Wednesday, June 26, 2013
The Type II U-boat was designed by Germany as a coastal U-boat, modeled after the CV-707 submarine, which was designed by the Dutch dummy company NV Ingenieurskantoor voor Scheepsbouw den Haag (I.v.S) (set up by Germany after World War I in order to maintain and develop German submarine technology and to circumvent the limitations set by the Treaty of Versailles) and built in 1933 by the Finnish Crichton-Vulcan shipyard in Turku, Finland. It was too small to undertake sustained operations far away from the home support facilities. Its primary role was found to be in the training schools, preparing new German naval officers for command. It appeared in four sub-types.
Germany was stripped of her U-boats by the Treaty of Versailles at the end of World War I, but in the late 1920s and early 1930s began to rebuild her armed forces. The pace of rearmament accelerated under Adolf Hitler, and the first Type II U-boat was laid down on 11 February 1935. Knowing that the world would see this step towards rearmament, Hitler reached an agreement with Britain to build a navy up to 35% of the size of the Royal Navy in surface vessels, but equal to the British in number of submarines. This agreement was signed on 18 June 1935, and U-1 was commissioned 11 days later.
The defining characteristic of the Type II was its tiny size. Known as the Einbaum ("dugout canoe"), it had the advantages over larger boats of the ability to work in shallow water, diving more quickly, and being more difficult to spot due to the low conning tower. However, it had a shallower maximum depth, short range, and cramped living conditions, and could carry few torpedoes.
The boat had a single hull, with no watertight compartments. There were three torpedo tubes forward (none aft), with space for another two torpedoes inside the pressure hull for reloads. A single 20 mm anti-aircraft gun was provided, but no deck gun was mounted.
Space inside was limited. The two spare torpedoes extended from just behind the torpedo tubes to just in front of the control room, and most of the 24-man crew lived in this forward area around the torpedoes, sharing 12 bunks. Four bunks were also provided aft of the engines for the engine room crew. Cooking and sanitary facilities were basic, and in this environment long patrols were very arduous.
Most Type IIs only saw operational service during the early years of the war, thereafter remaining in training bases. Six were stripped down to just a hull, transported by river and truck to Linz (on the Danube), and reassembled for use in the Black Sea against the Soviet Union.
In contrast to other German submarine types, few Type IIs were lost. This, of course, reflects their use as training boats, although accidents accounted for several vessels.
These boats were a first step towards re-armament, intended to provide Germany with experience in submarine construction and operation and lay the foundation for larger boats to build upon. Only one of these submarines survives to this day; the prototype CV-707, renamed Vesikko by the Finnish Navy which later bought it.
On February 3, 2008, The Telegraph reported that U-20 had been discovered by Selçuk Kolay, a Turkish marine engineer in 80 feet (24 m) of water off the coast of the Turkish city of Zonguldak. The paper also reported that Kolay knows where U-23 and U-19 are, scuttled in deeper water near U-20.
Deutsche Werke AG, of Kiel, built four Type IIBs in 1935 and 1936, Germaniawerft AG, of Kiel, built fourteen in 1935 and 1936, and Flender Werke AG, of Lübeck, built two between 1938 and 1940, for a total of twenty built.
German submarine U-23 was a Type IIB U-boat of the Nazi German Kriegsmarine, built in Germaniawerft, Kiel. She was laid down on 11 April 1936 and commissioned on 24 September.
At 4:45 am on 4 October 1939, U-23 scored one of the Kriegsmarine's early successes of the war when she torpedoed and sank with gunfire, the merchant ship Glen Farg about 60 mi (97 km) south-southwest of Sumburgh Head (southern Shetland). One person died, while 16 survivors were picked up by HMS Firedrake and landed at Kirkwall the next day.
In 16 patrols U-23 sank seven ships for a total of 11,179 gross register tons (GRT) including two warships, as well as damaging a warship and an auxiliary warship.
Over the course of her service with the Kriegsmarine, U-23 had ten commanding officers, the most famous of whom was Kapitänleutnant Otto Kretschmer, who went on to become the top scoring U-boat ace. After service in the Atlantic with the 1st U-boat Flotilla, U-23 served as a training boat with the 21st U-boat Flotilla from July 1940 until September 1942. U-23 was then refitted and transported overland to the Black Sea port of Konstanza, Romania, with the 30th U-boat Flotilla until September 1944.
U-23 was scuttled by her crew on 10 September 1944, off the coast of Turkey in the Black Sea at position Coordinates: to prevent her capture by the advancing Soviets.
On 3 February 2008, The Daily Telegraph newspaper reported that U-23 had been discovered by Selçuk Kolay, a Turkish marine engineer, in 160 ft (49 m) of water, three miles from the town of Agva
Sunday, June 23, 2013
It is sad that scenes like this will never be seen again.
