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The Douglas XC-115 was to have been a version of the XC-114 powered by four 1,650 Packard V-1650-209 engines. The XC-114 itself was an extended version of the C-54 Skymaster, with the fuselage extended from 93ft 10in in the C-54 up to 100ft 7in. Two prototypes were built, one XC-114 and one XC-116, which was the same design but with thermal de-icing equipment in place of the normal pneumatic boots of the C-54. The XC-115 itself was never built.
A repülőgépet a második világháború előtti időszakban fejlesztették ki, és az amerikai légierő korszerűsítésére irányuló program része volt. Úgy alakult a projekt keretében neve XBLR-2 (kísérleti állapot, bombázó, Long Range, 2. modell), és a legnagyobb bombázó az Egyesült Államokban a második világháború előtt, ugyanakkor a legnagyobb repülőgépek épült az Egyesült Államokban a mai napig és a világ legnagyobb négymotoros repülőgépe. Csak 1946-ban volt a Convair B-36 szárnyfesztávolsága és hossza 12% -kal nagyobb.
A fő futómű két hatalmas, egyenként 2,44 m átmérőjű kerékből állt. A gép első repülésére 1941. június 27-én kerül sor Long Beach felől . Mivel az építkezés ennyire elhúzódott, az amerikai hadsereg 1941 - ben további szerződéseket kötött az XB-35 és az XB-36 kapcsán. 1943-ban új 1940 kW - os Allison V-3420-11 V motorokat telepítettek, és a gépet ma XB-19A néven emlegetik .
A repülőgépet később szállító repülőgépként használták, de 1945 augusztusa után ritkán használták, és 1949-ben leselejtezték Davis-Monthan AFB- n.
The lightweight fighter program
The roots of the F / A-18 lie in a study begun by Northrop in 1966 for a successor to the Northrop F-5 . The goal of the study, led by Lee Begin JR , was a light, agile, and fast air superiority fighter , with two different teams working on a single-engine and twin-engine aircraft (the prototypes were named P-610 and P-600, respectively). A first mock-up was presented at the Paris Air Show in 1971 and was named Cobra .
In 1972, Northrop finally planned to build the first prototypes, but this was associated with high costs. Although the budget of the United States Air Force at that time was clearly focused on the development and introduction of the McDonnell Douglas F-15 Eagle , the Lightweight Fighter Program was initiated, which can also be explained by massive lobbying work by the so-called fighter mafia . This group of high-ranking officers within the Air Force believed that only light and cheap fighters should be purchased in large numbers. It was already foreseeable that the F-15 would be very expensive and that this would inevitably have resulted in a reduction in the squadron sizes . Even the allies of the United States, who were waiting for a successor to the Lockheed F-104 Starfighter , would have been overwhelmed by the high acquisition costs. Hence, Northrop essentially marketed the Cobra as a cheap export machine that was by no means intended to compete with the F-15.
Although the subsequent tender was expressly for demonstration purposes only, many important aircraft manufacturers, for example Boeing , Vought with the LTV V-507 Vagabond and General Dynamics , submitted their concepts, as they were hoping for subsequent large orders. Since Northrop was the driving force behind the program, the twin-engine P-600 was a perfect match for the requirements of the US Air Force. On April 13, 1972, this then awarded the orders for two prototypes each to Northrop (designation: YF-17) and General Dynamics (YF-16). Both companies received $ 38 million each for this.
The prototypes YF-16 and YF-17
Although the YF-17 had moved further and further away from the F-5 in the course of development, the influences were still clearly visible. New features were the V-tail , the generally much larger airframe , significantly more powerful engines and the newly developed leading edge extensions (see strakes ). The airframe consists essentially of aluminum alloys and some CFRP components, whereby it was very similar to the concept of the P-600 prototype. The YF-17 was powered by two General Electric YJ101-GE-100 turbofan engines, which could generate a thrust of up to 64 kN each with afterburners . The avionics were reduced to the bare essentials and comprised only a very simple radar , a radio and an IFF system.
On January 13, 1975, the Air Force announced the winner of the competition: General Dynamics' YF-16. It then became the F-16 Fighting Falcon , which later became an indispensable pillar of the Air Force and was very successful on the export market.
From the YF-17 to the F-18
Although the YF-17 lost in the Air Force competition, the project has not yet been abandoned. At the same time, the US Navy also needed a new aircraft that could complement the F-14 Tomcat and replace the outdated A-7 Corsair II and F-4 Phantom II aircraft. Although the Navy wanted to procure a machine adapted to its needs, the US Congress forced it to select it from the LWF program for cost reasons. The decision was made on May 2, 1975, despite noticeable displeasure about the procurement process, for the YF-17, as it saw greater air-to-ground potential and a twin-engine aircraft was preferred for reasons of flight safety.
