perjantai 26. elokuuta 2016

F6U Pirate

The Vought F6U Pirate was the Vought company's first jet fighter, designed for US Navy during the mid-1940s. Although pioneering the use of turbojet power as the first naval fighter with an afterburner and composite material construction, the aircraft proved to be underpowered and was judged unsuitable for combat. None were ever issued to operational squadrons and they were relegated to development, training and test roles before they were withdrawn from service in 1950.

A specification was issued by the U.S. Navy's Bureau of Aeronautics (BuAer) for a single-seat, carrier-based fighter powered by a Westinghouse 24C (later J34) axial turbojet on 5 September 1944. Chance Vought was awarded a contract for three V-340 (company designation) prototypes on 29 December 1944.

The XF6U was a small aircraft with tricycle landing gear and with straight wings and tail surfaces. The wings were short enough that they did not need to fold. In order to fit more aircraft into crowded hangars, the nose gear could be retracted and the aircraft's weight would rest on a small wheel attached by the ground crew. This raised the tail up so that it could overlap the nose of the aircraft behind it, allowing more aircraft to fit into available hangar space. The turbojet engine was mounted in the rear of the fuselage and was fed by ducts in each wing root.

The most unusual feature of the aircraft was its use of "Metalite" for its skin. This was made of balsa that was sandwiched between two thin sheets of aluminum. "Fabrilite" was also used for the surfaces of the vertical stabilizer and rudder; this was similar to Metalite, but used fiberglass instead of aluminum. Two fuel tanks were fitted in the center of the fuselage. The forward tank, ahead of the wing, contained 830 l and the rear tank 570 l. 

These were supplemented by two jettisonable 530 l tip tanks. The cockpit was well forward and was provided with a bubble canopy which gave the pilot good visibility. He was provided with a Mk 6 lead-computing gyro gunsight. Underneath the cockpit were four 20 mm M3 autocannon. Their 600 rounds of ammunition were carried behind the pilot. The empty casings of the two upper guns were retained in the aircraft, while those from the two lower guns were ejected overboard.

Kuvahaun tulos haulle F6U Pirate

After a company-wide contest to name the aircraft, the initial prototype received the name Pirate and made its first flight on 2 October 1946. Flight testing revealed severe aerodynamic problems, mostly caused by the airfoil section and thickness of the wing. The vertical stabilizer also had to be redesigned to smooth out the airflow at the intersection of the horizontal and vertical stabilizers. Other changes included the addition of dive brakes on the sides of the fuselage and the replacement of the Metalite panels near the engine's exhaust with stainless steel ones.

The first XF6U-1 prototype was powered by a Westinghouse J34-WE-22 turbojet with 13.34 kN thrust, one third of the weight of the aircraft. To help improve the underpowered aircraft's performance, the third prototype, which first flew on 10 November 1947, was lengthened by 2.4 m to use a Westinghouse J34-WE-30 afterburning engine of 18.78 kN thrust, the first United States Navy fighter to have such a powerplant.

General characteristics
Crew: 1
Length: 11.46 m
Wingspan: 10 m
Height: 3.39 m
Wing area: 18.9 m²
Empty weight: 3,320 kg
Loaded weight: 5,850 kg
Powerplant: 1 × Westinghouse J34-WE-30A turbojet
Dry thrust: 14.0 kN
Thrust with afterburner: 18.78 kN
Maximum speed: 959 km/h
Range: 1,880 km
Service ceiling: 14,100 m
Rate of climb: 40.95 m/s
Wing loading: 304 kg/m²
Thrust/weight: 0.327
Guns: 4 × 20 mm (0.79 in) M3 cannon under the nose

In 1947, before the flight testing of the prototypes was completed, 30 production aircraft were ordered. They incorporated an ejection seat and a redesigned vertical stabilizer as well as two auxiliary fins, one towards the tip on each side of the tailplane in an attempt to improve the directional stability of the aircraft. The fuselage was lengthened to fit additional equipment and the wing had fillets added at the rear junction with the fuselage.