Immediately at wars end in 1945 it was ordered that all Typhoons and Tempests be converted to scrap.
As a result only one Typhoon is left in existence sitting in a museum in Hendon North London England and a replica with some original parts sitting in France. There are no flying examples.
A sad end to such a famous aircraft :`(
Wednesday, June 19, 2013
The Hawker Typhoon (Tiffy in RAF slang), was a British single-seat fighter-bomber, produced by Hawker Aircraft. It was designed to be a medium-high altitude interceptor, as a direct replacement for the Hawker Hurricane, but several design problems were encountered, and it never completely satisfied this requirement.
Its service introduction in mid-1941 was plagued with problems, and for several months the aircraft faced a doubtful future. However, when the Luftwaffe brought the formidable Focke-Wulf Fw 190 into service in 1941 the Typhoon was the only RAF fighter capable of catching it at low altitudes; as a result it secured a new role as a low-altitude interceptor.
Through the support of pilots such as Roland Beamont it also established itself in roles such as night-time intruder and a long-range fighter.
From late 1942 the Typhoon was equipped with bombs, and from late 1943 RP-3 ground attack rockets were added to its armoury. Using these two weapons, the Typhoon became one of the Second World War's most successful ground-attack aircraft.
Even before the new Hurricane was rolling off the production lines in March 1937, Sydney Camm had moved on to designing its replacement. The two preliminary designs were very similar and were larger than the Hurricane. These later became known as the "N" and "R" (from the initial of the engine manufacturers), because they were designed for the newly developed Napier Sabre and Rolls-Royce Vulture engines respectively. Both engines used 24 cylinders and were designed to be able to deliver over 2,000 hp (1,491 kW); the difference between the two was primarily in the arrangement of the cylinders – an H-block in the Sabre and an X-block in the Vulture. Hawker submitted these preliminary designs in July 1937, but were advised to wait until a formal specification for a new fighter was issued.
In March 1938, Hawker received from the Air Ministry Specification F.18/37. F.18/37 asked for a fighter which would be able to achieve at least 400 mph (644 km/h) at 15,000 feet (4,600 m) and specified a British engine with a two-speed supercharger. The armament fitted was to be twelve Browning machine guns with 500 rounds per gun, with a provision for alternative combinations of weaponry. It was in response to this specification that Camm and his design team started formal development of the designs and construction of the prototypes.
The basic design of the Typhoon was a combination of traditional Hawker and more modern construction techniques; the front fuselage structure, from the engine mountings to the rear of the cockpit, was made up of bolted and welded duralumin or steel tubes, while the rear fuselage was a flush-riveted, semi-monocoque structure. The forward fuselage and cockpit skinning was made up of large, removable duralumin panels, allowing easy external access to the engine and engine accessories and most of the important hydraulic and electrical equipment.
The shallow-angle inverted gull wing had a span of 41-foot-7-inch (12.67 m), with a wing area of 279 sq ft (29.6 sq m). The airfoil used was a NACA 22 wing section, with a thickness to chord ratio of 19.5% at the root tapering to 12% at the tip. The wing possessed great structural strength, provided plenty of room for fuel tanks and a heavy armament, while allowing the aircraft to be a steady weapons platform. The inner wings, outboard of the fuselage had a 1° anhedral, while the outer wings, attached just outboard of the undercarriage legs, had a dihedral of 5½°. Each of the inner wings incorporated two fuel tanks; the "main" tanks, housed in a bay outboard and to the rear of the main undercarriage bays, had a capacity of 40 gallons; while the "nose" tanks, built into the wing leading edges, forward of the main spar, had a capacity of 37 gallons each. Also incorporated into the inner wings was an undercarriage with a track of 13 ft 6¾ in.
Although the Typhoon was expected to achieve over 400 mph (644 km/h) in level flight at 20,000 ft, the thick wings created a large drag rise and prevented higher speeds than the 410 mph at 20,000 feet (6,100 m) achieved in tests.The climb rate and performance above that level was also considered disappointing. In addition, when the Typhoon was dived at speeds of over 500 mph (805 km/h), the drag rise resulted in buffeting and trim changes. These compressibility problems led to Camm designing the Typhoon II, later known as the Tempest, which used much thinner wings with a laminar flow section.
As was usual with front line Second World War RAF aircraft, the Typhoon was modified and updated regularly, so that a 1945 production example looked quite different from one built in 1941. In the last months of the war, a number of older aircraft were taken out of storage and overhauled, sometimes seeing active service for the first time; for example, R7771 was from one of the first production batches, built in 1942 with the car-door canopy and other early production features. This Typhoon was delivered to, and served on the Fighter Interception Unit in 1942. In February 1945 R7771 was listed as being in front line service on 182 Sqn.; by then it was fitted with a clear-view "bubble" hood, rocket rails and other late series features.
