Lockheed U-2 / TR-1 / ER-2
The U-2 was designed by Kelly Johnson to fly high and far. His equation stressed simplicity: flush rivets, high aspect ratio wet wing, ultralight struc-ture, stunning power-to-weight ratio. Conceived originally to meet a CIA requirement for an aircraft with the potential of operating at extreme altitude and first flown in the mid-1950s, the U-2's unique capabilities rendered it virtually immune from interception, and made possible repeated overflights of the Soviet Union, as part of the intelligence-gathering efforts of that era.
The requirement for high altitude and long range needed an aircraft with low wing loading, the latter large quantities of heavy fuel to confer the necessary range. Therefore the U-2 is of very lightweight construction, dispensing with conventional landing gear and pressurisation to save extra weight, and having wings of large area. Landing gear is of bicycle type with single wheels fore and aft, and balanced on the ground by wing-tip 'pogos' - a strut and wheel device which drops away when the U-2 becomes airborne - was selected. The pilot is accommodated on a light-weight seat, dressed in a semi-pressure suit with his head enclosed in an astronaut-type helmet, and forced to breathe pure oxygen for his survival. A medium-powered turbojet is adequate to lift this lightweight aircraft, and long range is possible by shutting it down and gliding for long periods.
Development of the U-2 began in the spring of 1954 to meet a joint CIA/USAF requirement for a high-altitude strategic reconnaissance and special-purpose research aircraft. It took place in the Lockheed 'Skunk Works' at Burbank, California, where - after acceptance of the design in late 1954 - two prototypes were hand-built in great secrecy by a small team of engineers. The aircraft's true purpose was cloaked under the USAF U-for-Utility designation U-2, and the first flight took place on or about 1 August 1955. Once military power is on the engine for takeoff, the throttle was not touched again until ready for descent. Speed is kept fairly constant at Mach 0.715, and excess power was traded for cruise-climb altitude gain.
At about the same time US President Dwight D. Eisenhower was proposing his 'Open Skies' policy, one of mutual East/West aerial reconnaissance of territories. President Eisenhower hoped that his policy would reduce tension between East and West, thus preventing the growth of the nuclear arms race. Unfortunately the Soviet Union would have nothing to do with this proposal. Consequently 'Kelly' Johnson's new 'spy plane' assumed greater importance. The prototypes were followed by production of about 48 single-seat U-2A and U-2B with differing power plant, and five two-seat U-2D. Some U-2B were converted later to U-2D standard. An additional batch of 12 U-2R was ordered in 1967. A new version, known as the TR-1, is currently in production as a tactical-reconnaissance aircraft, equipped with a variety of electronic sensors.
Referred to as just U-2, there has been reference to a U-2B and U-2D, as well as single-seat and two-place versions. Early Lockheeds were powered by a single 11,000-1b thrust P&W J57, later models are reported to have the more powerful J75P-13. Forward landing gear is dual pneumatic type, approximately 20 in diameter, is non-steerable; rear gear is dual hard rubber of approximately 8" diameter and steerable. A lightly stressed thin skin covers the U-2. Lockheed Martin’s Skunk Works has rewired the U-2s over the years during maintenance checks to make the aircraft compatible in the electro-magnetic interference environment.
The initial U-2As built by Lockheed in the 1950s either have been destroyed by accidents, combat or have been retired. They have been operating from Edwards AFB since 1957. The 40% larger U-2R was developed in the late 1960s, and deliveries to the Air Force started in 1969.
In addition to photo and electronic reconnaissance, U-2 were used for weather reconnaissance, high-altitude research, measurement of radiation levels, and for the tracking and recovery of space capsules. They were used for reconnaissance during the Cuban crisis, in Vietnam and during the Arab-Israeli conflict.
The destruction of the U-2B aircraft being flown by Francis 'Gary' Powers on 1 May 1960 brought an abrupt halt to this phase of activities, CIA attentions then focussing on the People's Republic of China which in the early 1960s was fast emerging as a major nuclear power.
U-2 and TR-1 operations are usually conducted in what is best described as a 'permissive' environment on the friendly side of important frontiers.
Powered by the Pratt & Whitney J75, the craft rotates in less than 200 feet as wheeled outriggers fall away. Climbing at 160 knots and 6,000-plus fpm initially, sustaining 45 degrees pitch up. Only to the 45,000-foot physiological limit in the two-seat trainer version without pressure suits, but the U-2 will climb to 70,000-plus.
Stressed for 1.7 positive Gs and half a G negative, the U-2 demands a gentle hand.
Scrupulous energy management-altitude, attitude, airspeed, power setting measures successful landings. Each excess foot at the threshold puts you 1,000 foot farther to touchdown. Two-point land-ings are essential; touching front wheel first causes ballooning in ground effect.
A couple of original production examples were assigned to NASA.
The Strategic Air Command use the U-2R which entered service in the late 1960s and which differs from its predecessors by virtue of greatly increased length and wing span. The U-2R was joined by an increasing number of TR-1s, these externally being very similar although they are intended for tactical rather than strategic missions. At least 25 of these were ordered by the USAF in 1968.
From 2002, Lockheed Martin upgraded the 31 strong U-2 fleet with state of the art glass cockpit displays and controls as the U-2S.
The service bought 37 TR-1 s in the 1980s, with the last one delivered in 1989, and these were the core of the U-2S and U-2STs in operation by the 9th Reconnaissance Wing here. The replacement of the Pratt & Whitney J75 turbine engine by the General Electric F101-GE-F29 turbofan in the 1990s caused the redesignation of the U-2R to the U-2S. The GE engine was later redesignated the F 118-GE-101.
