maanantai 20. helmikuuta 2017

Grumman F7F Tigercat

The Grumman F7F Tigercat is a heavy fighter aircraft that served with the United States Navy (USN) and United States Marine Corps (USMC) from late in World War II until 1954. It was the first twin-engined fighter to be deployed by the USN. While the Tigercat was delivered too late to see combat in World War II, it saw action as a night fighter and attack aircraft during the Korean War.

Designed initially for service on Midway-class aircraft carriers, early production F7Fs were land-based variants. The type was too large to operate from older and smaller carriers, and only a late variant (F7F-4N) was certified for carrier service.
Based on the earlier Grumman XP-50 that was eventually canceled, the company developed the XP-65 (Model 51) further for a future "convoy fighter" concept. In 1943, work on the XP-65 was terminated in favor of the design that would eventually become the F7F. The contract for the prototype XF7F-1 was signed on 30 June 1941. Grumman's aim was to produce a fighter that outperformed and outgunned all existing fighter aircraft, and that had an auxiliary ground attack capability.

Grumman F7F Tigercat on kaksimoottorinen raskas yhdysvaltalainen tukialuksilta käytettävä hävittäjälentokone. Tigercat on kuuluisan ”kissa-sarjan” jatkaja, Grummanin valmistamat laivaston hävittäjäkoneet olivat cat-päätteisiä.

Tigercat oli Yhdysvaltain laivaston ensimmäinen nykyaikaista laskeutumistelinettä käyttänyt konetyyppi. Prototyyppi lensi ensilentonsa joulukuussa 1943. Konetyyppi ei ehtinyt toiseen maailmansotaan, mutta sitä käytettiin Korean sodassa. Sodan syttyessä nämä koneet olivat tukeutuneita Japaniin.
Kaksi turboahdettua Pratt & Whitney -ruiskutusmäntämoottoria tuottivat kukin 2 100 hevosvoiman tehon. Huippunopeus oli suunnilleen sama kuin P-51 Mustangin, 700 km/h. Siivet olivat trapetsista muotoa: etusiipi tasan suora, mutta jättöreuna kapeni rungosta siiven kärkeen päin.

Aseistuksena koneella oli neljä 20 mm tykkiä siipien tyvissä ja neljä 12,7 mm konekivääriä eturungossa. Kaikki tuliaseet ampuivat eteenpäin. Rungon alle sekä siipiripustuksiin voitiin liittää lisäpolttoainesäiliöitä, pommeja, rakettiaseistusta tai torpedo.
Armament was heavy: four 20 mm cannons and four 12.7 mm machine guns, as well as underwing and under-fuselage hardpoints for bombs and torpedoes. Performance met expectations too; the F7F Tigercat was one of the highest performance piston-engined fighters, with a top speed well in excess of the US Navy's single-engined aircraft 71 mph faster than a Grumman F6F Hellcat at sea level. 

General characteristics
Crew: 2 (pilot, radar operator)
Length: 13.8 m
Wingspan: 15.7 m
Height: 5.1 m
Wing area: 42.3 m²
Empty weight: 7,380 kg
Max. takeoff weight: 11,670 kg
Powerplant: 2 × Pratt & Whitney R-2800-34W Double Wasp radial engines, 2,100 hp (1,566 kW) each
Maximum speed: 740 km/h
Range:  1900 km
Service ceiling: 12,300 m
Rate of climb: 23 m/s
Armament: 4 × 20 mm cannon and 4 × 12.7 mm M2 Browning mg
Bombs: 2 × 450 kgbombs under wings or 1 × torpedo under fuselage
Avionics: AN/APS-19 radar

CAPT Fred M. Trapnell, one of the Navy's premier test pilots, opined that: "It's the best damn fighter I've ever flown." The Grumman F7F was originally named the "Tomcat" but this name was rejected as it was considered too suggestive, at the time. The name would much later be used for the Grumman F-14.

All this was bought at the cost of heavy weight and a high landing speed, but what caused the aircraft to fail carrier suitability trials was poor directional stability with only one engine operational, as well as problems with the arrestor hook design.
The initial production series was therefore used only from land bases by the USMC, as night fighters with APS-6 radar. At first, they were single-seat F7F-1N aircraft, but after the 34th production aircraft, a second seat for a radar operator was added; these aircraft were designated F7F-2N.

The next version produced, the F7F-3, was modified to correct the issues that caused the aircraft to fail carrier acceptance and this version was again trialled on the USS Shangri-La. A wing failure on a heavy landing caused the failure of this carrier qualification too. F7F-3 aircraft were produced in day fighter, night fighter and photo-reconnaissance versions.

A final version, the F7F-4N, was extensively rebuilt for additional strength and stability, and did pass carrier qualification, but only 12 were built.

Marine Corps night fighter squadron VMF(N)-513 flying F7F-3N Tigercats saw action in the early stages of the Korean War, flying night interdiction and fighter missions and shooting down two Polikarpov Po-2 biplanes. This was the only combat use of the aircraft.