The first problem encountered with the Typhoon after its entry into service was the seepage of carbon monoxide fumes into the cockpit. In an attempt to alleviate this, longer exhaust stubs were fitted in November 1941 ("Mod [modification] 239"), and at about the same time the port (left) cockpit doors were sealed. The Pilot's Notes for the Typhoon recommended that "Unless Mod. No. 239 has been embodied it is most important that oxygen be used at all times as a precaution against carbon monoxide poisoning." Despite the modifications, the problem was never entirely solved, and the standard procedure throughout the war was for Typhoon pilots to use oxygen from engine start-up to engine shut down. In addition to carbon monoxide seepage, pilots were experiencing unpleasantly high cockpit temperatures; eventually a ventilation tube helped alleviate, but did not solve the problem. In addition two small, rear opening vents were added below the port side radio hatch, just below the canopy.
A major problem, afflicting early production Typhoons in particular, was a series of structural failures leading to loss of the entire tail sections of some aircraft, mainly during high-speed dives. Eventually a combination of factors was identified, including harmonic vibration, which could quickly lead to metal fatigue, and a weak transport joint just forward of the horizontal tail unit. The loss of the tailplane of R7692 (having only 11 hours of flight recorded) on 11 August 1942, in the hands of an experienced test pilot (Seth-Smith), caused a major reassessment which concluded that the failure of the bracket holding the elevator mass balance bell crank linkage had allowed unrestrained flutter which led to structural failure of the fuselage at the transport joint.
Starting in September 1942, a steel strap was fitted internally across the rear fuselage transport joint, although this soon superseded by Mod 286 (modification number 286), in which 20 alloy "fishplates" were riveted externally across the rear fuselage transport joint, while internally some of the rear fuselage frames were strengthened. This was a permanent measure designed to stop in-flight rear fuselage structural failures and was introduced on the production line from the 820th production aircraft; between December 1942 and March 1943, all Typhoons without Mod 286 were taken out of service and modified. Modified balance weight assemblies were fitted from May 1943. Finally the entire unit was completely replaced with a redesigned assembly from August 1944.
Although these modifications reduced the numbers of Typhoons being lost due to tail assembly failure, towards the end of the Typhoon's life there were more tail failures, this time caused by a change to the undercarriage latch mechanism in late 1944; in high-speed flight the undercarriage fairings were pulled into the slipstream, creating an uneven airflow over the elevators and rudder resulting in tailplane and then rear fuselage structural failure. In total 25 aircraft were lost and 23 pilots killed due to tail failures.
The Typhoon was first produced with forward-opening side doors (complete with wind-down windows), with a transparent "roof" hinged to open to the left. The first 162 Typhoons featured a built-up metal-skinned fairing behind the pilot's armoured headrest; the mast for the radio aerial protruded through the fairing. From mid- to late 1941 the solid metal aft canopy fairing was replaced with a transparent structure (later nicknamed "The Coffin Hood"), the pilot's head armour plate was modified to a triangular shape and the side cut-outs were fitted with armoured glass; the first production Typhoon to be fitted with this new structure was R7803. All earlier aircraft were quickly withdrawn and modified. From early 1942 a rear-view mirror was mounted in perspex blister moulded into the later "car-door" canopy roofs. This modification was not very successful, because the mirror was subject to vibration. Despite the new canopy structure, the pilot's visibility was still restricted by the heavy frames and the clutter of equipment under the rear canopy; from August 1943, as an interim measure, pending the introduction of the new "bubble" canopy, the aerial mast and its associated bracing was removed and replaced with a whip aerial further back on the rear fuselage.
Starting in January 1943, R8809 was used to test a new, clear, one piece sliding "bubble" canopy and its associated new windscreen structure which had slimmer frames which provided a far superior field of view to the car-door type. From November 1943 all production aircraft, starting with JR333, were to be so fitted. However, the complex modifications required to the fuselage and a long lead time for new components to reach the production line meant that it took some time before the new canopy became standard. In order to have as many Typhoons of 2nd TAF fitted before "Operation Overlord" conversion kits were produced and Gloster, Hawker and Cunliffe-Owen modified older Typhoons still fitted with the car-door canopy.
Saturday, June 15, 2013
USS Akron (ZRS-4) was a helium-filled rigid airship of the U.S. Navy that was destroyed in a thunderstorm off the coast of New Jersey on the morning of 4 April 1933, killing 73 of her 76 crewmen and passenger. This accident was the largest loss of life for any known airship crash. During her accident-prone 18-month term of service, the Akron also served as a flying aircraft carrier for launching and recovering F9C Sparrowhawk fighter planes.
