised 3/32" birch three-ply outers, with 7/16" cores of Ecuadorean balsa . In many generally smaller but vital areas, such as around apertures and attachment zones, stronger timbers, including aircraft-quality spruce, replaced

13886-528: The project was discontinued. A further twelve PR Mk.XVI Mosquitos of the 25th Bomb Group (Reconnaissance) of the Eighth Air Force were fitted with H2X and beginning in May 1944, flew radar mapping night missions until February 1945. The sets tended to overload the Mosquito's electrical system and occasionally exploded. Mickey-equipped Mosquitos had the highest loss, abort, and mission failure rates of any version of

14017-407: The prototype, which was given the factory serial E-0234 . In May 1940, specification F.21/40 was issued, calling for a long-range fighter armed with four 20 mm cannon and four .303 machine guns in the nose, after which de Havilland was authorised to build a prototype of a fighter version of the DH.98. After debate, it was decided that this prototype, given the military serial number W4052 ,

14148-467: The radar signal: these are impulse, stepped frequency, frequency-modulated continuous-wave ( FMCW ), and noise. Systems on the market in 2009 also use Digital signal processing (DSP) to process the data during survey work rather than off-line. A special kind of GPR uses unmodulated continuous-wave signals. This holographic subsurface radar differs from other GPR types in that it records plan-view subsurface holograms. Depth penetration of this kind of radar

14279-504: The results on film due to the lack of suitable computer storage at the time. GPR has many applications in a number of fields. In the Earth sciences it is used to study bedrock , soils, groundwater , and ice . It is of some utility in prospecting for gold nuggets and for diamonds in alluvial gravel beds, by finding natural traps in buried stream beds that have the potential for accumulating heavier particles. The Chinese lunar rover Yutu has

14410-509: The same time, the design team had to fight conservative Air Ministry views on defensive armament. Guns and gun turrets, favoured by the ministry, would impair the aircraft's aerodynamic properties and reduce speed and manoeuvrability, in the opinion of the designers. Whilst submitting these arguments, Geoffrey de Havilland funded his private venture until a very late stage. The project was a success beyond all expectations. The initial bomber and photo-reconnaissance versions were extremely fast, whilst

14541-558: The stall was given by buffeting and would occur 12 mph (19 km/h) before stall was reached. The conditions and impact of the stall were not severe. The wing did not drop unless the control column was pulled back. The nose drooped gently and recovery was easy. Early on in the Mosquito's operational life, the intake shrouds that were to cool the exhausts on production aircraft overheated. Flame dampers prevented exhaust glow on night operations, but they had an effect on performance. Multiple ejector and open-ended exhaust stubs helped solve

14672-415: The tailplane were tested. These slots and wing-root fairings fitted to the forward fuselage and leading edge of the radiator intakes stopped some of the vibration experienced, but did not cure the tailplane buffeting. In February 1941, buffeting was eliminated by incorporating triangular fillets on the trailing edge of the wings and lengthening the nacelles, the trailing edge of which curved up to fair into

14803-539: The war effort. While the RAF Bomber Command utilized ground mapping radar as an aid to night area bombing , the primary use by the USAAF was as a fallback, to allow cities to be bombed even when hidden by cloud cover, an issue that had dogged their policy of precision daylight bombing since the start of the war, especially in cloud-prone Europe. With H2X, a city could be located and a general area targeted, night or day, cloud cover or no, with equal accuracy. H2X used

14934-486: The wing root and engine nacelle. In the central fuselage were twin fuel tanks mounted between bulkhead number two and three aft of the cockpit. In the FB.VI, these tanks contained 25 imp gal (30 US gal; 110 L) each, while in the B.IV and other unarmed Mosquitoes each of the two centre tanks contained 68 imp gal (82 US gal; 310 L). Both the inner wing, and fuselage tanks are listed as

15065-435: The wing-to-fuselage junction. The outer leading wing edge had to be brought 22 in (56 cm) further forward to accommodate this design. The main tail unit was all wood built. The control surfaces, the rudder , and elevator were aluminium -framed and fabric-covered. The total weight of metal castings and forgings used in the aircraft was only 280 lb (130 kg). In November 1944, several crashes occurred in

15196-412: Was against Ploiești on 5 April 1944. Due to the absence of radar maps, in late April 1944 six PR Mk.XVI de Havilland Mosquito aircraft in the 482nd Bomb Group were equipped with H2X equipment. The idea was to produce photographs of the radar screen during flights over Germany allowing easy interpretation of these radar images in later bombing runs. Three aircraft were subsequently lost in training, and

15327-408: Was carried on the aircraft belly between the bomb bays and was partially retractable. The radar operated at a frequency of 9,375 ± 45 megahertz and used a superheterodyne receiver . The radar was used for high altitude area bombing, search and navigation. Computation for bombing could be performed by an impact predictor. A range unit permitted a high degree of accuracy in locating beacons. Post-war ,

15458-444: Was constructed mostly of wood, it was nicknamed the "Wooden Wonder", or "Mossie". Lord Beaverbrook , Minister of Aircraft Production, nicknamed it "Freeman's Folly", alluding to Air Chief Marshal Sir Wilfrid Freeman , who defended Geoffrey de Havilland and his design concept against orders to scrap the project. In 1941, it was one of the fastest operational aircraft in the world. Originally conceived as an unarmed fast bomber ,