Since Northrop had no experience with carrier aircraft, the company now cooperated with McDonnell Douglas (MDD) to build the new machine, known as the "F-18". MDD was primarily responsible for the carrier-supported variant, while the development of the planned land variant F-18L was led by Northrop. Over time, this led to MDD leading the entire program, as the F-18L was later discarded due to a lack of demand. General Dynamics acted in a similar way together with LTV Aerospace , which developed the YF-16 to the F-16N under the Vought Model 1600 series in order to adapt it to the needs of the Navy. In contrast to the US Air Force, the Navy decided on the F / A-18.
The US Navy ordered a total of eleven pre-production machines (nine single-seaters and two two-seaters), as one variant for aerial combat (F-18) and one for air-to-ground attacks (A-18) was planned, which required an additional crew member. Compared to the YF-17 designed for the Air Force, the F-18 now had to be adapted to the requirements of the Navy. Above all, this required a more resilient airframe and a reinforced landing gear so that the machine could withstand the increased stresses of a carrier landing. Additional features such as foldable wings (saving space in the narrow aircraft carrier hangar) and catch hooks also had to be integrated. Increased reliability and simplified maintenance were also required, since maintenance work on aircraft carriers is a considerably more critical part of the deployment process than on land. These requirements led to a significant increase in weight and size, which is why General Electrics was commissioned in November 1975 to modernize the YJ101 engine and thus develop the new F404 engine. Furthermore, MDD should redesign the cockpit, as a lot of attention was paid to the workload of the pilot.
Testing and introduction
The first prototype, now known as the Hornet , took off on November 18, 1978 with the MDD chief test pilot Jack Krings . The last prototype was delivered in March 1980, with the test program lasting until October 1982. One of the two-seater planes crashed over Great Britain on September 8, 1980 . The pilots were supposed to transfer the machine from the Farnborough International Airshow to Spain , with a serious engine failure that forced the pilots to exit with the ejector seat .
Even during the flight tests and the final development phase, the numerous critics of the F-18 did not fall silent. The massive inflation of the 1970s led to steadily rising costs and the resilience of some components left a lot to be desired. At the same time, the specifications of the Navy ensured an increase in weight, which noticeably reduced the flight performance despite the improved engines (the range was about 8% below the specifications).
The program continued despite all the criticism and problems, mainly due to the lack of alternatives, and in May 1980 the first series models of the single-seater variant were delivered. At the same time the names were changed again. The two-seater version was renamed from TF-18A to F / A-18B and the single-seater was now called F / A-18A. The "F / A" stands for " fighter / attack " (German: "Hunter / Ground attack") and should clarify the versatility of the machine.
The first unit to receive the new F / A-18 was the United States Marine Corps' VMFA-314 "Black Knights" . The unit was declared fully operational on January 7, 1983.
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The first two were purchased by Wilmington-Catalina Airlines to fly passengers between Los Angeles and Santa Catalina Island, becoming the first successful Douglas airliners. Subsequent examples were ordered by the United States Navy and US Coast Guard for use as transports and search and rescue craft. The US Army Air Corps ordered several under the designations C-21, C-26, and C-29. Many were eventually ordered for their original purpose as luxury transports. Owners included William Boeing, the founder of the Boeing Company, and Philip K. Wrigley, the son of the founder of the Wm. Wrigley Jr. Company. William K. Vanderbilt bought two with custom interiors for use from the Vanderbilt yacht Alva as flying tenders. [ 6 ] [ 7 ]
One was procured by the US Navy as a transport for President Franklin D. Roosevelt. [ 8 ] Although never used by Roosevelt, this was the first aircraft procured to provide transportation for the President of the United States. [ 9 ]
The United States Army Air Forces commissioned the DC-6 project as the XC-112 in 1944. The Air Force wanted an expanded, pressurized version of the popular C-54 Skymaster transport with improved engines. By the time the XC-112 flew the war was over and the USAAF had rescinded its requirement.
Douglas converted its prototype into a civil transport (redesignated YC-112A, having significant differences from subsequent production DC-6 aircraft) and delivered the first production DC-6 in March 1947. However, a series of mysterious inflight fires (including the fatal crash of United Airlines Flight 608) grounded the DC-6 fleet later that year. The cause was found to be a fuel vent located adjacent to the cabin cooling turbine intake. All DC-6s in service were modified to correct the problem, and the fleet was flying again after just four months on the ground.