With lengths of 785 ft (239 m), 20 ft (6.1 m) shorter than the German commercial airship Hindenburg, Akron and her sister airship the Macon were among the largest flying objects in the world. Although the Hindenburg was longer, she was filled with hydrogen, so the two U.S. airships still hold the world record for helium-filled airships.
Construction of ZRS-4 commenced on October 31, 1929, at the Goodyear Airdock in Akron, Ohio by the Goodyear-Zeppelin Corporation.Because she was the biggest airship ever to be built in America up to that point, a special hangar was constructed in Akron and a team of experienced German airship engineers, led by Chief Designer Karl Arnstein, instructed and supported design and construction of both U.S. Navy airships USS Akron and USS Macon.
On November 7, 1931, Rear Admiral William A. Moffett — the Chief of the U.S. Navy's Bureau of Aeronautics — drove the "golden rivet" in the ship's main ring. Erection of the hull sections began in March 1930. On 10 May, Secretary of the Navy Charles Francis Adams chose the name Akron (for the city where she was being built) and Assistant Secretary of the Navy Ernest Lee Jahncke announced it four days later, on 14 May 1930.
The airship's frame was built of the lightweight alloy duralumin. Once completed, the Akron could store 20,000 US gal (76,000 L) of gasoline, which gave her a range of 10,500 mi (9,100 nmi; 16,900 km). Eight Maybach VL-2 gasoline engines were mounted inside the hull. Each engine turned one twin-bladed propeller via a driveshaft which allowed the propeller to swivel vertically and horizontally.
On August 8, 1931, the Akron was launched (floated free of the hangar floor) and christened by Mrs. Lou Henry Hoover, the wife of the President of the United States, Herbert Clark Hoover. The maiden flight of the Akron took place around Cleveland on the afternoon of 23 September with Secretary of the Navy Adams and Rear Admiral Moffett on board. The airship made eight more flights — principally over Lake Erie but ranging as far as Detroit, Michigan, Milwaukee, Wisconsin, Fort Wayne, Indiana, and Columbus, Ohio — before being flown from Akron to the Naval Air Station (NAS) at Lakehurst, New Jersey, where it was delivered to the Navy and commissioned on Navy Day, 27 October, with Lieutenant Commander Charles E. Rosendahl in command.
The Akron had a unique feature, somewhat like the World War I German zeppelin spähkorb developed by Ernst Lehmann, for determining whether the air was clear below a fog bank to descend. A small weather station containing a radio transmitter was lowered on a cable and reported back to the Akron whether there was clear air below the fog or whether it reached all the way to the ground.
On 2 November 1931, the Akron cast off for a maiden voyage as a commissioned "ship" of the U.S. Navy and cruised down the eastern seaboard to Washington, D.C., Over the weeks that followed, some 300 hours aloft were logged in a series of flights, including a 46-hour endurance flight to Mobile, Alabama, and back. The return leg of the trip was made via the valleys of the Mississippi River and the Ohio River.
On the evening of 3 April 1933, Akron cast off from the mooring mast to operate along the coast of New England, assisting in the calibration of radio direction finder stations. Rear Admiral Moffett was again on board along with his aide, Commander Henry Barton Cecil, Commander Fred T. Berry, the commanding officer of NAS Lakehurst, and Lieutenant Colonel Alfred F. Masury, USAR, a guest of the admiral, vice-president of the Mack Truck Co., and strong proponent of the potential civilian uses of rigid airships.
Akron soon encountered severe weather, which did not improve when the airship passed over Barnegat Light, New Jersey at 10:00 pm as wind gusts of terrific force struck its massive airframe. The airship was being flown into an area of lower barometric pressure than at take-off, which caused the actual altitude flown to be lower than that indicated in the control gondola. Around 12:30 am on 4 April, Akron was caught by an updraft, followed almost immediately by a downdraft. Commander McCord—the captain—ordered full speed ahead, ballast dropped. The executive officer—LCDR Herbert V. Wiley—handled the ballast and emptied the bow emergency ballast. Coupled with the elevator man holding nose up, this caused the nose to rise and the tail to rotate down. Akron's descent was only temporarily halted, whereupon downdrafts forced the airship down farther. Wiley activated the 18 "howlers" of the ship's telephone system, a signal to landing stations. At this point, Akron was nose up, between 12 and 25°.
The Engineering Officer called out "800 feet" (240 m), which was followed by a "gust" of intense violence. The steersman reported no response to his wheel as the lower rudder cables had been torn away. While the control gondola was still hundreds of feet high, the lower fin of Akron had struck the water and was torn off.