The F 118 fuel consumption is some 16% less than the J75, which allows for a 1,220 naut.mi. increase in range, or increased time on station. The 1,300 lb. lower weight of the General Electric engine also allows a 3,500-ft. increase in operational altitude and an increased payload.
The U-2's primary defense against both aircraft and surface-to-air missiles is its altitude, although newer variants of air-to-air and surface-to-air missiles can reach the U-2's altitude. The reconnaissance aircraft is equipped with a radar warning system, but not with active defenses, such as flares or chaff.
The Air Force will still only say that the U-2 will fly above 70,000 ft., but the actual normal operational altitude is below 80,000 ft. and above 75,000 ft.
For descent almost everything possible on the aircraft is extended. The throttle to idle, lowered landing gear, raised spoilers and flaps in the gust-up configuration and extended fuselage-mounted speed brakes. Once stable on descent, the rate iss dose to 3,000 fpm. A speed of Mach 0.715 is used to 53,000 ft., when a speed of 160 kt. is established. In the case of either an engine or electrical failure, with the aircraft descending clean, it could easily take longer than an hour to descend from altitude. The battery in the U-2S has a life of about 1 hr. and would run out just about when you needed to talk with the tower about deadstick landing instructions. The pilot also is able to raise the spoilers for landing with a micropump and accumulators, a new feature to the U-2.
Pilots claim that the U-2 is one of the hardest aircraft to land because of the need to stall the aircraft on landing and touch down rear wheel first, not to mention the effect of wind on the glider-like aircraft.
The U-2 aircraft was ordered back into production in 1979 as a high-altitude tactical reconnais-sance platform, this time as the TR-1A. The TR-1A is designed for tactical reconnaissance primarily in the European theatre, using UPD-X side-looking airborne radar (Slar) for surveillance up to 55km into hostile territory from friendly areas.
The first TR-1A flew on 1 August 1981 and the USAF acquired 26 of these single seaters plus two two-seat TR-1Bs. In 1984 the TR-1A flew with the precision location/strike system (PLSS) and, following successful trials, at least some of the fleet were to be allocated to this role. PLSS involves the use of three TR-lAs to detect and locate emitters and then direct attacks upon them.
In 1982 the USAF began taking delivery. Using the same basic airframe as the U-2R, the TR-1A high altitude battlefield reconnaissance aircraft was operational with the USAF flying from bases in Europe including the UK in 1990. It is equipped with an advanced sideways looking airborne radar (SLAR) and incorporates the latest ECM.
Two examples of a two-seat variant known as the TR-1B were assigned to training duties at Beale AFB, California. The TR-1B trainer has a second, raised cockpit in tandem.
Replacing earlier U-2C's, NASA took delivery of three ER--2's, (the NASA designation for the TR-1A). The three are 80-1063 / N706NA, 80-1069 / N708NA and 80-1097 / N709A. The first was delivered in June 1981 and the last (80-1097) was delivered in April 1989. Two are owned by NASA, while the third is leased from the USAF.
Engine: 1 x Pratt & Whitney J57-P-37A turbojet, 11,200 lb (5,080 kg) st.
Wing span: 80 ft 0 in (24.38 m).
Length: 49 ft 7 in (15.11 m).
Height: 13 ft 0 in (3.96 m).
Gross weight: 15,850 lb (7,190 kg).
Max speed: 495 mph (797 km/h) at 40,000 ft (12,200 m).
Typical range: 2,200 miles (3,540 km).
Engine: 1 x Pratt & Whitney J75.
Engine: 1 x Pratt-Whitney J75-P-13B, 7711kg
Max take-off weight: 10225 kg / 22542 lb
Wingspan: 24.38 m / 80 ft 2 in
Length: 15.24 m / 49 ft 8 in
Height: 4.57 m / 14 ft 12 in
Wing area: 52.49 sq.m / 565.00 sq ft
Cruise speed: 740 km/h / 460 mph
Op speed: Mach .73 to .80
Ceiling: 27000 m / 88600 ft
Range: 4635 km / 2880 miles at 475-mph at 70,000-ft
Flight endurance: 7.5 hr
Rate of climb: 8,000 fpm at 160-kt
Time to 30,000 ft: 5 min
Time to 50,000 ft: 9 min
Time to 60,000 ft: 12.5 min
Cruise climb to 70,000 ft: 28 min
Indicated airspeed (IAS) above 70,000 ft:110 kt
Mach buffet speed: 115 kt IAS / 410 kt TAS
Engine: 1 x Pratt & Whitney J75.
Range: 3,000-plus miles (2,609 nautical miles).
Engine: 1 x Pratt & Whitney J75-PW-13B turbojet, 7711 kg (17,000-lb) thrust
Estimated maximum cruise speed at over 21335 m (70,000 ft) 692 km/h (430 mph) (Mach 0.57)
Operational ceiling est: 27430 m (90,000 ft)
Maximum range: 4825+ km (3,000+ miles).
Fuel internal: 4450 lt.
Endurance: 12 hr.
Air refuel: No.
Empty weight: about 7258 kg (16,000 lb)
Maximum take-off 18144 kg (40,000 lb).
Wing span 31.39 m (103 ft 0 in)
Length 19.20 m (63 ft 0 in)
Height 4.88 m (16 ft 0 in)
Wing area about 92.90 sq.m (1,000 sq ft).
Wing span: 105 ft.
Op alt: 68,000 ft.
Endurance: 8 hr.