During the production run, the Navy decided to move the Chance Vought factory from Stratford, Connecticut to a much larger facility in Dallas, Texas which had been vacant since the end of World War II; this badly disrupted the production of the Pirate. The airframes were built in Stratford and trucked to Dallas where government-furnished equipment, such as the engines and afterburners, were installed. The completed aircraft were then taxied around the new plant's airfield, but the runway was deemed too short to handle jets. The aircraft had to be disassembled and trucked to an abandoned airfield at Ardmore, Oklahoma with a runway long enough for acceptance testing.

The first production F6U-1 performed its initial flight on 29 June 1949, and 20 of the aircraft were provided to VX-3, an operational evaluation squadron based at Naval Air Station Patuxent River in Maryland. The judgment from the evaluation was that the Pirate was unacceptable for operational use. Naval aviators disparagingly called the F6U the "groundhog". On 30 October 1950, BuAer informed Vought of the Navy's opinion of the Pirate in terms both bureaucratic and scathing: "The F6U-1 had proven so sub-marginal in performance that combat utilization is not feasible."

The aircraft ended up being used primarily to develop arresting gear and barriers, but were used operationally for a short time by at least one Texas-based United States Naval Reserve squadron as they transitioned to jets. Between them, the 30 production aircraft had only a total of 945 hours of flight time, only 31.5 hours each. Some aircraft flew only six hours which was enough for little more than their acceptance flight and the flight to their ultimate disposition.

torstai 25. elokuuta 2016

Arado AR 65

The Arado Ar 65 was the single-seat biplane fighter successor to the Ar 64. Both looked very similar. The only major difference was the use of the 12-cylinder inline versus the 64's radial. The wingspan was also increased.

The Ar 65 appeared in 1931 and six models were built. The first three 65a-c were the prototypes while the 65d-f were the production models. The Ar 65d was delivered in 1933 and served alongside the Ar 64 in the two fighter groups - Fliegergruppe Döberitz and Fliegergruppe Damm. In 1935, the Ar 65 was reduced to a training aircraft. Production of the fighter was discontinued in 1936. 

But the next year, 12 of them were presented to Germany's ally - the Royal Bulgarian Air Force. The final production total was 85 aircraft.

General characteristics Ar 65E
Crew: 1
Length: 8.4011 m 
Wingspan: 11.20 m 
Height: 3.4227 m 
Wing area: 23 m2 
Empty weight: 1,510 kg 
Gross weight: 1,930 kg 
Powerplant: 1 × BMW VI 7.3 liquid-cooled V-12 piston engine, 560 kW (750 hp) 
for take-off, 372.85 kW (500 hp) continuous maximum power
Maximum speed: 300 km/h  at 1,650 m 
Cruising speed: 246 km/h at 1,400 m 
Service ceiling: 7,600 m 
Rate of climb: 10.60 m/s 
Time to altitude: 1,000 m, in 1.5 minutes 5,000 m in 10.6 minutes

Guns: 2 × 7.92 mm MG 17 machine guns with 500 rpg.

keskiviikko 24. elokuuta 2016

Potez 25 A.2

Potez 25 (also written as Potez XXV) was a French twin-seat, single-engine biplane designed during the 1920s. A multi-purpose fighter-bomber, it was designed as a line aircraft and used in a variety of roles, including fighter and escort missions, tactical bombing and reconnaissance missions. In the late 1920s and early 1930s, Potez 25 was the standard multi-purpose aircraft of over 20 air forces, including French, Polish and American. It was also popular among private operators, notably mail transport companies.

The aircraft was further developed into the 25M, a standard parasol-wing monoplane, which never entered production.

In 1923, the Avions Henry Potez aircraft works started production of a successful Potez 15 reconnaissance biplane. Basing on experience gathered during the construction of that aircraft, Henry Potez started working on a new design of a heavier and faster multi-purpose aircraft. Designated Potez XXV or Potez 25, the prototype was built already in 1924. The main differences included a larger, more powerful engine and a new wing design. Instead of a classic biplane, Potez introduced a sesquiplane, with the lower wing significantly smaller. It was built in two main military variants: Potez 25A2 reconnaissance aircraft and Potez 25B2 bomber-reconnaissance aircraft.