Most F7F-2Ns were modified to control drones for combat training, and these gained bubble canopies over the rear cockpit for the drone controller. An F7F-2D used for pilot transitoning also had a rear sliding, bubble canopy.

In 1945, two Tigercats, serialled TT346 and TT349, were evaluated, but rejected, by the British Royal Navy, who preferred a navalized version of the de Havilland Hornet.

sunnuntai 19. helmikuuta 2017

Curtiss Hawk III

The Curtiss BF2C Goshawk (Model 67) was a United States 1930s naval biplane aircraft that saw limited success and was part of a long line of Hawk Series airplanes made by the Curtiss Aeroplane and Motor Company for the American military, and for export as the Model 68 Hawk III.

The United States Navy and Curtiss felt that the F11C-2 possessed development potential, and the Navy decided to procure a variant with retractable landing gear. This variant, which still had the F11C-2's classic "Hawk" wood wing with its flat-bottomed Clark Y airfoil, was designated XF11C-3 by the Navy and Model 67 by Curtiss. The main gear retraction system was inspired by the Grover Loening-designed system on the Grumman XFF-1 prototype, and was manually operated.

The XF11C-3 was first delivered to the USN in May 1933, with a Wright R-1820-80 radial engine rated at 700 hp (520 kW). Trials revealed a 17 mph (27 km/h) increase in speed over the F11C-2, but the extra weight caused a decrease in maneuverability. The Navy felt the handling degradation was more than offset by the increase in speed, however. During testing the XF11C-3 had its wood-framed wing replaced by the metal-structured, biconvex, NACA 2212 airfoil wing, and soon after was redesignated XBF2C-1 (Model 67A) in keeping with the new Bomber-Fighter category.
Twenty-seven BF2C-1 were ordered by the U.S. Navy, with a raised rear turtledeck, a semi-enclosed cockpit, and a metal-framed lower wing. It was armed with two .30 calibre Browning machine guns and three hardpoints for 500 lb (230 kg) of external stores. Delivered in October 1934, they were assigned to VB-5 on the aircraft carrier USS Ranger, but served only a few months before difficulties with the landing gear led to their withdrawal. In spite of its short service run many of the innovations developed for the Goshawk line found wide use in Navy aircraft for years to follow. They were the last Curtiss fighter accepted for service with the U.S. Navy.
The export version Model 68 Hawk III reverted to the classic wood/Clark Y wings and was powered by a 770 hp (570 kW) R-1820-F53. Chinese Hawk IIIs served as multi-purpose aircraft when combat operations against the Imperial Japanese Army and Navy Air Forces began in earnest in August 1937, and were considered the Nationalist Chinese Air Force's frontline fighter-pursuit aircraft along with their inventory of Hawk IIs, Boeing Model 281 "Peashooters" and Fiat CR.32s. 

These aircraft were used against both the Imperial Japanese Army and Navy Air Forces and both ground and naval targets with considerable success through the end of 1937, before being superseded by the better-armed and faster Polikarpov I-15 and I-16 fighters. In the summer of 1940, nine surviving Hawk-III fighters, the F11C exported to the Nationalist Chinese Air Force, served as night fighters to defend the Chinese wartime capital Chongqing from Japanese night bombing runs with the 22nd Squadron of the 4th Group.
In early 1935, Thailand placed an order for 24 Curtiss Hawk IIIs at a cost of 63,900 Baht each, and a manufacturing license was also bought. The first 12 Hawk IIIs were shipped to Thailand in August and the remaining 12 arrived in late 1935, which were named Fighter Type 10. A total of 50 Hawk IIIs were locally built during 1937 and 1939.

The type was used against the French in the Franco-Thai War and the Japanese invaders in December 1941, then relegated for use as trainers. Some of these aircraft were still active in 1949 and one airframe (KH-10) survives in the Royal Thai Air Force Museum.

The Model 79 Hawk IV demonstrator had a fully enclosed cockpit and a 790 hp (590 kW) R-1820-F56.

XBF2C-1 Hawk
The XF11C-3 prototype redesignated as a fighter-bomber.
BF2C-1 Goshawk (Model 67A)
Production version of the XF11C-3; 27 built.
Hawk III (Model 68)
Export version of BF2C-1 with an 770 hp (570 kW) R-1820-F53 for Argentina, China, Thailand and Turkey; 137 built.
Hawk IV (Model 79)
Export version with an 790 hp (590 kW) R-1820-F56 engine; one demonstrator built.
- Argentina Army Aviation Service Model 68A Hawk III and 1 Model 79 Hawk IV.
- Republic of China Air Force operated 102 Model 68C Hawk III
- Royal Thai Air Force operated 24 Model 68B Hawk III
- Turkish Air Force operated one Model 68B Hawk III
- United States Navy operated 27 BF2C-1s

torstai 16. helmikuuta 2017

Lavochkin La-200

The Lavochkin La-200 (a.k.a. Aircraft 200) was a two-seater, swept winged, night and bad weather jet interceptor fighter designed and manufactured by the Lavochkin Design Bureau from 1948.