15589-454: Was demonstrated to Lord Beaverbrook, the Minister of Aircraft Production . The Mosquito made a series of flights, including one rolling climb on one engine. Also present were US General Henry H. Arnold and his aide Major Elwood Quesada , who wrote "I ... recall the first time I saw the Mosquito as being impressed by its performance, which we were aware of. We were impressed by the appearance of

15720-428: Was done by H2X were called "Pathfinder missions" and the crews were called "Pathfinder crews", after the RAF practice of using highly trained Pathfinder crews to go in before the main bomber stream and identify and mark the target with flares. American practice used their Pathfinder crews as lead bombers, with radar equipped aircraft being followed by formations of radar-less bombers, which would all drop their loads when

15851-498: Was first demonstrated in 2012 for autonomous vehicle steering and fielded for military operation in 2013. Highway speed centimeter-level localization during a night-time snow-storm was demonstrated in 2016. This technology was exclusively licensed and commercialized for vehicle safety in ADAS and Autonomous Vehicle positioning and lane-keeping systems by GPR Inc. and marketed as Ground Positioning Radar(tm). Ground penetrating radar survey

15982-462: Was more durable. To provide for the edge joints for the fuselage halves, zones near the outer edges of the shells had their balsa sandwich cores replaced by much stronger inner laminations of birch plywood. For the bonding together of the two halves ("boxing up"), a longitudinal cut was machined into these edges. The profile of this cut was a form of V-groove. Part of the edge bonding process also included adding further longitudinal plywood lap strips on

16113-503: Was noted for light and effective control surfaces that provided good manoeuvrability, but required that the rudder not be used aggressively at high speeds. Poor aileron control at low speeds when landing and taking off was also a problem for inexperienced crews. For flying at low speeds, the flaps had to be set at 15°, speed reduced to 200 mph (320 km/h), and rpm set to 2,650. The speed could be reduced to an acceptable 150 mph (240 km/h) for low-speed flying. For cruising,

16244-716: Was often used on the Channel 4 television programme Time Team which used the technology to determine a suitable area for examination by means of excavations. GPR was also used to recover £150,000 in cash ransom that Michael Sams had buried in a field, following his 1992 kidnapping of an estate agent. Military applications of ground-penetrating radar include detection of unexploded ordnance and detecting tunnels. In military applications and other common GPR applications, practitioners often use GPR in conjunction with other available geophysical techniques such as electrical resistivity and electromagnetic induction methods. In May 2020,

16375-456: Was only after Beaverbrook was satisfied that Mosquito production would not hinder de Havilland's primary work of producing Tiger Moth and Airspeed Oxford trainers, repairing Hurricanes , and manufacturing Merlin engines under licence. In promising Beaverbrook such a number by the end of 1941, de Havilland was taking a gamble, because they were unlikely to be built in such a limited time. As it transpired, only 20 aircraft were built in 1941, but

16506-538: Was returned to the Salisbury Hall hangar where it was built, restored to its original configuration, and became one of the primary exhibits of the de Havilland Aircraft Heritage Centre . W4051 , which was designed from the outset to be the prototype for the photo-reconnaissance versions of the Mosquito, was slated to make its first flight in early 1941. However, the fuselage fracture in W4050 meant that W4051's fuselage

16637-426: Was stretched tightly over the shell and several coats of red, followed by silver dope, were added, followed by the final camouflage paint. The all-wood wing pairs formed a single structural unit throughout the wingspan, with no central longitudinal joint. Instead, the spars ran from wingtip to wingtip. There was a single continuous main spar and another continuous rear spar. Because of the combination of dihedral with

16768-401: Was submitted by Gotthelf Leimbach and Heinrich Löwy in 1910, six years after the first patent for radar itself (patent DE 237 944). A patent for a system using radar pulses rather than a continuous wave was filed in 1926 by Dr. Hülsenbeck (DE 489 434), leading to improved depth resolution. A glacier's depth was measured using ground penetrating radar in 1929 by W. Stern. Further developments in

16899-438: Was to carry aircraft interception (AI) Mk IV radar equipment as both a day fighter and night fighter. By June 1940, the DH.98 had been named "Mosquito". Having the fighter variant kept the Mosquito project alive, as doubts remained within the government and Air Ministry regarding the usefulness of an unarmed bomber, even after the prototype had shown its capabilities. With design of the DH.98 started, mock-ups were built,

17030-445: Was used as a replacement; W4051 was then rebuilt using a production standard fuselage and first flew on 10 June 1941. This prototype continued to use the short engine nacelles, single-piece trailing-edge flaps, and the 19 ft 5.5 in (5.931 m) "No. 1" tailplane used by W4050 , but had production-standard 54 ft 2 in (16.51 m) wings and became the only Mosquito prototype to fly operationally. Construction of

17161-637: Was used by the Cowessess First Nation in Saskatchewan to locate 751 unmarked gravesites on the Marieval Indian Residential School site, which had been in operation for a century until it was closed down in 1996. Advancements in GPR technology integrated with various 3D software modelling platforms generate three-dimensional reconstructions of subsurface "shapes and their spatial relationships". By 2021, this has been "emerging as

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