ZRS4 rapidly broke up and sank in the stormy Atlantic. Akron had been lost owing to operator error, having been flown to sea into an intense storm front. The crew of the nearby German motorship Phoebus saw lights descending toward the ocean at about 12:23 and altered course to starboard to investigate, believing they were witnessing a plane crash. At 12:55, an unconscious Commander Wiley was pulled from the water while the ship's boat picked up three more men: Chief Radioman Robert W. Copeland, Boatswain's Mate Second Class Richard E. Deal, and Aviation Metalsmith Second Class Moody E. Erwin. Despite artificial respiration, Copeland never regained consciousness and died aboard Phoebus.
Although the German sailors spotted four or five other men in the water, they did not know their ship had chanced upon the crash of Akron until Lieutenant Commander Wiley regained consciousness half an hour after being rescued. The crew of Phoebus combed the ocean in boats for over five hours in a fruitless search for more survivors. The Navy blimp J-3—sent out to join the search—also crashed, with the loss of two men.
The United States Coast Guard cutter Tucker—the first American vessel on the scene—arrived at 6:00, taking Akron's survivors and the body of Copeland aboard. Among the other ships combing the area for survivors were the heavy cruiser Portland, the destroyer Cole, the Coast Guard cutter Mojave, and the Coast Guard destroyers McDougal and Hunt, as well as two Coast Guard aircraft. The F/V Grace F out of Gloucester MA also assisted in the search, employing her seining gear in an effort to recover bodies. Most casualties had been caused by drowning and hypothermia, as the crew had not been issued life jackets, and there had not been time to deploy the single life raft. The accident left 73 dead, and only three survivors. Wiley, standing next to the two other survivors, gave a brief account on 6 April.
Akron's loss spelled the beginning of the end for the rigid airship in the US Navy, especially since one of its leading proponents, Rear Admiral William A. Moffett, was killed with 72 other men. As President Roosevelt commented afterward: "The loss of the Akron with its crew of gallant officers and men is a national disaster. I grieve with the Nation and especially with the wives and families of the men who were lost. Ships can be replaced, but the Nation can ill afford to lose such men as Rear Admiral William A. Moffett and his shipmates who died with him upholding to the end the finest traditions of the United States Navy."
The USS Macon and other airships received life jackets to avert a repetition of this tragedy.
The songwriter Bob Miller wrote and recorded a song — "The Crash of the Akron" — within one day of the disaster.
Thursday, June 13, 2013
The last Time I built this kit I must have been 10 years of age. I bought it right after "The Hindenburg" movie starring George C Scott came out. Memories!
LZ 129 Hindenburg (Luftschiff Zeppelin #129; Registration: D-LZ 129) was a large German commercial passenger-carrying rigid airship, the lead ship of the Hindenburg class, the longest class of flying machine and the largest airship by envelope volume. It was designed and built by the Zeppelin Company (Luftschiffbau Zeppelin GmbH) on the shores of Lake Constance in Friedrichshafen and was operated by the German Zeppelin Airline Company (Deutsche Zeppelin-Reederei). The airship flew from March 1936 until destroyed by fire 14 months later on May 6, 1937, at the end of the first North American transatlantic journey of its second season of service. Thirty-six people died in the accident, which occurred while landing at Lakehurst Naval Air Station in Manchester Township, New Jersey, United States.
Hindenburg was named after the late Field Marshal Paul von Hindenburg (1847–1934), President of Germany (1925–1934).
The Hindenburg had a duralumin structure, incorporating 15 Ferris wheel-like bulkheads along its length, with 16 cotton gas bags fitted between them. The bulkheads were braced to each other by longitudinal girders placed around their circumferences. The airship's outer skin was of cotton doped with a mixture of reflective materials intended to protect the gas bags within from radiation, both ultraviolet (which would damage them) and infrared (which might cause them to overheat). The gas cells were made by a new method pioneered by Goodyear using multiple layers of gelatinized latex rather than the previous goldbeater's skins. In 1931 the Zeppelin Company purchased 5,000 kg (11,000 lb) of duralumin salvaged from the wreckage of the October 1930 crash of the British airship R101, which might have been re-cast and used in the construction of the Hindenburg.
The interior furnishings of the Hindenburg were designed by Fritz August Breuhaus, whose design experience included Pullman coaches, ocean liners, and warships of the German Navy. The upper "A" Deck contained small passenger quarters in the middle flanked by large public rooms: a dining room to port and a lounge and writing room to starboard. Paintings on the dining room walls portrayed the Graf Zeppelin's trips to South America. A stylized world map covered the wall of the lounge. Long slanted windows ran the length of both decks. The passengers were expected to spend most of their time in the public areas, rather than their cramped cabins.
The lower "B" Deck contained washrooms, a mess hall for the crew, and a smoking lounge. Harold G. Dick, an American representative from the Goodyear Zeppelin Company, recalled "The only entrance to the smoking room, which was pressurized to prevent the admission of any leaking hydrogen, was via the bar, which had a swiveling air lock door, and all departing passengers were scrutinized by the bar steward to make sure they were not carrying out a lit cigarette or pipe."