In May 1925, the prototype was tested at the Service Technique d'Aeronautique Institute and was found a promising construction both for its manoeuvrability, speed and durability. Following the tests, the prototype entered serial production. To promote the new aircraft abroad, in a post-World War I market filled with hundreds of cheap demobilized aircraft, the Potez 25 was entered into a large number of races. 
Among the best-known achievements was a European rally (7,400 km/4,598 mi) and a Mediterranean rally (6,500 km/4,039 mi), both won by pilots flying the Potez. In 1920s, the Potez 25 was also used in a well-advertised Paris-Tehran rally (13,080 km/8,127 mi). In June 1930, Henri Guillaumet crashed with his Potez 25 in the Andes during an air mail flight. He survived after treking through the mountains and was found after one week of searching.
Military Operators
- Afghan Air Force
- Belgian Air Force 
- Brazilian Air Force
- Chinese Nationalist Air Force 
- Independent State of Croatia
- Royal Yugoslav Air Force.
Zrakoplovstvo Nezavisne Države Hrvatske captured 42 from the Royal Yugoslav Air 
- Ethiopian Air Force acquired 3 aircraft.
- Estonian Air Force operated Potez 25 Jupiter up to 1940.
- Finnish Air Force purchased one Potez 25 A2 to try out its flying qualities in 1927.     The aircraft was flown more than 700 hours, but no deal was made. It was used 
  until 1936.
- French Air Force
- Free French Air Force
- Hellenic Air Force
- Guatemalan Air Force
- Imperial Japanese Army Air Service
- Imperial Japanese Navy Air Service - Purchased as Potez CXP.
- Paraguayan Air Force operated a total of 14 aircraft, six Potez 25 A.2 
  and eight Potez 25 TOE during the Chaco War against Bolivia.
- Polish Air Force operated 16 aircraft bought in France 
  and another 300 aircraft manufactured in Poland.
- Portuguese Air Force
- Royal Romanian Air Force
- Spanish Republican Air Force
- Swiss Air Force
- Soviet Air Force - Two aircraft used for tests and trials.
- Turkish Air Force
- United States Army Air Corps
- Uruguayan Air Force
- Kingdom of Yugoslavia
- Yugoslav Royal Air Force operated 200 aircraft manufactured in Yugoslavia.

Specifications Potez 25
Crew: 2
Length: 9.2 m 
Wingspan: 14.14 m 
Height: 3.59 m 
Wing area: 51.4 m² 
Empty weight: 1,490 kg 
Loaded weight: 2,558 kg 
Useful load: 1,068 kg 
Powerplant: 1 × Lorraine-Dietrich 12Eb water-cooled W12 inline, 357 kW (478 hp)
Maximum speed: 214 km/h 
Range: 600 km 
Service ceiling: 5,500 m 
Rate of climb: 3.5 m/s 
Wing loading: 49.8 kg/m² 
Power/mass: 0.14 kW/kg 
Armament: 1 × 7.7 mm (.303 in) mg in front,  2 × 7.7 mm mg, on rear cockpit
+ 200 kg bombs
Such achievements added to aircraft's popularity and made it one of the most successful French aircraft of the epoch. It was bought by a number of air forces, including those of France, Switzerland, Belgium, Brazil, Croatia, Estonia, Ethiopia, Finland, Greece, Spain, Japan, Yugoslavia, Paraguay, Poland, Portugal, Romania, Turkey and the USSR. After the USSR acquired two aircraft for testing, they decided against further purchases, finding it comparable to the native Polikarpov R-5. Altogether, approximately 2,500 aircraft were built in France.

Already in 1925, Poland bought a licence for Potez 25 and started to manufacture them in Podlaska Wytwórnia Samolotów (PWS, 150 built) and Plage i Laśkiewicz aircraft works (150 built). In 1928 the first Polish-built Potez 25 were tested by the Technical Aviation Development Institute in Warsaw and the design was slightly modified to better fit the needs of the Polish air forces. Among the notable differences were the introduction of leading edge slots. The production in Poland ceased in 1932. Altogether, 300 aircraft were built in a number of versions for long- and short-range reconnaissance and daylight tactical bombing. As the original Lorraine-Dietrich 12Eb engine was unavailable in Poland, it was replaced in 47 aircraft with a more powerful PZL Bristol Jupiter VIIF radial engine, starting from 1936.
In Romania, Potez 25 was produced by IAR. Several other countries manufactured Potez 25s under licence.