In response to a requirement for a high performance night and bad weather interceptor, Lavochkin (OKB-310), Sukhoi (OKB-134) and Mikoyan-Gurevich (OKB-155) design bureau developed the La-200, Su-15, and I-320 (Istrebitel - 320) respectively. The major driver for the three competing aircraft, was the development of the "Toriy" - Thorium centimetre waveband NII-17 radar at NIIP - Naoochno-Issledovatel'skiy Institut Priborostroyeniya (Research Institute of Instrument Engineering), which was capable of detecting a B-29 Superfortress bomber at a range of 20 km (12 mi).
Crew: Two
Length: 16.351 m 
Wingspan: 12.96 m 
Wing area: 40.02 m2 
Empty weight: 8,810 kg
Gross weight: 12,630 kg 
Powerplant: 2 × Klimov VK-1, 26.487 kN (5,950 lbf) thrust each
Maximum speed: 1,070 km/h 
Maximum speed: Mach 0.95
Range: 1,170 internal, 2,170 drop tanks km (726 Internal, 1,347 Drop Tanks miles)
Service ceiling: 15,550 m 
Rate of climb: 27.78 m/s 

Armament: 3 x 37mm Nudelman-Suranov NS-37 cannon

The La-200 was an all-metal, two seater, twin-engined jet aircraft, with a tri-cycle undercarriage and mid set wings with 40° sweep at 1/4 chord. The two Klimov RD-45F centrifugal flow turbojet engines were to be fitted in tandem inside the front and rear fuselage with the air intake at the extreme nose. The forward engine exhausted under the centre fuselage and the rear engine exhausted at the end of the rear fuselage. Access to the engines for maintenance and removal was gained by removing the forward fuselage forward of the nose undercarriage and the rear fuselage forward of the fin.

The main and nose undercarriages were housed entirely within the fuselage. The nose undercarriage rotated 90° to lie flat under the forward engine, and the twin wheeled main undercarriage legs, with long travel levered suspension, retracted into the centre fuselage above the forward jet pipe and astride the fuel tank and intake trunking for the rear engine.

The swept wings were of constant chord with 2/3 span flaps, 1/3 span ailerons, and wing fences at approximately 1/4 and 1/2 span. The tail unit comprised a sharply swept broad chord tapered fin with a sharply swept tapered tailplane at 2/3 fin length. The swept wings maximised the speed performance but imposed a higher wing loading than specified by the Soviet Air Force, thus the RD-45F engines were replaced with Klimov VK-1 engines, (up-rated RD-45F's).

The "Toriy" radar was initially fitted in an ogival radome in the centre of the air intake.

The La-200 incorporated many innovative systems, including powered flying controls, high capacity hydraulic and pneumatic systems, high voltage AC electrical power system and a comprehensive avionics suite. OKB-301 carried out extensive ground tests, allowing problems revealed in the tests to be addressed before the first flight.

For initial tests the aircraft was fitted with dual controls in the side by side cockpit. Flight trials were relatively successful, but revealed a tendency to drop the starboard wing at high speeds (known colloquially as val'ozhka). Other problems included vibrations of the rear fuselage with the rear engine throttled back and the front engine at maximum power, the twin mainwheels proved troublesome as well as unreliable radio and very poor performance from the radar.

To help cure the problems the starboard wing incidence was increased by 1° 30', and the twin mainwheels were replaced by single wheel units. Spill doors were fitted to the rear fuselage, arranged to open automatically when the rear engine was throttled back. The flaps and wings were stiffened, and separate aileron hydraulic actuators were installed in the wings rather than a single actuator behind the cockpit seats. Cooling air was provided for the radio which was located close to the front engine jetpipe. To address the failings of the radar, it was decided to replace it with the Korshun -(Kite) radar also developed by NII-17. The single antenna was moved to the top lip of a redesigned air intake.

By the spring of 1951 Aircraft 200 was the only one of the three competitors to survive and pass State acceptance trials. Production was provisionally ordered as the La-17, but the production directive was not endorsed so production was abandoned.
While other OKB's were designing the next generation of all-weather interceptors, OKB-301 was tasked with fitting the new Sokol (Falcon) radar into the La-200. The result was Aircraft 200B, with a new fuselage nose housing the radar behind a large radome with three air intakes surrounding the radome. By mid 1953 the radar was working adequately but Aircraft 200B's performance was no longer good enough and further work was abandoned.

- 200 with Toriy (Thorium) radar
- 200 with Korshun (Kite) radar
- La-17 the proposed production version of the 200 with Korshun radar was not produced but designation re-used later for a target drone.
- 200B with Sokol (Falcon) radar