Use of hydrogen instead of heliumHelium was initially selected for the lifting gas because it was the safest to use in airships, as it is not flammable. At the time, however, helium was also relatively rare and extremely expensive as the gas was only available as a byproduct of mined natural gas reserves found in the United States. Hydrogen, by comparison, could be cheaply produced by any industrialized nation and being lighter than helium also provided more lift. Because of its expense and rarity, American rigid airships using helium were forced to conserve the gas at all costs and this hampered their operation.
Despite a U.S. ban on the export of helium under the Helium Control Act of 1927, the Germans designed the airship to use the far safer gas in the belief that they could convince the US government to license its export. When the designers learned that the National Munitions Control Board would refuse to lift the export ban, they were forced to re-engineer the Hindenburg to use hydrogen for lift. Despite the danger of using flammable hydrogen, no alternative gases that could provide sufficient lift could be produced in adequate quantities. One beneficial side effect of employing hydrogen was that more passenger cabins could be added. The Germans' long history of flying hydrogen-filled passenger airships without a single injury or fatality engendered a widely held belief they had mastered the safe use of hydrogen. The Hindenburg's first season performance appeared to demonstrate this.
After making the first South American flight of the 1937 season in late March, Hindenburg left Frankfurt for Lakehurst on the evening of May 3, on its first scheduled round trip between Europe and North America that season. Although strong headwinds slowed the crossing, the flight had otherwise proceeded routinely as it approached for a landing three days later.
The Hindenburg's arrival on May 6 was delayed for several hours to avoid a line of thunderstorms passing over Lakehurst, but around 7:00 pm the airship was cleared for its final approach to the Naval Air Station, which it made at an altitude of 650 ft (200 m) with Captain Max Pruss at the helm. Four minutes after ground handlers grabbed hold of a pair of landing lines dropped from the nose of the ship at 7:21 pm, the Hindenburg suddenly burst into flames and dropped to the ground in just 37 seconds. Of the 36 passengers and 61 crew on board, 13 passengers and 22 crew died, as well as one member of the ground crew, making a total of 36 lives lost in the disaster.
The exact location of the initial fire, its source of ignition, and the initial source of fuel remain subjects of debate. The cause of the accident has never been determined conclusively, although many hypotheses have been proposed. Escaping hydrogen gas will burn after mixing with air and will explode when mixed with air in the right proportions. The covering also contained material (such as cellulose nitrate and aluminium flakes) which Addison Bain and other experts claim are highly flammable when combined in the right proportions. This theory is highly controversial and has been rejected by other researchers because the outer skin burns too slowly to account for the rapid flame propagation and hydrogen fires had previously destroyed many other airships. The duralumin framework of Hindenburg was salvaged and shipped back to Germany. There the scrap was recycled and used in the construction of military aircraft for the Luftwaffe, as were the frames of Graf Zeppelin and Graf Zeppelin II when they were scrapped in 1940.
Wednesday, June 12, 2013
The Kawasaki Ki-61 Hien (飛燕, "flying swallow") was a Japanese World War II fighter aircraft used by the Imperial Japanese Army Air Force. The first encounter reports claimed Ki-61s were Messerschmitt Bf 109s: further reports claimed that the new aircraft was an Italian design, which led to the Allied reporting name of "Tony", assigned by the United States War Department. The Japanese Army designation was "Army Type 3 Fighter" (三式戦闘機). It was the only mass-produced Japanese fighter of the war to use a liquid-cooled inline V engine. Over 2,500 Ki-61s were produced, first seeing action around New Guinea in 1943, and continuing to fly combat missions throughout the war.
The Ki-61 was designed by Takeo Doi and his deputy Shin Owada in response to a late 1939 tender by the Koku Hombu for two fighters, each to be built around the Daimler-Benz DB 601Aa. Production aircraft would use a Kawasaki licensed DB 601, known as the Ha-40, which was to be manufactured at its Akashi plant. The Ki-60 was to be a heavily armed specialised interceptor, with a high wing loading; the Ki-61 was to be a more lightly loaded and armed general-purpose fighter, intended to be used mainly in an offensive, air superiority role at low to medium altitudes.
Both single-seat, single-engine fighters used the same basic construction, being of all-metal alloys with semi-monocoque fuselages and three-spar wings, with alloy-framed, fabric-covered ailerons, elevators and rudders. Priority was given to the Ki-60, which first flew in April 1941, while design work on the Ki-61 did not begin until December 1940. Although the Ki-61 was broadly similar to the Ki-60, it featured several refinements exploiting lessons learned from the disappointing flight characteristics of the earlier design.