The DC-3 was the culmination of a development effort that originated out of an inquiry from Transcontinental and Western Airlines (TWA) to Donald Douglas. TWA's rival in transcontinental air service, United Airlines, was inaugurating service with the Boeing 247 and Boeing refused to sell any 247s to other airlines until United's order for 60 aircraft had been filled. [ 4 ] TWA asked Douglas to design and build an aircraft that would enable TWA to compete with United. Douglas' resulting design, the 1933 DC-1, was promising, and led to the DC-2 in 1934. While the DC-2 was a success, there was still room for improvement.
The DC-3 was the result of a marathon telephone call from American Airlines CEO C. R. Smith to Donald Douglas, during which Smith persuaded a reluctant Douglas to design a sleeper aircraft based on the DC-2 to replace American's Curtiss Condor II biplanes. Douglas agreed to go ahead with development only after Smith informed him of American's intention to purchase twenty aircraft. The new aircraft was engineered by a team led by chief engineer Arthur E. Raymond over the next two years, and the prototype DST (for Douglas Sleeper Transport) first flew on December 17, 1935 (the 32nd anniversary of the Wright Brothers' flight at Kitty Hawk, North Carolina). A version with 21 passenger seats instead of the sleeping berths of the DST was also designed and given the designation DC-3. There was no prototype DC-3, the first DC-3 built followed seven DSTs off the production line and was delivered to American. [ 5 ]
The amenities of the DC-3 and DST popularized air travel in the United States. With only three refueling stops, eastbound transcontinental flights crossing the U.S. in approximately 15 hours became possible. Westbound trips took 17-1/2 hours due to prevailing headwinds — still a significant improvement over the competing Boeing 247. During an earlier era, such a trip would entail short hops in slower and shorter-range aircraft during the day, coupled with train travel overnight. [ 6 ]
A variety of radial engines were available for the DC-3 throughout the course of its development. Early-production civilian aircraft used Wright R-1820 Cyclone 9s, but later aircraft (and most military versions) used the Pratt & Whitney R-1830 Twin Wasp which offered better high-altitude and single engine performance. Three DC-3S Super DC-3s with Pratt & Whitney R-2000 Twin Wasps were built in the late 1940s.
Total production of all derivatives was 16,079. [ 7 ] More than 400 remained in commercial service in 1998. Production was as follows
607 civil variants of the DC-3. 10,048 military C-47 derivatives were built at Santa Monica, California, Long Beach, California, and Oklahoma City. 4,937 were built under license in Russia as the Lisunov Li-2 (NATO reporting name: Cab). 487 Mitsubishi Kinsei-engined aircraft were built by Showa and Nakajima in Japan, as the L2D2-L2D5 Type 0 transport. (Allied codename Tabby).
Production of civil DC-3s ceased in 1942, military versions were produced until the end of the war in 1945. In 1949, a larger, more powerful Super DC-3 was launched to positive reviews however, the civilian market was flooded with second-hand C-47s, many of which were converted to passenger and cargo versions and only three were built and delivered the following year. The prototype Super DC-3 served the US Navy with the designation YC-129 alongside 100 C-47s that had been upgraded to the Super DC-3 specification.
From the early 1950s, some DC-3s were modified to use Rolls-Royce Dart engines, as in the Conroy Turbo Three. Other conversions featured Armstrong Siddeley Mamba and Pratt & Whitney PT6A turbines.