The all-metal, semi-monocoque fuselage was basically oval in cross-section, changing to a tapered, semi-triangular oval behind the cockpit canopy, with a maximum depth of 1.35 m (4 ft 5 in). An unusual feature of the Ki-61 was that the engine bearers were constructed as an integral part of the forward fuselage, with the cowling side panels being fixed. For servicing or replacement, only the top and bottom cowling panels could be removed. A tapered, rectangular supercharger air intake was located on the port-side cowling. Behind the engine bulkhead were the ammunition boxes feeding a pair of synchronized 12.7 mm (.50 in) Ho-103 machine guns which were set in a "staggered" configuration (the port weapon slightly further forward than that to starboard) in a bay just above and behind the engine. The breeches partly projected into the cockpit, above the instrument panel. The Ho-103 was a light weapon for its caliber (around 23 kg/51 lb) and fired a light shell, but this was compensated for by its rapid rate of fire. The ammunition capacity was limited, having only around 250 rounds for each weapon. A self-sealing fuel tank with a capacity of 165 L (44 US gal) was located behind the pilot's seat. The windshield was armoured and there was a 13 mm (.51 in) armour plate behind the pilot. The radiator and oil cooler for the liquid-cooled engine were in a ventral location below the fuselage and wing trailing edge, covered by a rectangular section fairing with a large, adjustable exit flap.
The evenly tapered wings had an aspect ratio of 7.2 with a gross area of 20 m² (215.28 ft²) and featured three spars; a Warren truss main spar and two auxiliary spars. The rear spar carried the split flaps and long, narrow-chord ailerons, while the front spar incorporated the undercarriage pivot points. The undercarriage track was relatively wide at 4 m (13 ft 1.5 in). Each wing had a partially self-sealing 190 L (50 US gal) fuel tank behind the main spar, just outboard of the fuselage. A single weapon (initially a 7.7 mm/0.303 in Type 89 machine gun) was able to be carried in a weapons bay located behind the main spar.
The first prototype of the San-shiki-Sentohki ichi gata ("Type 3 Fighter, Model 1", the official IJAAF designation) first flew in December 1941 at Kagamigahara Airfield. Although test pilots were enthusiastic about its self-sealing fuel tanks, upgraded armament, and good dive performance, the wing loading of 146.3 kg/m² (30 lb/ft²) at an all-up weight of 2,950 kg (6,500 lb) was viewed with scepticism by many of the senior officers of the Koku Hombu, who still believed in the light, highly manoeuvrable, lightly armed fighter epitomised by the then new Ki-43-I-Hei which had a wing loading of 92.6 kg/m² (19 lb/ft²) (and even that was considered borderline compared to the earlier Ki-27).
To address these concerns, Kawasaki staged a fly-off between two Ki-61 prototypes and the Ki-43-I, a pre-production Ki-44-I, a LaGG-3 (flown to Manchuria by a defector), a Bf 109E-3, and a captured P-40E Warhawk. The Ki-61 proved the fastest of all the aircraft and was inferior only to the Ki-43 in manoeuvrability.
The Ki-61 was the last of the fighters powered by the DB-601 or its foreign derivatives, and it was soon overshadowed by fighters with more powerful engines. By the time it first flew in December 1941 –one year after the Macchi C.202's first flight and three years after the first Bf 109E– the engine was already underpowered compared to the new 1,120 kW (1,500 hp) inline or 1,491 kW (2,000 hp) radial engines being developed (and already nearing the mass-production stage) to power the next generation of combat aircraft such as the Republic P-47. Moreover, the inline Ha-40 engine proved to be an unreliable powerplant.
The DB-601 engine required precise and sophisticated manufacturing; the Ha-40 was lighter by roughly 30 kg (70 lb) and required even higher manufacturing standards. Reaching these standards proved to be a "stretch" for Japanese manufacturers, an issue further complicated by the variable quality of materials, fuel, and the lubricants needed to run a sensitive, high-performance engine. The Japanese equivalent of the more powerful DB-605 engine was the Ha-140, which was fitted onto the Type 3 to produce the Ki-61-II high-altitude interceptor.
Compared to the Ki-61-I, the Ki-61-II had 10% greater wing area, used more armour and was powered by the Kawasaki Ha-140 engine generating 1,120 kW (1,500 hp). After overcoming initial fuselage and wing stability problems, the new interceptor reverted to the original wing and was put into service as the Ki-61-II-KAI. However, the Ha-140 engine had severe reliability problems which were never fully resolved, and around half of the first batch of engines delivered were returned to the factory to be re-built. A US bombing raid on 19 January 1945 destroyed the engine factory in Akashi, Hyōgo, and 275 Ki-61-II-KAI airframes without engines were converted to use the Mitsubishi Ha-112-II radial engine, resulting in the Ki-100. While the Ha-112 solved the problems encountered with the Ha-140, the new engine still had a major weakness: a lack of power at altitude, which diminished its ability to intercept high-flying B-29s relative to the Ki-61-II.