The Basler BT-67 is a conversion of the DC-3/C-47s. Basler refurbishes C-47/DC-3s at Oshkosh, Wisconsin, fitting them with Pratt & Whitney Canada PT6A-67R turboprop engines, lengthening the fuselage by 40 in (100 cm) with a fuselage plug ahead of the wing and strengthening the airframe in selected areas. The airframe is rated as having "zero accumulated fatigue damage." This and extensive modifications to various systems and avionics result in a practically brand-new aircraft. The BT-67s have been supplied to civil and military customers in several countries. [ 8 ]
Braddick Specialised Air Services International PTY Ltd in South Africa is another company able to perform a Pratt & Whitney PT6 turboprop conversion of DC-3s. Over 50 DC-3/C-47s / 65ARTP / 67RTP / 67FTPs have been modified. [ 9 ]
Although overshadowed by its ubiquitous successor, it was the DC-2 that first showed that passenger air travel could be comfortable, safe and reliable. As a token of this, KLM entered its first DC-2 PH-AJU Uiver (Stork) in the October 1934 MacRobertson Air Race between London and Melbourne. Out of the 20 entrants, it finished second behind only the purpose built de Havilland DH.88 racer Grosvenor House. During the total journey time of 90 hours, 13 min, it was in the air for 81 hours, 10 min, and won the handicap section of the race. (The DH.88 finished first in the handicap section, but the crew was by regulations allowed to claim only one victory.) It flew KLM's regular 9,000 mile route, (a thousand miles longer than the official race route), carrying mails, making every scheduled passenger stop, turning back once to pick up a stranded passenger, and even became lost in a thunderstorm and briefly stuck in the mud after a diversionary landing at Albury racecourse on the very last leg of the journey. [ 3 ]
Το C-54 εισήλθε σε υπηρεσία με τις Αεροπορικές δυνάμεις του Αμερικανικού Στρατού το 1942, μεταφέροντας 26 επιβάτες, ενώ μετέπειτα εκδόσεις μπορούσαν να μεταφέρουν μέχρι 50. Το Αμερικανικό Πολεμικό Ναυτικό απέκτησε επίσης τον τύπο, δίνοντας του την ονομασία R5D. Το C-54 υπήρξε ένα από τα πλέον χρησιμοποιημένα μεταφορικά αεροσκάφη μεγάλων αποστάσεων των Αμερικανικών ενόπλων δυνάμεων στον πόλεμο. Συνολικά κατασκευάστηκαν 515 C-54 στην Σάντα Μόνικα (Santa Monica) της Καλιφόρνια και 655 στο Σικάγο.
Μετά το τέλος του πολέμου, το C-54 συνέχισε να υπηρετεί ως το βασικό μεταφορικό αεροσκάφος της νεοσύστατης Αμερικανικής Πολεμικής Αεροπορίας και του Αμερικανικού Ναυτικού.
Η Στρατηγική Αεροπορική Διοίκηση της USAF χρησιμοποίησε τα C-54 Skymaster από το 1946 έως το 1975.
Ο Αμερικανός πρόεδρος Χάρρυ Τρούμαν υπέγραψε τον Νόμο Εθνικής Ασφαλείας του 1947, με τον οποίο δημιουργήθηκε η Αμερικανική Πολεμική Αεροπορία ως ξεχωριστός κλάδος των Αμερικανικών ενόπλων δυνάμεων, όντας επιβιβασμένος στο «Sacred Cow», το προεδρικό C-54, το οποίο βρίσκεται σήμερα στο Εθνικό Μουσείο της Αμερικανικής Πολεμικής Αεροπορίας. Περισσότερα από 300 C-54 και R5D συμμετείχαν στην Αερογέφυρα του Βερολίνου το 1948, ενώ υπηρέτησαν και στον πόλεμο της Κορέας. Μετά τη λήξη του πολέμου στην Κορέα, το C-54 αντικαταστάθηκε από το Douglas C-124 Globemaster II, όμως συνέχισε να χρησιμοποιείται από την USAF μέχρι το 1972.
Το C-54 υπήρξε το προσωπικό μεταφορικό αεροσκάφος των Φραγκλίνου Ρούσβελτ, Ντάγκλας Μακάρθουρ και Ουίνστον Τσώρτσιλ (μαζί με το Avro York). Το C-54 επίσης χρησιμοποιήθηκε από την Βρετανική Βασιλική Αεροπορία, την Βασίλική Καναδική Αεροπορία, την Γαλλική Πολεμική Αεροπορία και τις αεροπορικές δυνάμεις πολλών ακόμα χωρών.
The first two were purchased by Wilmington-Catalina Airlines to fly passengers between Los Angeles and Santa Catalina Island, becoming the first successful Douglas airliners. Subsequent examples were ordered by the United States Navy and US Coast Guard for use as transports and search and rescue craft. The US Army Air Corps ordered several under the designations C-21, C-26, and C-29. Many were eventually ordered for their original purpose as luxury transports. Owners included William Boeing, the founder of the Boeing Company, and Philip K. Wrigley, the son of the founder of the Wm. Wrigley Jr. Company. William K. Vanderbilt bought two with custom interiors for use from the Vanderbilt yacht Alva as flying tenders.
One was procured by the US Navy as a transport for President Franklin D. Roosevelt. Although never used by Roosevelt, this was the first aircraft procured to provide transportation for the President of the United States. [ 2 ]