During testing, the Hien proved capable, but several shortcomings were subsequently revealed in operational service, namely lack of armor protection and a sub-standard engine that eventually led to a new engine being considered.
Sunday, June 9, 2013
The Supermarine Seafire was a naval version of the Supermarine Spitfire adapted for operation from aircraft carriers. The name Seafire was arrived at by abbreviating the longer name Sea Spitfire.
The final version of the Seafire was the Seafire F Mk 47 and FR Mk 47. There was no true prototype, instead the first production aircraft PS944 and PS945 served as trials aircraft. As the "definitive" carrier based Seafire the Mk 47 incorporated several refinements over earlier variants. After the first four aircraft, with manually folded wings, the Mk 47 incorporated hydraulically powered wing folding, the outer wings folding upwards in one piece, without the folding wingtips of earlier marks. All Mk 47s adopted the Rotol contra-rotating propellers. The Mk 47 also featured a long supercharger air-duct, the intake of which started just behind the spinner and a modified curved windscreen, similar to that used on the Mk XVII. Other features unique to the Mk 47s were spring-loaded elevator tabs, a large inertia weight in the elevator control system and beading on the trailing edges of the elevators. These changes improved longitudinal stability, especially when the aircraft was fully loaded. The modified windscreen proved to be unpopular with pilots because of continual problems with misting and the thicker, repositioned frames obstructed visibility during deck landings. In spite of recommendations to change the windscreen back to a standard Spitfire 24 unit, this was never done. Performance tests showed that the Mk 47 was slightly slower than the Mk 46 in maximum and climbing speeds, mainly due to the long supercharger air intake, which was less efficient than the shorter type fitted to earlier Seafires. The Seafire 47 saw action with 800 Squadron on board HMS Triumph during the Malayan Emergency of 1949 and during the Korean War in 1950. However, in 1951 all Seafires were withdrawn from front-line service. In all 90 F Mk 47s and FR Mk 47s were built, all by Supermarine. The last aircraft of the 22,000 of the entire Spitfire/Seafire lineage VR971 left the production line at Supermarine on 28 January 1949.
Thursday, June 6, 2013
Here are some more images of Dragon Model's 1/72 scale Apollo 11"Lunar Approach" North American CSM "Columbia" + Grumman LM "Eagle".
The Command Module was the control center for the Apollo spacecraft and living quarters for the three crewmen. It contained the pressurized main crew cabin, crew couches, control and instrument panel, optical and electronic guidance systems, communications systems, environmental control system, batteries, heat shield, reaction control system, forward docking hatch, side hatch, five windows and the parachute recovery system. It was the only part of the Apollo/Saturn launch vehicle that returned to Earth intact.
The Service Module was a portion of the spacecraft that was unpressurized and contained fuel cells, batteries, a high gain antenna, radiators, water, hydrogen, oxygen, a reaction control system and propellant to enter and leave lunar orbit, and service propulsion systems. On Apollo 15, 16 and 17 it also carried a scientific instrument package, mapping camera and a small sub-satellite to study the moon.
A major portion of the service module was taken up by propellant and the main rocket engine. Capable of multiple restarts, this engine placed the Apollo spacecraft into and out of lunar orbit, and was used for mid-course corrections between the earth and the moon.
The Service Module remained attached to the Command Module throughout the mission. It was jettisoned just prior to reentry into the Earth's atmosphere.
The Lunar Module was the portion of the Apollo spacecraft that landed on the moon and returned to lunar orbit and was the first true "spaceship" since it was designed to fly solely in the vacuum of space. It was divided into two major parts, the Descent Module and the Ascent Module. It supplied life support systems for two astronauts for a total of four to five days. The spacecraft was designed and manufactured by the Grumman Aircraft Company led by Tom Kelly.
The Descent Stage contained the landing gear, landing radar antenna, descent rocket engine, and fuel to land on the moon. It also had several cargo compartments used to carry among other things, the Apollo Lunar Surface Experiment Packages ALSEP, the Modularized Equipment Transporter (MET) (a hand-pulled equipment cart used on Apollo 14), the Lunar Rover (moon car - Apollo 15, 16 and 17), surface television camera, surface tools and lunar sample collection boxes.
The Ascent Stage contained the crew cabin, instrument panels, overhead hatch/docking port, forward hatch, optical and electronic guidance systems, reaction control system, radar and communications antennas, ascent rocket engine and fuel to return to lunar orbit and rendezvous with the Apollo Command and Service Modules.